ADD: bin directory with git lfs tracking

Remove bin from .gitignore and add all executables and libraries to LFS.
These files will be pushed only to Gitea server.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1 @@
+bin/** filter=lfs diff=lfs merge=lfs -text

.gitignore

@@ -1,5 +1,4 @@
 /build
-/bin
 /assets
 /.idea
 /cmake-build-debug

CMakeLists.txt

@@ -1,14 +1,28 @@
-cmake_minimum_required (VERSION 3.8)
+cmake_minimum_required(VERSION 3.16)
 
-project ("vulkan_engine")
+project(vulkan_engine LANGUAGES C CXX)
 
-if (WIN32)
-    set(VULKAN_SDK "$ENV{VULKAN_SDK}")
-    set(Vulkan_INCLUDE_DIR "C:/VulkanSDK/1.3.296.0/Include")
-    set(Vulkan_LIBRARY "C:/VulkanSDK/1.3.296.0/Lib/vulkan-1.lib")
+if(WIN32)
+    if(DEFINED ENV{VULKAN_SDK})
+        file(TO_CMAKE_PATH "$ENV{VULKAN_SDK}" _VULKAN_SDK)
+        set(Vulkan_INCLUDE_DIR "${_VULKAN_SDK}/Include")
+        if(CMAKE_SIZEOF_VOID_P EQUAL 8)
+            set(Vulkan_LIBRARY "${_VULKAN_SDK}/Lib/vulkan-1.lib")
+        else()
+            set(Vulkan_LIBRARY "${_VULKAN_SDK}/Lib32/vulkan-1.lib")
+        endif()
+    elseif(EXISTS "C:/VulkanSDK/1.3.296.0/Include")
+        # Fallback for a common SDK install path; update if your SDK version differs.
+        set(Vulkan_INCLUDE_DIR "C:/VulkanSDK/1.3.296.0/Include")
+        set(Vulkan_LIBRARY "C:/VulkanSDK/1.3.296.0/Lib/vulkan-1.lib")
+    endif()
 endif()
 
-find_package(Vulkan REQUIRED)
+find_package(Vulkan REQUIRED COMPONENTS glslangValidator)
+
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin")
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin")
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin")
 
 # Third-party deps are vendored; keep builds offline-friendly by default.
 # BVH2's CMake enables tests by default, which would FetchContent googletest.
@@ -16,44 +30,46 @@ set(BVH2_ENABLE_TESTS OFF CACHE BOOL "Disable BVH2 tests (offline builds)" FORCE
 
 add_subdirectory(third_party)
 
-if (MSVC AND CMAKE_C_COMPILER_ID MATCHES "Clang")
-    if (TARGET SDL2)
-        target_link_options(SDL2 PRIVATE /DEFAULTLIB:ucrt.lib /DEFAULTLIB:vcruntime.lib)
-    endif()
-    if (TARGET SDL2-static)
-        target_link_options(SDL2-static PRIVATE /DEFAULTLIB:ucrt.lib /DEFAULTLIB:vcruntime.lib)
-    endif()
+if(MSVC AND CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_SIMULATE_ID STREQUAL "MSVC")
+    foreach(_SDL_TARGET IN ITEMS SDL2 SDL2-static)
+        if(TARGET ${_SDL_TARGET})
+            target_link_options(${_SDL_TARGET} PRIVATE /DEFAULTLIB:ucrt.lib /DEFAULTLIB:vcruntime.lib)
+        endif()
+    endforeach()
 endif()
 
-set (CMAKE_RUNTIME_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin")
-set (CMAKE_LIBRARY_OUTPUT_DIRECTORY "${PROJECT_SOURCE_DIR}/bin")
-
 add_subdirectory(src)
 
-find_program(GLSL_VALIDATOR glslangValidator HINTS /usr/bin /usr/local/bin $ENV{VULKAN_SDK}/Bin/ $ENV{VULKAN_SDK}/Bin32/)
+option(VULKAN_ENGINE_BUILD_SHADERS "Compile GLSL shaders to SPIR-V at build time" ON)
 
+if(VULKAN_ENGINE_BUILD_SHADERS)
+    set(GLSL_VALIDATOR "${Vulkan_GLSLANG_VALIDATOR_EXECUTABLE}")
+    if(NOT GLSL_VALIDATOR)
+        find_program(GLSL_VALIDATOR glslangValidator HINTS /usr/bin /usr/local/bin)
+    endif()
 
+    if(NOT GLSL_VALIDATOR)
+        message(FATAL_ERROR "glslangValidator not found. Install the Vulkan SDK or disable shader compilation with -DVULKAN_ENGINE_BUILD_SHADERS=OFF.")
+    endif()
 
-
-file(GLOB_RECURSE GLSL_SOURCE_FILES
-    "${PROJECT_SOURCE_DIR}/shaders/*.frag"
-    "${PROJECT_SOURCE_DIR}/shaders/*.vert"
-    "${PROJECT_SOURCE_DIR}/shaders/*.comp"
+    file(GLOB_RECURSE GLSL_SOURCE_FILES CONFIGURE_DEPENDS
+        "${PROJECT_SOURCE_DIR}/shaders/*.frag"
+        "${PROJECT_SOURCE_DIR}/shaders/*.vert"
+        "${PROJECT_SOURCE_DIR}/shaders/*.comp"
     )
 
-foreach(GLSL ${GLSL_SOURCE_FILES})
-  message(STATUS "BUILDING SHADER")
-  get_filename_component(FILE_NAME ${GLSL} NAME)
-  set(SPIRV "${PROJECT_SOURCE_DIR}/shaders/${FILE_NAME}.spv")
-  message(STATUS ${GLSL})
-  add_custom_command(
-    OUTPUT ${SPIRV}
-    COMMAND ${GLSL_VALIDATOR} -V --target-env vulkan1.2 ${GLSL} -o ${SPIRV}
-    DEPENDS ${GLSL})
-  list(APPEND SPIRV_BINARY_FILES ${SPIRV})
-endforeach(GLSL)
+    set(SPIRV_BINARY_FILES "")
+    foreach(GLSL IN LISTS GLSL_SOURCE_FILES)
+        set(SPIRV "${GLSL}.spv")
+        add_custom_command(
+            OUTPUT "${SPIRV}"
+            COMMAND "${GLSL_VALIDATOR}" -V --target-env vulkan1.2 "${GLSL}" -o "${SPIRV}"
+            DEPENDS "${GLSL}"
+            VERBATIM
+        )
+        list(APPEND SPIRV_BINARY_FILES "${SPIRV}")
+    endforeach()
 
-add_custom_target(shaders_spirv DEPENDS ${SPIRV_BINARY_FILES})
-
-# Ensure shaders are built alongside the executable.
-add_dependencies(vulkan_engine shaders_spirv)
+    add_custom_target(shaders_spirv DEPENDS ${SPIRV_BINARY_FILES})
+    add_dependencies(vulkan_engine shaders_spirv)
+endif()

bin/libSDL2-2.0d.so

@@ -0,0 +1 @@
+libSDL2-2.0d.so.0

bin/libSDL2-2.0d.so.0

@@ -0,0 +1 @@
+libSDL2-2.0d.so.0.3200.10

docs/BUILD.md

@@ -2,7 +2,7 @@
 
 - Prerequisites
   - Vulkan SDK installed and `VULKAN_SDK` set.
-  - A C++20 compiler and CMake ≥ 3.8.
+  - A C++20 compiler and CMake ≥ 3.16.
   - GPU drivers with Vulkan 1.2+.
   - KTX software with libktx
 

docs/RenderGraph.md

@@ -7,29 +7,52 @@ Lightweight render graph that builds a per‑frame DAG from pass declarations, c
 - Centralize synchronization and image layout transitions across passes.
 - Make passes declarative: author declares reads/writes; the graph inserts barriers and begins/ends rendering.
 - Keep existing pass classes (`IRenderPass`) while migrating execution to the graph.
+- Provide runtime profiling and debugging capabilities for pass execution.
 
 ### High‑Level Flow
 
-- Engine creates the graph each frame and imports swapchain/G‑Buffer images: `src/core/engine.cpp:303`.
+- Engine creates the graph each frame and imports swapchain/G‑Buffer images: `src/core/engine.cpp`.
 - Each pass registers its work by calling `register_graph(graph, ...)` and declaring resources via a builder.
 - The graph appends a present chain (copy HDR `drawImage` → swapchain, then transition to `PRESENT`), optionally inserting ImGui before present.
-- `compile()` topologically sorts passes by data dependencies (read/write) and computes per‑pass barriers.
-- `execute(cmd)` emits barriers, begins dynamic rendering if attachments were declared, calls the pass record lambda, and ends rendering.
+- `compile()` topologically sorts passes by data dependencies (read/write hazards: RAW/WAW/WAR) and computes per‑pass barriers using `VkDependencyInfo` with `Vk*MemoryBarrier2`.
+- `execute(cmd)` creates timestamp query pools, emits barriers, begins dynamic rendering if attachments were declared, calls the pass record lambda, ends rendering, and records GPU/CPU timings.
+- `resolve_timings()` retrieves GPU timestamp results after the fence is signaled, converting them to milliseconds.
 
 ### Core API
 
+**Lifecycle:**
+- `RenderGraph::init(ctx)` — Initialize with engine context. See `src/render/graph/graph.cpp:28`.
+- `RenderGraph::clear()` — Clear all passes and reset resources. See `src/render/graph/graph.cpp:34`.
+- `RenderGraph::shutdown()` — Destroy GPU resources (query pools) before device shutdown. See `src/render/graph/graph.cpp:40`.
+
+**Pass Registration:**
 - `RenderGraph::add_pass(name, RGPassType type, BuildCallback build, RecordCallback record)`
   - Declare image/buffer accesses and attachments inside `build` using `RGPassBuilder`.
   - Do your actual rendering/copies in `record` using resolved Vulkan objects from `RGPassResources`.
-  - See: `src/render/graph/graph.h:36`, `src/render/graph/graph.cpp:51`.
+  - See: `src/render/graph/graph.h:42`, `src/render/graph/graph.cpp:91`.
+- Legacy form: `add_pass(name, type, record)` for passes with no resource declarations. See `src/render/graph/graph.cpp:117`.
 
-- `RenderGraph::compile()` → builds ordering and per‑pass `Vk*MemoryBarrier2` lists. See `src/render/graph/graph.cpp:83`.
+**Resource Creation:**
+- `import_image(desc)` / `import_buffer(desc)` — Import externally owned resources (deduplicated by VkImage/VkBuffer handle).
+- `create_image(desc)` / `create_buffer(desc)` — Create transient resources (destroyed at end of frame via deletion queue).
+- `create_depth_image(name, extent, format=D32_SFLOAT)` — Convenience helper for depth-only images with depth attachment + sampled usage. See `src/render/graph/graph.cpp:67`.
 
-- `RenderGraph::execute(cmd)` → emits barriers and dynamic rendering begin/end. See `src/render/graph/graph.cpp:592`.
+**Compilation and Execution:**
+- `RenderGraph::compile()` — Build topological ordering (Kahn's algorithm) and per‑pass `VkImageMemoryBarrier2` / `VkBufferMemoryBarrier2` lists. Returns false on error. See `src/render/graph/graph.cpp:123`.
+- `RenderGraph::execute(cmd)` — Creates timestamp query pool, emits barriers via `vkCmdPipelineBarrier2`, begins dynamic rendering if attachments exist, invokes record callbacks, ends rendering, and writes GPU timestamps. See `src/render/graph/graph.cpp:874`.
+- `RenderGraph::resolve_timings()` — Fetch GPU timestamp results after fence wait and convert to milliseconds. Must be called before next `execute()`. See `src/render/graph/graph.cpp:1314`.
 
-- Import helpers for engine images: `import_draw_image()`, `import_depth_image()`, `import_gbuffer_*()`, `import_swapchain_image(index)`. See `src/render/graph/graph.cpp:740`.
+**Import Helpers:**
+- `import_draw_image()`, `import_depth_image()`, `import_gbuffer_position()`, `import_gbuffer_normal()`, `import_gbuffer_albedo()`, `import_gbuffer_extra()`, `import_id_buffer()`, `import_swapchain_image(index)` — Convenience wrappers for engine-owned images. See `src/render/graph/graph.cpp:1147–1312`.
 
-- Present chain: `add_present_chain(draw, swapchain, appendExtra)` inserts Copy→Present passes and lets you inject extra passes (e.g., ImGui) in between. See `src/render/graph/graph.cpp:705`.
+**Present Chain:**
+- `add_present_chain(draw, swapchain, appendExtra)` — Inserts `PresentLetterbox` pass (blit draw→swapchain with letterboxing) and `PreparePresent` pass (layout transition to `PRESENT_SRC_KHR`). Optional `appendExtra` callback injects passes (e.g., ImGui) in between. See `src/render/graph/graph.cpp:1043`.
+
+**Debug and Profiling:**
+- `pass_count()`, `pass_name(i)`, `pass_enabled(i)`, `set_pass_enabled(i, enabled)` — Runtime pass enable/disable. See `src/render/graph/graph.h:105–108`.
+- `debug_get_passes(out)` — Retrieve pass metadata including GPU/CPU timings, resource access counts, attachment info. See `src/render/graph/graph.cpp:1163`.
+- `debug_get_images(out)` — Retrieve image metadata (imported/transient, format, extent, usage, lifetime). See `src/render/graph/graph.cpp:1186`.
+- `debug_get_buffers(out)` — Retrieve buffer metadata. See `src/render/graph/graph.cpp:1207`.
 
 ### Declaring a Pass
 
@@ -65,63 +88,155 @@ void MyPass::register_graph(RenderGraph* graph,
 
 ### Builder Reference (`RGPassBuilder`)
 
-- Images
-  - `read(RGImageHandle, RGImageUsage)` → sample/read usage for this pass.
-  - `write(RGImageHandle, RGImageUsage)` → write usage (compute/storage/transfer).
-  - `write_color(RGImageHandle, bool clearOnLoad=false, VkClearValue clear={})` → declares a color attachment.
-  - `write_depth(RGImageHandle, bool clearOnLoad=false, VkClearValue clear={})` → declares a depth attachment.
+Passed to the `BuildCallback` to declare resource accesses and attachments. See `src/render/graph/builder.h:40`.
 
-- Buffers
-  - `read_buffer(RGBufferHandle, RGBufferUsage)` / `write_buffer(RGBufferHandle, RGBufferUsage)`.
-  - Convenience import: `read_buffer(VkBuffer, RGBufferUsage, size, name)` and `write_buffer(VkBuffer, ...)` dedup by raw handle.
+**Image Access:**
+- `read(RGImageHandle, RGImageUsage)` — Declare sampled/read usage (e.g., `SampledFragment`, `TransferSrc`). See `src/render/graph/builder.cpp:20`.
+- `write(RGImageHandle, RGImageUsage)` — Declare write usage (e.g., `ComputeWrite`, `TransferDst`). See `src/render/graph/builder.cpp:25`.
+- `write_color(RGImageHandle, bool clearOnLoad=false, VkClearValue clear={})` — Declare color attachment with optional clear. Sets usage to `ColorAttachment` and `store=true` by default. See `src/render/graph/builder.cpp:30`.
+- `write_depth(RGImageHandle, bool clearOnLoad=false, VkClearValue clear={})` — Declare depth attachment with optional clear. See `src/render/graph/builder.cpp:40`.
 
-See `src/render/graph/builder.h:39` and impl in `src/render/graph/builder.cpp:20`.
+**Buffer Access:**
+- `read_buffer(RGBufferHandle, RGBufferUsage)` — Declare buffer read (e.g., `VertexRead`, `IndexRead`, `UniformRead`, `StorageRead`). See `src/render/graph/builder.cpp:50`.
+- `write_buffer(RGBufferHandle, RGBufferUsage)` — Declare buffer write (e.g., `StorageReadWrite`, `TransferDst`). See `src/render/graph/builder.cpp:55`.
+- Convenience overloads: `read_buffer(VkBuffer, RGBufferUsage, size, name)` and `write_buffer(VkBuffer, ...)` automatically import and deduplicate by raw `VkBuffer` handle. See `src/render/graph/builder.cpp:60,70`.
+
+**Resource Resolution (`RGPassResources`):**
+Used inside the `RecordCallback` to fetch resolved Vulkan objects. See `src/render/graph/builder.h:22`.
+- `image(RGImageHandle)` → `VkImage`
+- `image_view(RGImageHandle)` → `VkImageView`
+- `buffer(RGBufferHandle)` → `VkBuffer`
 
 ### Resource Model (`RGResourceRegistry`)
 
-- Imported vs transient resources are tracked uniformly with lifetime indices (`firstUse/lastUse`).
-- Imports are deduplicated by `VkImage`/`VkBuffer` and keep initial layout/stage/access as the starting state.
-- Transients are created via `ResourceManager` and auto‑destroyed at end of frame using the frame deletion queue.
-- See `src/render/graph/resources.h:11` and `src/render/graph/resources.cpp:1`.
+Manages both imported (externally owned) and transient (graph-owned) resources. See `src/render/graph/resources.h:52`.
+
+**Imported Resources:**
+- Deduplicated by raw Vulkan handle (`VkImage`/`VkBuffer`) using hash maps (`_imageLookup`/`_bufferLookup`). See `src/render/graph/resources.cpp`.
+- Initial layout/stage/access preserved from `RGImportedImageDesc`/`RGImportedBufferDesc`.
+- Ownership remains external; graph does not destroy these resources.
+
+**Transient Resources:**
+- Created via `ResourceManager` (`AllocatedImage`/`AllocatedBuffer`) with VMA allocations. See `src/render/graph/resources.cpp`.
+- Automatically destroyed at end of frame via frame deletion queue.
+- Usage flags must cover all declared usages (validated during `compile()`).
+
+**Lifetime Tracking:**
+- `firstUse` and `lastUse` indices computed during `compile()` (see `src/render/graph/graph.cpp:854–869`).
+- Used for debug visualization and future aliasing/pooling optimizations.
+
+**Records (`RGImageRecord`/`RGBufferRecord`):**
+Unified representation storing `VkImage`/`VkBuffer`, `VkImageView`, format, extent, initial state, and allocation info. See `src/render/graph/resources.h:11,34`.
 
 ### Synchronization and Layouts
 
-- For each pass, `compile()` compares previous state with desired usage and, if needed, adds a pre‑pass barrier:
-  - Images: `VkImageMemoryBarrier2` with stage/access/layout derived from `RGImageUsage`.
-  - Buffers: `VkBufferMemoryBarrier2` with stage/access derived from `RGBufferUsage`.
-- Initial state comes from the imported descriptor; if unknown, buffers default to `TOP_OF_PIPE`.
-- Format/usage checks:
-  - Warns if binding a depth format as color (and vice‑versa).
-  - Warns if a transient resource is used with flags it wasn’t created with.
+**Barrier Generation (see `src/render/graph/graph.cpp:232–851`):**
 
-Image usage → layout/stage examples (subset):
+For each enabled pass, `compile()` tracks per-resource state (`ImageState`/`BufferState`) and inserts barriers when hazards are detected:
 
-- `SampledFragment` → `SHADER_READ_ONLY_OPTIMAL`, `FRAGMENT_SHADER`.
-- `ColorAttachment` → `COLOR_ATTACHMENT_OPTIMAL`, `COLOR_ATTACHMENT_OUTPUT` (read|write).
-- `DepthAttachment` → `DEPTH_ATTACHMENT_OPTIMAL`, `EARLY|LATE_FRAGMENT_TESTS`.
-- `TransferDst` → `TRANSFER_DST_OPTIMAL`, `TRANSFER`.
-- `Present` → `PRESENT_SRC_KHR`, `BOTTOM_OF_PIPE`.
+**Image Barriers (`VkImageMemoryBarrier2`):**
+- Triggered by: layout change, prior write before read/write (RAW/WAW), prior reads before write (WAR).
+- Stage/access/layout derived from `RGImageUsage` via `usage_info_image()` (see `src/render/graph/graph.cpp:313–365`).
+- Aspect determined by usage and format (depth formats get `DEPTH_BIT`, others `COLOR_BIT`).
+- Initial state from `RGImportedImageDesc::currentLayout/currentStage/currentAccess`; if unknown (layout ≠ UNDEFINED but stage=NONE), conservatively assumes `ALL_COMMANDS + MEMORY_READ|WRITE`.
 
-Buffer usage → stage/access examples:
+**Buffer Barriers (`VkBufferMemoryBarrier2`):**
+- Triggered by: prior write before read/write, prior reads before write.
+- Stage/access derived from `RGBufferUsage` via `usage_info_buffer()` (see `src/render/graph/graph.cpp:367–411`).
+- Size: exact size for transients, `VK_WHOLE_SIZE` for imports (to avoid validation errors).
 
-- `IndexRead` → `INDEX_INPUT`, `INDEX_READ`.
-- `VertexRead` → `VERTEX_INPUT`, `VERTEX_ATTRIBUTE_READ`.
-- `UniformRead` → `ALL_GRAPHICS|COMPUTE`, `UNIFORM_READ`.
-- `StorageReadWrite` → `COMPUTE|FRAGMENT`, `SHADER_STORAGE_READ|WRITE`.
+**Usage Priority and Conflict Resolution:**
+When a pass declares multiple conflicting usages for the same resource (e.g., both `SampledFragment` and `ColorAttachment`), the graph selects the highest-priority usage for layout determination (see `image_usage_priority()` at `src/render/graph/graph.cpp:499`). Stages and access masks are unioned. Warns if layout mismatch detected.
+
+**Image Usage → Layout/Stage/Access Mapping:**
+See `usage_info_image()` at `src/render/graph/graph.cpp:313`.
+
+| RGImageUsage | Layout | Stage | Access |
+|---|---|---|---|
+| `SampledFragment` | `SHADER_READ_ONLY_OPTIMAL` | `FRAGMENT_SHADER` | `SHADER_SAMPLED_READ` |
+| `SampledCompute` | `SHADER_READ_ONLY_OPTIMAL` | `COMPUTE_SHADER` | `SHADER_SAMPLED_READ` |
+| `TransferSrc` | `TRANSFER_SRC_OPTIMAL` | `TRANSFER` | `TRANSFER_READ` |
+| `TransferDst` | `TRANSFER_DST_OPTIMAL` | `TRANSFER` | `TRANSFER_WRITE` |
+| `ColorAttachment` | `COLOR_ATTACHMENT_OPTIMAL` | `COLOR_ATTACHMENT_OUTPUT` | `COLOR_ATTACHMENT_READ\|WRITE` |
+| `DepthAttachment` | `DEPTH_ATTACHMENT_OPTIMAL` | `EARLY_FRAGMENT_TESTS\|LATE_FRAGMENT_TESTS` | `DEPTH_STENCIL_ATTACHMENT_READ\|WRITE` |
+| `ComputeWrite` | `GENERAL` | `COMPUTE_SHADER` | `SHADER_STORAGE_READ\|WRITE` |
+| `Present` | `PRESENT_SRC_KHR` | `BOTTOM_OF_PIPE` | `MEMORY_READ` |
+
+**Buffer Usage → Stage/Access Mapping:**
+See `usage_info_buffer()` at `src/render/graph/graph.cpp:367`.
+
+| RGBufferUsage | Stage | Access |
+|---|---|---|
+| `TransferSrc` | `TRANSFER` | `TRANSFER_READ` |
+| `TransferDst` | `TRANSFER` | `TRANSFER_WRITE` |
+| `VertexRead` | `VERTEX_INPUT` | `VERTEX_ATTRIBUTE_READ` |
+| `IndexRead` | `INDEX_INPUT` | `INDEX_READ` |
+| `UniformRead` | `ALL_GRAPHICS\|COMPUTE_SHADER` | `UNIFORM_READ` |
+| `StorageRead` | `COMPUTE_SHADER\|ALL_GRAPHICS` | `SHADER_STORAGE_READ` |
+| `StorageReadWrite` | `COMPUTE_SHADER\|ALL_GRAPHICS` | `SHADER_STORAGE_READ\|WRITE` |
+| `IndirectArgs` | `DRAW_INDIRECT` | `INDIRECT_COMMAND_READ` |
+
+**Validation Warnings:**
+- Depth-format image declared as color attachment (or vice versa). See `src/render/graph/graph.cpp:645–657`.
+- Transient resource used without required usage flags. See `src/render/graph/graph.cpp:659–667` (images), `818–826` (buffers).
+- Multiple conflicting layouts in single pass. See `src/render/graph/graph.cpp:536–543`.
 
 ### Built‑In Pass Wiring (Current)
 
 - Resource uploads (if any) → Background (compute) → Geometry (G‑Buffer) → Lighting (deferred) → SSR → Tonemap+Bloom → FXAA → Transparent → CopyToSwapchain → ImGui → PreparePresent.
 - See registrations in `src/core/engine.cpp`.
 
+### Topological Sorting and Scheduling
+
+**Dependency Graph Construction (see `src/render/graph/graph.cpp:127–231`):**
+- Reads/writes create directed edges: `writer → reader` (RAW), `writer → writer` (WAW), `reader → writer` (WAR).
+- Disabled passes are skipped during edge construction but remain in the pass list.
+- Kahn's algorithm produces a linear execution order respecting all dependencies.
+- If cycle detected (topological sort fails), falls back to insertion order but still computes barriers.
+
+**Execution Order:**
+Passes execute in sorted order (or insertion order if cycle). Only enabled passes run; disabled passes are skipped during `execute()`. See `src/render/graph/graph.cpp:895`.
+
+### Dynamic Rendering Setup
+
+**Render Area Calculation (see `src/render/graph/graph.cpp:936–1000`):**
+- Chooses min extent across all color/depth attachments.
+- Falls back to `EngineContext::drawExtent` if no attachments.
+- Warns if color attachments have mismatched extents.
+
+**Attachment Construction:**
+- Color attachments: `VkRenderingAttachmentInfo` with `clearOnLoad` → `LOAD_OP_CLEAR` / `LOAD_OP_LOAD`, `store` → `STORE_OP_STORE` / `STORE_OP_DONT_CARE`.
+- Depth attachment: similar logic; `clearValue.depthStencil` used if `clearOnLoad=true`.
+- Layout forced to `COLOR_ATTACHMENT_OPTIMAL` or `DEPTH_ATTACHMENT_OPTIMAL`.
+
+See `src/render/graph/graph.cpp:927–1012`.
+
+### Profiling and Timing
+
+**GPU Timing (Timestamps):**
+- Per-frame `VkQueryPool` with 2 queries per pass (begin/end). Created in `execute()`, destroyed in `resolve_timings()` or next `execute()`.
+- `vkCmdWriteTimestamp2()` at `ALL_COMMANDS_BIT` stage before/after pass recording (see `src/render/graph/graph.cpp:919–923`, `1028–1032`).
+- `resolve_timings()` fetches results with `VK_QUERY_RESULT_WAIT_BIT`, converts ticks to milliseconds using `timestampPeriod`. See `src/render/graph/graph.cpp:1314–1355`.
+
+**CPU Timing:**
+- `std::chrono::high_resolution_clock` measures command recording duration (`cpuStart`/`cpuEnd`). See `src/render/graph/graph.cpp:924`, `1026`.
+- Stored in `_lastCpuMillis` vector; accessible via `debug_get_passes()`.
+
+**Debug Structures:**
+- `RGDebugPassInfo`: name, type, enabled, resource counts, attachment info, `gpuMillis`, `cpuMillis`. See `src/render/graph/graph.h:66`.
+- `RGDebugImageInfo`: id, name, imported, format, extent, usage, lifetime. See `src/render/graph/graph.h:83`.
+- `RGDebugBufferInfo`: id, name, imported, size, usage, lifetime. See `src/render/graph/graph.h:94`.
+
 ### Notes & Limits
 
-- No aliasing or transient pooling yet; images created via `create_*` are released end‑of‑frame.
-- Graph scheduling uses a topological order by data dependency; it does not parallelize across queues.
-- Load/store control for attachments is minimal (`clearOnLoad`, `store` on `RGAttachmentInfo`).
-- Render area is the min of all declared attachment extents and `EngineContext::drawExtent`.
+- **No aliasing or transient pooling**: Transient images/buffers created via `create_*` are released end‑of‑frame via frame deletion queue.
+- **Single-queue execution**: Topological order is linear; no multi-queue parallelization.
+- **Minimal load/store control**: Only `clearOnLoad` and `store` flags on `RGAttachmentInfo`; no resolve or stencil control.
+- **No mid-pass barriers**: Conflicting usages within a single pass cannot be synchronized (warns but proceeds with unioned stages/access).
+- **No automatic resource aliasing**: Future work could reuse transient allocations based on lifetime non-overlap.
 
 ### Debugging
 
-- Each pass is wrapped with a debug label (`RG: <name>`).
-- Compile prints warnings for suspicious usages or format mismatches.
+- **Per-pass debug labels**: `vkdebug::cmd_begin_label(cmd, "RG: <name>")` wraps each pass (see `src/render/graph/graph.cpp:903–906`, `1035–1038`).
+- **Compile-time validation warnings**: Printed via `fmt::println` for format mismatches, missing usage flags, layout conflicts.
+- **Runtime introspection**: Use `debug_get_*` APIs to export pass/image/buffer metadata for visualization/debugging tools.

docs/asset_manager.md

@@ -22,15 +22,22 @@ auto chairPath = assets->modelPath("models/chair.glb");
 - Paths
   - `std::string shaderPath(std::string_view)`
   - `std::string assetPath(std::string_view)` / `modelPath(std::string_view)`
+  - `const AssetPaths& paths() const` / `void setPaths(const AssetPaths &p)` — get/set asset paths
 - glTF
   - `std::optional<std::shared_ptr<LoadedGLTF>> loadGLTF(std::string_view nameOrPath)` — cached by canonical absolute path
+  - `std::optional<std::shared_ptr<LoadedGLTF>> loadGLTF(std::string_view nameOrPath, const GLTFLoadCallbacks *cb)` — with custom callbacks
+  - `size_t prefetchGLTFTextures(std::string_view nameOrPath)` — schedule texture loads ahead of time
+  - `GLTFTexturePrefetchResult prefetchGLTFTexturesWithHandles(std::string_view nameOrPath)` — returns handles for tracking
 - Meshes
   - `std::shared_ptr<MeshAsset> createMesh(const MeshCreateInfo &info)`
-  - `std::shared_ptr<MeshAsset> createMesh(const std::string &name, std::span<Vertex> v, std::span<uint32_t> i, std::shared_ptr<GLTFMaterial> material = {})`
+  - `std::shared_ptr<MeshAsset> createMesh(const std::string &name, std::span<Vertex> v, std::span<uint32_t> i, std::shared_ptr<GLTFMaterial> material = {}, bool build_bvh = true)`
   - `std::shared_ptr<MeshAsset> getMesh(const std::string &name) const`
-  - `std::shared_ptr<MeshAsset> getPrimitive(std::string_view name) const` (returns existing default primitives if created)
+  - `std::shared_ptr<MeshAsset> getPrimitive(std::string_view name) const` — returns existing default primitives if created
   - `bool removeMesh(const std::string &name)`
+  - `bool removeMeshDeferred(const std::string &name, DeletionQueue &dq)` — deferred cleanup via deletion queue
   - `void cleanup()` — releases meshes, material buffers, and any images owned by the manager
+- Materials
+  - `std::shared_ptr<GLTFMaterial> createMaterialFromConstants(const std::string &name, const GLTFMetallic_Roughness::MaterialConstants &constants, MaterialPass pass = MaterialPass::MainColor)` — create PBR material from constants using engine default textures
 
 ### Mesh Creation Model
 
@@ -41,15 +48,19 @@ struct AssetManager::MaterialOptions {
   std::string albedoPath;        // resolved through AssetManager
   std::string metalRoughPath;    // resolved through AssetManager
   std::string normalPath;        // resolved through AssetManager (tangent-space normal)
+  std::string occlusionPath;     // resolved through AssetManager (ambient occlusion)
+  std::string emissivePath;      // resolved through AssetManager (emissive/glow)
   bool albedoSRGB      = true;   // VK_FORMAT_R8G8B8A8_SRGB when true
   bool metalRoughSRGB  = false;  // VK_FORMAT_R8G8B8A8_UNORM when false
   bool normalSRGB      = false;  // normal maps should be UNORM
+  bool occlusionSRGB   = false;  // occlusion should be UNORM
+  bool emissiveSRGB    = true;   // emissive is typically sRGB
   GLTFMetallic_Roughness::MaterialConstants constants{}; // extra[0].x as normalScale
   MaterialPass pass    = MaterialPass::MainColor; // or Transparent
 };
 
 struct AssetManager::MeshGeometryDesc {
-  enum class Type { Provided, Cube, Sphere };
+  enum class Type { Provided, Cube, Sphere, Plane, Capsule };
   Type type = Type::Provided;
   std::span<Vertex> vertices{};  // when Provided
   std::span<uint32_t> indices{}; // when Provided
@@ -65,8 +76,9 @@ struct AssetManager::MeshMaterialDesc {
 
 struct AssetManager::MeshCreateInfo {
   std::string name;              // cache key; reused if already created
-  MeshGeometryDesc geometry;     // Provided / Cube / Sphere
+  MeshGeometryDesc geometry;     // Provided / Cube / Sphere / Plane / Capsule
   MeshMaterialDesc material;     // Default or Textured
+  std::optional<BoundsType> boundsType; // optional override for collision/picking bounds
 };
 ```
 
@@ -113,9 +125,23 @@ si.material.kind = AssetManager::MeshMaterialDesc::Kind::Default;
 auto sphere = ctx->getAssets()->createMesh(si);
 ctx->scene->addMeshInstance("sphere.instance", sphere,
     glm::translate(glm::mat4(1.f), glm::vec3(2.f, 0.f, -2.f)));
+
+// Plane primitive
+AssetManager::MeshCreateInfo pi{};
+pi.name = "groundPlane";
+pi.geometry.type = AssetManager::MeshGeometryDesc::Type::Plane;
+pi.material.kind = AssetManager::MeshMaterialDesc::Kind::Default;
+auto plane = ctx->getAssets()->createMesh(pi);
+
+// Capsule primitive
+AssetManager::MeshCreateInfo capi{};
+capi.name = "capsuleA";
+capi.geometry.type = AssetManager::MeshGeometryDesc::Type::Capsule;
+capi.material.kind = AssetManager::MeshMaterialDesc::Kind::Default;
+auto capsule = ctx->getAssets()->createMesh(capi);
 ```
 
-Textured primitive (albedo + metal-rough + normal):
+Textured primitive (albedo + metal-rough + normal + occlusion + emissive):
 
 ```c++
 AssetManager::MeshCreateInfo ti{};
@@ -128,6 +154,8 @@ ti.material.kind = AssetManager::MeshMaterialDesc::Kind::Textured;
 ti.material.options.albedoPath = "textures/ground_albedo.png";     // sRGB
 ti.material.options.metalRoughPath = "textures/ground_mr.png";     // UNORM, G=roughness, B=metallic
 ti.material.options.normalPath     = "textures/ground_n.png";      // UNORM
+ti.material.options.occlusionPath  = "textures/ground_ao.png";     // UNORM (optional)
+ti.material.options.emissivePath   = "textures/ground_emit.png";   // sRGB (optional)
 ti.material.options.constants.extra[0].x = 1.0f;                    // normalScale
 // ti.material.options.pass = MaterialPass::Transparent; // optional
 
@@ -136,7 +164,25 @@ glm::mat4 tx = glm::scale(glm::mat4(1.f), glm::vec3(10.f, 1.f, 10.f));
 ctx->scene->addMeshInstance("ground.textured", texturedPlane, tx);
 ```
 
-Textured cube/sphere via options is analogous — set `geometry.type` to `Cube` or `Sphere` and fill `material.options`.
+Textured cube/sphere/plane/capsule via options is analogous — set `geometry.type` to `Cube`, `Sphere`, `Plane`, or `Capsule` and fill `material.options`.
+
+Using custom material from constants:
+
+```c++
+// Create a material with custom PBR values (using engine default textures)
+GLTFMetallic_Roughness::MaterialConstants constants{};
+constants.colorFactors = glm::vec4(1.0f, 0.0f, 0.0f, 1.0f); // red
+constants.metal_rough_factors = glm::vec4(0.0f, 0.8f, 0.0f, 0.0f); // non-metallic, rough
+
+auto redMaterial = ctx->getAssets()->createMaterialFromConstants(
+    "red_rough_material",
+    constants,
+    MaterialPass::MainColor
+);
+
+// Use with custom mesh
+auto mesh = ctx->getAssets()->createMesh("custom_mesh", vertices, indices, redMaterial);
+```
 
 Runtime glTF spawning:
 
@@ -154,11 +200,74 @@ ctx->scene->addGLTFInstance("chair01", *chair,
 ctx->scene->removeGLTFInstance("chair01");
 ```
 
+### Texture Prefetching
+
+Queue texture loads for a glTF file ahead of time. This parses the glTF, builds TextureCache keys for referenced images (both external URIs and embedded images in buffers), and issues `TextureCache::request()` calls. Actual uploads happen via the normal per-frame pump.
+
+```c++
+// Simple version: returns number of textures scheduled
+size_t count = ctx->getAssets()->prefetchGLTFTextures("models/heavy_asset.glb");
+
+// Advanced version: returns handles for tracking progress
+auto result = ctx->getAssets()->prefetchGLTFTexturesWithHandles("models/heavy_asset.glb");
+fmt::println("Scheduled {} textures", result.scheduled);
+// Use result.handles with TextureCache to monitor loading state
+```
+
+Texture prefetching is particularly useful when combined with `AsyncAssetLoader` for loading large models in the background.
+
+### Async Asset Loading
+
+The `AsyncAssetLoader` class provides asynchronous glTF loading with worker threads for CPU-bound tasks (file I/O, parsing, mesh/BVH building). GPU uploads are still deferred through ResourceManager and the Render Graph.
+
+```c++
+// Access via EngineContext
+auto *loader = ctx->async_loader;
+
+// Queue a model to load in the background
+auto jobID = loader->load_gltf_async(
+    "spaceship_01",                      // scene instance name
+    "models/spaceship.glb",              // model path (resolved via AssetManager)
+    glm::translate(glm::mat4(1.f), glm::vec3(0, 5, -10)), // transform
+    true                                  // preload textures
+);
+
+// Check progress in your update loop
+JobState state;
+float progress;
+std::string error;
+if (loader->get_job_status(jobID, state, progress, &error)) {
+    if (state == JobState::Completed) {
+        fmt::println("Model loaded successfully!");
+    } else if (state == JobState::Failed) {
+        fmt::println("Failed to load: {}", error);
+    }
+}
+
+// Commit completed jobs to the scene (call once per frame)
+loader->pump_main_thread(*ctx->scene);
+
+// Alternative: use WorldVec3 for large-world coordinates
+auto jobID2 = loader->load_gltf_async(
+    "distant_building",
+    "models/building.glb",
+    WorldVec3{1000000.0, 0.0, 500000.0}, // world position
+    glm::quat(1.0f, 0.0f, 0.0f, 0.0f),   // rotation
+    glm::vec3(1.0f),                      // scale
+    false                                  // don't preload textures
+);
+```
+
+The `AsyncAssetLoader` integrates with `TextureCache` to track texture streaming progress. When `preload_textures` is true, the loader will schedule all model textures for loading and track their residency state.
+
 ### Notes
 
-- Default primitives: The engine creates default Cube/Sphere meshes via `AssetManager` and registers them as dynamic scene instances.
+- Default primitives: The engine creates default Cube/Sphere/Plane/Capsule meshes via `AssetManager` and registers them as dynamic scene instances.
 - Reuse by name: `createMesh("name", ...)` returns the cached mesh if it already exists. Use a unique name or call `removeMesh(name)` to replace.
-- sRGB/UNORM: Albedo is sRGB by default, metal-rough is UNORM by default. Adjust via `MaterialOptions`.
+- sRGB/UNORM: Albedo and emissive are sRGB by default, metal-rough/normal/occlusion are UNORM by default. Adjust via `MaterialOptions`.
 - Hot reload: Shaders are resolved via `shaderPath()`; pipeline hot reload is handled by the pipeline manager, not the AssetManager.
 - Normal maps: Supported. If `normalPath` is empty, a flat normal is used.
+- Occlusion & Emissive: Supported via `occlusionPath` and `emissivePath` in `MaterialOptions`.
 - Tangents: Loaded from glTF when present; otherwise generated. Enable MikkTSpace at configure time with `-DENABLE_MIKKTS=ON`.
+- BVH building: Enabled by default for meshes (`build_bvh = true`). Required for picking and ray-tracing.
+- Deferred cleanup: Use `removeMeshDeferred()` when destroying meshes during rendering to avoid destroying resources that are in-flight on the GPU.

shaders/deferred_lighting.frag

@@ -35,6 +35,26 @@ const float SHADOW_MIN_BIAS = 1e-5;
 const float SHADOW_RAY_TMIN = 0.02;// start a bit away from the surface
 const float SHADOW_RAY_ORIGIN_BIAS = 0.01;// world units
 
+// Estimate the float ULP scale at this world position magnitude, used to keep
+// ray bias and tMin effective even when world coordinates are very large.
+float world_pos_ulp(vec3 p)
+{
+    float m = max(max(abs(p.x), abs(p.y)), abs(p.z));
+    // For IEEE-754 float, relative precision is ~2^-23 (~1.192e-7). Clamp to a
+    // small baseline to avoid tiny values near the origin.
+    return max(1e-4, m * 1.1920929e-7);
+}
+
+float shadow_ray_origin_bias(vec3 p)
+{
+    return max(SHADOW_RAY_ORIGIN_BIAS, world_pos_ulp(p) * 8.0);
+}
+
+float shadow_ray_tmin(vec3 p)
+{
+    return max(SHADOW_RAY_TMIN, world_pos_ulp(p) * 16.0);
+}
+
 vec3 getCameraWorldPosition()
 {
     // view = [ R^T  -R^T*C ]
@@ -223,9 +243,11 @@ float calcShadowVisibility(vec3 worldPos, vec3 N, vec3 L)
         #ifdef GL_EXT_ray_query
         float farR = max(max(sceneData.cascadeSplitsView.x, sceneData.cascadeSplitsView.y),
         max(sceneData.cascadeSplitsView.z, sceneData.cascadeSplitsView.w));
+        float originBias = shadow_ray_origin_bias(wp);
+        float tmin = shadow_ray_tmin(wp);
         rayQueryEXT rq;
         rayQueryInitializeEXT(rq, topLevelAS, gl_RayFlagsTerminateOnFirstHitEXT | gl_RayFlagsOpaqueEXT,
-        0xFF, wp + N * SHADOW_RAY_ORIGIN_BIAS, SHADOW_RAY_TMIN, L, farR);
+        0xFF, wp + N * originBias, tmin, L, farR);
         while (rayQueryProceedEXT(rq)) { }
         bool hit = (rayQueryGetIntersectionTypeEXT(rq, true) != gl_RayQueryCommittedIntersectionNoneEXT);
         return hit ? 0.0 : 1.0;
@@ -249,10 +271,12 @@ float calcShadowVisibility(vec3 worldPos, vec3 N, vec3 L)
             if (cascadeEnabled && NoL < sceneData.rtParams.x)
             {
                 float maxT = sceneData.cascadeSplitsView[cm.i0];
+                float originBias = shadow_ray_origin_bias(wp);
+                float tmin = shadow_ray_tmin(wp);
                 rayQueryEXT rq;
                 // tmin: small offset to avoid self-hits
                 rayQueryInitializeEXT(rq, topLevelAS, gl_RayFlagsTerminateOnFirstHitEXT | gl_RayFlagsOpaqueEXT,
-                0xFF, wp + N * SHADOW_RAY_ORIGIN_BIAS, SHADOW_RAY_TMIN, L, maxT);
+                0xFF, wp + N * originBias, tmin, L, maxT);
                 bool hit = false;
                 while (rayQueryProceedEXT(rq)) { }
                 hit = (rayQueryGetIntersectionTypeEXT(rq, true) != gl_RayQueryCommittedIntersectionNoneEXT);
@@ -278,9 +302,11 @@ float calcShadowVisibility(vec3 worldPos, vec3 N, vec3 L)
             float maxT0 = sceneData.cascadeSplitsView[cm.i0];
             float maxT1 = sceneData.cascadeSplitsView[cm.i1];
             float maxT = max(maxT0, maxT1);
+            float originBias = shadow_ray_origin_bias(wp);
+            float tmin = shadow_ray_tmin(wp);
             rayQueryEXT rq;
             rayQueryInitializeEXT(rq, topLevelAS, gl_RayFlagsTerminateOnFirstHitEXT | gl_RayFlagsOpaqueEXT,
-            0xFF, wp + N * SHADOW_RAY_ORIGIN_BIAS, SHADOW_RAY_TMIN, L, maxT);
+            0xFF, wp + N * originBias, tmin, L, maxT);
             while (rayQueryProceedEXT(rq)) { }
             bool hit = (rayQueryGetIntersectionTypeEXT(rq, true) != gl_RayQueryCommittedIntersectionNoneEXT);
             if (hit) vis = min(vis, 0.0);
@@ -335,7 +361,9 @@ void main(){
             if (maxT > 0.01)
             {
                 vec3 dir = toL / maxT;
-                vec3 origin = pos + N * SHADOW_RAY_ORIGIN_BIAS;
+                float originBias = shadow_ray_origin_bias(pos);
+                float tmin = shadow_ray_tmin(pos);
+                vec3 origin = pos + N * originBias;
 
                 rayQueryEXT rq;
                 rayQueryInitializeEXT(
@@ -344,7 +372,7 @@ void main(){
                     gl_RayFlagsTerminateOnFirstHitEXT | gl_RayFlagsOpaqueEXT,
                     0xFF,
                     origin,
-                    SHADOW_RAY_TMIN,
+                    tmin,
                     dir,
                     maxT
                 );
@@ -380,7 +408,9 @@ void main(){
                 float cosTheta = dot(-L, dir);
                 if (cosTheta > sceneData.spotLights[i].direction_cos_outer.w)
                 {
-                    vec3 origin = pos + N * SHADOW_RAY_ORIGIN_BIAS;
+                    float originBias = shadow_ray_origin_bias(pos);
+                    float tmin = shadow_ray_tmin(pos);
+                    vec3 origin = pos + N * originBias;
 
                     rayQueryEXT rq;
                     rayQueryInitializeEXT(
@@ -389,7 +419,7 @@ void main(){
                         gl_RayFlagsTerminateOnFirstHitEXT | gl_RayFlagsOpaqueEXT,
                         0xFF,
                         origin,
-                        SHADOW_RAY_TMIN,
+                        tmin,
                         L,
                         maxT
                     );

src/CMakeLists.txt

@@ -117,6 +117,25 @@ add_executable (vulkan_engine
   scene/tangent_space.cpp
   scene/camera.h
   scene/camera.cpp
+  scene/camera/icamera_mode.h
+  scene/camera/camera_rig.h
+  scene/camera/camera_rig.cpp
+  scene/camera/mode_free.h
+  scene/camera/mode_free.cpp
+  scene/camera/mode_orbit.h
+  scene/camera/mode_orbit.cpp
+  scene/camera/mode_follow.h
+  scene/camera/mode_follow.cpp
+  scene/camera/mode_chase.h
+  scene/camera/mode_chase.cpp
+  scene/camera/mode_fixed.h
+  scene/camera/mode_fixed.cpp
+  scene/planet/cubesphere.h
+  scene/planet/cubesphere.cpp
+  scene/planet/planet_quadtree.h
+  scene/planet/planet_quadtree.cpp
+  scene/planet/planet_system.h
+  scene/planet/planet_system.cpp
   # compute
   compute/vk_compute.h
   compute/vk_compute.cpp
@@ -182,7 +201,7 @@ if (CMAKE_BUILD_TYPE STREQUAL "Release" OR CMAKE_BUILD_TYPE STREQUAL "RelWithDeb
             /OPT:ICF
         )
         # Optional: AVX2
-        # target_compile_options(vulkan_engine PRIVATE /arch:AVX2)
+        target_compile_options(vulkan_engine PRIVATE /arch:AVX2)
 
     elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
         # GCC (g++)
@@ -298,23 +317,73 @@ target_include_directories(vma_impl PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/../thir
 target_link_libraries(vma_impl PRIVATE Vulkan::Vulkan)
 target_link_libraries(vulkan_engine PUBLIC $<TARGET_OBJECTS:vma_impl>)
 
-target_precompile_headers(vulkan_engine PUBLIC <optional> <vector> <memory> <string> <vector> <unordered_map> <glm/mat4x4.hpp>  <glm/vec4.hpp> <vulkan/vulkan.h>)
+target_precompile_headers(vulkan_engine PRIVATE
+  <optional>
+  <vector>
+  <memory>
+  <string>
+  <unordered_map>
+  <glm/mat4x4.hpp>
+  <glm/vec4.hpp>
+  <vulkan/vulkan.h>
+)
 
-add_custom_command(TARGET vulkan_engine POST_BUILD
-  COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_RUNTIME_DLLS:vulkan_engine> $<TARGET_FILE_DIR:vulkan_engine>
-  COMMAND_EXPAND_LISTS
-  )
+if(WIN32)
+  if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.21)
+    add_custom_command(TARGET vulkan_engine POST_BUILD
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_RUNTIME_DLLS:vulkan_engine> $<TARGET_FILE_DIR:vulkan_engine>
+      COMMAND_EXPAND_LISTS
+    )
+  else()
+    message(WARNING "CMake < 3.21: skipping runtime DLL copy step for vulkan_engine")
+  endif()
+endif()
 
-find_package(ktx CONFIG REQUIRED)
-set(_KTX_TARGET "")
-if (TARGET ktx::ktx)
-  set(_KTX_TARGET ktx::ktx)
-elseif (TARGET KTX::ktx)
-  set(_KTX_TARGET KTX::ktx)
-elseif (TARGET ktx)
-  set(_KTX_TARGET ktx)
+# KTX (libktx)
+# NOTE: Under WSL it's easy to accidentally pick up the Windows KTX package (ktx.dll),
+# which will configure but fail to link on Linux. Prefer the native library when needed.
+find_package(ktx CONFIG QUIET)
+
+set(_KTX_CMAKE_TARGET "")
+if(TARGET ktx::ktx)
+  set(_KTX_CMAKE_TARGET ktx::ktx)
+elseif(TARGET KTX::ktx)
+  set(_KTX_CMAKE_TARGET KTX::ktx)
+elseif(TARGET ktx)
+  set(_KTX_CMAKE_TARGET ktx)
 endif()
-if (_KTX_TARGET STREQUAL "")
-  message(FATAL_ERROR "libktx not found; please install KTX v2 and expose its CMake package")
+
+set(_KTX_USE_FALLBACK OFF)
+if(_KTX_CMAKE_TARGET STREQUAL "")
+  set(_KTX_USE_FALLBACK ON)
+else()
+  get_target_property(_KTX_IMPORTED "${_KTX_CMAKE_TARGET}" IMPORTED)
+  if(_KTX_IMPORTED)
+    set(_KTX_IMPORTED_LOCATION "")
+    get_target_property(_KTX_IMPORTED_LOCATION "${_KTX_CMAKE_TARGET}" IMPORTED_LOCATION)
+    if(NOT _KTX_IMPORTED_LOCATION)
+      get_target_property(_KTX_IMPORTED_LOCATION "${_KTX_CMAKE_TARGET}" IMPORTED_LOCATION_RELEASE)
+    endif()
+    if(NOT _KTX_IMPORTED_LOCATION)
+      get_target_property(_KTX_IMPORTED_LOCATION "${_KTX_CMAKE_TARGET}" IMPORTED_LOCATION_DEBUG)
+    endif()
+
+    if(NOT _KTX_IMPORTED_LOCATION)
+      set(_KTX_USE_FALLBACK ON)
+    elseif(NOT WIN32 AND _KTX_IMPORTED_LOCATION MATCHES "\\.dll$|\\.lib$")
+      set(_KTX_USE_FALLBACK ON)
+    endif()
+  endif()
+endif()
+
+if(_KTX_USE_FALLBACK)
+  find_path(KTX_INCLUDE_DIR NAMES ktx.h)
+  find_library(KTX_LIBRARY NAMES ktx)
+  if(NOT KTX_INCLUDE_DIR OR NOT KTX_LIBRARY)
+    message(FATAL_ERROR "libktx not found; please install KTX v2 and make it discoverable via ktx_DIR or CMAKE_PREFIX_PATH")
+  endif()
+  target_include_directories(vulkan_engine PUBLIC "${KTX_INCLUDE_DIR}")
+  target_link_libraries(vulkan_engine PUBLIC "${KTX_LIBRARY}")
+else()
+  target_link_libraries(vulkan_engine PUBLIC "${_KTX_CMAKE_TARGET}")
 endif()
-target_link_libraries(vulkan_engine PUBLIC ${_KTX_TARGET})

src/core/assets/manager.cpp

@@ -587,7 +587,8 @@ std::pair<AllocatedImage, bool> AssetManager::loadImageFromAsset(std::string_vie
 std::shared_ptr<MeshAsset> AssetManager::createMesh(const std::string &name,
                                                     std::span<Vertex> vertices,
                                                     std::span<uint32_t> indices,
-                                                    std::shared_ptr<GLTFMaterial> material)
+                                                    std::shared_ptr<GLTFMaterial> material,
+                                                    bool build_bvh)
 {
     if (!_engine || !_engine->_resourceManager) return {};
     if (name.empty()) return {};
@@ -631,9 +632,12 @@ std::shared_ptr<MeshAsset> AssetManager::createMesh(const std::string &name,
     surf.bounds = compute_bounds(vertices);
     mesh->surfaces.push_back(surf);
 
-    // Build CPU-side BVH for precise ray picking over this mesh.
-    // This uses the same mesh-local vertex/index data as the GPU upload.
-    mesh->bvh = build_mesh_bvh(*mesh, vertices, indices);
+    if (build_bvh)
+    {
+        // Build CPU-side BVH for precise ray picking over this mesh.
+        // This uses the same mesh-local vertex/index data as the GPU upload.
+        mesh->bvh = build_mesh_bvh(*mesh, vertices, indices);
+    }
 
     _meshCache.emplace(name, mesh);
     return mesh;
@@ -665,6 +669,26 @@ std::shared_ptr<GLTFMaterial> AssetManager::createMaterialFromConstants(
     return createMaterial(pass, res);
 }
 
+VkImageView AssetManager::fallback_checkerboard_view() const
+{
+    return (_engine) ? _engine->_errorCheckerboardImage.imageView : VK_NULL_HANDLE;
+}
+
+VkImageView AssetManager::fallback_white_view() const
+{
+    return (_engine) ? _engine->_whiteImage.imageView : VK_NULL_HANDLE;
+}
+
+VkImageView AssetManager::fallback_flat_normal_view() const
+{
+    return (_engine) ? _engine->_flatNormalImage.imageView : VK_NULL_HANDLE;
+}
+
+VkImageView AssetManager::fallback_black_view() const
+{
+    return (_engine) ? _engine->_blackImage.imageView : VK_NULL_HANDLE;
+}
+
 std::shared_ptr<MeshAsset> AssetManager::getMesh(const std::string &name) const
 {
     auto it = _meshCache.find(name);
@@ -709,3 +733,65 @@ bool AssetManager::removeMesh(const std::string &name)
     }
     return true;
 }
+
+bool AssetManager::removeMeshDeferred(const std::string &name, DeletionQueue &dq)
+{
+    auto it = _meshCache.find(name);
+    if (it == _meshCache.end()) return false;
+
+    const std::shared_ptr<MeshAsset> mesh = it->second;
+    if (!mesh) return false;
+
+    // Remove from cache immediately so callers won't retrieve a mesh we plan to destroy.
+    _meshCache.erase(it);
+
+    if (_engine && _engine->_rayManager)
+    {
+        // Clean up BLAS cached for this mesh (if ray tracing is enabled).
+        // RayTracingManager defers actual AS destruction internally.
+        _engine->_rayManager->removeBLASForBuffer(mesh->meshBuffers.vertexBuffer.buffer);
+    }
+
+    ResourceManager *rm = (_engine && _engine->_resourceManager) ? _engine->_resourceManager.get() : nullptr;
+    if (!rm)
+    {
+        return true;
+    }
+
+    const AllocatedBuffer indexBuffer = mesh->meshBuffers.indexBuffer;
+    const AllocatedBuffer vertexBuffer = mesh->meshBuffers.vertexBuffer;
+
+    std::optional<AllocatedBuffer> materialBuffer;
+    auto itb = _meshMaterialBuffers.find(name);
+    if (itb != _meshMaterialBuffers.end())
+    {
+        materialBuffer = itb->second;
+        _meshMaterialBuffers.erase(itb);
+    }
+
+    std::vector<AllocatedImage> ownedImages;
+    auto iti = _meshOwnedImages.find(name);
+    if (iti != _meshOwnedImages.end())
+    {
+        ownedImages = std::move(iti->second);
+        _meshOwnedImages.erase(iti);
+    }
+
+    dq.push_function([rm, indexBuffer, vertexBuffer, materialBuffer, ownedImages = std::move(ownedImages)]() mutable
+    {
+        if (indexBuffer.buffer) rm->destroy_buffer(indexBuffer);
+        if (vertexBuffer.buffer) rm->destroy_buffer(vertexBuffer);
+
+        if (materialBuffer.has_value() && materialBuffer->buffer)
+        {
+            rm->destroy_buffer(*materialBuffer);
+        }
+
+        for (const auto &img : ownedImages)
+        {
+            if (img.image) rm->destroy_image(img);
+        }
+    });
+
+    return true;
+}

src/core/assets/manager.h

@@ -107,17 +107,25 @@ public:
     std::shared_ptr<MeshAsset> createMesh(const std::string &name,
                                           std::span<Vertex> vertices,
                                           std::span<uint32_t> indices,
-                                          std::shared_ptr<GLTFMaterial> material = {});
+                                          std::shared_ptr<GLTFMaterial> material = {},
+                                          bool build_bvh = true);
 
     std::shared_ptr<MeshAsset> getMesh(const std::string &name) const;
 
     bool removeMesh(const std::string &name);
+    bool removeMeshDeferred(const std::string &name, DeletionQueue &dq);
 
     // Convenience: create a PBR material from constants using engine default textures
     std::shared_ptr<GLTFMaterial> createMaterialFromConstants(const std::string &name,
                                                               const GLTFMetallic_Roughness::MaterialConstants &constants,
                                                               MaterialPass pass = MaterialPass::MainColor);
 
+    // Access engine-provided fallback textures for procedural systems.
+    VkImageView fallback_checkerboard_view() const;
+    VkImageView fallback_white_view() const;
+    VkImageView fallback_flat_normal_view() const;
+    VkImageView fallback_black_view() const;
+
     const AssetPaths &paths() const { return _locator.paths(); }
     void setPaths(const AssetPaths &p) { _locator.setPaths(p); }
 

src/core/device/resource.cpp

@@ -359,6 +359,44 @@ GPUMeshBuffers ResourceManager::uploadMesh(std::span<uint32_t> indices, std::spa
     return newSurface;
 }
 
+AllocatedBuffer ResourceManager::upload_buffer(const void *data, size_t size, VkBufferUsageFlags usage,
+                                              VmaMemoryUsage memoryUsage)
+{
+    if (data == nullptr || size == 0)
+    {
+        return {};
+    }
+
+    AllocatedBuffer dst = create_buffer(size, usage | VK_BUFFER_USAGE_TRANSFER_DST_BIT, memoryUsage);
+
+    AllocatedBuffer staging = create_buffer(size, VK_BUFFER_USAGE_TRANSFER_SRC_BIT,
+                                           VMA_MEMORY_USAGE_CPU_ONLY);
+
+    memcpy(staging.info.pMappedData, data, size);
+    vmaFlushAllocation(_deviceManager->allocator(), staging.allocation, 0, size);
+
+    PendingBufferUpload pending{};
+    pending.staging = staging;
+    pending.copies.push_back(BufferCopyRegion{
+        .destination = dst.buffer,
+        .dstOffset = 0,
+        .size = size,
+        .stagingOffset = 0,
+    });
+
+    {
+        std::lock_guard<std::mutex> lk(_pendingMutex);
+        _pendingBufferUploads.push_back(std::move(pending));
+    }
+
+    if (!_deferUploads)
+    {
+        process_queued_uploads_immediate();
+    }
+
+    return dst;
+}
+
 bool ResourceManager::has_pending_uploads() const
 {
     std::lock_guard<std::mutex> lk(_pendingMutex);

src/core/device/resource.h

@@ -94,6 +94,12 @@ public:
 
     GPUMeshBuffers uploadMesh(std::span<uint32_t> indices, std::span<Vertex> vertices);
 
+    // Upload raw bytes into a GPU buffer. The destination buffer is created with the provided 'usage'
+    // flags plus VK_BUFFER_USAGE_TRANSFER_DST_BIT. Staging is handled internally and freed via the
+    // per-frame deletion queue when deferred uploads are enabled.
+    AllocatedBuffer upload_buffer(const void *data, size_t size, VkBufferUsageFlags usage,
+                                  VmaMemoryUsage memoryUsage = VMA_MEMORY_USAGE_GPU_ONLY);
+
     void immediate_submit(std::function<void(VkCommandBuffer)> &&function) const;
 
     bool has_pending_uploads() const;

src/core/engine.cpp

@@ -1671,7 +1671,7 @@ void VulkanEngine::run()
 
         if (_sceneManager && _input)
         {
-            _sceneManager->getMainCamera().process_input(*_input, ui_capture_keyboard, ui_capture_mouse);
+            _sceneManager->getCameraRig().process_input(*_input, ui_capture_keyboard, ui_capture_mouse);
         }
 
         if (freeze_rendering)

src/core/engine.h

@@ -39,8 +39,8 @@
 #include "core/assets/ibl_manager.h"
 #include "core/ui/imgui_system.h"
 #include "core/picking/picking_system.h"
+#include "core/input/input_system.h"
 
-class InputSystem;
 class DebugDrawSystem;
 
 struct DebugDrawDeleter

src/core/engine_ui.cpp

@@ -21,6 +21,7 @@
 #include "render/passes/background.h"
 #include "render/passes/particles.h"
 #include <glm/gtx/euler_angles.hpp>
+#include <glm/gtx/quaternion.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 #include "render/graph/graph.h"
 #include "core/pipeline/manager.h"
@@ -36,6 +37,7 @@
 #include <string>
 
 #include "mesh_bvh.h"
+#include "scene/planet/planet_system.h"
 
 namespace
 {
@@ -781,6 +783,213 @@ namespace
         }
     }
 
+    static void ui_camera(VulkanEngine *eng)
+    {
+        if (!eng || !eng->_sceneManager)
+        {
+            ImGui::TextUnformatted("SceneManager not available");
+            return;
+        }
+
+        SceneManager *sceneMgr = eng->_sceneManager.get();
+        CameraRig &rig = sceneMgr->getCameraRig();
+        Camera &cam = sceneMgr->getMainCamera();
+
+        // Mode switch
+        static const char *k_mode_names[] = {"Free", "Orbit", "Follow", "Chase", "Fixed"};
+        int mode = static_cast<int>(rig.mode());
+        if (ImGui::Combo("Mode", &mode, k_mode_names, IM_ARRAYSIZE(k_mode_names)))
+        {
+            rig.set_mode(static_cast<CameraMode>(mode), *sceneMgr, cam);
+            if (eng->_input)
+            {
+                eng->_input->set_cursor_mode(CursorMode::Normal);
+            }
+        }
+
+        ImGui::Text("Active mode: %s", rig.mode_name());
+        ImGui::Separator();
+
+        // Camera state (world)
+        double pos[3] = {cam.position_world.x, cam.position_world.y, cam.position_world.z};
+        if (ImGui::InputScalarN("Position (world)", ImGuiDataType_Double, pos, 3, nullptr, nullptr, "%.3f"))
+        {
+            cam.position_world = WorldVec3(pos[0], pos[1], pos[2]);
+        }
+        float fov = cam.fovDegrees;
+        if (ImGui::SliderFloat("FOV (deg)", &fov, 30.0f, 110.0f))
+        {
+            cam.fovDegrees = fov;
+        }
+
+        WorldVec3 origin = sceneMgr->get_world_origin();
+        glm::vec3 camLocal = sceneMgr->get_camera_local_position();
+        ImGui::Text("Origin (world): (%.3f, %.3f, %.3f)", origin.x, origin.y, origin.z);
+        ImGui::Text("Camera (local): (%.3f, %.3f, %.3f)", camLocal.x, camLocal.y, camLocal.z);
+
+        auto target_from_last_pick = [&](CameraTarget &target) -> bool {
+            PickingSystem *picking = eng->picking();
+            if (!picking) return false;
+            const auto &pick = picking->last_pick();
+            if (!pick.valid) return false;
+
+            if (pick.ownerType == RenderObject::OwnerType::MeshInstance)
+            {
+                target.type = CameraTargetType::MeshInstance;
+                target.name = pick.ownerName;
+            }
+            else if (pick.ownerType == RenderObject::OwnerType::GLTFInstance)
+            {
+                target.type = CameraTargetType::GLTFInstance;
+                target.name = pick.ownerName;
+            }
+            else
+            {
+                target.type = CameraTargetType::WorldPoint;
+                target.world_point = pick.worldPos;
+                target.name.clear();
+            }
+            return true;
+        };
+
+        auto draw_target = [&](const char *id, CameraTarget &target, char *name_buf, size_t name_buf_size) {
+            ImGui::PushID(id);
+            static const char *k_target_types[] = {"None", "WorldPoint", "MeshInstance", "GLTFInstance"};
+            int type = static_cast<int>(target.type);
+            if (ImGui::Combo("Target type", &type, k_target_types, IM_ARRAYSIZE(k_target_types)))
+            {
+                target.type = static_cast<CameraTargetType>(type);
+                if (target.type != CameraTargetType::MeshInstance && target.type != CameraTargetType::GLTFInstance)
+                {
+                    target.name.clear();
+                    if (name_buf_size > 0)
+                    {
+                        name_buf[0] = '\0';
+                    }
+                }
+            }
+
+            if (target.type == CameraTargetType::WorldPoint)
+            {
+                double p[3] = {target.world_point.x, target.world_point.y, target.world_point.z};
+                if (ImGui::InputScalarN("World point", ImGuiDataType_Double, p, 3, nullptr, nullptr, "%.3f"))
+                {
+                    target.world_point = WorldVec3(p[0], p[1], p[2]);
+                }
+            }
+            else if (target.type == CameraTargetType::MeshInstance || target.type == CameraTargetType::GLTFInstance)
+            {
+                if (std::strncmp(name_buf, target.name.c_str(), name_buf_size) != 0)
+                {
+                    std::snprintf(name_buf, name_buf_size, "%s", target.name.c_str());
+                }
+                ImGui::InputText("Target name", name_buf, name_buf_size);
+                target.name = name_buf;
+            }
+
+            WorldVec3 tpos{};
+            glm::quat trot{};
+            bool ok = rig.resolve_target(*sceneMgr, target, tpos, trot);
+            ImGui::Text("Resolved: %s", ok ? "yes" : "no");
+            if (ok)
+            {
+                ImGui::Text("Target world: (%.3f, %.3f, %.3f)", tpos.x, tpos.y, tpos.z);
+            }
+            ImGui::PopID();
+        };
+
+        // Free
+        if (ImGui::CollapsingHeader("Free", ImGuiTreeNodeFlags_DefaultOpen))
+        {
+            auto &s = rig.free_settings();
+            ImGui::InputFloat("Move speed (u/s)", &s.move_speed);
+            s.move_speed = std::clamp(s.move_speed, 0.06f, 300.0f);
+            ImGui::InputFloat("Look sensitivity", &s.look_sensitivity);
+            ImGui::InputFloat("Roll speed (rad/s)", &s.roll_speed);
+            ImGui::TextUnformatted("Roll keys: Q/E");
+        }
+
+        // Orbit
+        if (ImGui::CollapsingHeader("Orbit"))
+        {
+            auto &s = rig.orbit_settings();
+            static char orbitName[128] = "";
+            draw_target("orbit_target", s.target, orbitName, IM_ARRAYSIZE(orbitName));
+            if (ImGui::Button("Orbit target = Last Pick"))
+            {
+                target_from_last_pick(s.target);
+            }
+            ImGui::InputDouble("Distance", &s.distance, 0.1, 1.0, "%.3f");
+            s.distance = std::clamp(s.distance, 0.2, 100000.0);
+            float yawDeg = glm::degrees(s.yaw);
+            float pitchDeg = glm::degrees(s.pitch);
+            if (ImGui::SliderFloat("Yaw (deg)", &yawDeg, -180.0f, 180.0f))
+            {
+                s.yaw = glm::radians(yawDeg);
+            }
+            if (ImGui::SliderFloat("Pitch (deg)", &pitchDeg, -89.0f, 89.0f))
+            {
+                s.pitch = glm::radians(pitchDeg);
+            }
+            ImGui::InputFloat("Look sensitivity##orbit", &s.look_sensitivity);
+        }
+
+        // Follow
+        if (ImGui::CollapsingHeader("Follow"))
+        {
+            auto &s = rig.follow_settings();
+            static char followName[128] = "";
+            draw_target("follow_target", s.target, followName, IM_ARRAYSIZE(followName));
+            if (ImGui::Button("Follow target = Last Pick"))
+            {
+                target_from_last_pick(s.target);
+            }
+            ImGui::InputFloat3("Position offset (local)", &s.position_offset_local.x);
+
+            glm::vec3 rotDeg = glm::degrees(glm::eulerAngles(s.rotation_offset));
+            float r[3] = {rotDeg.x, rotDeg.y, rotDeg.z};
+            if (ImGui::InputFloat3("Rotation offset (deg XYZ)", r))
+            {
+                glm::mat4 R = glm::eulerAngleXYZ(glm::radians(r[0]), glm::radians(r[1]), glm::radians(r[2]));
+                s.rotation_offset = glm::quat_cast(R);
+            }
+            if (ImGui::Button("Reset rotation offset"))
+            {
+                s.rotation_offset = glm::quat(1.0f, 0.0f, 0.0f, 0.0f);
+            }
+        }
+
+        // Chase
+        if (ImGui::CollapsingHeader("Chase"))
+        {
+            auto &s = rig.chase_settings();
+            static char chaseName[128] = "";
+            draw_target("chase_target", s.target, chaseName, IM_ARRAYSIZE(chaseName));
+            if (ImGui::Button("Chase target = Last Pick"))
+            {
+                target_from_last_pick(s.target);
+            }
+            ImGui::InputFloat3("Position offset (local)##chase", &s.position_offset_local.x);
+
+            glm::vec3 rotDeg = glm::degrees(glm::eulerAngles(s.rotation_offset));
+            float r[3] = {rotDeg.x, rotDeg.y, rotDeg.z};
+            if (ImGui::InputFloat3("Rotation offset (deg XYZ)##chase", r))
+            {
+                glm::mat4 R = glm::eulerAngleXYZ(glm::radians(r[0]), glm::radians(r[1]), glm::radians(r[2]));
+                s.rotation_offset = glm::quat_cast(R);
+            }
+
+            ImGui::SliderFloat("Position lag (1/s)", &s.position_lag, 0.0f, 30.0f);
+            ImGui::SliderFloat("Rotation lag (1/s)", &s.rotation_lag, 0.0f, 30.0f);
+        }
+
+        // Fixed
+        if (ImGui::CollapsingHeader("Fixed"))
+        {
+            ImGui::TextUnformatted("Fixed mode does not modify the camera automatically.");
+        }
+    }
+
     // Texture streaming + budget UI
     static const char *stateName(uint8_t s)
     {
@@ -1386,97 +1595,17 @@ namespace
         }
     }
 
-    // Scene debug bits
-    static void ui_scene(VulkanEngine *eng)
+    // Scene editor - spawn and delete instances
+    static void ui_scene_editor(VulkanEngine *eng)
     {
-        if (!eng) return;
-        const DrawContext &dc = eng->_context->getMainDrawContext();
-        ImGui::Text("Opaque draws: %zu", dc.OpaqueSurfaces.size());
-        ImGui::Text("Transp draws: %zu", dc.TransparentSurfaces.size());
+        if (!eng || !eng->_sceneManager)
+        {
+            ImGui::TextUnformatted("SceneManager not available");
+            return;
+        }
+
+        SceneManager *sceneMgr = eng->_sceneManager.get();
         PickingSystem *picking = eng->picking();
-        if (picking)
-        {
-            bool use_id = picking->use_id_buffer_picking();
-            if (ImGui::Checkbox("Use ID-buffer picking", &use_id))
-            {
-                picking->set_use_id_buffer_picking(use_id);
-            }
-            ImGui::Text("Picking mode: %s",
-                        use_id ? "ID buffer (async, 1-frame latency)" : "CPU raycast");
-
-            bool debug_bvh = picking->debug_draw_bvh();
-            if (ImGui::Checkbox("Debug draw mesh BVH (last pick)", &debug_bvh))
-            {
-                picking->set_debug_draw_bvh(debug_bvh);
-            }
-        }
-        else
-        {
-            ImGui::TextUnformatted("Picking system not available");
-        }
-
-        // Debug draw settings (engine-owned collector + render pass)
-        if (eng->_context && eng->_context->debug_draw)
-        {
-            DebugDrawSystem *dd = eng->_context->debug_draw;
-            auto &s = dd->settings();
-
-            bool enabled = s.enabled;
-            if (ImGui::Checkbox("Enable debug draw", &enabled))
-            {
-                s.enabled = enabled;
-            }
-            if (s.enabled)
-            {
-                ImGui::SameLine();
-                ImGui::Text("Commands: %zu", dd->command_count());
-
-                int seg = s.segments;
-                if (ImGui::SliderInt("Circle segments", &seg, 3, 128))
-                {
-                    s.segments = seg;
-                }
-
-                bool depth_tested = s.show_depth_tested;
-                bool overlay = s.show_overlay;
-                if (ImGui::Checkbox("Depth-tested", &depth_tested))
-                {
-                    s.show_depth_tested = depth_tested;
-                }
-                ImGui::SameLine();
-                if (ImGui::Checkbox("Overlay", &overlay))
-                {
-                    s.show_overlay = overlay;
-                }
-
-                auto layer_checkbox = [&s](const char *label, DebugDrawLayer layer) {
-                    const uint32_t bit = static_cast<uint32_t>(layer);
-                    bool on = (s.layer_mask & bit) != 0u;
-                    if (ImGui::Checkbox(label, &on))
-                    {
-                        if (on) s.layer_mask |= bit;
-                        else s.layer_mask &= ~bit;
-                    }
-                };
-
-                ImGui::TextUnformatted("Layers");
-                layer_checkbox("Physics##dd_layer_physics", DebugDrawLayer::Physics);
-                ImGui::SameLine();
-                layer_checkbox("Picking##dd_layer_picking", DebugDrawLayer::Picking);
-                ImGui::SameLine();
-                layer_checkbox("Lights##dd_layer_lights", DebugDrawLayer::Lights);
-                layer_checkbox("Particles##dd_layer_particles", DebugDrawLayer::Particles);
-                ImGui::SameLine();
-                layer_checkbox("Volumetrics##dd_layer_volumetrics", DebugDrawLayer::Volumetrics);
-                ImGui::SameLine();
-                layer_checkbox("Misc##dd_layer_misc", DebugDrawLayer::Misc);
-            }
-        }
-        else
-        {
-            ImGui::TextUnformatted("Debug draw system not available");
-        }
-        ImGui::Separator();
 
         // Spawn glTF instances (runtime)
         ImGui::TextUnformatted("Spawn glTF instance");
@@ -1530,13 +1659,73 @@ namespace
             }
         }
 
-        // Point light editor
-        if (eng->_sceneManager)
+        ImGui::Separator();
+        // Delete selected model/primitive (uses last pick if valid, otherwise hover)
+        static std::string deleteStatus;
+        if (ImGui::Button("Delete selected"))
         {
-            ImGui::Separator();
-            ImGui::TextUnformatted("Point lights");
+            deleteStatus.clear();
+            const PickingSystem::PickInfo *pick = nullptr;
+            if (picking)
+            {
+                const auto &last = picking->last_pick();
+                const auto &hover = picking->hover_pick();
+                pick = last.valid ? &last : (hover.valid ? &hover : nullptr);
+            }
+            if (!pick || pick->ownerName.empty())
+            {
+                deleteStatus = "No selection to delete.";
+            }
+            else if (pick->ownerType == RenderObject::OwnerType::MeshInstance)
+            {
+                bool ok = eng->_sceneManager->removeMeshInstance(pick->ownerName);
+                if (ok && picking)
+                {
+                    picking->clear_owner_picks(RenderObject::OwnerType::MeshInstance, pick->ownerName);
+                }
+                deleteStatus = ok ? "Removed mesh instance: " + pick->ownerName
+                                  : "Mesh instance not found: " + pick->ownerName;
+            }
+            else if (pick->ownerType == RenderObject::OwnerType::GLTFInstance)
+            {
+                bool ok = eng->_sceneManager->removeGLTFInstance(pick->ownerName);
+                if (ok)
+                {
+                    deleteStatus = "Removed glTF instance: " + pick->ownerName;
+                    if (picking)
+                    {
+                        picking->clear_owner_picks(RenderObject::OwnerType::GLTFInstance, pick->ownerName);
+                    }
+                }
+                else
+                {
+                    deleteStatus = "glTF instance not found: " + pick->ownerName;
+                }
+            }
+            else
+            {
+                deleteStatus = "Cannot delete this object type (static scene).";
+            }
+        }
+        if (!deleteStatus.empty())
+        {
+            ImGui::TextUnformatted(deleteStatus.c_str());
+        }
+    }
 
-            SceneManager *sceneMgr = eng->_sceneManager.get();
+    // Lights editor (Point + Spot lights)
+    static void ui_lights(VulkanEngine *eng)
+    {
+        if (!eng || !eng->_sceneManager)
+        {
+            ImGui::TextUnformatted("SceneManager not available");
+            return;
+        }
+
+        SceneManager *sceneMgr = eng->_sceneManager.get();
+
+        // Point light editor
+        ImGui::TextUnformatted("Point lights");
             const auto &lights = sceneMgr->getPointLights();
             ImGui::Text("Active lights: %zu", lights.size());
 
@@ -1730,62 +1919,21 @@ namespace
                 sceneMgr->clearSpotLights();
                 selectedSpot = -1;
             }
+    }
+
+    // Picking & Gizmo - picking info and transform editor
+    static void ui_picking_gizmo(VulkanEngine *eng)
+    {
+        if (!eng || !eng->_sceneManager)
+        {
+            ImGui::TextUnformatted("SceneManager not available");
+            return;
         }
 
-        ImGui::Separator();
-        // Delete selected model/primitive (uses last pick if valid, otherwise hover)
-        static std::string deleteStatus;
-        if (ImGui::Button("Delete selected"))
-        {
-            deleteStatus.clear();
-            const PickingSystem::PickInfo *pick = nullptr;
-            if (picking)
-            {
-                const auto &last = picking->last_pick();
-                const auto &hover = picking->hover_pick();
-                pick = last.valid ? &last : (hover.valid ? &hover : nullptr);
-            }
-            if (!pick || pick->ownerName.empty())
-            {
-                deleteStatus = "No selection to delete.";
-            }
-            else if (pick->ownerType == RenderObject::OwnerType::MeshInstance)
-            {
-                bool ok = eng->_sceneManager->removeMeshInstance(pick->ownerName);
-                if (ok && picking)
-                {
-                    picking->clear_owner_picks(RenderObject::OwnerType::MeshInstance, pick->ownerName);
-                }
-                deleteStatus = ok ? "Removed mesh instance: " + pick->ownerName
-                                  : "Mesh instance not found: " + pick->ownerName;
-            }
-            else if (pick->ownerType == RenderObject::OwnerType::GLTFInstance)
-            {
-                bool ok = eng->_sceneManager->removeGLTFInstance(pick->ownerName);
-                if (ok)
-                {
-                    deleteStatus = "Removed glTF instance: " + pick->ownerName;
-                    if (picking)
-                    {
-                        picking->clear_owner_picks(RenderObject::OwnerType::GLTFInstance, pick->ownerName);
-                    }
-                }
-                else
-                {
-                    deleteStatus = "glTF instance not found: " + pick->ownerName;
-                }
-            }
-            else
-            {
-                deleteStatus = "Cannot delete this object type (static scene).";
-            }
-        }
-        if (!deleteStatus.empty())
-        {
-            ImGui::TextUnformatted(deleteStatus.c_str());
-        }
-        ImGui::Separator();
+        SceneManager *sceneMgr = eng->_sceneManager.get();
+        PickingSystem *picking = eng->picking();
 
+        // Last pick info
         if (picking && picking->last_pick().valid)
         {
             const auto &last = picking->last_pick();
@@ -1866,14 +2014,6 @@ namespace
         ImGui::Separator();
         ImGui::TextUnformatted("Object Gizmo (ImGuizmo)");
 
-        if (!eng->_sceneManager)
-        {
-            ImGui::TextUnformatted("SceneManager not available");
-            return;
-        }
-
-        SceneManager *sceneMgr = eng->_sceneManager.get();
-
         // Choose a pick to edit: prefer last pick, then hover.
         PickingSystem::PickInfo *pick = nullptr;
         if (picking)
@@ -2034,27 +2174,206 @@ namespace
             pick->worldPos = local_to_world(glm::vec3(targetTransform[3]), sceneMgr->get_world_origin());
         }
     }
+
+    static void ui_planets(VulkanEngine *eng)
+    {
+        if (!eng || !eng->_sceneManager)
+        {
+            return;
+        }
+
+        SceneManager *scene = eng->_sceneManager.get();
+        PlanetSystem *planets = scene->get_planet_system();
+        if (!planets)
+        {
+            ImGui::TextUnformatted("Planet system not available");
+            return;
+        }
+
+        bool enabled = planets->enabled();
+        if (ImGui::Checkbox("Enable planet rendering", &enabled))
+        {
+            planets->set_enabled(enabled);
+        }
+
+        const WorldVec3 origin_world = scene->get_world_origin();
+        const WorldVec3 cam_world = scene->getMainCamera().position_world;
+        const glm::vec3 cam_local = scene->get_camera_local_position();
+
+        ImGui::Separator();
+        ImGui::Text("Camera world (m):  %.3f, %.3f, %.3f", cam_world.x, cam_world.y, cam_world.z);
+        ImGui::Text("Camera local (m):  %.3f, %.3f, %.3f", cam_local.x, cam_local.y, cam_local.z);
+        ImGui::Text("World origin (m):  %.3f, %.3f, %.3f", origin_world.x, origin_world.y, origin_world.z);
+
+        auto look_at_world = [](Camera &cam, const WorldVec3 &target_world)
+        {
+            glm::dvec3 dirD = glm::normalize(target_world - cam.position_world);
+            glm::vec3 dir = glm::normalize(glm::vec3(dirD));
+
+            glm::vec3 up(0.0f, 1.0f, 0.0f);
+            if (glm::length2(glm::cross(dir, up)) < 1e-6f)
+            {
+                up = glm::vec3(0.0f, 0.0f, 1.0f);
+            }
+
+            glm::vec3 f = dir;
+            glm::vec3 r = glm::normalize(glm::cross(up, f));
+            glm::vec3 u = glm::cross(f, r);
+
+            glm::mat3 rot;
+            rot[0] = r;
+            rot[1] = u;
+            rot[2] = -f; // -Z forward
+            cam.orientation = glm::quat_cast(rot);
+        };
+
+        PlanetSystem::PlanetBody *earth = planets->get_body(PlanetSystem::BodyID::Earth);
+        PlanetSystem::PlanetBody *moon = planets->get_body(PlanetSystem::BodyID::Moon);
+
+	        if (earth)
+	        {
+	            ImGui::Separator();
+
+	            bool vis = earth->visible;
+            if (ImGui::Checkbox("Render Earth", &vis))
+            {
+                earth->visible = vis;
+            }
+            ImGui::SameLine();
+            ImGui::Text("(R=%.1f km)", earth->radius_m / 1000.0);
+
+            const double dist = glm::length(cam_world - earth->center_world);
+            const double alt_m = dist - earth->radius_m;
+            ImGui::Text("Altitude above Earth: %.3f km", alt_m / 1000.0);
+
+            if (ImGui::Button("Teleport: 10000 km above surface"))
+            {
+                scene->getMainCamera().position_world =
+                    earth->center_world + WorldVec3(0.0, 0.0, earth->radius_m + 1.0e7);
+                look_at_world(scene->getMainCamera(), earth->center_world);
+            }
+
+	            if (ImGui::Button("Teleport: 1000 km orbit"))
+	            {
+	                scene->getMainCamera().position_world =
+	                    earth->center_world + WorldVec3(0.0, 0.0, earth->radius_m + 1.0e6);
+	                look_at_world(scene->getMainCamera(), earth->center_world);
+	            }
+	            ImGui::SameLine();
+	            if (ImGui::Button("Teleport: 10 km above surface"))
+	            {
+	                scene->getMainCamera().position_world =
+	                    earth->center_world + WorldVec3(0.0, 0.0, earth->radius_m + 1.0e4);
+	                look_at_world(scene->getMainCamera(), earth->center_world);
+	            }
+
+	            ImGui::Separator();
+	            if (ImGui::CollapsingHeader("Earth LOD / Perf", ImGuiTreeNodeFlags_DefaultOpen))
+	            {
+	                auto settings = planets->earth_quadtree_settings();
+	                bool changed = false;
+
+                    bool tint = planets->earth_debug_tint_patches_by_lod();
+                    if (ImGui::Checkbox("Debug: tint patches by LOD", &tint))
+                    {
+                        planets->set_earth_debug_tint_patches_by_lod(tint);
+                    }
+
+	                int maxLevel = static_cast<int>(settings.max_level);
+	                if (ImGui::SliderInt("Max LOD level", &maxLevel, 0, 20))
+	                {
+	                    settings.max_level = static_cast<uint32_t>(std::max(0, maxLevel));
+	                    changed = true;
+	                }
+
+	                if (ImGui::SliderFloat("Target SSE (px)", &settings.target_sse_px, 4.0f, 128.0f, "%.1f"))
+	                {
+	                    settings.target_sse_px = std::max(settings.target_sse_px, 0.1f);
+	                    changed = true;
+	                }
+
+	                int maxPatches = static_cast<int>(settings.max_patches_visible);
+	                if (ImGui::SliderInt("Max visible patches", &maxPatches, 64, 20000))
+	                {
+	                    settings.max_patches_visible = static_cast<uint32_t>(std::max(6, maxPatches));
+	                    changed = true;
+	                }
+
+	                int createBudget = static_cast<int>(planets->earth_patch_create_budget_per_frame());
+	                if (ImGui::SliderInt("Patch create budget/frame", &createBudget, 0, 512))
+	                {
+	                    planets->set_earth_patch_create_budget_per_frame(static_cast<uint32_t>(std::max(0, createBudget)));
+	                }
+
+	                float createBudgetMs = planets->earth_patch_create_budget_ms();
+	                if (ImGui::DragFloat("Patch create budget (ms)", &createBudgetMs, 0.25f, 0.0f, 50.0f, "%.2f"))
+	                {
+	                    planets->set_earth_patch_create_budget_ms(std::max(0.0f, createBudgetMs));
+	                }
+
+	                int cacheMax = static_cast<int>(planets->earth_patch_cache_max());
+	                if (ImGui::SliderInt("Patch cache max", &cacheMax, 0, 50000))
+	                {
+	                    planets->set_earth_patch_cache_max(static_cast<uint32_t>(std::max(0, cacheMax)));
+	                }
+
+	                if (ImGui::Checkbox("Frustum cull", &settings.frustum_cull)) changed = true;
+	                if (ImGui::Checkbox("Horizon cull", &settings.horizon_cull)) changed = true;
+
+	                if (ImGui::Checkbox("RT guardrail (LOD floor)", &settings.rt_guardrail)) changed = true;
+	                if (settings.rt_guardrail)
+	                {
+	                    float maxEdge = static_cast<float>(settings.max_patch_edge_rt_m);
+	                    if (ImGui::DragFloat("RT max patch edge (m)", &maxEdge, 100.0f, 0.0f, 200000.0f, "%.0f"))
+	                    {
+	                        settings.max_patch_edge_rt_m = static_cast<double>(std::max(0.0f, maxEdge));
+	                        changed = true;
+	                    }
+
+	                    float maxAlt = static_cast<float>(settings.rt_guardrail_max_altitude_m);
+	                    if (ImGui::DragFloat("RT max altitude (m)", &maxAlt, 1000.0f, 0.0f, 2.0e6f, "%.0f"))
+	                    {
+	                        settings.rt_guardrail_max_altitude_m = static_cast<double>(std::max(0.0f, maxAlt));
+	                        changed = true;
+	                    }
+	                }
+
+	                if (changed)
+	                {
+	                    planets->set_earth_quadtree_settings(settings);
+	                }
+
+	                const PlanetSystem::EarthDebugStats &s = planets->earth_debug_stats();
+	                ImGui::Separator();
+	                ImGui::Text("Visible patches: %u  (est. tris: %u)", s.visible_patches, s.estimated_triangles);
+	                ImGui::Text("Cache size: %u  (created this frame: %u)", s.patch_cache_size, s.created_patches);
+	                ImGui::Text("Quadtree: max level used %u | visited %u | culled %u | budget-limited %u",
+	                            s.quadtree.max_level_used,
+	                            s.quadtree.nodes_visited,
+	                            s.quadtree.nodes_culled,
+	                            s.quadtree.splits_budget_limited);
+	                ImGui::Text("CPU ms: quadtree %.2f | create %.2f | emit %.2f | total %.2f",
+	                            s.ms_quadtree, s.ms_patch_create, s.ms_emit, s.ms_total);
+	            }
+	        }
+
+        if (moon)
+        {
+            bool vis = moon->visible;
+            if (ImGui::Checkbox("Render Moon", &vis))
+            {
+                moon->visible = vis;
+            }
+            ImGui::SameLine();
+            ImGui::Text("(R=%.1f km)", moon->radius_m / 1000.0);
+        }
+    }
 } // namespace
 
 // Window visibility states for menu-bar toggles
 namespace
 {
-    struct DebugWindowStates
-    {
-        bool show_overview{false};
-        bool show_window{false};
-        bool show_background{false};
-        bool show_particles{false};
-        bool show_shadows{false};
-        bool show_render_graph{false};
-        bool show_pipelines{false};
-        bool show_ibl{false};
-        bool show_postfx{false};
-        bool show_scene{false};
-        bool show_async_assets{false};
-        bool show_textures{false};
-    };
-    static DebugWindowStates g_debug_windows;
+    static bool g_show_debug_window = false;
 } // namespace
 
 void vk_engine_draw_debug_ui(VulkanEngine *eng)
@@ -2068,21 +2387,7 @@ void vk_engine_draw_debug_ui(VulkanEngine *eng)
     {
         if (ImGui::BeginMenu("View"))
         {
-            ImGui::MenuItem("Overview", nullptr, &g_debug_windows.show_overview);
-            ImGui::MenuItem("Window", nullptr, &g_debug_windows.show_window);
-            ImGui::Separator();
-            ImGui::MenuItem("Scene", nullptr, &g_debug_windows.show_scene);
-            ImGui::MenuItem("Render Graph", nullptr, &g_debug_windows.show_render_graph);
-            ImGui::MenuItem("Pipelines", nullptr, &g_debug_windows.show_pipelines);
-            ImGui::Separator();
-            ImGui::MenuItem("Shadows", nullptr, &g_debug_windows.show_shadows);
-            ImGui::MenuItem("IBL", nullptr, &g_debug_windows.show_ibl);
-            ImGui::MenuItem("PostFX", nullptr, &g_debug_windows.show_postfx);
-            ImGui::MenuItem("Background", nullptr, &g_debug_windows.show_background);
-            ImGui::Separator();
-            ImGui::MenuItem("Particles", nullptr, &g_debug_windows.show_particles);
-            ImGui::MenuItem("Textures", nullptr, &g_debug_windows.show_textures);
-            ImGui::MenuItem("Async Assets", nullptr, &g_debug_windows.show_async_assets);
+            ImGui::MenuItem("Engine Debug", nullptr, &g_show_debug_window);
             ImGui::EndMenu();
         }
 
@@ -2096,111 +2401,112 @@ void vk_engine_draw_debug_ui(VulkanEngine *eng)
         ImGui::EndMainMenuBar();
     }
 
-    // Individual debug windows (only shown when toggled)
-    if (g_debug_windows.show_overview)
+    // Single consolidated debug window with tabs
+    if (g_show_debug_window)
     {
-        if (ImGui::Begin("Overview", &g_debug_windows.show_overview))
+        ImGui::SetNextWindowSize(ImVec2(800, 600), ImGuiCond_FirstUseEver);
+        if (ImGui::Begin("Engine Debug", &g_show_debug_window))
         {
-            ui_overview(eng);
-        }
-        ImGui::End();
-    }
+            if (ImGui::BeginTabBar("DebugTabs", ImGuiTabBarFlags_None))
+            {
+                if (ImGui::BeginTabItem("Overview"))
+                {
+                    ui_overview(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_window)
-    {
-        if (ImGui::Begin("Window Settings", &g_debug_windows.show_window))
-        {
-            ui_window(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Scene Editor"))
+                {
+                    ui_scene_editor(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_background)
-    {
-        if (ImGui::Begin("Background", &g_debug_windows.show_background))
-        {
-            ui_background(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Lights"))
+                {
+                    ui_lights(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_particles)
-    {
-        if (ImGui::Begin("Particles", &g_debug_windows.show_particles))
-        {
-            ui_particles(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Picking & Gizmo"))
+                {
+                    ui_picking_gizmo(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_shadows)
-    {
-        if (ImGui::Begin("Shadows", &g_debug_windows.show_shadows))
-        {
-            ui_shadows(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Camera"))
+                {
+                    ui_camera(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_render_graph)
-    {
-        if (ImGui::Begin("Render Graph", &g_debug_windows.show_render_graph))
-        {
-            ui_render_graph(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Planets"))
+                {
+                    ui_planets(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_pipelines)
-    {
-        if (ImGui::Begin("Pipelines", &g_debug_windows.show_pipelines))
-        {
-            ui_pipelines(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Render Graph"))
+                {
+                    ui_render_graph(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_ibl)
-    {
-        if (ImGui::Begin("IBL", &g_debug_windows.show_ibl))
-        {
-            ui_ibl(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Pipelines"))
+                {
+                    ui_pipelines(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_postfx)
-    {
-        if (ImGui::Begin("PostFX", &g_debug_windows.show_postfx))
-        {
-            ui_postfx(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("Shadows"))
+                {
+                    ui_shadows(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_scene)
-    {
-        if (ImGui::Begin("Scene", &g_debug_windows.show_scene))
-        {
-            ui_scene(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("IBL"))
+                {
+                    ui_ibl(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_async_assets)
-    {
-        if (ImGui::Begin("Async Assets", &g_debug_windows.show_async_assets))
-        {
-            ui_async_assets(eng);
-        }
-        ImGui::End();
-    }
+                if (ImGui::BeginTabItem("PostFX"))
+                {
+                    ui_postfx(eng);
+                    ImGui::EndTabItem();
+                }
 
-    if (g_debug_windows.show_textures)
-    {
-        if (ImGui::Begin("Textures", &g_debug_windows.show_textures))
-        {
-            ui_textures(eng);
+                if (ImGui::BeginTabItem("Background"))
+                {
+                    ui_background(eng);
+                    ImGui::EndTabItem();
+                }
+
+                if (ImGui::BeginTabItem("Particles"))
+                {
+                    ui_particles(eng);
+                    ImGui::EndTabItem();
+                }
+
+                if (ImGui::BeginTabItem("Window"))
+                {
+                    ui_window(eng);
+                    ImGui::EndTabItem();
+                }
+
+                if (ImGui::BeginTabItem("Textures"))
+                {
+                    ui_textures(eng);
+                    ImGui::EndTabItem();
+                }
+
+                if (ImGui::BeginTabItem("Async Assets"))
+                {
+                    ui_async_assets(eng);
+                    ImGui::EndTabItem();
+                }
+
+                ImGui::EndTabBar();
+            }
         }
         ImGui::End();
     }

src/core/game_api.cpp

@@ -13,6 +13,7 @@
 #include "core/picking/picking_system.h"
 #include "scene/vk_scene.h"
 #include "scene/camera.h"
+#include "scene/camera/camera_rig.h"
 
 #include <glm/gtx/matrix_decompose.hpp>
 #include <glm/gtx/quaternion.hpp>
@@ -1579,6 +1580,268 @@ void Engine::camera_look_at(const glm::dvec3& target)
     cam.orientation = glm::quat_cast(rot);
 }
 
+namespace
+{
+    ::CameraMode to_internal_camera_mode(GameAPI::CameraMode mode)
+    {
+        switch (mode)
+        {
+            case GameAPI::CameraMode::Free: return ::CameraMode::Free;
+            case GameAPI::CameraMode::Orbit: return ::CameraMode::Orbit;
+            case GameAPI::CameraMode::Follow: return ::CameraMode::Follow;
+            case GameAPI::CameraMode::Chase: return ::CameraMode::Chase;
+            case GameAPI::CameraMode::Fixed: return ::CameraMode::Fixed;
+            default: return ::CameraMode::Free;
+        }
+    }
+
+    GameAPI::CameraMode to_api_camera_mode(::CameraMode mode)
+    {
+        switch (mode)
+        {
+            case ::CameraMode::Free: return GameAPI::CameraMode::Free;
+            case ::CameraMode::Orbit: return GameAPI::CameraMode::Orbit;
+            case ::CameraMode::Follow: return GameAPI::CameraMode::Follow;
+            case ::CameraMode::Chase: return GameAPI::CameraMode::Chase;
+            case ::CameraMode::Fixed: return GameAPI::CameraMode::Fixed;
+            default: return GameAPI::CameraMode::Free;
+        }
+    }
+
+    ::CameraTargetType to_internal_target_type(GameAPI::CameraTargetType type)
+    {
+        switch (type)
+        {
+            case GameAPI::CameraTargetType::None: return ::CameraTargetType::None;
+            case GameAPI::CameraTargetType::WorldPoint: return ::CameraTargetType::WorldPoint;
+            case GameAPI::CameraTargetType::MeshInstance: return ::CameraTargetType::MeshInstance;
+            case GameAPI::CameraTargetType::GLTFInstance: return ::CameraTargetType::GLTFInstance;
+            default: return ::CameraTargetType::None;
+        }
+    }
+
+    GameAPI::CameraTargetType to_api_target_type(::CameraTargetType type)
+    {
+        switch (type)
+        {
+            case ::CameraTargetType::None: return GameAPI::CameraTargetType::None;
+            case ::CameraTargetType::WorldPoint: return GameAPI::CameraTargetType::WorldPoint;
+            case ::CameraTargetType::MeshInstance: return GameAPI::CameraTargetType::MeshInstance;
+            case ::CameraTargetType::GLTFInstance: return GameAPI::CameraTargetType::GLTFInstance;
+            default: return GameAPI::CameraTargetType::None;
+        }
+    }
+
+    ::CameraTarget to_internal_target(const GameAPI::CameraTarget &target)
+    {
+        ::CameraTarget t;
+        t.type = to_internal_target_type(target.type);
+        t.name = target.name;
+        t.world_point = WorldVec3(target.worldPoint);
+        return t;
+    }
+
+    GameAPI::CameraTarget to_api_target(const ::CameraTarget &target)
+    {
+        GameAPI::CameraTarget t;
+        t.type = to_api_target_type(target.type);
+        t.name = target.name;
+        t.worldPoint = glm::dvec3(target.world_point);
+        return t;
+    }
+} // namespace
+
+void Engine::set_camera_mode(CameraMode mode)
+{
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return;
+    }
+
+    SceneManager *scene = _engine->_sceneManager.get();
+    Camera &cam = scene->getMainCamera();
+    CameraRig &rig = scene->getCameraRig();
+
+    if (_engine->_input)
+    {
+        _engine->_input->set_cursor_mode(CursorMode::Normal);
+    }
+
+    rig.set_mode(to_internal_camera_mode(mode), *scene, cam);
+}
+
+CameraMode Engine::get_camera_mode() const
+{
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return CameraMode::Free;
+    }
+    return to_api_camera_mode(_engine->_sceneManager->getCameraRig().mode());
+}
+
+void Engine::set_free_camera_settings(const FreeCameraSettings& settings)
+{
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return;
+    }
+
+    ::FreeCameraSettings &s = _engine->_sceneManager->getCameraRig().free_settings();
+    s.move_speed = settings.moveSpeed;
+    s.look_sensitivity = settings.lookSensitivity;
+    s.roll_speed = settings.rollSpeed;
+}
+
+FreeCameraSettings Engine::get_free_camera_settings() const
+{
+    FreeCameraSettings out{};
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return out;
+    }
+
+    const ::FreeCameraSettings &s = _engine->_sceneManager->getCameraRig().free_settings();
+    out.moveSpeed = s.move_speed;
+    out.lookSensitivity = s.look_sensitivity;
+    out.rollSpeed = s.roll_speed;
+    return out;
+}
+
+void Engine::set_orbit_camera_settings(const OrbitCameraSettings& settings)
+{
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return;
+    }
+
+    ::OrbitCameraSettings &s = _engine->_sceneManager->getCameraRig().orbit_settings();
+    s.target = to_internal_target(settings.target);
+    s.distance = settings.distance;
+    s.yaw = settings.yaw;
+    s.pitch = settings.pitch;
+    s.look_sensitivity = settings.lookSensitivity;
+}
+
+OrbitCameraSettings Engine::get_orbit_camera_settings() const
+{
+    OrbitCameraSettings out{};
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return out;
+    }
+
+    const ::OrbitCameraSettings &s = _engine->_sceneManager->getCameraRig().orbit_settings();
+    out.target = to_api_target(s.target);
+    out.distance = s.distance;
+    out.yaw = s.yaw;
+    out.pitch = s.pitch;
+    out.lookSensitivity = s.look_sensitivity;
+    return out;
+}
+
+void Engine::set_follow_camera_settings(const FollowCameraSettings& settings)
+{
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return;
+    }
+
+    ::FollowCameraSettings &s = _engine->_sceneManager->getCameraRig().follow_settings();
+    s.target = to_internal_target(settings.target);
+    s.position_offset_local = settings.positionOffsetLocal;
+    s.rotation_offset = settings.rotationOffset;
+}
+
+FollowCameraSettings Engine::get_follow_camera_settings() const
+{
+    FollowCameraSettings out{};
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return out;
+    }
+
+    const ::FollowCameraSettings &s = _engine->_sceneManager->getCameraRig().follow_settings();
+    out.target = to_api_target(s.target);
+    out.positionOffsetLocal = s.position_offset_local;
+    out.rotationOffset = s.rotation_offset;
+    return out;
+}
+
+void Engine::set_chase_camera_settings(const ChaseCameraSettings& settings)
+{
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return;
+    }
+
+    ::ChaseCameraSettings &s = _engine->_sceneManager->getCameraRig().chase_settings();
+    s.target = to_internal_target(settings.target);
+    s.position_offset_local = settings.positionOffsetLocal;
+    s.rotation_offset = settings.rotationOffset;
+    s.position_lag = settings.positionLag;
+    s.rotation_lag = settings.rotationLag;
+}
+
+ChaseCameraSettings Engine::get_chase_camera_settings() const
+{
+    ChaseCameraSettings out{};
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return out;
+    }
+
+    const ::ChaseCameraSettings &s = _engine->_sceneManager->getCameraRig().chase_settings();
+    out.target = to_api_target(s.target);
+    out.positionOffsetLocal = s.position_offset_local;
+    out.rotationOffset = s.rotation_offset;
+    out.positionLag = s.position_lag;
+    out.rotationLag = s.rotation_lag;
+    return out;
+}
+
+bool Engine::set_camera_target_from_last_pick()
+{
+    if (!_engine || !_engine->_sceneManager)
+    {
+        return false;
+    }
+
+    const PickingSystem *picking = _engine->picking();
+    if (!picking)
+    {
+        return false;
+    }
+
+    const auto &pick = picking->last_pick();
+    if (!pick.valid)
+    {
+        return false;
+    }
+
+    ::CameraTarget t;
+    if (pick.ownerType == RenderObject::OwnerType::MeshInstance)
+    {
+        t.type = ::CameraTargetType::MeshInstance;
+        t.name = pick.ownerName;
+    }
+    else if (pick.ownerType == RenderObject::OwnerType::GLTFInstance)
+    {
+        t.type = ::CameraTargetType::GLTFInstance;
+        t.name = pick.ownerName;
+    }
+    else
+    {
+        t.type = ::CameraTargetType::WorldPoint;
+        t.world_point = pick.worldPos;
+    }
+
+    CameraRig &rig = _engine->_sceneManager->getCameraRig();
+    rig.orbit_settings().target = t;
+    rig.follow_settings().target = t;
+    rig.chase_settings().target = t;
+    return true;
+}
+
 // ----------------------------------------------------------------------------
 // Rendering
 // ----------------------------------------------------------------------------

src/core/game_api.h

@@ -304,6 +304,66 @@ struct Stats
     int drawCallCount{0};
 };
 
+// ============================================================================
+// Camera Rig Types
+// ============================================================================
+
+enum class CameraMode : uint8_t
+{
+    Free = 0,
+    Orbit = 1,
+    Follow = 2,
+    Chase = 3,
+    Fixed = 4
+};
+
+enum class CameraTargetType : uint8_t
+{
+    None = 0,
+    WorldPoint = 1,
+    MeshInstance = 2,
+    GLTFInstance = 3
+};
+
+struct CameraTarget
+{
+    CameraTargetType type{CameraTargetType::None};
+    std::string name{};
+    glm::dvec3 worldPoint{0.0, 0.0, 0.0};
+};
+
+struct FreeCameraSettings
+{
+    float moveSpeed{1.8f};        // world units / second
+    float lookSensitivity{0.0020f};
+    float rollSpeed{1.0f};        // radians / second
+};
+
+struct OrbitCameraSettings
+{
+    CameraTarget target{};
+    double distance{10.0};
+    float yaw{0.0f};              // radians
+    float pitch{0.0f};            // radians
+    float lookSensitivity{0.0020f};
+};
+
+struct FollowCameraSettings
+{
+    CameraTarget target{};
+    glm::vec3 positionOffsetLocal{0.0f, 2.0f, 6.0f};
+    glm::quat rotationOffset{1.0f, 0.0f, 0.0f, 0.0f};
+};
+
+struct ChaseCameraSettings
+{
+    CameraTarget target{};
+    glm::vec3 positionOffsetLocal{0.0f, 2.0f, 6.0f};
+    glm::quat rotationOffset{1.0f, 0.0f, 0.0f, 0.0f};
+    float positionLag{8.0f};      // smoothing rate (1/sec), higher = snappier
+    float rotationLag{10.0f};     // smoothing rate (1/sec)
+};
+
 // ============================================================================
 // Main API Class
 // ============================================================================
@@ -651,6 +711,25 @@ public:
     void camera_look_at(const glm::vec3& target);
     void camera_look_at(const glm::dvec3& target);
 
+    // Camera mode and per-mode settings
+    void set_camera_mode(CameraMode mode);
+    CameraMode get_camera_mode() const;
+
+    void set_free_camera_settings(const FreeCameraSettings& settings);
+    FreeCameraSettings get_free_camera_settings() const;
+
+    void set_orbit_camera_settings(const OrbitCameraSettings& settings);
+    OrbitCameraSettings get_orbit_camera_settings() const;
+
+    void set_follow_camera_settings(const FollowCameraSettings& settings);
+    FollowCameraSettings get_follow_camera_settings() const;
+
+    void set_chase_camera_settings(const ChaseCameraSettings& settings);
+    ChaseCameraSettings get_chase_camera_settings() const;
+
+    // Convenience: set Orbit/Follow/Chase target from the engine's last pick.
+    bool set_camera_target_from_last_pick();
+
     // ------------------------------------------------------------------------
     // Rendering
     // ------------------------------------------------------------------------

src/core/pipeline/sampler.cpp

@@ -29,6 +29,13 @@ void SamplerManager::init(DeviceManager *deviceManager)
     sampl.minFilter = VK_FILTER_LINEAR;
     vkCreateSampler(_deviceManager->device(), &sampl, nullptr, &_defaultSamplerLinear);
 
+    // Linear clamp-to-edge (useful for tiled textures)
+    VkSamplerCreateInfo clampEdge = sampl;
+    clampEdge.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+    clampEdge.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+    clampEdge.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE;
+    vkCreateSampler(_deviceManager->device(), &clampEdge, nullptr, &_linearClampEdge);
+
     // Shadow linear clamp sampler (border=white)
     VkSamplerCreateInfo sh = sampl;
     sh.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER;
@@ -60,4 +67,10 @@ void SamplerManager::cleanup()
         vkDestroySampler(_deviceManager->device(), _shadowLinearClamp, nullptr);
         _shadowLinearClamp = VK_NULL_HANDLE;
     }
+
+    if (_linearClampEdge)
+    {
+        vkDestroySampler(_deviceManager->device(), _linearClampEdge, nullptr);
+        _linearClampEdge = VK_NULL_HANDLE;
+    }
 }

src/core/pipeline/sampler.h

@@ -14,6 +14,7 @@ public:
     VkSampler defaultLinear() const { return _defaultSamplerLinear; }
     VkSampler defaultNearest() const { return _defaultSamplerNearest; }
     VkSampler shadowLinearClamp() const { return _shadowLinearClamp; }
+    VkSampler linearClampEdge() const { return _linearClampEdge; }
 
 
 private:
@@ -21,4 +22,5 @@ private:
     VkSampler _defaultSamplerLinear = VK_NULL_HANDLE;
     VkSampler _defaultSamplerNearest = VK_NULL_HANDLE;
     VkSampler _shadowLinearClamp = VK_NULL_HANDLE;
+    VkSampler _linearClampEdge = VK_NULL_HANDLE;
 };

src/main.cpp

@@ -33,6 +33,16 @@ public:
             api.load_global_ibl(ibl);
         }
 
+        // Planet demo defaults (Milestone A): start outside Earth and speed up the free camera.
+        {
+            constexpr double kEarthRadiusM = 6378137.0;
+            GameAPI::FreeCameraSettings free = api.get_free_camera_settings();
+            free.moveSpeed = 20000.0f;
+            api.set_free_camera_settings(free);
+
+            api.set_camera_position(glm::dvec3(0.0, 0.0, kEarthRadiusM + 1.0e6));
+            api.camera_look_at(glm::dvec3(0.0, 0.0, 0.0));
+        }
 
         // Load a glTF model asynchronously
         // api.add_gltf_instance_async("example_model", "models/example.gltf",

src/runtime/game_runtime.cpp

@@ -128,7 +128,7 @@ namespace GameRuntime
             // --- Camera input (if not captured by UI) ---
             if (_renderer->_sceneManager && input)
             {
-                _renderer->_sceneManager->getMainCamera().process_input(*input, ui_capture_keyboard, ui_capture_mouse);
+                _renderer->_sceneManager->getCameraRig().process_input(*input, ui_capture_keyboard, ui_capture_mouse);
             }
 
             // --- Throttle when minimized ---

src/scene/camera.cpp

@@ -1,102 +1,6 @@
 #include "camera.h"
 #include <glm/gtx/transform.hpp>
 #include <glm/gtx/quaternion.hpp>
-#include <algorithm>
-#include <cmath>
-
-void Camera::update()
-{
-    glm::mat4 cameraRotation = getRotationMatrix();
-    glm::vec3 delta = glm::vec3(cameraRotation * glm::vec4(velocity * moveSpeed, 0.f));
-    position_world += glm::dvec3(delta);
-}
-
-void Camera::process_input(InputSystem &input, bool ui_capture_keyboard, bool ui_capture_mouse)
-{
-    const InputState &st = input.state();
-
-    // Movement is state-based so simultaneous keys work naturally.
-    if (ui_capture_keyboard)
-    {
-        velocity = glm::vec3(0.0f);
-    }
-    else
-    {
-        glm::vec3 v(0.0f);
-        if (st.key_down(Key::W)) { v.z -= 1.0f; }
-        if (st.key_down(Key::S)) { v.z += 1.0f; }
-        if (st.key_down(Key::A)) { v.x -= 1.0f; }
-        if (st.key_down(Key::D)) { v.x += 1.0f; }
-        velocity = v;
-    }
-
-    // Event-based mouse handling so we don't apply motion that happened before RMB was pressed in the same frame.
-    for (const InputEvent &e : input.events())
-    {
-        if (ui_capture_mouse)
-        {
-            continue;
-        }
-
-        if (e.type == InputEvent::Type::MouseButtonDown && e.mouse_button == MouseButton::Right)
-        {
-            rmbDown = true;
-            input.set_cursor_mode(CursorMode::Relative);
-        }
-        else if (e.type == InputEvent::Type::MouseButtonUp && e.mouse_button == MouseButton::Right)
-        {
-            rmbDown = false;
-            input.set_cursor_mode(CursorMode::Normal);
-        }
-        else if (e.type == InputEvent::Type::MouseMove && rmbDown)
-        {
-            // Convert mouse motion to incremental yaw/pitch angles.
-            float dx = e.mouse_delta.x * lookSensitivity;
-            float dy = e.mouse_delta.y * lookSensitivity;
-
-            // Mouse right (xrel > 0) turns view right with -Z-forward: yaw around +Y.
-            glm::quat yawRotation = glm::angleAxis(dx, glm::vec3 { 0.f, 1.f, 0.f });
-
-            // Mouse up (yrel < 0) looks up with -Z-forward: negative dy.
-            float pitchDelta = -dy;
-            // Pitch around the camera's local X (right) axis in world space.
-            glm::vec3 right = glm::rotate(orientation, glm::vec3 { 1.f, 0.f, 0.f });
-            glm::quat pitchRotation = glm::angleAxis(pitchDelta, glm::vec3(right));
-
-            // Apply yaw, then pitch, to the current orientation.
-            orientation = glm::normalize(pitchRotation * yawRotation * orientation);
-        }
-        else if (e.type == InputEvent::Type::MouseWheel)
-        {
-            const float steps = e.wheel_delta.y; // positive = wheel up
-            if (std::abs(steps) < 0.001f)
-            {
-                continue;
-            }
-
-            // Ctrl modifies FOV, otherwise adjust move speed
-            if (e.mods.ctrl)
-            {
-                // Wheel up -> zoom in (smaller FOV)
-                fovDegrees -= steps * 2.0f;
-                fovDegrees = std::clamp(fovDegrees, 30.0f, 110.0f);
-            }
-            else
-            {
-                // Exponential scale for pleasant feel
-                float factor = std::pow(1.15f, steps);
-                moveSpeed = std::clamp(moveSpeed * factor, 0.001f, 5.0f);
-            }
-        }
-    }
-
-    // Safety: if mouse state shows RMB is no longer down, release relative mode.
-    if (rmbDown && !st.mouse_down(MouseButton::Right))
-    {
-        rmbDown = false;
-        input.set_cursor_mode(CursorMode::Normal);
-    }
-}
 
 glm::mat4 Camera::getViewMatrix(const glm::vec3 &position_local) const
 {

src/scene/camera.h

@@ -2,29 +2,15 @@
 
 #include <core/types.h>
 
-#include <core/input/input_system.h>
-
-#include "glm/vec3.hpp"
-
 class Camera {
 public:
-    glm::vec3 velocity{0.0f, 0.0f, 0.0f};
     glm::dvec3 position_world{0.0, 0.0, 0.0};
     // Orientation stored as a quaternion (local -> world).
     glm::quat orientation { 1.0f, 0.0f, 0.0f, 0.0f };
 
-    // Movement/look tuning
-    float moveSpeed { 0.03f };
-    float lookSensitivity { 0.0020f };
-    bool rmbDown { false };
-
     // Field of view in degrees for projection
     float fovDegrees { 50.f };
 
     glm::mat4 getViewMatrix(const glm::vec3 &position_local) const;
     glm::mat4 getRotationMatrix() const;
-
-    void process_input(InputSystem &input, bool ui_capture_keyboard, bool ui_capture_mouse);
-
-    void update();
 };

src/scene/camera/camera_rig.cpp

@@ -0,0 +1,129 @@
+#include "camera_rig.h"
+
+#include <scene/camera/mode_chase.h>
+#include <scene/camera/mode_fixed.h>
+#include <scene/camera/mode_follow.h>
+#include <scene/camera/mode_free.h>
+#include <scene/camera/mode_orbit.h>
+#include <scene/camera.h>
+#include <scene/vk_scene.h>
+
+#include <core/input/input_system.h>
+
+namespace
+{
+    std::unique_ptr<ICameraMode> make_mode(CameraMode mode,
+                                           FreeCameraSettings &free_settings,
+                                           OrbitCameraSettings &orbit_settings,
+                                           FollowCameraSettings &follow_settings,
+                                           ChaseCameraSettings &chase_settings,
+                                           FixedCameraSettings &fixed_settings)
+    {
+        switch (mode)
+        {
+            case CameraMode::Free: return std::make_unique<FreeCameraMode>(free_settings);
+            case CameraMode::Orbit: return std::make_unique<OrbitCameraMode>(orbit_settings);
+            case CameraMode::Follow: return std::make_unique<FollowCameraMode>(follow_settings);
+            case CameraMode::Chase: return std::make_unique<ChaseCameraMode>(chase_settings);
+            case CameraMode::Fixed: return std::make_unique<FixedCameraMode>(fixed_settings);
+            default: return std::make_unique<FreeCameraMode>(free_settings);
+        }
+    }
+} // namespace
+
+CameraRig::CameraRig() = default;
+CameraRig::~CameraRig() = default;
+
+void CameraRig::init(SceneManager &scene, Camera &camera)
+{
+    _scene = &scene;
+    _camera = &camera;
+    recreate_mode(scene, camera);
+}
+
+void CameraRig::set_mode(CameraMode mode, SceneManager &scene, Camera &camera)
+{
+    if (_mode == mode)
+    {
+        return;
+    }
+    _mode = mode;
+    recreate_mode(scene, camera);
+}
+
+const char *CameraRig::mode_name() const
+{
+    if (_mode_impl)
+    {
+        return _mode_impl->name();
+    }
+    return "None";
+}
+
+void CameraRig::process_input(InputSystem &input, bool ui_capture_keyboard, bool ui_capture_mouse)
+{
+    if (_mode_impl && _scene && _camera)
+    {
+        _mode_impl->process_input(*_scene, *_camera, input, ui_capture_keyboard, ui_capture_mouse);
+    }
+}
+
+void CameraRig::update(SceneManager &scene, Camera &camera, float dt)
+{
+    if (_mode_impl)
+    {
+        _mode_impl->update(scene, camera, dt);
+    }
+}
+
+bool CameraRig::resolve_target(SceneManager &scene,
+                               const CameraTarget &target,
+                               WorldVec3 &out_position_world,
+                               glm::quat &out_rotation) const
+{
+    out_rotation = glm::quat(1.0f, 0.0f, 0.0f, 0.0f);
+
+    switch (target.type)
+    {
+        case CameraTargetType::WorldPoint:
+            out_position_world = target.world_point;
+            return true;
+        case CameraTargetType::MeshInstance:
+        {
+            WorldVec3 t{};
+            glm::quat r{};
+            glm::vec3 s{};
+            if (!scene.getMeshInstanceTRSWorld(target.name, t, r, s))
+            {
+                return false;
+            }
+            out_position_world = t;
+            out_rotation = r;
+            return true;
+        }
+        case CameraTargetType::GLTFInstance:
+        {
+            WorldVec3 t{};
+            glm::quat r{};
+            glm::vec3 s{};
+            if (!scene.getGLTFInstanceTRSWorld(target.name, t, r, s))
+            {
+                return false;
+            }
+            out_position_world = t;
+            out_rotation = r;
+            return true;
+        }
+        default:
+            return false;
+    }
+}
+
+void CameraRig::recreate_mode(SceneManager &scene, Camera &camera)
+{
+    _mode_impl = make_mode(_mode, _free, _orbit, _follow, _chase, _fixed);
+    if (_mode_impl)
+    {
+        _mode_impl->on_activate(scene, camera);
+    }
+}

src/scene/camera/camera_rig.h

@@ -0,0 +1,124 @@
+#pragma once
+
+#include <core/world.h>
+
+#include <glm/gtc/quaternion.hpp>
+
+#include <cstdint>
+#include <memory>
+#include <string>
+
+class Camera;
+class InputSystem;
+class SceneManager;
+
+enum class CameraMode : uint8_t
+{
+    Free = 0,
+    Orbit = 1,
+    Follow = 2,
+    Chase = 3,
+    Fixed = 4
+};
+
+enum class CameraTargetType : uint8_t
+{
+    None = 0,
+    WorldPoint = 1,
+    MeshInstance = 2,
+    GLTFInstance = 3
+};
+
+struct CameraTarget
+{
+    CameraTargetType type{CameraTargetType::None};
+    std::string name{};
+    WorldVec3 world_point{0.0, 0.0, 0.0};
+};
+
+struct FreeCameraSettings
+{
+    float move_speed{1.8f};      // world units / second
+    float look_sensitivity{0.0020f};
+    float roll_speed{1.0f};      // radians / second
+};
+
+struct OrbitCameraSettings
+{
+    CameraTarget target{};
+    double distance{10.0};
+    float yaw{0.0f};             // radians
+    float pitch{0.0f};           // radians
+    float look_sensitivity{0.0020f};
+};
+
+struct FollowCameraSettings
+{
+    CameraTarget target{};
+    glm::vec3 position_offset_local{0.0f, 2.0f, 6.0f};
+    glm::quat rotation_offset{1.0f, 0.0f, 0.0f, 0.0f};
+};
+
+struct ChaseCameraSettings
+{
+    CameraTarget target{};
+    glm::vec3 position_offset_local{0.0f, 2.0f, 6.0f};
+    glm::quat rotation_offset{1.0f, 0.0f, 0.0f, 0.0f};
+    float position_lag{8.0f};    // smoothing rate (1/sec), higher = snappier
+    float rotation_lag{10.0f};   // smoothing rate (1/sec)
+};
+
+struct FixedCameraSettings
+{
+};
+
+class CameraRig
+{
+public:
+    CameraRig();
+    ~CameraRig();
+
+    CameraRig(const CameraRig &) = delete;
+    CameraRig &operator=(const CameraRig &) = delete;
+
+    void init(SceneManager &scene, Camera &camera);
+
+    CameraMode mode() const { return _mode; }
+    void set_mode(CameraMode mode, SceneManager &scene, Camera &camera);
+
+    const char *mode_name() const;
+
+    FreeCameraSettings &free_settings() { return _free; }
+    OrbitCameraSettings &orbit_settings() { return _orbit; }
+    FollowCameraSettings &follow_settings() { return _follow; }
+    ChaseCameraSettings &chase_settings() { return _chase; }
+    FixedCameraSettings &fixed_settings() { return _fixed; }
+
+    const FreeCameraSettings &free_settings() const { return _free; }
+    const OrbitCameraSettings &orbit_settings() const { return _orbit; }
+    const FollowCameraSettings &follow_settings() const { return _follow; }
+    const ChaseCameraSettings &chase_settings() const { return _chase; }
+    const FixedCameraSettings &fixed_settings() const { return _fixed; }
+
+    void process_input(InputSystem &input, bool ui_capture_keyboard, bool ui_capture_mouse);
+    void update(SceneManager &scene, Camera &camera, float dt);
+
+    bool resolve_target(SceneManager &scene,
+                        const CameraTarget &target,
+                        WorldVec3 &out_position_world,
+                        glm::quat &out_rotation) const;
+
+private:
+    void recreate_mode(SceneManager &scene, Camera &camera);
+
+    CameraMode _mode{CameraMode::Free};
+    std::unique_ptr<class ICameraMode> _mode_impl;
+    SceneManager *_scene = nullptr;
+    Camera *_camera = nullptr;
+
+    FreeCameraSettings _free{};
+    OrbitCameraSettings _orbit{};
+    FollowCameraSettings _follow{};
+    ChaseCameraSettings _chase{};
+    FixedCameraSettings _fixed{};
+};

src/scene/camera/icamera_mode.h

@@ -0,0 +1,20 @@
+#pragma once
+
+class Camera;
+class InputSystem;
+class SceneManager;
+
+class ICameraMode
+{
+public:
+    virtual ~ICameraMode() = default;
+
+    virtual const char *name() const = 0;
+    virtual void on_activate(SceneManager &scene, Camera &camera) = 0;
+    virtual void process_input(SceneManager &scene,
+                               Camera &camera,
+                               InputSystem &input,
+                               bool ui_capture_keyboard,
+                               bool ui_capture_mouse) = 0;
+    virtual void update(SceneManager &scene, Camera &camera, float dt) = 0;
+};

src/scene/camera/mode_chase.cpp

@@ -0,0 +1,74 @@
+#include "mode_chase.h"
+
+#include <scene/camera/camera_rig.h>
+#include <scene/camera.h>
+#include <scene/vk_scene.h>
+
+#include <glm/gtx/quaternion.hpp>
+
+#include <cmath>
+
+ChaseCameraMode::ChaseCameraMode(ChaseCameraSettings &settings)
+    : _settings(settings)
+{
+}
+
+void ChaseCameraMode::on_activate(SceneManager &scene, Camera &camera)
+{
+    // If no target set, chase a point in front of the camera.
+    if (_settings.target.type == CameraTargetType::None)
+    {
+        glm::vec3 forward = glm::rotate(camera.orientation, glm::vec3(0.0f, 0.0f, -1.0f));
+        _settings.target.type = CameraTargetType::WorldPoint;
+        _settings.target.world_point = camera.position_world + WorldVec3(forward) * 10.0;
+    }
+
+    // Preserve current relative transform to the target when possible.
+    WorldVec3 target_pos{};
+    glm::quat target_rot{};
+    if (!scene.getCameraRig().resolve_target(scene, _settings.target, target_pos, target_rot))
+    {
+        return;
+    }
+
+    glm::quat inv_target = glm::inverse(target_rot);
+    glm::vec3 rel_pos = glm::vec3(camera.position_world - target_pos);
+    _settings.position_offset_local = glm::rotate(inv_target, rel_pos);
+    _settings.rotation_offset = glm::normalize(inv_target * camera.orientation);
+}
+
+void ChaseCameraMode::process_input(SceneManager & /*scene*/,
+                                    Camera & /*camera*/,
+                                    InputSystem & /*input*/,
+                                    bool /*ui_capture_keyboard*/,
+                                    bool /*ui_capture_mouse*/)
+{
+}
+
+void ChaseCameraMode::update(SceneManager &scene, Camera &camera, float dt)
+{
+    WorldVec3 target_pos{};
+    glm::quat target_rot{};
+    if (!scene.getCameraRig().resolve_target(scene, _settings.target, target_pos, target_rot))
+    {
+        return;
+    }
+
+    glm::vec3 offset_world = glm::rotate(target_rot, _settings.position_offset_local);
+    WorldVec3 desired_pos = target_pos + WorldVec3(offset_world);
+    glm::quat desired_rot = glm::normalize(target_rot * _settings.rotation_offset);
+
+    if (dt > 0.0f)
+    {
+        float pos_alpha = 1.0f - std::exp(-_settings.position_lag * dt);
+        float rot_alpha = 1.0f - std::exp(-_settings.rotation_lag * dt);
+
+        camera.position_world += (desired_pos - camera.position_world) * static_cast<double>(pos_alpha);
+        camera.orientation = glm::normalize(glm::slerp(camera.orientation, desired_rot, rot_alpha));
+    }
+    else
+    {
+        camera.position_world = desired_pos;
+        camera.orientation = desired_rot;
+    }
+}

src/scene/camera/mode_chase.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <scene/camera/icamera_mode.h>
+
+struct ChaseCameraSettings;
+
+class ChaseCameraMode : public ICameraMode
+{
+public:
+    explicit ChaseCameraMode(ChaseCameraSettings &settings);
+    ~ChaseCameraMode() override = default;
+
+    const char *name() const override { return "Chase"; }
+    void on_activate(SceneManager &scene, Camera &camera) override;
+    void process_input(SceneManager &scene,
+                       Camera &camera,
+                       InputSystem &input,
+                       bool ui_capture_keyboard,
+                       bool ui_capture_mouse) override;
+    void update(SceneManager &scene, Camera &camera, float dt) override;
+
+private:
+    ChaseCameraSettings &_settings;
+};

src/scene/camera/mode_fixed.cpp

@@ -0,0 +1,25 @@
+#include "mode_fixed.h"
+
+#include <scene/camera/camera_rig.h>
+
+FixedCameraMode::FixedCameraMode(FixedCameraSettings &settings)
+    : _settings(settings)
+{
+}
+
+void FixedCameraMode::on_activate(SceneManager & /*scene*/, Camera & /*camera*/)
+{
+}
+
+void FixedCameraMode::process_input(SceneManager & /*scene*/,
+                                    Camera & /*camera*/,
+                                    InputSystem & /*input*/,
+                                    bool /*ui_capture_keyboard*/,
+                                    bool /*ui_capture_mouse*/)
+{
+}
+
+void FixedCameraMode::update(SceneManager & /*scene*/, Camera & /*camera*/, float /*dt*/)
+{
+    (void)_settings;
+}

src/scene/camera/mode_fixed.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <scene/camera/icamera_mode.h>
+
+struct FixedCameraSettings;
+
+class FixedCameraMode : public ICameraMode
+{
+public:
+    explicit FixedCameraMode(FixedCameraSettings &settings);
+    ~FixedCameraMode() override = default;
+
+    const char *name() const override { return "Fixed"; }
+    void on_activate(SceneManager &scene, Camera &camera) override;
+    void process_input(SceneManager &scene,
+                       Camera &camera,
+                       InputSystem &input,
+                       bool ui_capture_keyboard,
+                       bool ui_capture_mouse) override;
+    void update(SceneManager &scene, Camera &camera, float dt) override;
+
+private:
+    FixedCameraSettings &_settings;
+};

src/scene/camera/mode_follow.cpp

@@ -0,0 +1,58 @@
+#include "mode_follow.h"
+
+#include <scene/camera/camera_rig.h>
+#include <scene/camera.h>
+#include <scene/vk_scene.h>
+
+#include <glm/gtx/quaternion.hpp>
+
+FollowCameraMode::FollowCameraMode(FollowCameraSettings &settings)
+    : _settings(settings)
+{
+}
+
+void FollowCameraMode::on_activate(SceneManager &scene, Camera &camera)
+{
+    // If no target set, follow a point in front of the camera.
+    if (_settings.target.type == CameraTargetType::None)
+    {
+        glm::vec3 forward = glm::rotate(camera.orientation, glm::vec3(0.0f, 0.0f, -1.0f));
+        _settings.target.type = CameraTargetType::WorldPoint;
+        _settings.target.world_point = camera.position_world + WorldVec3(forward) * 10.0;
+    }
+
+    // Preserve current relative transform to the target when possible.
+    WorldVec3 target_pos{};
+    glm::quat target_rot{};
+    if (!scene.getCameraRig().resolve_target(scene, _settings.target, target_pos, target_rot))
+    {
+        return;
+    }
+
+    glm::quat inv_target = glm::inverse(target_rot);
+    glm::vec3 rel_pos = glm::vec3(camera.position_world - target_pos);
+    _settings.position_offset_local = glm::rotate(inv_target, rel_pos);
+    _settings.rotation_offset = glm::normalize(inv_target * camera.orientation);
+}
+
+void FollowCameraMode::process_input(SceneManager & /*scene*/,
+                                     Camera & /*camera*/,
+                                     InputSystem & /*input*/,
+                                     bool /*ui_capture_keyboard*/,
+                                     bool /*ui_capture_mouse*/)
+{
+}
+
+void FollowCameraMode::update(SceneManager &scene, Camera &camera, float /*dt*/)
+{
+    WorldVec3 target_pos{};
+    glm::quat target_rot{};
+    if (!scene.getCameraRig().resolve_target(scene, _settings.target, target_pos, target_rot))
+    {
+        return;
+    }
+
+    glm::vec3 offset_world = glm::rotate(target_rot, _settings.position_offset_local);
+    camera.position_world = target_pos + WorldVec3(offset_world);
+    camera.orientation = glm::normalize(target_rot * _settings.rotation_offset);
+}

src/scene/camera/mode_follow.h

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <scene/camera/icamera_mode.h>
+
+struct FollowCameraSettings;
+
+class FollowCameraMode : public ICameraMode
+{
+public:
+    explicit FollowCameraMode(FollowCameraSettings &settings);
+    ~FollowCameraMode() override = default;
+
+    const char *name() const override { return "Follow"; }
+    void on_activate(SceneManager &scene, Camera &camera) override;
+    void process_input(SceneManager &scene,
+                       Camera &camera,
+                       InputSystem &input,
+                       bool ui_capture_keyboard,
+                       bool ui_capture_mouse) override;
+    void update(SceneManager &scene, Camera &camera, float dt) override;
+
+private:
+    FollowCameraSettings &_settings;
+};

src/scene/camera/mode_free.cpp

@@ -0,0 +1,147 @@
+#include "mode_free.h"
+
+#include <scene/camera/camera_rig.h>
+#include <scene/camera.h>
+
+#include <core/input/input_system.h>
+
+#include <glm/gtx/quaternion.hpp>
+
+#include <algorithm>
+#include <cmath>
+
+FreeCameraMode::FreeCameraMode(FreeCameraSettings &settings)
+    : _settings(settings)
+{
+}
+
+void FreeCameraMode::on_activate(SceneManager & /*scene*/, Camera & /*camera*/)
+{
+    _velocity = glm::vec3(0.0f);
+    _roll_dir = 0.0f;
+    _rmb_down = false;
+}
+
+void FreeCameraMode::process_input(SceneManager & /*scene*/,
+                                   Camera &camera,
+                                   InputSystem &input,
+                                   bool ui_capture_keyboard,
+                                   bool ui_capture_mouse)
+{
+    const InputState &st = input.state();
+
+    // Movement is state-based so simultaneous keys work naturally.
+    if (ui_capture_keyboard)
+    {
+        _velocity = glm::vec3(0.0f);
+        _roll_dir = 0.0f;
+    }
+    else
+    {
+        glm::vec3 v(0.0f);
+        if (st.key_down(Key::W)) { v.z -= 1.0f; }
+        if (st.key_down(Key::S)) { v.z += 1.0f; }
+        if (st.key_down(Key::A)) { v.x -= 1.0f; }
+        if (st.key_down(Key::D)) { v.x += 1.0f; }
+        _velocity = v;
+
+        float roll = 0.0f;
+        if (st.key_down(Key::Q)) { roll -= 1.0f; }
+        if (st.key_down(Key::E)) { roll += 1.0f; }
+        _roll_dir = roll;
+    }
+
+    // Event-based mouse handling so we don't apply motion that happened
+    // before RMB was pressed in the same frame.
+    for (const InputEvent &e : input.events())
+    {
+        if (ui_capture_mouse)
+        {
+            continue;
+        }
+
+        if (e.type == InputEvent::Type::MouseButtonDown && e.mouse_button == MouseButton::Right)
+        {
+            _rmb_down = true;
+            input.set_cursor_mode(CursorMode::Relative);
+        }
+        else if (e.type == InputEvent::Type::MouseButtonUp && e.mouse_button == MouseButton::Right)
+        {
+            _rmb_down = false;
+            input.set_cursor_mode(CursorMode::Normal);
+        }
+        else if (e.type == InputEvent::Type::MouseMove && _rmb_down)
+        {
+            // Convert mouse motion to incremental yaw/pitch angles.
+            float dx = e.mouse_delta.x * _settings.look_sensitivity;
+            float dy = e.mouse_delta.y * _settings.look_sensitivity;
+
+            // Mouse right (xrel > 0) turns view right with -Z-forward: yaw around +Y.
+            glm::quat yaw_rotation = glm::angleAxis(dx, glm::vec3{0.f, 1.f, 0.f});
+
+            // Mouse up (yrel < 0) looks up with -Z-forward: negative dy.
+            float pitch_delta = -dy;
+            // Pitch around the camera's local X (right) axis in world space.
+            glm::vec3 right = glm::rotate(camera.orientation, glm::vec3{1.f, 0.f, 0.f});
+            glm::quat pitch_rotation = glm::angleAxis(pitch_delta, glm::vec3(right));
+
+            // Apply yaw, then pitch, to the current orientation.
+            camera.orientation = glm::normalize(pitch_rotation * yaw_rotation * camera.orientation);
+        }
+        else if (e.type == InputEvent::Type::MouseWheel)
+        {
+            const float steps = e.wheel_delta.y; // positive = wheel up
+            if (std::abs(steps) < 0.001f)
+            {
+                continue;
+            }
+
+            // Ctrl modifies FOV, otherwise adjust move speed.
+            if (e.mods.ctrl)
+            {
+                // Wheel up -> zoom in (smaller FOV)
+                camera.fovDegrees -= steps * 2.0f;
+                camera.fovDegrees = std::clamp(camera.fovDegrees, 30.0f, 110.0f);
+            }
+            else
+            {
+                // Exponential scale for pleasant feel
+                float factor = std::pow(1.15f, steps);
+                _settings.move_speed = std::clamp(_settings.move_speed * factor, 0.06f, 300.0f);
+            }
+        }
+    }
+
+    // Safety: if mouse state shows RMB is no longer down, release relative mode.
+    if (_rmb_down && !st.mouse_down(MouseButton::Right))
+    {
+        _rmb_down = false;
+        input.set_cursor_mode(CursorMode::Normal);
+    }
+}
+
+void FreeCameraMode::update(SceneManager & /*scene*/, Camera &camera, float dt)
+{
+    if (dt <= 0.0f)
+    {
+        return;
+    }
+
+    // Roll around the camera's forward axis (world-space axis).
+    if (_roll_dir != 0.0f && _settings.roll_speed > 0.0f)
+    {
+        glm::vec3 forward = glm::rotate(camera.orientation, glm::vec3{0.0f, 0.0f, -1.0f});
+        float angle = _roll_dir * _settings.roll_speed * dt;
+        glm::quat roll_rotation = glm::angleAxis(angle, glm::normalize(forward));
+        camera.orientation = glm::normalize(roll_rotation * camera.orientation);
+    }
+
+    // Move in camera-local space.
+    if (_velocity.x != 0.0f || _velocity.y != 0.0f || _velocity.z != 0.0f)
+    {
+        glm::vec3 local_delta = _velocity * (_settings.move_speed * dt);
+        glm::mat4 camera_rotation = camera.getRotationMatrix();
+        glm::vec3 world_delta = glm::vec3(camera_rotation * glm::vec4(local_delta, 0.0f));
+        camera.position_world += glm::dvec3(world_delta);
+    }
+}

src/scene/camera/mode_free.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <scene/camera/icamera_mode.h>
+
+struct FreeCameraSettings;
+
+class FreeCameraMode : public ICameraMode
+{
+public:
+    explicit FreeCameraMode(FreeCameraSettings &settings);
+    ~FreeCameraMode() override = default;
+
+    const char *name() const override { return "Free"; }
+    void on_activate(SceneManager &scene, Camera &camera) override;
+    void process_input(SceneManager &scene,
+                       Camera &camera,
+                       InputSystem &input,
+                       bool ui_capture_keyboard,
+                       bool ui_capture_mouse) override;
+    void update(SceneManager &scene, Camera &camera, float dt) override;
+
+private:
+    FreeCameraSettings &_settings;
+    glm::vec3 _velocity{0.0f, 0.0f, 0.0f};
+    float _roll_dir = 0.0f;
+    bool _rmb_down = false;
+};

src/scene/camera/mode_orbit.cpp

@@ -0,0 +1,163 @@
+#include "mode_orbit.h"
+
+#include <scene/camera/camera_rig.h>
+#include <scene/camera.h>
+#include <scene/vk_scene.h>
+
+#include <core/input/input_system.h>
+
+#include <glm/gtc/constants.hpp>
+#include <glm/gtx/quaternion.hpp>
+
+#include <algorithm>
+#include <cmath>
+
+OrbitCameraMode::OrbitCameraMode(OrbitCameraSettings &settings)
+    : _settings(settings)
+{
+}
+
+void OrbitCameraMode::on_activate(SceneManager &scene, Camera &camera)
+{
+    _rmb_down = false;
+
+    // If no target set, orbit around a point in front of the camera.
+    if (_settings.target.type == CameraTargetType::None)
+    {
+        glm::vec3 forward = glm::rotate(camera.orientation, glm::vec3(0.0f, 0.0f, -1.0f));
+        _settings.target.type = CameraTargetType::WorldPoint;
+        _settings.target.world_point = camera.position_world + WorldVec3(forward) * _settings.distance;
+    }
+
+    // Derive yaw/pitch/distance from current camera pose to avoid snapping.
+    WorldVec3 target_pos{};
+    glm::quat target_rot{};
+    if (!scene.getCameraRig().resolve_target(scene, _settings.target, target_pos, target_rot))
+    {
+        return;
+    }
+
+    WorldVec3 to_cam = camera.position_world - target_pos;
+    double dist = glm::length(to_cam);
+    if (!std::isfinite(dist) || dist < 0.001)
+    {
+        dist = _settings.distance;
+    }
+    _settings.distance = dist;
+
+    glm::vec3 dir = glm::normalize(glm::vec3(to_cam / dist)); // target -> camera
+    _settings.yaw = std::atan2(dir.x, dir.z);
+    _settings.pitch = std::asin(std::clamp(-dir.y, -1.0f, 1.0f));
+}
+
+void OrbitCameraMode::process_input(SceneManager & /*scene*/,
+                                    Camera &camera,
+                                    InputSystem &input,
+                                    bool /*ui_capture_keyboard*/,
+                                    bool ui_capture_mouse)
+{
+    const InputState &st = input.state();
+
+    for (const InputEvent &e : input.events())
+    {
+        if (ui_capture_mouse)
+        {
+            continue;
+        }
+
+        if (e.type == InputEvent::Type::MouseButtonDown && e.mouse_button == MouseButton::Right)
+        {
+            _rmb_down = true;
+            input.set_cursor_mode(CursorMode::Relative);
+        }
+        else if (e.type == InputEvent::Type::MouseButtonUp && e.mouse_button == MouseButton::Right)
+        {
+            _rmb_down = false;
+            input.set_cursor_mode(CursorMode::Normal);
+        }
+        else if (e.type == InputEvent::Type::MouseMove && _rmb_down)
+        {
+            float dx = e.mouse_delta.x * _settings.look_sensitivity;
+            float dy = e.mouse_delta.y * _settings.look_sensitivity;
+
+            _settings.yaw += dx;
+            _settings.pitch += dy;
+
+            const float limit = glm::half_pi<float>() - 0.01f;
+            _settings.pitch = std::clamp(_settings.pitch, -limit, limit);
+        }
+        else if (e.type == InputEvent::Type::MouseWheel)
+        {
+            const float steps = e.wheel_delta.y; // positive = wheel up
+            if (std::abs(steps) < 0.001f)
+            {
+                continue;
+            }
+
+            if (e.mods.ctrl)
+            {
+                camera.fovDegrees -= steps * 2.0f;
+                camera.fovDegrees = std::clamp(camera.fovDegrees, 30.0f, 110.0f);
+            }
+            else
+            {
+                const double factor = std::pow(1.15, -static_cast<double>(steps));
+                _settings.distance = std::clamp(_settings.distance * factor, 0.2, 100000.0);
+            }
+        }
+    }
+
+    if (_rmb_down && !st.mouse_down(MouseButton::Right))
+    {
+        _rmb_down = false;
+        input.set_cursor_mode(CursorMode::Normal);
+    }
+}
+
+void OrbitCameraMode::update(SceneManager &scene, Camera &camera, float /*dt*/)
+{
+    WorldVec3 target_pos{};
+    glm::quat target_rot{};
+    if (!scene.getCameraRig().resolve_target(scene, _settings.target, target_pos, target_rot))
+    {
+        return;
+    }
+
+    auto wrap_pi = [](float a) -> float {
+        // Wrap angle to [-pi, pi] to avoid precision issues over long play sessions.
+        constexpr float two_pi = glm::two_pi<float>();
+        a = std::fmod(a + glm::pi<float>(), two_pi);
+        if (a < 0.0f) a += two_pi;
+        return a - glm::pi<float>();
+    };
+
+    float yaw = wrap_pi(_settings.yaw);
+    float pitch = std::clamp(_settings.pitch,
+                             -glm::half_pi<float>() + 0.01f,
+                             glm::half_pi<float>() - 0.01f);
+    _settings.yaw = yaw;
+    _settings.pitch = pitch;
+    double dist = std::max(0.2, _settings.distance);
+
+    glm::quat yaw_q = glm::angleAxis(yaw, glm::vec3(0.0f, 1.0f, 0.0f));
+    glm::vec3 right = glm::rotate(yaw_q, glm::vec3(1.0f, 0.0f, 0.0f));
+    glm::quat pitch_q = glm::angleAxis(pitch, right);
+    glm::quat orbit_q = glm::normalize(pitch_q * yaw_q);
+
+    // Place the camera on its local +Z axis relative to the target so the camera's
+    // -Z forward axis points toward the target.
+    const double yaw_d = static_cast<double>(yaw);
+    const double pitch_d = static_cast<double>(pitch);
+    const double cos_pitch = std::cos(pitch_d);
+    const double sin_pitch = std::sin(pitch_d);
+    const double sin_yaw = std::sin(yaw_d);
+    const double cos_yaw = std::cos(yaw_d);
+
+    const glm::dvec3 dir_target_to_camera(
+        sin_yaw * cos_pitch,
+        -sin_pitch,
+        cos_yaw * cos_pitch);
+
+    camera.position_world = target_pos + dir_target_to_camera * dist;
+    camera.orientation = orbit_q;
+}

src/scene/camera/mode_orbit.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <scene/camera/icamera_mode.h>
+
+struct OrbitCameraSettings;
+
+class OrbitCameraMode : public ICameraMode
+{
+public:
+    explicit OrbitCameraMode(OrbitCameraSettings &settings);
+    ~OrbitCameraMode() override = default;
+
+    const char *name() const override { return "Orbit"; }
+    void on_activate(SceneManager &scene, Camera &camera) override;
+    void process_input(SceneManager &scene,
+                       Camera &camera,
+                       InputSystem &input,
+                       bool ui_capture_keyboard,
+                       bool ui_capture_mouse) override;
+    void update(SceneManager &scene, Camera &camera, float dt) override;
+
+private:
+    OrbitCameraSettings &_settings;
+    bool _rmb_down = false;
+};

src/scene/planet/cubesphere.cpp

@@ -0,0 +1,314 @@
+#include "cubesphere.h"
+
+#include <scene/tangent_space.h>
+
+#include <cmath>
+
+#include <glm/gtc/constants.hpp>
+
+namespace planet
+{
+    glm::dvec3 cubesphere_unit_direction(CubeFace face, double u, double v)
+    {
+        // Convention: u increases right, v increases down (image space).
+        glm::dvec3 d(0.0);
+        switch (face)
+        {
+            case CubeFace::PosX: d = glm::dvec3(1.0, -v, -u); break;
+            case CubeFace::NegX: d = glm::dvec3(-1.0, -v, u); break;
+            case CubeFace::PosY: d = glm::dvec3(u, 1.0, v); break;
+            case CubeFace::NegY: d = glm::dvec3(u, -1.0, -v); break;
+            case CubeFace::PosZ: d = glm::dvec3(u, -v, 1.0); break;
+            case CubeFace::NegZ: d = glm::dvec3(-u, -v, -1.0); break;
+        }
+
+        const double len2 = glm::dot(d, d);
+        if (len2 <= 0.0)
+        {
+            return glm::dvec3(0.0, 0.0, 1.0);
+        }
+        return d * (1.0 / std::sqrt(len2));
+    }
+
+    void cubesphere_tile_uv_bounds(uint32_t level, uint32_t x, uint32_t y,
+                                   double &out_u0, double &out_u1,
+                                   double &out_v0, double &out_v1)
+    {
+        const uint32_t tiles_u = (level < 31u) ? (1u << level) : 0u;
+        const double inv_tiles = (tiles_u > 0u) ? (1.0 / static_cast<double>(tiles_u)) : 1.0;
+
+        const double u0_01 = static_cast<double>(x) * inv_tiles;
+        const double u1_01 = static_cast<double>(x + 1u) * inv_tiles;
+        const double v0_01 = static_cast<double>(y) * inv_tiles;
+        const double v1_01 = static_cast<double>(y + 1u) * inv_tiles;
+
+        out_u0 = u0_01 * 2.0 - 1.0;
+        out_u1 = u1_01 * 2.0 - 1.0;
+        out_v0 = v0_01 * 2.0 - 1.0;
+        out_v1 = v1_01 * 2.0 - 1.0;
+    }
+
+    glm::dvec3 cubesphere_patch_center_direction(CubeFace face, uint32_t level, uint32_t x, uint32_t y)
+    {
+        double u0 = 0.0, u1 = 0.0, v0 = 0.0, v1 = 0.0;
+        cubesphere_tile_uv_bounds(level, x, y, u0, u1, v0, v1);
+        const double u_mid = 0.5 * (u0 + u1);
+        const double v_mid = 0.5 * (v0 + v1);
+        return cubesphere_unit_direction(face, u_mid, v_mid);
+    }
+
+    WorldVec3 cubesphere_patch_center_world(const WorldVec3 &center_world,
+                                            double radius_m,
+                                            CubeFace face,
+                                            uint32_t level,
+                                            uint32_t x,
+                                            uint32_t y)
+    {
+        const glm::dvec3 dir = cubesphere_patch_center_direction(face, level, x, y);
+        return center_world + dir * radius_m;
+    }
+
+    double cubesphere_patch_edge_m(double radius_m, uint32_t level)
+    {
+        // Each cube face spans 90 degrees. Use arc length per tile edge as a simple estimate.
+        const double face_arc_m = (glm::pi<double>() * 0.5) * radius_m;
+        const uint32_t safe_level = (level < 30u) ? level : 30u;
+        const double tiles_per_axis = static_cast<double>(1u << safe_level);
+        return face_arc_m / tiles_per_axis;
+    }
+
+    double cubesphere_skirt_depth_m(double radius_m, uint32_t level)
+    {
+        const double edge_m = cubesphere_patch_edge_m(radius_m, level);
+        return glm::max(10.0, 0.02 * edge_m);
+    }
+
+    void build_cubesphere_patch_indices(std::vector<uint32_t> &out_indices, uint32_t resolution)
+    {
+        out_indices.clear();
+
+        if (resolution < 2)
+        {
+            return;
+        }
+
+        const size_t grid_index_count =
+            static_cast<size_t>(resolution - 1u) * static_cast<size_t>(resolution - 1u) * 6u;
+        const size_t skirt_index_count = static_cast<size_t>(4u) * static_cast<size_t>(resolution - 1u) * 6u;
+        out_indices.reserve(grid_index_count + skirt_index_count);
+
+        // Base grid indices
+        for (uint32_t j = 0; j + 1 < resolution; ++j)
+        {
+            for (uint32_t i = 0; i + 1 < resolution; ++i)
+            {
+                const uint32_t i0 = j * resolution + i;
+                const uint32_t i1 = i0 + 1;
+                const uint32_t i2 = i0 + resolution;
+                const uint32_t i3 = i2 + 1;
+
+                // CCW winding when viewed from outside the sphere.
+                out_indices.push_back(i0);
+                out_indices.push_back(i1);
+                out_indices.push_back(i2);
+
+                out_indices.push_back(i2);
+                out_indices.push_back(i1);
+                out_indices.push_back(i3);
+            }
+        }
+
+        auto add_skirt_quads = [&](uint32_t base0, uint32_t base1, uint32_t skirt0, uint32_t skirt1)
+        {
+            out_indices.push_back(base0);
+            out_indices.push_back(base1);
+            out_indices.push_back(skirt0);
+
+            out_indices.push_back(skirt0);
+            out_indices.push_back(base1);
+            out_indices.push_back(skirt1);
+        };
+
+        const uint32_t base_vertex_count = resolution * resolution;
+        const uint32_t top_skirt_start = base_vertex_count + 0u * resolution;
+        const uint32_t right_skirt_start = base_vertex_count + 1u * resolution;
+        const uint32_t bottom_skirt_start = base_vertex_count + 2u * resolution;
+        const uint32_t left_skirt_start = base_vertex_count + 3u * resolution;
+
+        // Skirt indices: 4 edges, (N-1) segments each.
+        for (uint32_t i = 0; i + 1 < resolution; ++i)
+        {
+            // Top edge
+            add_skirt_quads(0u * resolution + i,
+                            0u * resolution + (i + 1u),
+                            top_skirt_start + i,
+                            top_skirt_start + (i + 1u));
+            // Bottom edge
+            add_skirt_quads((resolution - 1u) * resolution + i,
+                            (resolution - 1u) * resolution + (i + 1u),
+                            bottom_skirt_start + i,
+                            bottom_skirt_start + (i + 1u));
+        }
+        for (uint32_t j = 0; j + 1 < resolution; ++j)
+        {
+            // Left edge
+            add_skirt_quads(j * resolution + 0u,
+                            (j + 1u) * resolution + 0u,
+                            left_skirt_start + j,
+                            left_skirt_start + (j + 1u));
+            // Right edge
+            add_skirt_quads(j * resolution + (resolution - 1u),
+                            (j + 1u) * resolution + (resolution - 1u),
+                            right_skirt_start + j,
+                            right_skirt_start + (j + 1u));
+        }
+    }
+
+    glm::dvec3 build_cubesphere_patch_vertices(std::vector<Vertex> &out_vertices,
+                                               double radius_m,
+                                               CubeFace face,
+                                               uint32_t level,
+                                               uint32_t x,
+                                               uint32_t y,
+                                               uint32_t resolution,
+                                               const glm::vec4 &vertex_color)
+    {
+        out_vertices.clear();
+
+        if (resolution < 2)
+        {
+            return glm::dvec3(0.0, 0.0, 1.0);
+        }
+
+        const glm::dvec3 patch_center_dir = cubesphere_patch_center_direction(face, level, x, y);
+
+        const double skirt_depth_m = cubesphere_skirt_depth_m(radius_m, level);
+        const double skirt_radius_m = glm::max(0.0, radius_m - skirt_depth_m);
+
+        double u0 = 0.0, u1 = 0.0, v0 = 0.0, v1 = 0.0;
+        cubesphere_tile_uv_bounds(level, x, y, u0, u1, v0, v1);
+
+        const uint32_t base_vertex_count = resolution * resolution;
+        const uint32_t skirt_vertex_count = 4u * resolution;
+        out_vertices.resize(static_cast<size_t>(base_vertex_count) + static_cast<size_t>(skirt_vertex_count));
+
+        const uint32_t tiles_per_axis = (level < 31u) ? (1u << level) : 1u;
+        const double inv_tiles = (tiles_per_axis > 0u) ? (1.0 / static_cast<double>(tiles_per_axis)) : 1.0;
+
+        const double inv = 1.0 / static_cast<double>(resolution - 1u);
+        const double du = (u1 - u0) * inv;
+        const double dv = (v1 - v0) * inv;
+        for (uint32_t j = 0; j < resolution; ++j)
+        {
+            const float t = static_cast<float>(static_cast<double>(j) * inv);
+            const double v = v0 + dv * static_cast<double>(j);
+
+            for (uint32_t i = 0; i < resolution; ++i)
+            {
+                const float s = static_cast<float>(static_cast<double>(i) * inv);
+                const double u = u0 + du * static_cast<double>(i);
+
+                const glm::dvec3 unit_dir = cubesphere_unit_direction(face, u, v);
+                const glm::dvec3 delta_d = (unit_dir - patch_center_dir) * radius_m;
+
+                Vertex vert{};
+                vert.position = glm::vec3(static_cast<float>(delta_d.x),
+                                          static_cast<float>(delta_d.y),
+                                          static_cast<float>(delta_d.z));
+                vert.normal = glm::vec3(static_cast<float>(unit_dir.x),
+                                        static_cast<float>(unit_dir.y),
+                                        static_cast<float>(unit_dir.z));
+
+                // UVs cover the entire cube face (0..1) so all patches on this face
+                // sample from a single per-face texture.
+                const double u_face = (static_cast<double>(x) + static_cast<double>(s)) * inv_tiles;
+                const double v_face = (static_cast<double>(y) + static_cast<double>(t)) * inv_tiles;
+                vert.uv_x = static_cast<float>(u_face);
+                vert.uv_y = static_cast<float>(v_face);
+                vert.color = vertex_color;
+                vert.tangent = glm::vec4(1.0f, 0.0f, 0.0f, 1.0f);
+
+                const uint32_t idx = j * resolution + i;
+                out_vertices[idx] = vert;
+            }
+        }
+
+        auto add_skirt_vertex = [&](uint32_t base_index, uint32_t skirt_index)
+        {
+            const glm::vec3 n = out_vertices[base_index].normal;
+            const glm::dvec3 unit_dir(static_cast<double>(n.x),
+                                      static_cast<double>(n.y),
+                                      static_cast<double>(n.z));
+            const glm::dvec3 delta_d = unit_dir * skirt_radius_m - patch_center_dir * radius_m;
+
+            Vertex vert = out_vertices[base_index];
+            vert.position = glm::vec3(static_cast<float>(delta_d.x),
+                                      static_cast<float>(delta_d.y),
+                                      static_cast<float>(delta_d.z));
+            vert.normal = glm::vec3(static_cast<float>(unit_dir.x),
+                                    static_cast<float>(unit_dir.y),
+                                    static_cast<float>(unit_dir.z));
+            out_vertices[skirt_index] = vert;
+        };
+
+        const uint32_t top_skirt_start = base_vertex_count + 0u * resolution;
+        const uint32_t right_skirt_start = base_vertex_count + 1u * resolution;
+        const uint32_t bottom_skirt_start = base_vertex_count + 2u * resolution;
+        const uint32_t left_skirt_start = base_vertex_count + 3u * resolution;
+
+        // Top edge (j=0)
+        for (uint32_t i = 0; i < resolution; ++i)
+        {
+            add_skirt_vertex(0u * resolution + i, top_skirt_start + i);
+        }
+        // Right edge (i=resolution-1)
+        for (uint32_t j = 0; j < resolution; ++j)
+        {
+            add_skirt_vertex(j * resolution + (resolution - 1u), right_skirt_start + j);
+        }
+        // Bottom edge (j=resolution-1)
+        for (uint32_t i = 0; i < resolution; ++i)
+        {
+            add_skirt_vertex((resolution - 1u) * resolution + i, bottom_skirt_start + i);
+        }
+        // Left edge (i=0)
+        for (uint32_t j = 0; j < resolution; ++j)
+        {
+            add_skirt_vertex(j * resolution + 0u, left_skirt_start + j);
+        }
+
+        return patch_center_dir;
+    }
+
+    void build_cubesphere_patch_mesh(CubeSpherePatchMesh &out,
+                                     const WorldVec3 &center_world,
+                                     double radius_m,
+                                     CubeFace face,
+                                     uint32_t level,
+                                     uint32_t x,
+                                     uint32_t y,
+                                     uint32_t resolution,
+                                     const glm::vec4 &vertex_color,
+                                     bool generate_tangents)
+    {
+        out.vertices.clear();
+        out.indices.clear();
+        out.patch_center_world = center_world;
+
+        if (resolution < 2)
+        {
+            return;
+        }
+
+        const glm::dvec3 patch_center_dir =
+            build_cubesphere_patch_vertices(out.vertices, radius_m, face, level, x, y, resolution, vertex_color);
+        build_cubesphere_patch_indices(out.indices, resolution);
+
+        out.patch_center_world = center_world + patch_center_dir * radius_m;
+
+        if (generate_tangents)
+        {
+            geom::generate_tangents(out.vertices, out.indices);
+        }
+    }
+} // namespace planet

src/scene/planet/cubesphere.h

@@ -0,0 +1,84 @@
+#pragma once
+
+#include <core/types.h>
+#include <core/world.h>
+
+#include <cstdint>
+#include <vector>
+
+#include <glm/vec4.hpp>
+
+namespace planet
+{
+    // Cube face ordering matches KTX/Vulkan cubemap face order:
+    // +X, -X, +Y, -Y, +Z, -Z
+    enum class CubeFace : uint8_t
+    {
+        PosX = 0,
+        NegX = 1,
+        PosY = 2,
+        NegY = 3,
+        PosZ = 4,
+        NegZ = 5,
+    };
+
+    // u,v are in [-1,+1] on the chosen face. Convention:
+    // - u increases to the right
+    // - v increases downward (image space)
+    glm::dvec3 cubesphere_unit_direction(CubeFace face, double u, double v);
+
+    // Tile bounds on a face in cube-face parametric space:
+    // u,v in [-1,+1], where [0..1] maps to [-1..+1].
+    void cubesphere_tile_uv_bounds(uint32_t level, uint32_t x, uint32_t y,
+                                   double &out_u0, double &out_u1,
+                                   double &out_v0, double &out_v1);
+
+    glm::dvec3 cubesphere_patch_center_direction(CubeFace face, uint32_t level, uint32_t x, uint32_t y);
+
+    WorldVec3 cubesphere_patch_center_world(const WorldVec3 &center_world,
+                                            double radius_m,
+                                            CubeFace face,
+                                            uint32_t level,
+                                            uint32_t x,
+                                            uint32_t y);
+
+    // Approximate world-space tile edge length on the sphere surface.
+    double cubesphere_patch_edge_m(double radius_m, uint32_t level);
+
+    // Skirt depth heuristic (meters).
+    double cubesphere_skirt_depth_m(double radius_m, uint32_t level);
+
+    struct CubeSpherePatchMesh
+    {
+        std::vector<Vertex> vertices;
+        std::vector<uint32_t> indices;
+        WorldVec3 patch_center_world{0.0, 0.0, 0.0};
+    };
+
+    // Build the shared index list for a patch grid with skirts. Indices are identical for all
+    // patches as long as 'resolution' is constant.
+    void build_cubesphere_patch_indices(std::vector<uint32_t> &out_indices, uint32_t resolution);
+
+    // Build patch vertices (including skirts). Vertex positions are relative to the patch center on
+    // the sphere surface (computed from face/level/x/y). Returns the patch center direction.
+    glm::dvec3 build_cubesphere_patch_vertices(std::vector<Vertex> &out_vertices,
+                                               double radius_m,
+                                               CubeFace face,
+                                               uint32_t level,
+                                               uint32_t x,
+                                               uint32_t y,
+                                               uint32_t resolution,
+                                               const glm::vec4 &vertex_color);
+
+    // Build a cube-sphere patch mesh with skirts. Vertex positions are relative to patch_center_world.
+    void build_cubesphere_patch_mesh(CubeSpherePatchMesh &out,
+                                     const WorldVec3 &center_world,
+                                     double radius_m,
+                                     CubeFace face,
+                                     uint32_t level,
+                                     uint32_t x,
+                                     uint32_t y,
+                                     uint32_t resolution,
+                                     const glm::vec4 &vertex_color,
+                                     bool generate_tangents = true);
+} // namespace planet

src/scene/planet/planet_quadtree.cpp

@@ -0,0 +1,296 @@
+#include "planet_quadtree.h"
+
+#include <algorithm>
+#include <array>
+#include <cmath>
+#include <limits>
+
+#include <glm/gtc/constants.hpp>
+
+namespace planet
+{
+    namespace
+    {
+        struct Node
+        {
+            PatchKey key{};
+        };
+
+        void compute_patch_visibility_terms(const PatchKey &key,
+                                            const glm::dvec3 &patch_center_dir,
+                                            double radius_m,
+                                            double &out_cos_patch_radius,
+                                            double &out_sin_patch_radius,
+                                            double &out_bound_radius_m)
+        {
+            glm::dvec3 c = patch_center_dir;
+            const double c_len2 = glm::dot(c, c);
+            if (!(c_len2 > 0.0))
+            {
+                c = glm::dvec3(0.0, 0.0, 1.0);
+            }
+            else
+            {
+                c *= (1.0 / std::sqrt(c_len2));
+            }
+
+            double u0 = 0.0, u1 = 0.0, v0 = 0.0, v1 = 0.0;
+            cubesphere_tile_uv_bounds(key.level, key.x, key.y, u0, u1, v0, v1);
+
+            // Conservative angular radius: max angle from patch center direction to any corner direction.
+            double min_dot = 1.0;
+            min_dot = std::min(min_dot, glm::dot(c, cubesphere_unit_direction(key.face, u0, v0)));
+            min_dot = std::min(min_dot, glm::dot(c, cubesphere_unit_direction(key.face, u1, v0)));
+            min_dot = std::min(min_dot, glm::dot(c, cubesphere_unit_direction(key.face, u0, v1)));
+            min_dot = std::min(min_dot, glm::dot(c, cubesphere_unit_direction(key.face, u1, v1)));
+
+            const double cos_a = glm::clamp(min_dot, -1.0, 1.0);
+            const double sin_a = std::sqrt(glm::max(0.0, 1.0 - cos_a * cos_a));
+
+            // Vertex positions are built as (unit_dir - patch_center_dir) * radius (chord length).
+            const double chord_r = radius_m * std::sqrt(glm::max(0.0, 2.0 - 2.0 * cos_a));
+
+            // Skirts extend inward; add a small safety margin so CPU culling stays conservative.
+            const double skirt_depth = cubesphere_skirt_depth_m(radius_m, key.level);
+
+            out_cos_patch_radius = cos_a;
+            out_sin_patch_radius = sin_a;
+            out_bound_radius_m = glm::max(1.0, chord_r + skirt_depth);
+        }
+
+        bool is_patch_visible_horizon(const WorldVec3 &body_center_world,
+                                      double radius_m,
+                                      const WorldVec3 &camera_world,
+                                      const glm::dvec3 &patch_center_dir,
+                                      double cos_patch_radius,
+                                      double sin_patch_radius)
+        {
+            const glm::dvec3 w = camera_world - body_center_world;
+            const double d = glm::length(w);
+            if (d <= radius_m || d <= 0.0)
+            {
+                return true;
+            }
+
+            const glm::dvec3 w_dir = w / d;
+            const double cos_theta = glm::dot(patch_center_dir, w_dir);
+
+            // Horizon angle: cos(theta_h) = R / d
+            const double cos_h = glm::clamp(radius_m / d, 0.0, 1.0);
+            const double sin_h = std::sqrt(glm::max(0.0, 1.0 - cos_h * cos_h));
+
+            // Visible if theta <= theta_h + ang:
+            // cos(theta) >= cos(theta_h + ang)
+            const double cos_limit = cos_h * cos_patch_radius - sin_h * sin_patch_radius;
+            if (!std::isfinite(cos_theta) || !std::isfinite(cos_limit))
+            {
+                return true; // fail-safe: avoid catastrophic full culls
+            }
+            return cos_theta >= cos_limit;
+        }
+
+        bool is_patch_visible_frustum(const glm::vec3 &center_local, float bound_radius_m, const glm::mat4 &viewproj)
+        {
+            if (!(bound_radius_m > 0.0f))
+            {
+                bound_radius_m = 1.0f;
+            }
+
+            // Conservative AABB-in-clip test for a cube around the patch center.
+            const std::array<glm::vec3, 8> corners{
+                glm::vec3{+1, +1, +1}, glm::vec3{+1, +1, -1}, glm::vec3{+1, -1, +1}, glm::vec3{+1, -1, -1},
+                glm::vec3{-1, +1, +1}, glm::vec3{-1, +1, -1}, glm::vec3{-1, -1, +1}, glm::vec3{-1, -1, -1},
+            };
+
+            glm::vec4 clip[8];
+            for (int i = 0; i < 8; ++i)
+            {
+                const glm::vec3 p = center_local + corners[i] * bound_radius_m;
+                clip[i] = viewproj * glm::vec4(p, 1.0f);
+            }
+
+            auto all_out = [&](auto pred) {
+                for (int i = 0; i < 8; ++i)
+                {
+                    if (!pred(clip[i])) return false;
+                }
+                return true;
+            };
+
+            // Clip volume in Vulkan (ZO): -w<=x<=w, -w<=y<=w, 0<=z<=w
+            if (all_out([](const glm::vec4 &v) { return v.x < -v.w; })) return false; // left
+            if (all_out([](const glm::vec4 &v) { return v.x >  v.w; })) return false; // right
+            if (all_out([](const glm::vec4 &v) { return v.y < -v.w; })) return false; // bottom
+            if (all_out([](const glm::vec4 &v) { return v.y >  v.w; })) return false; // top
+            if (all_out([](const glm::vec4 &v) { return v.z <  0.0f; })) return false; // near (ZO)
+            if (all_out([](const glm::vec4 &v) { return v.z >  v.w; })) return false; // far
+
+            return true;
+        }
+    } // namespace
+
+    void PlanetQuadtree::update(const WorldVec3 &body_center_world,
+                                double radius_m,
+                                const WorldVec3 &camera_world,
+                                const WorldVec3 &origin_world,
+                                const GPUSceneData &scene_data,
+                                VkExtent2D logical_extent)
+    {
+        _visible_leaves.clear();
+        _stats = {};
+
+        if (radius_m <= 0.0)
+        {
+            return;
+        }
+
+        if (logical_extent.width == 0 || logical_extent.height == 0)
+        {
+            logical_extent = VkExtent2D{1920, 1080};
+        }
+
+        const bool rt_shadows_enabled = (scene_data.rtOptions.x != 0u) && (scene_data.rtOptions.z != 0u);
+        const double cam_alt_m = glm::max(0.0, glm::length(camera_world - body_center_world) - radius_m);
+        const bool rt_guardrail_active =
+            _settings.rt_guardrail &&
+            rt_shadows_enabled &&
+            (_settings.max_patch_edge_rt_m > 0.0) &&
+            (cam_alt_m <= _settings.rt_guardrail_max_altitude_m);
+
+        const float proj_y = scene_data.proj[1][1];
+        const float proj_scale = std::abs(proj_y) * (static_cast<float>(logical_extent.height) * 0.5f);
+        if (!(proj_scale > 0.0f))
+        {
+            return;
+        }
+
+        thread_local std::vector<Node> stack;
+        stack.clear();
+        stack.reserve(256);
+
+        const size_t max_visible_leaves =
+            (_settings.max_patches_visible > 0u)
+                ? static_cast<size_t>(std::max(_settings.max_patches_visible, 6u))
+                : std::numeric_limits<size_t>::max();
+
+        auto push_root = [&](CubeFace face)
+        {
+            Node n{};
+            n.key.face = face;
+            n.key.level = 0;
+            n.key.x = 0;
+            n.key.y = 0;
+            stack.push_back(n);
+        };
+
+        // Push in reverse order so pop_back visits in +X,-X,+Y,-Y,+Z,-Z order.
+        push_root(CubeFace::NegZ);
+        push_root(CubeFace::PosZ);
+        push_root(CubeFace::NegY);
+        push_root(CubeFace::PosY);
+        push_root(CubeFace::NegX);
+        push_root(CubeFace::PosX);
+
+        while (!stack.empty())
+        {
+            Node n = stack.back();
+            stack.pop_back();
+            _stats.nodes_visited++;
+
+            const PatchKey &k = n.key;
+
+            const double patch_edge_m = cubesphere_patch_edge_m(radius_m, k.level);
+            const glm::dvec3 patch_dir = cubesphere_patch_center_direction(k.face, k.level, k.x, k.y);
+
+            double cos_patch_radius = 1.0;
+            double sin_patch_radius = 0.0;
+            double patch_bound_r_m = 1.0;
+            if (_settings.horizon_cull || _settings.frustum_cull)
+            {
+                compute_patch_visibility_terms(k, patch_dir, radius_m, cos_patch_radius, sin_patch_radius, patch_bound_r_m);
+            }
+
+            if (_settings.horizon_cull)
+            {
+                if (!is_patch_visible_horizon(body_center_world,
+                                              radius_m,
+                                              camera_world,
+                                              patch_dir,
+                                              cos_patch_radius,
+                                              sin_patch_radius))
+                {
+                    _stats.nodes_culled++;
+                    continue;
+                }
+            }
+
+            const WorldVec3 patch_center_world =
+                body_center_world + patch_dir * radius_m;
+
+            if (_settings.frustum_cull)
+            {
+                const glm::vec3 patch_center_local = world_to_local(patch_center_world, origin_world);
+                const float bound_r = static_cast<float>(patch_bound_r_m);
+                if (!is_patch_visible_frustum(patch_center_local, bound_r, scene_data.viewproj))
+                {
+                    _stats.nodes_culled++;
+                    continue;
+                }
+            }
+
+            const double dist_m = glm::max(1.0, glm::length(camera_world - patch_center_world));
+
+            // Screen-space error metric.
+            const double error_m = 0.5 * patch_edge_m;
+            const float sse_px = static_cast<float>((error_m / dist_m) * static_cast<double>(proj_scale));
+
+            bool refine = (k.level < _settings.max_level) && (sse_px > _settings.target_sse_px);
+            if (!refine && rt_guardrail_active && (k.level < _settings.max_level) && (patch_edge_m > _settings.max_patch_edge_rt_m))
+            {
+                refine = true;
+            }
+
+            if (refine)
+            {
+                // Budget check: splitting replaces this node with 4 children (adds +3 leaves minimum).
+                // Keep a stable upper bound on the final leaf count: leaves_so_far + stack.size() + 4.
+                const size_t min_leaves_if_split = _visible_leaves.size() + stack.size() + 4u;
+                if (min_leaves_if_split > max_visible_leaves)
+                {
+                    refine = false;
+                    _stats.splits_budget_limited++;
+                }
+            }
+
+            if (refine)
+            {
+                // Child order: (0,0), (1,0), (0,1), (1,1) with y increasing downward.
+                const uint32_t cl = k.level + 1u;
+                const uint32_t cx = k.x * 2u;
+                const uint32_t cy = k.y * 2u;
+
+                stack.push_back(Node{PatchKey{k.face, cl, cx + 1u, cy + 1u}});
+                stack.push_back(Node{PatchKey{k.face, cl, cx + 0u, cy + 1u}});
+                stack.push_back(Node{PatchKey{k.face, cl, cx + 1u, cy + 0u}});
+                stack.push_back(Node{PatchKey{k.face, cl, cx + 0u, cy + 0u}});
+                continue;
+            }
+
+            _visible_leaves.push_back(k);
+            _stats.max_level_used = std::max(_stats.max_level_used, k.level);
+        }
+
+        _stats.visible_leaves = static_cast<uint32_t>(_visible_leaves.size());
+
+        // Keep deterministic order for stability (optional).
+        // DFS already stable; sort is useful when culling changes traversal.
+        std::sort(_visible_leaves.begin(), _visible_leaves.end(),
+                  [](const PatchKey &a, const PatchKey &b)
+                  {
+                      if (a.face != b.face) return a.face < b.face;
+                      if (a.level != b.level) return a.level < b.level;
+                      if (a.x != b.x) return a.x < b.x;
+                      return a.y < b.y;
+                  });
+    }
+} // namespace planet

src/scene/planet/planet_quadtree.h

@@ -0,0 +1,82 @@
+#pragma once
+
+#include "cubesphere.h"
+
+#include <core/types.h>
+#include <core/world.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <vector>
+
+namespace planet
+{
+    struct PatchKey
+    {
+        CubeFace face = CubeFace::PosX;
+        uint32_t level = 0;
+        uint32_t x = 0;
+        uint32_t y = 0;
+
+        friend bool operator==(const PatchKey &, const PatchKey &) = default;
+    };
+
+    struct PatchKeyHash
+    {
+        size_t operator()(const PatchKey &k) const noexcept
+        {
+            const uint64_t f = static_cast<uint64_t>(k.face) & 0xFFull;
+            const uint64_t l = static_cast<uint64_t>(k.level) & 0x3Full;
+            const uint64_t x = static_cast<uint64_t>(k.x) & 0x1FFFFFull;
+            const uint64_t y = static_cast<uint64_t>(k.y) & 0x1FFFFFull;
+
+            // Simple stable packing: [face:8 | level:6 | x:21 | y:21]
+            const uint64_t packed = (f << 56) | (l << 50) | (x << 29) | (y << 8);
+            return std::hash<uint64_t>{}(packed);
+        }
+    };
+
+    class PlanetQuadtree
+    {
+    public:
+        struct Settings
+        {
+            uint32_t max_level = 14;
+            float target_sse_px = 32.0f;    // screen space error pixel
+            uint32_t max_patches_visible = 8192;
+            bool frustum_cull = true;
+            bool horizon_cull = true;
+
+            // RT stability guardrail (only applied near-surface).
+            bool rt_guardrail = true;
+            double max_patch_edge_rt_m = 5000.0;
+            double rt_guardrail_max_altitude_m = 200000.0;
+        };
+
+        struct Stats
+        {
+            uint32_t visible_leaves = 0;
+            uint32_t max_level_used = 0;
+            uint32_t nodes_visited = 0;
+            uint32_t nodes_culled = 0;
+            uint32_t splits_budget_limited = 0;
+        };
+
+        void set_settings(const Settings &settings) { _settings = settings; }
+        const Settings &settings() const { return _settings; }
+        const Stats &stats() const { return _stats; }
+        const std::vector<PatchKey> &visible_leaves() const { return _visible_leaves; }
+
+        void update(const WorldVec3 &body_center_world,
+                    double radius_m,
+                    const WorldVec3 &camera_world,
+                    const WorldVec3 &origin_world,
+                    const GPUSceneData &scene_data,
+                    VkExtent2D logical_extent);
+
+    private:
+        Settings _settings{};
+        Stats _stats{};
+        std::vector<PatchKey> _visible_leaves;
+    };
+} // namespace planet

src/scene/planet/planet_system.cpp

@@ -0,0 +1,989 @@
+#include "planet_system.h"
+
+#include <core/context.h>
+#include <core/device/resource.h>
+#include <core/frame/resources.h>
+#include <core/types.h>
+#include <core/assets/manager.h>
+#include <render/materials.h>
+#include <render/primitives.h>
+#include <core/pipeline/sampler.h>
+#include <scene/planet/cubesphere.h>
+#include <scene/tangent_space.h>
+#include <scene/vk_scene.h>
+
+#include <glm/gtc/quaternion.hpp>
+
+#include <algorithm>
+#include <chrono>
+#include <cmath>
+
+#include "device.h"
+
+namespace
+{
+    constexpr double kEarthRadiusM = 6378137.0;    // WGS84 equatorial radius
+    constexpr double kMoonRadiusM = 1737400.0;     // mean radius
+    constexpr double kMoonDistanceM = 384400000.0; // mean Earth-Moon distance
+
+    struct PatchBoundsData
+    {
+        glm::vec3 origin{0.0f};
+        glm::vec3 extents{0.5f};
+        float sphere_radius{0.5f};
+    };
+
+    PatchBoundsData compute_patch_bounds(const std::vector<Vertex> &vertices)
+    {
+        PatchBoundsData b{};
+        if (vertices.empty())
+        {
+            return b;
+        }
+
+        glm::vec3 minpos = vertices[0].position;
+        glm::vec3 maxpos = vertices[0].position;
+        for (const auto &v : vertices)
+        {
+            minpos = glm::min(minpos, v.position);
+            maxpos = glm::max(maxpos, v.position);
+        }
+        b.origin = (maxpos + minpos) * 0.5f;
+        b.extents = (maxpos - minpos) * 0.5f;
+        b.sphere_radius = glm::length(b.extents);
+        return b;
+    }
+
+    GLTFMetallic_Roughness::MaterialConstants make_planet_constants()
+    {
+        GLTFMetallic_Roughness::MaterialConstants c{};
+        c.colorFactors = glm::vec4(1.0f);
+        // metal_rough_factors.x = metallic, .y = roughness
+        c.metal_rough_factors = glm::vec4(0.0f, 1.0f, 0.0f, 0.0f);
+        return c;
+    }
+
+    glm::vec4 debug_color_for_level(uint32_t level)
+    {
+        const float t = static_cast<float>(level) * 0.37f;
+        const float r = 0.35f + 0.65f * std::sin(t + 0.0f);
+        const float g = 0.35f + 0.65f * std::sin(t + 2.1f);
+        const float b = 0.35f + 0.65f * std::sin(t + 4.2f);
+        return glm::vec4(r, g, b, 1.0f);
+    }
+} // namespace
+
+void PlanetSystem::init(EngineContext *context)
+{
+    _context = context;
+}
+
+void PlanetSystem::set_earth_debug_tint_patches_by_lod(bool enabled)
+{
+    if (_earth_debug_tint_patches_by_lod == enabled)
+    {
+        return;
+    }
+    _earth_debug_tint_patches_by_lod = enabled;
+    _earth_patch_cache_dirty = true;
+}
+
+void PlanetSystem::cleanup()
+{
+    if (!_context)
+    {
+        return;
+    }
+
+    TextureCache *textures = _context->textures;
+    if (textures)
+    {
+        for (MaterialInstance &mat : _earth_face_materials)
+        {
+            if (mat.materialSet != VK_NULL_HANDLE)
+            {
+                textures->unwatchSet(mat.materialSet);
+            }
+        }
+    }
+
+    ResourceManager *rm = _context->getResources();
+    if (rm)
+    {
+        for (EarthPatch &p : _earth_patches)
+        {
+            if (p.vertex_buffer.buffer != VK_NULL_HANDLE)
+            {
+                rm->destroy_buffer(p.vertex_buffer);
+                p.vertex_buffer = {};
+                p.vertex_buffer_address = 0;
+            }
+        }
+
+        if (_earth_patch_index_buffer.buffer != VK_NULL_HANDLE)
+        {
+            rm->destroy_buffer(_earth_patch_index_buffer);
+            _earth_patch_index_buffer = {};
+        }
+
+        if (_earth_patch_material_constants_buffer.buffer != VK_NULL_HANDLE)
+        {
+            rm->destroy_buffer(_earth_patch_material_constants_buffer);
+            _earth_patch_material_constants_buffer = {};
+        }
+    }
+
+    if (_earth_patch_material_allocator_initialized)
+    {
+        if (DeviceManager *device = _context->getDevice())
+        {
+            _earth_patch_material_allocator.destroy_pools(device->device());
+        }
+        _earth_patch_material_allocator_initialized = false;
+    }
+
+    if (_earth_patch_material_layout != VK_NULL_HANDLE)
+    {
+        if (DeviceManager *device = _context->getDevice())
+        {
+            vkDestroyDescriptorSetLayout(device->device(), _earth_patch_material_layout, nullptr);
+        }
+        _earth_patch_material_layout = VK_NULL_HANDLE;
+    }
+
+    _earth_patch_lookup.clear();
+    _earth_patch_lru.clear();
+    _earth_patch_free.clear();
+    _earth_patches.clear();
+    _earth_face_materials = {};
+
+    _earth_patch_index_count = 0;
+    _earth_patch_index_resolution = 0;
+    _earth_patch_frame_stamp = 0;
+}
+
+const PlanetSystem::PlanetBody *PlanetSystem::get_body(BodyID id) const
+{
+    size_t i = static_cast<size_t>(id);
+    if (i >= _bodies.size())
+    {
+        return nullptr;
+    }
+    return &_bodies[i];
+}
+
+PlanetSystem::PlanetBody *PlanetSystem::get_body(BodyID id)
+{
+    size_t i = static_cast<size_t>(id);
+    if (i >= _bodies.size())
+    {
+        return nullptr;
+    }
+    return &_bodies[i];
+}
+
+void PlanetSystem::ensure_bodies_created()
+{
+    if (!_bodies.empty())
+    {
+        return;
+    }
+
+    PlanetBody earth{};
+    earth.name = "Earth";
+    earth.center_world = WorldVec3(0.0, 0.0, 0.0);
+    earth.radius_m = kEarthRadiusM;
+
+    PlanetBody moon{};
+    moon.name = "Moon";
+    moon.center_world = WorldVec3(kMoonDistanceM, 0.0, 0.0);
+    moon.radius_m = kMoonRadiusM;
+
+    if (_context && _context->assets)
+    {
+        AssetManager *assets = _context->assets;
+
+        // Earth: cube-sphere quadtree patches (Milestones B2-B4). Material is shared.
+        {
+            GLTFMetallic_Roughness::MaterialConstants mc = make_planet_constants();
+            mc.colorFactors = glm::vec4(1.0f);
+            earth.material = assets->createMaterialFromConstants("Planet_EarthMaterial", mc, MaterialPass::MainColor);
+        }
+
+        // Moon: constant albedo (no texture yet).
+        {
+            GLTFMetallic_Roughness::MaterialConstants mc = make_planet_constants();
+            mc.colorFactors = glm::vec4(0.72f, 0.72f, 0.75f, 1.0f);
+
+            moon.material = assets->createMaterialFromConstants("Planet_MoonMaterial", mc, MaterialPass::MainColor);
+
+            std::vector<Vertex> verts;
+            std::vector<uint32_t> inds;
+            primitives::buildSphere(verts, inds, 48, 24);
+            geom::generate_tangents(verts, inds);
+
+            moon.mesh = assets->createMesh("Planet_MoonSphere", verts, inds, moon.material);
+        }
+    }
+
+    _bodies.push_back(std::move(earth));
+    _bodies.push_back(std::move(moon));
+}
+
+PlanetSystem::EarthPatch *PlanetSystem::find_earth_patch(const planet::PatchKey &key)
+{
+    auto it = _earth_patch_lookup.find(key);
+    if (it == _earth_patch_lookup.end())
+    {
+        return nullptr;
+    }
+    const uint32_t idx = it->second;
+    if (idx >= _earth_patches.size())
+    {
+        return nullptr;
+    }
+    return &_earth_patches[idx];
+}
+
+void PlanetSystem::clear_earth_patch_cache()
+{
+    if (!_context)
+    {
+        return;
+    }
+
+    ResourceManager *rm = _context->getResources();
+    FrameResources *frame = _context->currentFrame;
+
+    if (rm)
+    {
+        for (EarthPatch &p : _earth_patches)
+        {
+            if (p.vertex_buffer.buffer == VK_NULL_HANDLE)
+            {
+                continue;
+            }
+
+            const AllocatedBuffer vb = p.vertex_buffer;
+            if (frame)
+            {
+                frame->_deletionQueue.push_function([rm, vb]() { rm->destroy_buffer(vb); });
+            }
+            else
+            {
+                rm->destroy_buffer(vb);
+            }
+
+            p.vertex_buffer = {};
+            p.vertex_buffer_address = 0;
+        }
+    }
+
+    _earth_patch_lookup.clear();
+    _earth_patch_lru.clear();
+    _earth_patch_free.clear();
+    _earth_patches.clear();
+}
+
+void PlanetSystem::ensure_earth_patch_index_buffer()
+{
+    if (_earth_patch_index_buffer.buffer != VK_NULL_HANDLE && _earth_patch_index_resolution == _earth_patch_resolution)
+    {
+        return;
+    }
+
+    if (!_context)
+    {
+        return;
+    }
+
+    ResourceManager *rm = _context->getResources();
+    if (!rm)
+    {
+        return;
+    }
+
+    // Resolution changed (or first init): clear existing patch cache and shared index buffer.
+    if (_earth_patch_index_buffer.buffer != VK_NULL_HANDLE)
+    {
+        FrameResources *frame = _context->currentFrame;
+
+        // Destroy per-patch vertex buffers.
+        for (const auto &kv : _earth_patch_lookup)
+        {
+            const uint32_t idx = kv.second;
+            if (idx >= _earth_patches.size())
+            {
+                continue;
+            }
+            EarthPatch &p = _earth_patches[idx];
+            if (p.vertex_buffer.buffer == VK_NULL_HANDLE)
+            {
+                continue;
+            }
+
+            const AllocatedBuffer vb = p.vertex_buffer;
+            if (frame)
+            {
+                frame->_deletionQueue.push_function([rm, vb]() { rm->destroy_buffer(vb); });
+            }
+            else
+            {
+                rm->destroy_buffer(vb);
+            }
+        }
+
+        _earth_patch_lookup.clear();
+        _earth_patch_lru.clear();
+        _earth_patch_free.clear();
+        _earth_patches.clear();
+
+        const AllocatedBuffer ib = _earth_patch_index_buffer;
+        if (frame)
+        {
+            frame->_deletionQueue.push_function([rm, ib]() { rm->destroy_buffer(ib); });
+        }
+        else
+        {
+            rm->destroy_buffer(ib);
+        }
+        _earth_patch_index_buffer = {};
+        _earth_patch_index_count = 0;
+        _earth_patch_index_resolution = 0;
+    }
+
+    std::vector<uint32_t> indices;
+    planet::build_cubesphere_patch_indices(indices, _earth_patch_resolution);
+    _earth_patch_index_count = static_cast<uint32_t>(indices.size());
+    _earth_patch_index_buffer =
+        rm->upload_buffer(indices.data(),
+                          indices.size() * sizeof(uint32_t),
+                          VK_BUFFER_USAGE_INDEX_BUFFER_BIT |
+                              VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT |
+                              VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_BIT_KHR);
+    _earth_patch_index_resolution = _earth_patch_resolution;
+}
+
+void PlanetSystem::ensure_earth_patch_material_layout()
+{
+    if (_earth_patch_material_layout != VK_NULL_HANDLE)
+    {
+        return;
+    }
+
+    if (!_context)
+    {
+        return;
+    }
+
+    DeviceManager *device = _context->getDevice();
+    if (!device)
+    {
+        return;
+    }
+
+    DescriptorLayoutBuilder layoutBuilder;
+    layoutBuilder.add_binding(0, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER);
+    layoutBuilder.add_binding(1, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+    layoutBuilder.add_binding(2, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+    layoutBuilder.add_binding(3, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+    layoutBuilder.add_binding(4, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+    layoutBuilder.add_binding(5, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+
+    _earth_patch_material_layout = layoutBuilder.build(device->device(),
+                                                       VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT,
+                                                       nullptr,
+                                                       VK_DESCRIPTOR_SET_LAYOUT_CREATE_UPDATE_AFTER_BIND_POOL_BIT);
+}
+
+void PlanetSystem::ensure_earth_patch_material_constants_buffer()
+{
+    if (_earth_patch_material_constants_buffer.buffer != VK_NULL_HANDLE)
+    {
+        return;
+    }
+
+    if (!_context)
+    {
+        return;
+    }
+
+    ResourceManager *rm = _context->getResources();
+    DeviceManager *device = _context->getDevice();
+    if (!rm || !device)
+    {
+        return;
+    }
+
+    const GLTFMetallic_Roughness::MaterialConstants constants = make_planet_constants();
+
+    _earth_patch_material_constants_buffer =
+        rm->create_buffer(sizeof(GLTFMetallic_Roughness::MaterialConstants),
+                          VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT,
+                          VMA_MEMORY_USAGE_CPU_TO_GPU);
+
+    if (_earth_patch_material_constants_buffer.buffer == VK_NULL_HANDLE)
+    {
+        return;
+    }
+
+    VmaAllocationInfo allocInfo{};
+    vmaGetAllocationInfo(device->allocator(), _earth_patch_material_constants_buffer.allocation, &allocInfo);
+    auto *mapped = static_cast<GLTFMetallic_Roughness::MaterialConstants *>(allocInfo.pMappedData);
+    if (mapped)
+    {
+        *mapped = constants;
+        vmaFlushAllocation(device->allocator(), _earth_patch_material_constants_buffer.allocation, 0, sizeof(constants));
+    }
+}
+
+void PlanetSystem::ensure_earth_face_materials(const PlanetBody &earth)
+{
+    if (!_context || !earth.material)
+    {
+        return;
+    }
+
+    DeviceManager *device = _context->getDevice();
+    SamplerManager *samplers = _context->getSamplers();
+    AssetManager *assets = _context->assets;
+    TextureCache *textures = _context->textures;
+    if (!device || !assets)
+    {
+        return;
+    }
+
+    ensure_earth_patch_material_layout();
+    ensure_earth_patch_material_constants_buffer();
+
+    if (_earth_patch_material_layout == VK_NULL_HANDLE ||
+        _earth_patch_material_constants_buffer.buffer == VK_NULL_HANDLE)
+    {
+        return;
+    }
+
+    if (!_earth_patch_material_allocator_initialized)
+    {
+        std::vector<DescriptorAllocatorGrowable::PoolSizeRatio> sizes = {
+            {VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER, 1},
+            {VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, 6},
+        };
+        _earth_patch_material_allocator.init(device->device(), 16, sizes);
+        _earth_patch_material_allocator_initialized = true;
+    }
+
+    VkSampler tileSampler = samplers ? samplers->linearClampEdge() : VK_NULL_HANDLE;
+    if (tileSampler == VK_NULL_HANDLE && samplers)
+    {
+        tileSampler = samplers->defaultLinear();
+    }
+    if (tileSampler == VK_NULL_HANDLE)
+    {
+        return;
+    }
+
+    VkImageView checker = assets->fallback_checkerboard_view();
+    VkImageView white = assets->fallback_white_view();
+    VkImageView flatNormal = assets->fallback_flat_normal_view();
+    VkImageView black = assets->fallback_black_view();
+
+    if (checker == VK_NULL_HANDLE) checker = white;
+    if (white == VK_NULL_HANDLE) white = checker;
+    if (flatNormal == VK_NULL_HANDLE) flatNormal = white;
+    if (black == VK_NULL_HANDLE) black = white;
+
+    auto face_legacy = [](planet::CubeFace f) -> const char * {
+        switch (f)
+        {
+            case planet::CubeFace::PosX: return "px";
+            case planet::CubeFace::NegX: return "nx";
+            case planet::CubeFace::PosY: return "py";
+            case planet::CubeFace::NegY: return "ny";
+            case planet::CubeFace::PosZ: return "pz";
+            case planet::CubeFace::NegZ: return "nz";
+        }
+        return "px";
+    };
+
+    for (size_t face_index = 0; face_index < _earth_face_materials.size(); ++face_index)
+    {
+        MaterialInstance &mat = _earth_face_materials[face_index];
+
+        mat.pipeline = earth.material->data.pipeline;
+        mat.passType = earth.material->data.passType;
+
+        if (mat.materialSet == VK_NULL_HANDLE)
+        {
+            mat.materialSet = _earth_patch_material_allocator.allocate(device->device(), _earth_patch_material_layout);
+
+            DescriptorWriter writer;
+            writer.write_buffer(0,
+                                _earth_patch_material_constants_buffer.buffer,
+                                sizeof(GLTFMetallic_Roughness::MaterialConstants),
+                                0,
+                                VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER);
+            writer.write_image(1,
+                               checker,
+                               tileSampler,
+                               VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
+                               VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+            writer.write_image(2,
+                               white,
+                               tileSampler,
+                               VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
+                               VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+            writer.write_image(3,
+                               flatNormal,
+                               tileSampler,
+                               VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
+                               VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+            writer.write_image(4,
+                               white,
+                               tileSampler,
+                               VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
+                               VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+            writer.write_image(5,
+                               black,
+                               tileSampler,
+                               VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
+                               VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+            writer.update_set(device->device(), mat.materialSet);
+
+            if (textures && tileSampler != VK_NULL_HANDLE)
+            {
+                const planet::CubeFace face = static_cast<planet::CubeFace>(face_index);
+                const std::string rel = fmt::format("planets/earth/albedo/L0/{}.ktx2", face_legacy(face));
+
+                TextureCache::TextureKey tk{};
+                tk.kind = TextureCache::TextureKey::SourceKind::FilePath;
+                tk.path = assets->assetPath(rel);
+                tk.srgb = true;
+                tk.mipmapped = true;
+
+                TextureCache::TextureHandle h = textures->request(tk, tileSampler);
+                textures->watchBinding(h, mat.materialSet, 1u, tileSampler, checker);
+                textures->pin(h);
+            }
+        }
+    }
+}
+
+PlanetSystem::EarthPatch *PlanetSystem::get_or_create_earth_patch(const PlanetBody &earth,
+                                                                  const planet::PatchKey &key,
+                                                                  uint32_t frame_index)
+{
+    if (EarthPatch *p = find_earth_patch(key))
+    {
+        p->last_used_frame = frame_index;
+        _earth_patch_lru.splice(_earth_patch_lru.begin(), _earth_patch_lru, p->lru_it);
+        return p;
+    }
+
+    if (!_context)
+    {
+        return nullptr;
+    }
+
+    ResourceManager *rm = _context->getResources();
+    DeviceManager *device = _context->getDevice();
+    if (!rm || !device)
+    {
+        return nullptr;
+    }
+
+    if (_earth_patch_index_buffer.buffer == VK_NULL_HANDLE || _earth_patch_index_count == 0)
+    {
+        return nullptr;
+    }
+
+    const glm::vec4 vertex_color =
+        _earth_debug_tint_patches_by_lod ? debug_color_for_level(key.level) : glm::vec4(1.0f);
+
+    std::vector<Vertex> vertices;
+    const glm::dvec3 patch_center_dir =
+        planet::build_cubesphere_patch_vertices(vertices,
+                                                earth.radius_m,
+                                                key.face,
+                                                key.level,
+                                                key.x,
+                                                key.y,
+                                                _earth_patch_resolution,
+                                                vertex_color);
+
+    if (vertices.empty())
+    {
+        return nullptr;
+    }
+
+    const PatchBoundsData bounds = compute_patch_bounds(vertices);
+
+    AllocatedBuffer vb =
+        rm->upload_buffer(vertices.data(),
+                          vertices.size() * sizeof(Vertex),
+                          VK_BUFFER_USAGE_STORAGE_BUFFER_BIT |
+                              VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT |
+                              VK_BUFFER_USAGE_ACCELERATION_STRUCTURE_BUILD_INPUT_READ_ONLY_BIT_KHR);
+    if (vb.buffer == VK_NULL_HANDLE)
+    {
+        return nullptr;
+    }
+
+    VkBufferDeviceAddressInfo addrInfo{.sType = VK_STRUCTURE_TYPE_BUFFER_DEVICE_ADDRESS_INFO};
+    addrInfo.buffer = vb.buffer;
+    VkDeviceAddress addr = vkGetBufferDeviceAddress(device->device(), &addrInfo);
+
+    uint32_t idx = 0;
+    if (!_earth_patch_free.empty())
+    {
+        idx = _earth_patch_free.back();
+        _earth_patch_free.pop_back();
+    }
+    else
+    {
+        idx = static_cast<uint32_t>(_earth_patches.size());
+        _earth_patches.emplace_back();
+    }
+
+    if (idx >= _earth_patches.size())
+    {
+        return nullptr;
+    }
+
+    EarthPatch &p = _earth_patches[idx];
+    p.key = key;
+    p.state = EarthPatchState::Ready;
+    p.vertex_buffer = vb;
+    p.vertex_buffer_address = addr;
+    p.bounds_origin = bounds.origin;
+    p.bounds_extents = bounds.extents;
+    p.bounds_sphere_radius = bounds.sphere_radius;
+    p.patch_center_dir = patch_center_dir;
+    p.last_used_frame = frame_index;
+    _earth_patch_lru.push_front(idx);
+    p.lru_it = _earth_patch_lru.begin();
+
+    _earth_patch_lookup.emplace(key, idx);
+    return &p;
+}
+
+void PlanetSystem::trim_earth_patch_cache()
+{
+    if (_earth_patch_cache_max == 0)
+    {
+        return;
+    }
+
+    if (_earth_patch_lookup.size() <= static_cast<size_t>(_earth_patch_cache_max))
+    {
+        return;
+    }
+
+    if (!_context)
+    {
+        return;
+    }
+
+    ResourceManager *rm = _context->getResources();
+    if (!rm)
+    {
+        return;
+    }
+
+    FrameResources *frame = _context->currentFrame;
+    const uint32_t now = _earth_patch_frame_stamp;
+
+    size_t guard = 0;
+    const size_t guard_limit = _earth_patch_lru.size();
+
+    while (_earth_patch_lookup.size() > static_cast<size_t>(_earth_patch_cache_max) && !_earth_patch_lru.empty())
+    {
+        if (guard++ >= guard_limit)
+        {
+            // No evictable patches (all used this frame). Avoid thrashing.
+            break;
+        }
+
+        const uint32_t idx = _earth_patch_lru.back();
+        if (idx >= _earth_patches.size())
+        {
+            _earth_patch_lru.pop_back();
+            continue;
+        }
+
+        EarthPatch &p = _earth_patches[idx];
+        if (p.last_used_frame == now)
+        {
+            // Keep all patches referenced this frame.
+            _earth_patch_lru.splice(_earth_patch_lru.begin(), _earth_patch_lru, p.lru_it);
+            continue;
+        }
+
+        // Made progress: we found an evictable patch.
+        guard = 0;
+
+        _earth_patch_lru.erase(p.lru_it);
+        _earth_patch_lookup.erase(p.key);
+
+        if (p.vertex_buffer.buffer != VK_NULL_HANDLE)
+        {
+            const AllocatedBuffer vb = p.vertex_buffer;
+            if (frame)
+            {
+                frame->_deletionQueue.push_function([rm, vb]() { rm->destroy_buffer(vb); });
+            }
+            else
+            {
+                rm->destroy_buffer(vb);
+            }
+        }
+
+        p = EarthPatch{};
+        _earth_patch_free.push_back(idx);
+    }
+}
+
+void PlanetSystem::update_and_emit(const SceneManager &scene, DrawContext &draw_context)
+{
+    if (!_enabled)
+    {
+        return;
+    }
+
+    ensure_bodies_created();
+
+    const WorldVec3 origin_world = scene.get_world_origin();
+
+    // Earth: quadtree patches.
+    {
+        using Clock = std::chrono::steady_clock;
+
+        PlanetBody *earth = get_body(BodyID::Earth);
+        if (earth && earth->visible && earth->material && _context)
+        {
+            if (_earth_patch_cache_dirty)
+            {
+                clear_earth_patch_cache();
+                _earth_patch_cache_dirty = false;
+            }
+
+            const Clock::time_point t0 = Clock::now();
+
+            _earth_quadtree.set_settings(_earth_quadtree_settings);
+
+            const VkExtent2D logical_extent = _context->getLogicalRenderExtent();
+            const WorldVec3 cam_world = scene.getMainCamera().position_world;
+
+            const Clock::time_point t_q0 = Clock::now();
+            _earth_quadtree.update(earth->center_world,
+                                   earth->radius_m,
+                                   cam_world,
+                                   origin_world,
+                                   scene.getSceneData(),
+                                   logical_extent);
+            const Clock::time_point t_q1 = Clock::now();
+
+            ensure_earth_patch_index_buffer();
+            ensure_earth_face_materials(*earth);
+            if (_context->textures)
+            {
+                for (const MaterialInstance &mat : _earth_face_materials)
+                {
+                    if (mat.materialSet != VK_NULL_HANDLE)
+                    {
+                        _context->textures->markSetUsed(mat.materialSet, _context->frameIndex);
+                    }
+                }
+            }
+
+            size_t desired_capacity =
+                static_cast<size_t>(_earth_patches.size()) +
+                static_cast<size_t>(_earth_patch_create_budget_per_frame) +
+                32u;
+            if (_earth_patch_cache_max != 0)
+            {
+                desired_capacity = std::max(
+                    desired_capacity,
+                    static_cast<size_t>(_earth_patch_cache_max) +
+                        static_cast<size_t>(_earth_patch_create_budget_per_frame) +
+                        32u);
+            }
+            if (_earth_patches.capacity() < desired_capacity)
+            {
+                _earth_patches.reserve(desired_capacity);
+            }
+
+            uint32_t created_patches = 0;
+            double ms_patch_create = 0.0;
+            const uint32_t max_create = _earth_patch_create_budget_per_frame;
+            const double max_create_ms =
+                (_earth_patch_create_budget_ms > 0.0f) ? static_cast<double>(_earth_patch_create_budget_ms) : 0.0;
+            const uint32_t frame_index = ++_earth_patch_frame_stamp;
+
+            const Clock::time_point t_emit0 = Clock::now();
+            std::vector<uint32_t> ready_patch_indices;
+            ready_patch_indices.reserve(_earth_quadtree.visible_leaves().size());
+
+            for (const planet::PatchKey &k : _earth_quadtree.visible_leaves())
+            {
+                EarthPatch *patch = find_earth_patch(k);
+                {
+                    if (patch)
+                    {
+                        patch->last_used_frame = frame_index;
+                        _earth_patch_lru.splice(_earth_patch_lru.begin(), _earth_patch_lru, patch->lru_it);
+                    }
+                    else
+                    {
+                        const bool hit_count_budget = (max_create != 0u) && (created_patches >= max_create);
+                        const bool hit_time_budget = (max_create_ms > 0.0) && (ms_patch_create >= max_create_ms);
+                        if (!hit_count_budget && !hit_time_budget)
+                        {
+                            const Clock::time_point t_c0 = Clock::now();
+                            patch = get_or_create_earth_patch(*earth, k, frame_index);
+                            const Clock::time_point t_c1 = Clock::now();
+
+                            if (patch)
+                            {
+                                created_patches++;
+                            }
+                            ms_patch_create += std::chrono::duration<double, std::milli>(t_c1 - t_c0).count();
+                        }
+                    }
+                }
+                if (patch)
+                {
+                    const uint32_t idx = static_cast<uint32_t>(patch - _earth_patches.data());
+                    ready_patch_indices.push_back(idx);
+                }
+            }
+
+            for (uint32_t idx : ready_patch_indices)
+            {
+                if (idx >= _earth_patches.size())
+                {
+                    continue;
+                }
+
+                EarthPatch &patch = _earth_patches[idx];
+                if (patch.state != EarthPatchState::Ready ||
+                    patch.vertex_buffer.buffer == VK_NULL_HANDLE ||
+                    patch.vertex_buffer_address == 0 ||
+                    _earth_patch_index_buffer.buffer == VK_NULL_HANDLE ||
+                    _earth_patch_index_count == 0)
+                {
+                    continue;
+                }
+
+                const uint32_t face_index = static_cast<uint32_t>(patch.key.face);
+                if (face_index >= _earth_face_materials.size())
+                {
+                    continue;
+                }
+                MaterialInstance *material = &_earth_face_materials[face_index];
+                if (material->materialSet == VK_NULL_HANDLE || material->pipeline == nullptr)
+                {
+                    continue;
+                }
+
+                const WorldVec3 patch_center_world =
+                    earth->center_world + patch.patch_center_dir * earth->radius_m;
+                const glm::vec3 patch_center_local = world_to_local(patch_center_world, origin_world);
+                const glm::mat4 transform = glm::translate(glm::mat4(1.0f), patch_center_local);
+
+                Bounds b{};
+                b.origin = patch.bounds_origin;
+                b.extents = patch.bounds_extents;
+                b.sphereRadius = patch.bounds_sphere_radius;
+                b.type = BoundsType::Box;
+
+                RenderObject obj{};
+                obj.indexCount = _earth_patch_index_count;
+                obj.firstIndex = 0;
+                obj.indexBuffer = _earth_patch_index_buffer.buffer;
+                obj.vertexBuffer = patch.vertex_buffer.buffer;
+                obj.vertexBufferAddress = patch.vertex_buffer_address;
+                obj.material = material;
+                obj.bounds = b;
+                obj.transform = transform;
+                // Planet terrain patches are not meaningful RT occluders; skip BLAS/TLAS builds.
+                obj.sourceMesh = nullptr;
+                obj.surfaceIndex = 0;
+                obj.objectID = draw_context.nextID++;
+                obj.ownerType = RenderObject::OwnerType::MeshInstance;
+                obj.ownerName = earth->name;
+
+                draw_context.OpaqueSurfaces.push_back(obj);
+            }
+            const Clock::time_point t_emit1 = Clock::now();
+
+            trim_earth_patch_cache();
+
+            const uint32_t visible_patches = static_cast<uint32_t>(_earth_quadtree.visible_leaves().size());
+            const uint32_t n = _earth_patch_resolution;
+            const uint32_t patch_tris = (n >= 2u) ? (2u * (n - 1u) * (n + 3u)) : 0u;
+            const uint32_t estimated_tris = patch_tris * visible_patches;
+
+            _earth_debug_stats = {};
+            _earth_debug_stats.quadtree = _earth_quadtree.stats();
+            _earth_debug_stats.visible_patches = visible_patches;
+            _earth_debug_stats.created_patches = created_patches;
+            _earth_debug_stats.patch_cache_size = static_cast<uint32_t>(_earth_patch_lookup.size());
+            _earth_debug_stats.estimated_triangles = estimated_tris;
+            _earth_debug_stats.ms_quadtree = static_cast<float>(std::chrono::duration<double, std::milli>(t_q1 - t_q0).count());
+            _earth_debug_stats.ms_patch_create = static_cast<float>(ms_patch_create);
+            const double ms_emit_total = std::chrono::duration<double, std::milli>(t_emit1 - t_emit0).count();
+            _earth_debug_stats.ms_emit = static_cast<float>(std::max(0.0, ms_emit_total - ms_patch_create));
+            _earth_debug_stats.ms_total = static_cast<float>(std::chrono::duration<double, std::milli>(Clock::now() - t0).count());
+        }
+    }
+
+    // Other bodies (moon etc.): regular mesh instances.
+    for (size_t body_index = 0; body_index < _bodies.size(); ++body_index)
+    {
+        PlanetBody &b = _bodies[body_index];
+
+        if (body_index == static_cast<size_t>(BodyID::Earth))
+        {
+            continue;
+        }
+
+        if (!b.visible || !b.mesh || b.mesh->surfaces.empty())
+        {
+            continue;
+        }
+
+        const glm::vec3 t_local = world_to_local(b.center_world, origin_world);
+        const float r = static_cast<float>(b.radius_m);
+        const glm::vec3 s = glm::vec3(r * 2.0f); // primitive sphere radius is 0.5
+        const glm::quat q = glm::quat(1.0f, 0.0f, 0.0f, 0.0f);
+        const glm::mat4 transform = make_trs_matrix(t_local, q, s);
+
+        uint32_t surface_index = 0;
+        for (const GeoSurface &surf : b.mesh->surfaces)
+        {
+            RenderObject obj{};
+            obj.indexCount = surf.count;
+            obj.firstIndex = surf.startIndex;
+            obj.indexBuffer = b.mesh->meshBuffers.indexBuffer.buffer;
+            obj.vertexBuffer = b.mesh->meshBuffers.vertexBuffer.buffer;
+            obj.vertexBufferAddress = b.mesh->meshBuffers.vertexBufferAddress;
+            obj.material = surf.material ? &surf.material->data : nullptr;
+            obj.bounds = surf.bounds;
+            obj.transform = transform;
+            obj.sourceMesh = b.mesh.get();
+            obj.surfaceIndex = surface_index++;
+            obj.objectID = draw_context.nextID++;
+            obj.ownerType = RenderObject::OwnerType::MeshInstance;
+            obj.ownerName = b.name;
+
+            if (obj.material && obj.material->passType == MaterialPass::Transparent)
+            {
+                draw_context.TransparentSurfaces.push_back(obj);
+            }
+            else
+            {
+                draw_context.OpaqueSurfaces.push_back(obj);
+            }
+        }
+    }
+}

src/scene/planet/planet_system.h

@@ -0,0 +1,148 @@
+#pragma once
+
+#include <core/world.h>
+#include <core/descriptor/descriptors.h>
+#include <scene/planet/planet_quadtree.h>
+
+#include <cstdint>
+#include <array>
+#include <list>
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+class EngineContext;
+class SceneManager;
+struct DrawContext;
+class MeshAsset;
+struct GLTFMaterial;
+
+class PlanetSystem
+{
+public:
+    enum class BodyID : uint8_t
+    {
+        Earth = 0,
+        Moon = 1,
+    };
+
+    struct EarthDebugStats
+    {
+        planet::PlanetQuadtree::Stats quadtree{};
+        uint32_t visible_patches = 0;
+        uint32_t created_patches = 0;
+        uint32_t patch_cache_size = 0;
+        uint32_t estimated_triangles = 0;
+        float ms_quadtree = 0.0f;
+        float ms_patch_create = 0.0f;
+        float ms_emit = 0.0f;
+        float ms_total = 0.0f;
+    };
+
+    struct PlanetBody
+    {
+        std::string name;
+        WorldVec3 center_world{0.0, 0.0, 0.0};
+        double radius_m = 1.0;
+        bool visible = true;
+
+        std::shared_ptr<MeshAsset> mesh;
+        std::shared_ptr<GLTFMaterial> material;
+    };
+
+    void init(EngineContext *context);
+    void cleanup();
+
+    void update_and_emit(const SceneManager &scene, DrawContext &draw_context);
+
+    bool enabled() const { return _enabled; }
+    void set_enabled(bool enabled) { _enabled = enabled; }
+
+    const PlanetBody *get_body(BodyID id) const;
+    PlanetBody *get_body(BodyID id);
+    const std::vector<PlanetBody> &bodies() const { return _bodies; }
+
+    const planet::PlanetQuadtree::Settings &earth_quadtree_settings() const { return _earth_quadtree_settings; }
+    void set_earth_quadtree_settings(const planet::PlanetQuadtree::Settings &settings) { _earth_quadtree_settings = settings; }
+    const EarthDebugStats &earth_debug_stats() const { return _earth_debug_stats; }
+
+    uint32_t earth_patch_create_budget_per_frame() const { return _earth_patch_create_budget_per_frame; }
+    void set_earth_patch_create_budget_per_frame(uint32_t budget) { _earth_patch_create_budget_per_frame = budget; }
+
+    float earth_patch_create_budget_ms() const { return _earth_patch_create_budget_ms; }
+    void set_earth_patch_create_budget_ms(float budget_ms) { _earth_patch_create_budget_ms = budget_ms; }
+
+    uint32_t earth_patch_cache_max() const { return _earth_patch_cache_max; }
+    void set_earth_patch_cache_max(uint32_t max_patches) { _earth_patch_cache_max = max_patches; }
+
+    bool earth_debug_tint_patches_by_lod() const { return _earth_debug_tint_patches_by_lod; }
+    void set_earth_debug_tint_patches_by_lod(bool enabled);
+
+private:
+    enum class EarthPatchState : uint8_t
+    {
+        Allocating = 0,
+        Ready = 1,
+    };
+
+    struct EarthPatch
+    {
+        planet::PatchKey key{};
+        EarthPatchState state = EarthPatchState::Allocating;
+
+        AllocatedBuffer vertex_buffer{};
+        VkDeviceAddress vertex_buffer_address = 0;
+
+        glm::vec3 bounds_origin{0.0f};
+        glm::vec3 bounds_extents{0.5f};
+        float bounds_sphere_radius = 0.5f;
+
+        WorldVec3 patch_center_dir{0.0, 0.0, 1.0};
+        uint32_t last_used_frame = 0;
+        std::list<uint32_t>::iterator lru_it{};
+    };
+
+    void ensure_bodies_created();
+    EarthPatch *find_earth_patch(const planet::PatchKey &key);
+    EarthPatch *get_or_create_earth_patch(const PlanetBody &earth,
+                                          const planet::PatchKey &key,
+                                          uint32_t frame_index);
+    void ensure_earth_patch_index_buffer();
+    void ensure_earth_patch_material_layout();
+    void ensure_earth_patch_material_constants_buffer();
+    void ensure_earth_face_materials(const PlanetBody &earth);
+    void clear_earth_patch_cache();
+    void trim_earth_patch_cache();
+
+    EngineContext *_context = nullptr;
+    bool _enabled = true;
+    std::vector<PlanetBody> _bodies;
+
+    // Earth cube-sphere quadtree
+    planet::PlanetQuadtree _earth_quadtree{};
+    planet::PlanetQuadtree::Settings _earth_quadtree_settings{};
+    EarthDebugStats _earth_debug_stats{};
+    std::unordered_map<planet::PatchKey, uint32_t, planet::PatchKeyHash> _earth_patch_lookup;
+    std::vector<EarthPatch> _earth_patches;
+    std::vector<uint32_t> _earth_patch_free;
+    std::list<uint32_t> _earth_patch_lru;
+    AllocatedBuffer _earth_patch_index_buffer{};
+    uint32_t _earth_patch_index_count = 0;
+    uint32_t _earth_patch_index_resolution = 0;
+
+    VkDescriptorSetLayout _earth_patch_material_layout = VK_NULL_HANDLE;
+    DescriptorAllocatorGrowable _earth_patch_material_allocator{};
+    bool _earth_patch_material_allocator_initialized = false;
+    AllocatedBuffer _earth_patch_material_constants_buffer{};
+    std::array<MaterialInstance, 6> _earth_face_materials{};
+
+    uint32_t _earth_patch_frame_stamp = 0;
+    uint32_t _earth_patch_resolution = 33;
+    uint32_t _earth_patch_create_budget_per_frame = 16;
+    float _earth_patch_create_budget_ms = 2.0f;
+    uint32_t _earth_patch_cache_max = 2048;
+
+    bool _earth_debug_tint_patches_by_lod = false;
+    bool _earth_patch_cache_dirty = false;
+};

src/scene/vk_scene.cpp

@@ -4,6 +4,7 @@
 #include <unordered_set>
 #include <chrono>
 
+#include "scene/planet/planet_system.h"
 #include "core/device/swapchain.h"
 #include "core/context.h"
 #include "core/config.h"
@@ -19,6 +20,8 @@
 #include "core/config.h"
 #include <fmt/core.h>
 
+SceneManager::SceneManager() = default;
+
 SceneManager::~SceneManager()
 {
     fmt::println("[SceneManager] dtor: loadedScenes={} dynamicGLTFInstances={} pendingGLTFRelease={}",
@@ -111,7 +114,6 @@ void SceneManager::init(EngineContext *context)
 {
     _context = context;
 
-    mainCamera.velocity = glm::vec3(0.f);
     mainCamera.position_world = WorldVec3(30.0, 0.0, 85.0);
     mainCamera.orientation = glm::quat(1.0f, 0.0f, 0.0f, 0.0f);
 
@@ -119,7 +121,12 @@ void SceneManager::init(EngineContext *context)
     sceneData.sunlightDirection = glm::vec4(-0.2f, -1.0f, -0.3f, 1.0f);
     sceneData.sunlightColor = glm::vec4(1.0f, 1.0f, 1.0f, 3.0f);
 
+    cameraRig.init(*this, mainCamera);
+
     _camera_position_local = world_to_local(mainCamera.position_world, _origin_world);
+
+    _planetSystem = std::make_unique<PlanetSystem>();
+    _planetSystem->init(_context);
 }
 
 void SceneManager::update_scene()
@@ -151,7 +158,25 @@ void SceneManager::update_scene()
     mainDrawContext.nextID = 1;
     mainDrawContext.gltfNodeLocalOverrides = nullptr;
 
-    mainCamera.update();
+    // Simple per-frame dt (seconds) for animations and camera behavior.
+    auto now = std::chrono::steady_clock::now();
+    if (_lastFrameTime.time_since_epoch().count() == 0)
+    {
+        _lastFrameTime = now;
+    }
+    float dt = std::chrono::duration<float>(now - _lastFrameTime).count();
+    _lastFrameTime = now;
+    if (dt < 0.f)
+    {
+        dt = 0.f;
+    }
+    if (dt > 0.1f)
+    {
+        dt = 0.1f;
+    }
+    _deltaTime = dt;
+
+    cameraRig.update(*this, mainCamera, dt);
 
     // Floating origin: keep render-local coordinates near (0,0,0) by shifting the origin
     // when the camera drifts too far in world space.
@@ -171,24 +196,6 @@ void SceneManager::update_scene()
 
     _camera_position_local = world_to_local(mainCamera.position_world, _origin_world);
 
-    // Simple per-frame dt (seconds) for animations
-    auto now = std::chrono::steady_clock::now();
-    if (_lastFrameTime.time_since_epoch().count() == 0)
-    {
-        _lastFrameTime = now;
-    }
-    float dt = std::chrono::duration<float>(now - _lastFrameTime).count();
-    _lastFrameTime = now;
-    if (dt < 0.f)
-    {
-        dt = 0.f;
-    }
-    if (dt > 0.1f)
-    {
-        dt = 0.1f;
-    }
-    _deltaTime = dt;
-
     auto tagOwner = [&](RenderObject::OwnerType type, const std::string &name,
                         size_t opaqueBegin, size_t transpBegin)
     {
@@ -425,6 +432,11 @@ void SceneManager::update_scene()
         sceneData.rtParams  = glm::vec4(ss.hybridRayNoLThreshold, ss.enabled ? 1.0f : 0.0f, 0.0f, 0.0f);
     }
 
+    if (_planetSystem)
+    {
+        _planetSystem->update_and_emit(*this, mainDrawContext);
+    }
+
     // Fill punctual lights into GPUSceneData
     const uint32_t lightCount = static_cast<uint32_t>(std::min(pointLights.size(), static_cast<size_t>(kMaxPunctualLights)));
     for (uint32_t i = 0; i < lightCount; ++i)
@@ -515,6 +527,12 @@ std::shared_ptr<LoadedGLTF> SceneManager::getScene(const std::string &name)
 
 void SceneManager::cleanup()
 {
+    if (_planetSystem)
+    {
+        _planetSystem->cleanup();
+        _planetSystem.reset();
+    }
+
     // Explicitly clear dynamic instances first to drop any extra shared_ptrs
     // that could keep GPU resources alive.
     clearMeshInstances();

src/scene/vk_scene.h

@@ -2,6 +2,7 @@
 #include <core/types.h>
 #include <core/world.h>
 #include <scene/camera.h>
+#include <scene/camera/camera_rig.h>
 #include <unordered_map>
 #include <memory>
 #include <optional>
@@ -11,6 +12,7 @@
 
 #include "scene/vk_loader.h"
 class EngineContext;
+class PlanetSystem;
 
 struct RenderObject
 {
@@ -60,6 +62,7 @@ struct DrawContext
 class SceneManager
 {
 public:
+    SceneManager();
     ~SceneManager();
     void init(EngineContext *context);
 
@@ -68,6 +71,9 @@ public:
     void update_scene();
 
     Camera &getMainCamera() { return mainCamera; }
+    const Camera &getMainCamera() const { return mainCamera; }
+    CameraRig &getCameraRig() { return cameraRig; }
+    const CameraRig &getCameraRig() const { return cameraRig; }
 
     WorldVec3 get_world_origin() const { return _origin_world; }
     glm::vec3 get_camera_local_position() const { return _camera_position_local; }
@@ -220,6 +226,8 @@ public:
 
     const PickingDebug &getPickingDebug() const { return pickingDebug; }
 
+    PlanetSystem *get_planet_system() const { return _planetSystem.get(); }
+
     // Returns the LoadedGLTF scene for a named GLTF instance, or nullptr if not found.
     std::shared_ptr<LoadedGLTF> getGLTFInstanceScene(const std::string &instanceName) const;
 
@@ -227,6 +235,7 @@ private:
     EngineContext *_context = nullptr;
 
     Camera mainCamera = {};
+    CameraRig cameraRig{};
     GPUSceneData sceneData = {};
     DrawContext mainDrawContext;
     std::vector<PointLight> pointLights;
@@ -248,5 +257,7 @@ private:
     // GPU resources that might still be in-flight.
     std::vector<std::shared_ptr<LoadedGLTF>> pendingGLTFRelease;
 
+    std::unique_ptr<PlanetSystem> _planetSystem;
+
     PickingDebug pickingDebug{};
 };

third_party/CMakeLists.txt

@@ -1,5 +1,3 @@
-find_package(Vulkan REQUIRED)
-
 add_library(vkbootstrap STATIC)
 add_library(glm INTERFACE)
 add_library(vma INTERFACE)
@@ -62,11 +60,6 @@ target_include_directories(ImGuizmo PUBLIC
   imgui
 )
 
-target_compile_definitions(ImGuizmo
-        PRIVATE
-        IMGUI_DEFINE_MATH_OPERATORS
-)
-
 target_link_libraries(ImGuizmo PUBLIC imgui)
 
 add_subdirectory(BVH)