EDIT: Docs and minor bug fixed

docs/ASSETS.md

@@ -0,0 +1,23 @@
+**Assets & Paths**
+
+- Default locations
+  - `assets/` for models/textures and `shaders/` for GLSL live at the repo root.
+  - The engine auto‑detects these folders by walking up from the working directory.
+
+- Override root via environment
+  - Set `VKG_ASSET_ROOT` to a directory containing `assets/` and/or `shaders/`.
+  - Example: `VKG_ASSET_ROOT=/home/user/vulkan-engine ./bin/vulkan_engine`
+
+- API
+  - Use `AssetLocator` through `EngineContext::getAssets()` helpers:
+    - `shaderPath("name.spv")` resolves a shader.
+    - `assetPath("relative/or/absolute")` resolves runtime assets.
+    - `modelPath("some.glb")` is an alias for `assetPath`.
+
+- Sample content
+  - The engine loads `assets/police_office.glb` by default in `VulkanEngine::init()`.
+  - Ensure this file (and any textures it references) exists under your asset root, or adjust the path used by the sample scene.
+
+- Materials & sRGB
+  - See `docs/asset_manager.md` for mesh/material creation and sRGB/UNORM handling.
+

docs/BUILD.md

@@ -0,0 +1,38 @@
+**Build & Environment**
+
+- Prerequisites
+  - Vulkan SDK installed and `VULKAN_SDK` set.
+  - A C++20 compiler and CMake ≥ 3.8.
+  - GPU drivers with Vulkan 1.2+.
+
+- Configure
+  - `cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug`
+  - Re-run configure after toolchain or dependency changes.
+
+- Build (single-config)
+  - `cmake --build build --target vulkan_engine`
+
+- Build (multi-config, e.g., MSVC)
+  - `cmake --build build --config Release`
+
+- Run
+  - `./bin/vulkan_engine` (Linux/macOS)
+  - `bin/vulkan_engine.exe` (Windows)
+
+- Shaders
+  - CMake compiles GLSL via `glslangValidator` to SPIR‑V targeting Vulkan 1.2:
+    - Files under `shaders/*.vert|*.frag|*.comp` are rebuilt on `cmake --build`.
+  - Windows helper: `./compile_shaders.ps1` uses `glslc` with `--target-env=vulkan1.3` and supports additional stages (mesh/task/ray tracing).
+  - Ensure `glslangValidator`/`glslc` is on `PATH`. See `docs/SHADERS.md`.
+
+- Windows SDK note
+  - `CMakeLists.txt` includes a default SDK path for Windows `1.3.296.0`:
+    - Update the path or set `VULKAN_SDK` accordingly if your version differs.
+
+- Third‑party deps
+  - Vendored under `third_party/` and brought in via CMake. Do not edit headers directly; update through targets.
+
+- Validation Layers
+  - Enabled in Debug (`kUseValidationLayers = true` in `src/core/config.h`).
+  - Disable by building Release or toggling the flag during local experimentation.
+

docs/FrameResources.md

@@ -0,0 +1,34 @@
+## Frame Resources: Per-Frame Command, Sync, and Transient Descriptors
+
+Per-frame struct that owns the command buffer, semaphores/fence, a transient descriptor allocator, and a small deletion queue. Frames are indexed by `FRAME_OVERLAP` (currently 2) and rotated by `_frameNumber` in `VulkanEngine`.
+
+- File: `src/core/frame_resources.h/.cpp`
+
+### Responsibilities
+- Command recording: `_mainCommandBuffer` allocated from a per-frame `_commandPool` with RESET flag.
+- Synchronization: `_swapchainSemaphore` (image acquired), `_renderSemaphore` (render finished), `_renderFence` (CPU wait per frame).
+- Transient descriptors: `_frameDescriptors` is a `DescriptorAllocatorGrowable` cleared every frame via `clear_pools()`.
+- Lifetime: `_deletionQueue` holds lambdas for transient GPU objects created during the frame (buffers/images) and is flushed at the start of the next frame.
+
+### Frame Flow (engine side)
+- Start of frame:
+  - Wait on `_renderFence` (previous GPU work for this frame index), flush `_deletionQueue`, and clear `_frameDescriptors` pools.
+  - Acquire swapchain image signaling `_swapchainSemaphore`.
+  - Reset `_renderFence` and `_mainCommandBuffer`; begin recording.
+  - Publish `currentFrame` pointer and `drawExtent` on `EngineContext`.
+- Graph build and execute:
+  - Render Graph is cleared and rebuilt; `ResourceManager::register_upload_pass(...)` is added first if there are pending uploads.
+  - Passes record using the published `currentFrame` to allocate transient descriptor sets and to enqueue per-frame cleanups.
+- Submit and present:
+  - Submit `cmd` with wait on `_swapchainSemaphore` and signal `_renderSemaphore`, fence `_renderFence`.
+  - Present waits on `_renderSemaphore`.
+
+### Do/Don’t
+- Do use `currentFrame->_frameDescriptors` for descriptor sets that live only for this frame.
+- Do push transient resource destruction into `currentFrame->_deletionQueue`.
+- Don’t stash per-frame descriptor sets across frames — they are reset on `clear_pools()`.
+
+### Extending
+- If a pass needs additional short-lived command buffers, allocate them from `_commandPool` and reset per frame.
+- If you add frames-in-flight, update `FRAME_OVERLAP` and verify fences/semaphores and swapchain image acquisition logic.
+

docs/RUNTIME.md

@@ -0,0 +1,21 @@
+**Runtime Controls & Debug UI**
+
+- Camera
+  - Move: `W/A/S/D`
+  - Look: hold Right Mouse Button
+  - Mouse wheel: adjust movement speed
+  - Ctrl + wheel: adjust FOV (30°..110°)
+
+- Windows (ImGui)
+  - Background: choose compute background effect and `Render Scale`.
+  - Stats: frame/draw/update timings, triangle and draw counts.
+  - GPU/Resources: per‑frame allocations and render‑graph resource view.
+  - Pipelines: list graphics pipelines and hot‑reload changed shaders.
+  - Targets: swapchain/draw extent/format info.
+  - PostFX: tonemap operator (Reinhard/ACES) and exposure.
+  - Scene: counts of opaque/transparent draws.
+
+- Shadow Modes
+  - Cascaded shadow mapping (CSM) is the default; cascades are created per‑frame via the render graph.
+  - If ray tracing extensions and device support are present, ray‑traced shadows can be enabled via `_context->shadowSettings.mode` (see `src/core/config.h` and usage in `LightingPass`).
+

docs/RayTracing.md

@@ -0,0 +1,42 @@
+## Ray Tracing Manager: BLAS Cache and Per-Frame TLAS
+
+Optional subsystem that enables hybrid or full ray traced shadows via Ray Query. It builds and caches BLAS per mesh and rebuilds a TLAS from the current `DrawContext` when enabled.
+
+- Files: `src/core/vk_raytracing.h/.cpp`
+
+### Device Feature & Extension Enablement
+- Feature detection happens in `DeviceManager::init_vulkan()` and sets:
+  - `VK_KHR_acceleration_structure`, `VK_KHR_ray_query`, and `VK_KHR_deferred_host_operations` (if supported).
+  - Device features are appended via `DeviceBuilder.add_pNext(...)`.
+- `DescriptorManager::gpuSceneDataLayout()` adds a TLAS binding at `(set=0, binding=1)` when AS is supported.
+
+### BLAS Build & Cache
+- `AccelStructureHandle getOrBuildBLAS(const std::shared_ptr<MeshAsset>& mesh)`:
+  - One GAS per `MeshAsset`, keyed by vertex buffer `VkBuffer`.
+  - Populated with one triangle geometry per `GeoSurface`.
+  - Built with `VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR` and device-local storage + scratch.
+  - Cached in `_blasByVB` for reuse across frames.
+  - Called from `AssetManager::createMesh(...)` and from GLTF loader after mesh upload.
+
+### TLAS Rebuild Per Frame
+- `VkAccelerationStructureKHR buildTLASFromDrawContext(const DrawContext& dc)`:
+  - Iterates `dc.OpaqueSurfaces` and creates one instance per render object.
+  - Looks up BLAS by `RenderObject::vertexBuffer`; if missing, instance is skipped.
+  - Uploads instances to a CPU→GPU buffer with device address.
+  - Builds TLAS with `immediate_submit` and stores device address for Ray Query.
+
+### Renderer Integration
+- In `VulkanEngine::draw()` before building passes:
+  - If RT mode is enabled (`shadowSettings.mode != 0`) and manager exists, TLAS is rebuilt from the latest draw context.
+- Lighting pass binds the TLAS at `set=0,binding=1` when available.
+
+### Modes & UI
+- Mode 0: Shadow maps only (CSM).
+- Mode 1: Hybrid — selected cascades assisted by Ray Query (configurable bitmask).
+- Mode 2: Ray Query only (no shadow maps).
+
+### Notes & Caveats
+- BLAS cache key is the vertex buffer handle; if you rebuild meshes in-place, BLAS must be invalidated.
+- CPU→GPU memory is used for the TLAS instance buffer to simplify updates. On some platforms, you may prefer staging + device-local.
+- The RT path requires Vulkan 1.2+ with Ray Query and Acceleration Structure features available.
+

docs/RenderPasses.md

@@ -70,6 +70,8 @@ addPass(std::move(myPass));
 - Background (compute): Declares `ComputeWrite(drawImage)` and dispatches a selected effect instance.
 - Geometry (G-Buffer): Declares 3 color attachments and `DepthAttachment`, plus buffer reads for shared index/vertex buffers.
 - Lighting (deferred): Reads G‑Buffer as sampled images and writes to `drawImage`.
+- Shadows: Cascaded shadow maps render to per-frame transient depth images (four cascades). If Ray Query is enabled,
+  the lighting pass additionally samples TLAS to evaluate shadow visibility according to the selected mode.
 - Transparent (forward): Writes to `drawImage` with depth test against `depthImage` after lighting.
 - ImGui: Inserted just before present to draw on the swapchain image.
 

docs/ResourceManager.md

@@ -47,3 +47,7 @@ Central allocator and uploader built on VMA. Provides creation helpers, an immed
 - For tooling and one‑off setup, use `immediate_submit(lambda)` to avoid per‑frame queuing.
 - When creating transient images/buffers used only inside a pass, prefer the Render Graph’s `create_*` so destruction is automatic at frame end.
 
+### Known Issue (transition after mip generation)
+
+- In the Render Graph upload pass, the mipmap path should leave the image in `VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL` after `vkutil::generate_mipmaps(...)`. If you see an extra transition back to `TRANSFER_DST_OPTIMAL` after mip generation, remove it. The helper already transitions to the final sampled layout.
+

docs/SHADERS.md

@@ -0,0 +1,25 @@
+**Shaders & Hot Reload**
+
+- Locations
+  - Sources live under `shaders/` and are compiled to `.spv` next to the sources.
+
+- Build integration
+  - CMake invokes `glslangValidator -V` for `*.vert`, `*.frag`, `*.comp` targeting Vulkan 1.2.
+  - Windows PowerShell helper `compile_shaders.ps1` uses `glslc` targeting Vulkan 1.3 and supports additional stages:
+    - `.mesh` (`-fshader-stage=mesh`), `.task`, and ray tracing stages (`.rgen`, `.rmiss`, `.rchit`, `.rahit`, `.rint`, `.rcall`).
+  - Keep `glslangValidator`/`glslc` on `PATH` and ensure your Vulkan SDK is installed.
+
+- Hot reload
+  - `PipelineManager::hotReloadChanged()` watches `.spv` modification times.
+  - Pipelines rebind the next frame when a shader file timestamp changes.
+  - ImGui → Pipelines window provides a manual “Reload Changed” button and lists currently registered pipelines.
+
+- Conventions
+  - Name SPIR‑V files with full extension, e.g. `fullscreen.vert.spv`, `deferred_lighting.frag.spv`.
+  - Use `EngineContext::getAssets()->shaderPath("<name>.spv")` when registering pipelines.
+  - Use sRGB formats for albedo textures and UNORM for PBR control textures (see `docs/asset_manager.md`).
+
+- Adding a pipeline (graphics)
+  - Fill `GraphicsPipelineCreateInfo` with shader paths, descriptor set layouts, optional push constants, and a `configure(PipelineBuilder&)` callback to set topology, raster, depth/blend, and attachment formats.
+  - Register with `PipelineManager::createGraphicsPipeline(name, info)`. Retrieve via `getGraphics` or `getMaterialPipeline`.
+

docs/TROUBLESHOOTING.md

@@ -0,0 +1,26 @@
+**Troubleshooting**
+
+- Shader compiler not found
+  - Ensure `glslangValidator` (and/or `glslc` on Windows) is on `PATH`.
+  - Re‑open your terminal after installing the Vulkan SDK.
+
+- Windows SDK version mismatch
+  - `CMakeLists.txt` references `C:/VulkanSDK/1.3.296.0` by default.
+  - Update the path or set `VULKAN_SDK` to your installed version.
+
+- Validation errors on startup
+  - Update GPU drivers and Vulkan SDK.
+  - Try running a Release build to confirm if the issue is validation‑only.
+
+- Black screen or out‑of‑date swapchain
+  - Resize the window once to force a swapchain rebuild.
+  - Check the ImGui “Targets” window for swapchain/draw formats and extent.
+
+- No models rendering
+  - Verify `assets/police_office.glb` exists (see `docs/ASSETS.md`).
+  - Open the “Scene” window to confirm draw counts > 0.
+
+- Shader changes not visible
+  - Confirm the `.spv` file changed (timestamp) and click “Reload Changed” in the Pipelines window.
+  - Ensure you are editing the correct files referenced by `shaderPath()`.
+

src/compute/vk_compute.h

@@ -120,6 +120,9 @@ private:
     void cleanup();
 };
 
+// Small compute manager for one-off pipelines and persistent instances.
+// It owns a dedicated descriptor allocator and provides helpers to build
+// pipelines, set bindings, and dispatch work (immediate or on a provided cmd).
 class ComputeManager
 {
 public:

src/core/asset_manager.cpp

@@ -309,6 +309,11 @@ bool AssetManager::removeMesh(const std::string &name)
 {
     auto it = _meshCache.find(name);
     if (it == _meshCache.end()) return false;
+    if (_engine && _engine->_rayManager)
+    {
+        // Clean up BLAS cached for this mesh (if ray tracing is enabled)
+        _engine->_rayManager->removeBLASForBuffer(it->second->meshBuffers.vertexBuffer.buffer);
+    }
     if (_engine && _engine->_resourceManager)
     {
         _engine->_resourceManager->destroy_buffer(it->second->meshBuffers.indexBuffer);

src/core/frame_resources.h

@@ -5,6 +5,9 @@
 
 class DeviceManager;
 
+// Per-frame state used by the renderer and passes.
+// Owns a command buffer, sync primitives, a transient descriptor pool, and a
+// deletion queue for resources that should be destroyed when the frame is done.
 struct FrameResources
 {
     VkSemaphore _swapchainSemaphore = VK_NULL_HANDLE;

src/core/vk_device.cpp

@@ -3,6 +3,9 @@
 #include "SDL2/SDL.h"
 #include "SDL2/SDL_vulkan.h"
 
+// Create Vulkan instance/device, enable debug/validation (in Debug), pick a GPU,
+// and set up VMA with buffer device address. If available, enable Ray Query and
+// Acceleration Structure extensions + features.
 void DeviceManager::init_vulkan(SDL_Window *window)
 {
    vkb::InstanceBuilder builder;

src/core/vk_engine.cpp

@@ -1,3 +1,17 @@
+// Engine bootstrap, frame loop, and render-graph wiring.
+//
+// Responsibilities
+// - Initialize SDL + Vulkan managers (device, resources, descriptors, samplers, pipelines).
+// - Create swapchain + default images and build the Render Graph each frame.
+// - Publish an EngineContext so passes and subsystems access per‑frame state uniformly.
+// - Drive ImGui + debug UIs and optional ray‑tracing TLAS rebuilds.
+//
+// See also:
+//  - docs/EngineContext.md
+//  - docs/RenderGraph.md
+//  - docs/FrameResources.md
+//  - docs/RayTracing.md
+//
 //> includes
 #include "vk_engine.h"
 #include <core/vk_images.h>

src/core/vk_engine.h

@@ -32,6 +32,8 @@
 #include "render/rg_graph.h"
 #include "core/vk_raytracing.h"
 
+// Number of frames-in-flight. Affects per-frame command buffers, fences,
+// semaphores, and transient descriptor pools in FrameResources.
 constexpr unsigned int FRAME_OVERLAP = 2;
 
 // Compute push constants and effects are declared in compute/vk_compute.h now.

src/core/vk_pipeline_manager.h

@@ -25,6 +25,9 @@ struct GraphicsPipelineCreateInfo
     std::function<void(PipelineBuilder &)> configure;
 };
 
+// Graphics pipeline registry with hot-reload support.
+// Stores specs keyed by name, builds on demand, and can rebuild when shader
+// timestamps change. Also forwards a minimal Compute API to ComputeManager.
 class PipelineManager
 {
 public:

src/core/vk_raytracing.cpp

@@ -307,3 +307,21 @@ VkAccelerationStructureKHR RayTracingManager::buildTLASFromDrawContext(const Dra
 
     return _tlas.handle;
 }
+
+void RayTracingManager::removeBLASForBuffer(VkBuffer vertexBuffer)
+{
+    if (!vertexBuffer) return;
+    VkDevice dv = _device->device();
+    auto it = _blasByVB.find(vertexBuffer);
+    if (it == _blasByVB.end()) return;
+
+    if (it->second.handle)
+    {
+        _vkDestroyAccelerationStructureKHR(dv, it->second.handle, nullptr);
+    }
+    if (it->second.storage.buffer)
+    {
+        _resources->destroy_buffer(it->second.storage);
+    }
+    _blasByVB.erase(it);
+}

src/core/vk_raytracing.h

@@ -15,8 +15,10 @@
      VkDeviceAddress deviceAddress{0};
  };
  
- class RayTracingManager {
- public:
+// Ray tracing helper that caches BLAS per mesh and rebuilds TLAS per frame
+// for hybrid/full ray query shadows. See docs/RayTracing.md.
+class RayTracingManager {
+public:
     void init(DeviceManager* dev, ResourceManager* res);
     void cleanup();
  
@@ -28,6 +30,10 @@
     VkAccelerationStructureKHR tlas() const { return _tlas.handle; }
     VkDeviceAddress tlasAddress() const { return _tlas.deviceAddress; }
 
+    // Remove and destroy a cached BLAS associated with a vertex buffer.
+    // Safe to call even if no BLAS exists for the buffer.
+    void removeBLASForBuffer(VkBuffer vertexBuffer);
+ 
  private:
      // function pointers (resolved on init)
      PFN_vkCreateAccelerationStructureKHR            _vkCreateAccelerationStructureKHR{};

src/core/vk_resource.cpp

@@ -48,7 +48,12 @@ AllocatedBuffer ResourceManager::create_buffer(size_t allocSize, VkBufferUsageFl
 
     VmaAllocationCreateInfo vmaallocInfo = {};
     vmaallocInfo.usage = memoryUsage;
+    // Map buffers only when CPU-visible memory is requested
+    if (memoryUsage == VMA_MEMORY_USAGE_CPU_TO_GPU ||
+        memoryUsage == VMA_MEMORY_USAGE_CPU_ONLY)
+    {
         vmaallocInfo.flags = VMA_ALLOCATION_CREATE_MAPPED_BIT;
+    }
 
     AllocatedBuffer newBuffer{};
     VK_CHECK(vmaCreateBuffer(_deviceManager->allocator(), &bufferInfo, &vmaallocInfo,
@@ -129,11 +134,33 @@ AllocatedImage ResourceManager::create_image(VkExtent3D size, VkFormat format, V
     return newImage;
 }
 
+// Returns byte size per texel for a subset of common formats.
+static inline size_t bytes_per_texel(VkFormat fmt)
+{
+    switch (fmt)
+    {
+        case VK_FORMAT_R8_UNORM:
+        case VK_FORMAT_R8_SRGB:
+            return 1;
+        case VK_FORMAT_R8G8_UNORM:
+        case VK_FORMAT_R8G8_SRGB:
+            return 2;
+        case VK_FORMAT_R8G8B8A8_UNORM:
+        case VK_FORMAT_R8G8B8A8_SRGB:
+        case VK_FORMAT_B8G8R8A8_UNORM:
+        case VK_FORMAT_B8G8R8A8_SRGB:
+            return 4;
+        default:
+            return 4; // STB path uploads 4 channels
+    }
+}
+
 AllocatedImage ResourceManager::create_image(const void *data, VkExtent3D size, VkFormat format,
                                              VkImageUsageFlags usage,
                                              bool mipmapped)
 {
-    size_t data_size = size.depth * size.width * size.height * 4;
+    size_t bpp = bytes_per_texel(format);
+    size_t data_size = static_cast<size_t>(size.depth) * size.width * size.height * bpp;
     AllocatedBuffer uploadbuffer = create_buffer(data_size, VK_BUFFER_USAGE_TRANSFER_SRC_BIT,
                                                  VMA_MEMORY_USAGE_CPU_TO_GPU);
 
@@ -480,8 +507,10 @@ void ResourceManager::register_upload_pass(RenderGraph &graph, FrameResources &f
 
                 if (upload.generateMips)
                 {
+                    // NOTE: generate_mipmaps() transitions the image to
+                    // VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL at the end.
+                    // Do not transition back to TRANSFER here. See docs/ResourceManager.md.
                     vkutil::generate_mipmaps(cmd, image, VkExtent2D{upload.extent.width, upload.extent.height});
-                    vkutil::transition_image(cmd, image, VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL, VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL);
                 }
             }
         });

src/core/vk_resource.h

@@ -7,6 +7,9 @@ class DeviceManager;
 class RenderGraph;
 struct FrameResources;
 
+// VMA-backed allocator + upload helper.
+// Creates buffers/images, offers an immediate-submit path, and supports
+// deferring uploads into a single Render Graph transfer pass per frame.
 class ResourceManager
 {
 public:

src/core/vk_swapchain.cpp

@@ -1,11 +1,17 @@
 #include "vk_swapchain.h"
 
 #include <SDL_video.h>
+#include "SDL2/SDL_vulkan.h"
 
 #include "vk_device.h"
 #include "vk_initializers.h"
 #include "vk_resource.h"
 
+// Swapchain + per-frame targets (HDR draw, depth, GBuffer) management.
+//
+// Create/resize/destroy logic keeps per-frame images in a local deletion queue
+// so they are cleaned up with the swapchain. The engine imports those images
+// into the Render Graph each frame.
 void SwapchainManager::init_swapchain()
 {
     create_swapchain(_windowExtent.width, _windowExtent.height);
@@ -115,12 +121,13 @@ void SwapchainManager::create_swapchain(uint32_t width, uint32_t height)
 
 void SwapchainManager::destroy_swapchain() const
 {
-    vkDestroySwapchainKHR(_deviceManager->device(), _swapchain, nullptr);
-
-    for (auto _swapchainImageView: _swapchainImageViews)
+    // Destroy image views before the swapchain for stricter driver orderliness.
+    // (Most drivers tolerate either order, but views reference swapchain images.)
+    for (auto view : _swapchainImageViews)
     {
-        vkDestroyImageView(_deviceManager->device(), _swapchainImageView, nullptr);
+        vkDestroyImageView(_deviceManager->device(), view, nullptr);
     }
+    vkDestroySwapchainKHR(_deviceManager->device(), _swapchain, nullptr);
 }
 
 void SwapchainManager::resize_swapchain(struct SDL_Window *window)
@@ -133,7 +140,8 @@ void SwapchainManager::resize_swapchain(struct SDL_Window *window)
     _deletionQueue.flush();
 
     int w, h;
-    SDL_GetWindowSize(window, &w, &h);
+    // HiDPI-aware drawable size for correct pixel dimensions
+    SDL_Vulkan_GetDrawableSize(window, &w, &h);
     _windowExtent.width = w;
     _windowExtent.height = h;
 

src/render/rg_graph.cpp

@@ -59,6 +59,15 @@ RGBufferHandle RenderGraph::create_buffer(const RGBufferDesc &desc)
 	return _resources.add_transient(desc);
 }
 
+// Render Graph: builds a per-frame DAG from declared image/buffer accesses,
+// inserts precise barriers and layouts, and records passes using dynamic rendering.
+//
+// Key steps:
+//  - add_pass(): store declarations and callbacks (build to declare, record to issue commands)
+//  - compile():  topologically sort by read/write hazards and generate Vk*Barrier2 sequences
+//  - execute():  emit pre-pass barriers, begin dynamic rendering if attachments exist, invoke record()
+//
+// See docs/RenderGraph.md for API overview and pass patterns.
 void RenderGraph::add_pass(const char *name, RGPassType type, BuildCallback build, RecordCallback record)
 {
 	Pass p{};

src/render/vk_renderpass_geometry.cpp

@@ -15,6 +15,8 @@
 #include "vk_swapchain.h"
 #include "render/rg_graph.h"
 
+// Basic conservative frustum test against RenderObject AABB.
+// Clip space uses Vulkan Z0 (0..w). Returns true if any part of the box is inside.
 bool is_visible(const RenderObject &obj, const glm::mat4 &viewproj)
 {
     const std::array<glm::vec3, 8> corners{

src/render/vk_renderpass_lighting.cpp

@@ -185,7 +185,9 @@ void LightingPass::draw_lighting(VkCommandBuffer cmd,
     vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, _pipelineLayout, 1, 1,
                             &_gBufferInputDescriptorSet, 0, nullptr);
 
-    // Allocate and write shadow descriptor set for this frame (set = 2)
+    // Allocate and write shadow descriptor set for this frame (set = 2).
+    // When RT is enabled, TLAS is bound in the global set at (set=0, binding=1)
+    // via DescriptorManager::gpuSceneDataLayout(). See docs/RayTracing.md.
     VkDescriptorSet shadowSet = ctxLocal->currentFrame->_frameDescriptors.allocate(
         deviceManager->device(), _shadowDescriptorLayout);
     {

src/render/vk_renderpass_transparent.cpp

@@ -92,7 +92,9 @@ void TransparentPass::draw_transparent(VkCommandBuffer cmd,
     writer.write_buffer(0, gpuSceneDataBuffer.buffer, sizeof(GPUSceneData), 0, VK_DESCRIPTOR_TYPE_UNIFORM_BUFFER);
     writer.update_set(deviceManager->device(), globalDescriptor);
 
-    // Sort transparent back-to-front using camera-space depth
+    // Sort transparent back-to-front using camera-space depth.
+    // We approximate object depth by transforming the mesh bounds origin.
+    // For better results consider using per-object center or per-draw depth range.
     std::vector<const RenderObject *> draws;
     draws.reserve(dc.TransparentSurfaces.size());
     for (const auto &r: dc.TransparentSurfaces) draws.push_back(&r);

src/scene/vk_loader.cpp

@@ -576,6 +576,10 @@ void LoadedGLTF::clearAll()
 
     for (auto &[k, v]: meshes)
     {
+        if (creator->_rayManager)
+        {
+            creator->_rayManager->removeBLASForBuffer(v->meshBuffers.vertexBuffer.buffer);
+        }
         creator->_resourceManager->destroy_buffer(v->meshBuffers.indexBuffer);
         creator->_resourceManager->destroy_buffer(v->meshBuffers.vertexBuffer);
     }