ADD: CSM base code

src/core/config.h

@@ -6,3 +6,14 @@ inline constexpr bool kUseValidationLayers = false;
 #else
 inline constexpr bool kUseValidationLayers = true;
 #endif
+
+// Shadow mapping configuration
+inline constexpr int kShadowCascadeCount = 4;
+// Maximum shadow distance for CSM in view-space units
+inline constexpr float kShadowCSMFar = 50.0f;
+// Shadow map resolution used for stabilization (texel snapping). Must match actual image size.
+inline constexpr float kShadowMapResolution = 2048.0f;
+// Extra XY expansion for cascade footprint (safety against FOV/aspect changes)
+inline constexpr float kShadowCascadeRadiusScale = 1.15f;
+// Additive XY margin in world units (light-space) beyond scaled radius
+inline constexpr float kShadowCascadeRadiusMargin = 10.0f;

src/core/vk_descriptors.cpp

@@ -1,10 +1,10 @@
 #include <core/vk_descriptors.h>
 
-void DescriptorLayoutBuilder::add_binding(uint32_t binding, VkDescriptorType type)
+void DescriptorLayoutBuilder::add_binding(uint32_t binding, VkDescriptorType type, uint32_t count)
 {
     VkDescriptorSetLayoutBinding newbind{};
     newbind.binding = binding;
-    newbind.descriptorCount = 1;
+    newbind.descriptorCount = count;
     newbind.descriptorType = type;
 
     bindings.push_back(newbind);

src/core/vk_descriptors.h

@@ -7,7 +7,7 @@ struct DescriptorLayoutBuilder
 {
     std::vector<VkDescriptorSetLayoutBinding> bindings;
 
-    void add_binding(uint32_t binding, VkDescriptorType type);
+    void add_binding(uint32_t binding, VkDescriptorType type, uint32_t count = 1);
 
     void clear();
 

src/core/vk_engine.cpp

@@ -16,6 +16,8 @@
 #include "render/vk_pipelines.h"
 #include <iostream>
 #include <glm/gtx/transform.hpp>
+
+#include "config.h"
 #include "render/primitives.h"
 
 #include "vk_mem_alloc.h"
@@ -315,8 +317,14 @@ void VulkanEngine::draw()
         RGImageHandle hSwapchain = _renderGraph->import_swapchain_image(swapchainImageIndex);
 
         // Create a transient shadow depth target (fixed resolution for now)
+        // Create transient depth targets for cascaded shadow maps
         const VkExtent2D shadowExtent{2048, 2048};
-        RGImageHandle hShadow = _renderGraph->create_depth_image("shadow.depth", shadowExtent, VK_FORMAT_D32_SFLOAT);
+        std::array<RGImageHandle, kShadowCascadeCount> hShadowCascades{};
+        for (int i = 0; i < kShadowCascadeCount; ++i)
+        {
+            std::string name = std::string("shadow.cascade.") + std::to_string(i);
+            hShadowCascades[i] = _renderGraph->create_depth_image(name.c_str(), shadowExtent, VK_FORMAT_D32_SFLOAT);
+        }
 
         _resourceManager->register_upload_pass(*_renderGraph, get_current_frame());
 
@@ -331,7 +339,7 @@ void VulkanEngine::draw()
             }
             if (auto *shadow = _renderPassManager->getPass<ShadowPass>())
             {
-                shadow->register_graph(_renderGraph.get(), hShadow, shadowExtent);
+                shadow->register_graph(_renderGraph.get(), std::span<RGImageHandle>(hShadowCascades.data(), hShadowCascades.size()), shadowExtent);
             }
             if (auto *geometry = _renderPassManager->getPass<GeometryPass>())
             {
@@ -339,7 +347,8 @@ void VulkanEngine::draw()
             }
             if (auto *lighting = _renderPassManager->getPass<LightingPass>())
             {
-                lighting->register_graph(_renderGraph.get(), hDraw, hGBufferPosition, hGBufferNormal, hGBufferAlbedo, hShadow);
+                lighting->register_graph(_renderGraph.get(), hDraw, hGBufferPosition, hGBufferNormal, hGBufferAlbedo,
+                                         std::span<RGImageHandle>(hShadowCascades.data(), hShadowCascades.size()));
             }
             if (auto *transparent = _renderPassManager->getPass<TransparentPass>())
             {

src/core/vk_sampler_manager.cpp

@@ -28,6 +28,16 @@ void SamplerManager::init(DeviceManager *deviceManager)
     sampl.magFilter = VK_FILTER_LINEAR;
     sampl.minFilter = VK_FILTER_LINEAR;
     vkCreateSampler(_deviceManager->device(), &sampl, nullptr, &_defaultSamplerLinear);
+
+    // Shadow linear clamp sampler (border=white)
+    VkSamplerCreateInfo sh = sampl;
+    sh.addressModeU = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER;
+    sh.addressModeV = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER;
+    sh.addressModeW = VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_BORDER;
+    sh.compareEnable = VK_FALSE; // manual PCF
+    sh.borderColor = VK_BORDER_COLOR_FLOAT_OPAQUE_WHITE;
+    vkCreateSampler(_deviceManager->device(), &sh, nullptr, &_shadowLinearClamp);
+
 }
 
 void SamplerManager::cleanup()
@@ -44,4 +54,10 @@ void SamplerManager::cleanup()
         vkDestroySampler(_deviceManager->device(), _defaultSamplerLinear, nullptr);
         _defaultSamplerLinear = VK_NULL_HANDLE;
     }
+
+    if (_shadowLinearClamp)
+    {
+        vkDestroySampler(_deviceManager->device(), _shadowLinearClamp, nullptr);
+        _shadowLinearClamp = VK_NULL_HANDLE;
+    }
 }

src/core/vk_sampler_manager.h

@@ -13,10 +13,13 @@ public:
 
     VkSampler defaultLinear() const { return _defaultSamplerLinear; }
     VkSampler defaultNearest() const { return _defaultSamplerNearest; }
+    VkSampler shadowLinearClamp() const { return _shadowLinearClamp; }
+
 
 private:
     DeviceManager *_deviceManager = nullptr;
     VkSampler _defaultSamplerLinear = VK_NULL_HANDLE;
     VkSampler _defaultSamplerNearest = VK_NULL_HANDLE;
+    VkSampler _shadowLinearClamp = VK_NULL_HANDLE;
 };
 

src/core/vk_types.h

@@ -75,6 +75,9 @@ struct GPUSceneData {
     glm::vec4 ambientColor;
     glm::vec4 sunlightDirection; // w for sun power
     glm::vec4 sunlightColor;
+
+    glm::mat4 lightViewProjCascades[4];
+    glm::vec4 cascadeSplitsView;
 };
 
 enum class MaterialPass :uint8_t {

src/render/rg_graph.cpp

@@ -676,6 +676,15 @@ void RenderGraph::execute(VkCommandBuffer cmd)
                 if (rec && rec->imageView != VK_NULL_HANDLE)
                 {
                     depthInfo = vkinit::depth_attachment_info(rec->imageView, VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL);
+                	if (p.depthAttachment.clearOnLoad)
+                	{
+                		depthInfo.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
+                		depthInfo.clearValue = p.depthAttachment.clear;
+                	}
+                	else
+                	{
+                		depthInfo.loadOp = VK_ATTACHMENT_LOAD_OP_LOAD;
+                	}
                 	if (p.depthAttachment.clearOnLoad) depthInfo.loadOp = VK_ATTACHMENT_LOAD_OP_CLEAR;
                     else depthInfo.loadOp = VK_ATTACHMENT_LOAD_OP_LOAD;
                     if (!p.depthAttachment.store) depthInfo.storeOp = VK_ATTACHMENT_STORE_OP_DONT_CARE;

src/render/vk_renderpass_lighting.cpp

@@ -10,11 +10,13 @@
 #include "core/vk_pipeline_manager.h"
 #include "core/asset_manager.h"
 #include "core/vk_descriptors.h"
+#include "core/config.h"
 
 #include "vk_mem_alloc.h"
 #include "vk_sampler_manager.h"
 #include "vk_swapchain.h"
 #include "render/rg_graph.h"
+#include <array>
 
 void LightingPass::init(EngineContext *context)
 {
@@ -43,10 +45,10 @@ void LightingPass::init(EngineContext *context)
         writer.update_set(_context->getDevice()->device(), _gBufferInputDescriptorSet);
     }
 
-    // Shadow map descriptor layout (set = 2, updated per-frame)
+    // Shadow map descriptor layout (set = 2, updated per-frame). Use array of cascades
     {
         DescriptorLayoutBuilder builder;
-        builder.add_binding(0, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+        builder.add_binding(0, VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER, kShadowCascadeCount);
         _shadowDescriptorLayout = builder.build(_context->getDevice()->device(), VK_SHADER_STAGE_FRAGMENT_BIT);
     }
 
@@ -95,9 +97,9 @@ void LightingPass::register_graph(RenderGraph *graph,
                                   RGImageHandle gbufferPosition,
                                   RGImageHandle gbufferNormal,
                                   RGImageHandle gbufferAlbedo,
-                                  RGImageHandle shadowDepth)
+                                  std::span<RGImageHandle> shadowCascades)
 {
-    if (!graph || !drawHandle.valid() || !gbufferPosition.valid() || !gbufferNormal.valid() || !gbufferAlbedo.valid() || !shadowDepth.valid())
+    if (!graph || !drawHandle.valid() || !gbufferPosition.valid() || !gbufferNormal.valid() || !gbufferAlbedo.valid())
     {
         return;
     }
@@ -105,18 +107,21 @@ void LightingPass::register_graph(RenderGraph *graph,
     graph->add_pass(
         "Lighting",
         RGPassType::Graphics,
-        [drawHandle, gbufferPosition, gbufferNormal, gbufferAlbedo, shadowDepth](RGPassBuilder &builder, EngineContext *)
+        [drawHandle, gbufferPosition, gbufferNormal, gbufferAlbedo, shadowCascades](RGPassBuilder &builder, EngineContext *)
         {
             builder.read(gbufferPosition, RGImageUsage::SampledFragment);
             builder.read(gbufferNormal, RGImageUsage::SampledFragment);
             builder.read(gbufferAlbedo, RGImageUsage::SampledFragment);
-            builder.read(shadowDepth, RGImageUsage::SampledFragment);
+            for (size_t i = 0; i < shadowCascades.size(); ++i)
+            {
+                if (shadowCascades[i].valid()) builder.read(shadowCascades[i], RGImageUsage::SampledFragment);
+            }
 
             builder.write_color(drawHandle);
         },
-        [this, drawHandle, shadowDepth](VkCommandBuffer cmd, const RGPassResources &res, EngineContext *ctx)
+        [this, drawHandle, shadowCascades](VkCommandBuffer cmd, const RGPassResources &res, EngineContext *ctx)
         {
-            draw_lighting(cmd, ctx, res, drawHandle, shadowDepth);
+            draw_lighting(cmd, ctx, res, drawHandle, shadowCascades);
         });
 }
 
@@ -124,7 +129,7 @@ void LightingPass::draw_lighting(VkCommandBuffer cmd,
                                  EngineContext *context,
                                  const RGPassResources &resources,
                                  RGImageHandle drawHandle,
-                                 RGImageHandle shadowDepth)
+                                 std::span<RGImageHandle> shadowCascades)
 {
     EngineContext *ctxLocal = context ? context : _context;
     if (!ctxLocal || !ctxLocal->currentFrame) return;
@@ -173,12 +178,21 @@ void LightingPass::draw_lighting(VkCommandBuffer cmd,
     VkDescriptorSet shadowSet = ctxLocal->currentFrame->_frameDescriptors.allocate(
         deviceManager->device(), _shadowDescriptorLayout);
     {
-        VkImageView shadowView = resources.image_view(shadowDepth);
+        const uint32_t cascadeCount = std::min<uint32_t>(kShadowCascadeCount, static_cast<uint32_t>(shadowCascades.size()));
-        DescriptorWriter writer2;
+        std::array<VkDescriptorImageInfo, kShadowCascadeCount> infos{};
-        writer2.write_image(0, shadowView, ctxLocal->getSamplers()->defaultLinear(),
+        for (uint32_t i = 0; i < cascadeCount; ++i)
-                            VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL,
+        {
-                            VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER);
+            infos[i].sampler = ctxLocal->getSamplers()->shadowLinearClamp();
-        writer2.update_set(deviceManager->device(), shadowSet);
+            infos[i].imageView = resources.image_view(shadowCascades[i]);
+            infos[i].imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
+        }
+        VkWriteDescriptorSet write{.sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET};
+        write.dstSet = shadowSet;
+        write.dstBinding = 0;
+        write.descriptorCount = cascadeCount;
+        write.descriptorType = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
+        write.pImageInfo = infos.data();
+        vkUpdateDescriptorSets(deviceManager->device(), 1, &write, 0, nullptr);
     }
     vkCmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, _pipelineLayout, 2, 1, &shadowSet, 0, nullptr);
 

src/render/vk_renderpass_lighting.h

@@ -17,8 +17,7 @@ public:
                         RGImageHandle drawHandle,
                         RGImageHandle gbufferPosition,
                         RGImageHandle gbufferNormal,
-                        RGImageHandle gbufferAlbedo,
+                        RGImageHandle gbufferAlbedo, std::span<RGImageHandle> shadowCascades);
-                        RGImageHandle shadowDepth);
 
 private:
     EngineContext *_context = nullptr;
@@ -34,7 +33,7 @@ private:
                        EngineContext *context,
                        const class RGPassResources &resources,
                        RGImageHandle drawHandle,
-                       RGImageHandle shadowDepth);
+                       std::span<RGImageHandle> shadowCascades);
 
     DeletionQueue _deletionQueue;
 };

src/render/vk_renderpass_shadow.cpp

@@ -1,6 +1,7 @@
 #include "vk_renderpass_shadow.h"
 
 #include <unordered_set>
+#include <string>
 
 #include "core/engine_context.h"
 #include "render/rg_graph.h"
@@ -24,9 +25,13 @@ void ShadowPass::init(EngineContext *context)
     if (!_context || !_context->pipelines) return;
 
     // Build a depth-only graphics pipeline for shadow map rendering
+    // Keep push constants matching current shader layout for now
     VkPushConstantRange pc{};
     pc.offset = 0;
-    pc.size = sizeof(GPUDrawPushConstants);
+    // Push constants layout in shadow.vert is mat4 + device address + uint, rounded to 16 bytes
+    const uint32_t pcRaw = static_cast<uint32_t>(sizeof(GPUDrawPushConstants) + sizeof(uint32_t));
+    const uint32_t pcAligned = (pcRaw + 15u) & ~15u; // 16-byte alignment to match std430 expectations
+    pc.size = pcAligned;
     pc.stageFlags = VK_SHADER_STAGE_VERTEX_BIT;
 
     GraphicsPipelineCreateInfo info{};
@@ -40,11 +45,11 @@ void ShadowPass::init(EngineContext *context)
         b.set_cull_mode(VK_CULL_MODE_BACK_BIT, VK_FRONT_FACE_CLOCKWISE);
         b.set_multisampling_none();
         b.disable_blending();
-        // Reverse-Z depth test & depth-only pipeline
+        // Reverse-Z depth test for shadow maps (clear=0.0, GREATER_OR_EQUAL)
         b.enable_depthtest(true, VK_COMPARE_OP_GREATER_OR_EQUAL);
         b.set_depth_format(VK_FORMAT_D32_SFLOAT);
 
-        // Static depth bias to help with surface acne (will tune later)
+        // Static depth bias to help with surface acne (tune later)
         b._rasterizer.depthBiasEnable = VK_TRUE;
         b._rasterizer.depthBiasConstantFactor = 2.0f;
         b._rasterizer.depthBiasSlopeFactor = 2.0f;
@@ -65,12 +70,18 @@ void ShadowPass::execute(VkCommandBuffer)
     // Shadow rendering is done via the RenderGraph registration.
 }
 
-void ShadowPass::register_graph(RenderGraph *graph, RGImageHandle shadowDepth, VkExtent2D extent)
+void ShadowPass::register_graph(RenderGraph *graph, std::span<RGImageHandle> cascades, VkExtent2D extent)
 {
-    if (!graph || !shadowDepth.valid()) return;
+    if (!graph || cascades.empty()) return;
 
+    for (uint32_t i = 0; i < cascades.size(); ++i)
+    {
+        RGImageHandle shadowDepth = cascades[i];
+        if (!shadowDepth.valid()) continue;
+
+        std::string passName = std::string("ShadowMap[") + std::to_string(i) + "]";
         graph->add_pass(
-        "ShadowMap",
+            passName.c_str(),
             RGPassType::Graphics,
             [shadowDepth](RGPassBuilder &builder, EngineContext *ctx)
             {
@@ -93,7 +104,7 @@ void ShadowPass::register_graph(RenderGraph *graph, RGImageHandle shadowDepth, V
                         }
                     };
                     collect(dc.OpaqueSurfaces);
-                // Transparent surfaces are ignored for shadow map in this simple pass
+                    // Ignore transparent for shadow map
 
                     for (VkBuffer b : indexSet)
                         builder.read_buffer(b, RGBufferUsage::IndexRead, 0, "shadow.index");
@@ -101,17 +112,19 @@ void ShadowPass::register_graph(RenderGraph *graph, RGImageHandle shadowDepth, V
                         builder.read_buffer(b, RGBufferUsage::StorageRead, 0, "shadow.vertex");
                 }
             },
-        [this, shadowDepth, extent](VkCommandBuffer cmd, const RGPassResources &res, EngineContext *ctx)
+            [this, shadowDepth, extent, i](VkCommandBuffer cmd, const RGPassResources &res, EngineContext *ctx)
             {
-            draw_shadow(cmd, ctx, res, shadowDepth, extent);
+                draw_shadow(cmd, ctx, res, shadowDepth, extent, i);
             });
+    }
 }
 
 void ShadowPass::draw_shadow(VkCommandBuffer cmd,
                              EngineContext *context,
                              const RGPassResources &/*resources*/,
                              RGImageHandle /*shadowDepth*/,
-                             VkExtent2D extent) const
+                             VkExtent2D extent,
+                             uint32_t cascadeIndex) const
 {
     EngineContext *ctxLocal = context ? context : _context;
     if (!ctxLocal || !ctxLocal->currentFrame) return;
@@ -166,6 +179,12 @@ void ShadowPass::draw_shadow(VkCommandBuffer cmd,
     const DrawContext &dc = ctxLocal->getMainDrawContext();
 
     VkBuffer lastIndexBuffer = VK_NULL_HANDLE;
+
+    struct ShadowPC
+    {
+        GPUDrawPushConstants draw;
+        uint32_t cascadeIndex;
+    };
     for (const auto &r : dc.OpaqueSurfaces)
     {
         if (r.indexBuffer != lastIndexBuffer)
@@ -174,11 +193,11 @@ void ShadowPass::draw_shadow(VkCommandBuffer cmd,
             vkCmdBindIndexBuffer(cmd, r.indexBuffer, 0, VK_INDEX_TYPE_UINT32);
         }
 
-        GPUDrawPushConstants pc{};
+        ShadowPC spc{};
-        pc.worldMatrix = r.transform;
+        spc.draw.worldMatrix = r.transform;
-        pc.vertexBuffer = r.vertexBufferAddress;
+        spc.draw.vertexBuffer = r.vertexBufferAddress;
-        vkCmdPushConstants(cmd, layout, VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(GPUDrawPushConstants), &pc);
+        spc.cascadeIndex = cascadeIndex;
-
+        vkCmdPushConstants(cmd, layout, VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(ShadowPC), &spc);
         vkCmdDrawIndexed(cmd, r.indexCount, 1, r.firstIndex, 0, 0);
     }
 }

src/render/vk_renderpass_shadow.h

@@ -2,14 +2,13 @@
 
 #include "vk_renderpass.h"
 #include <render/rg_types.h>
+#include <span>
 
 class RenderGraph;
 class EngineContext;
 class RGPassResources;
 
-// Depth-only directional shadow map pass (skeleton)
+// Depth-only directional shadow map pass (CSM-ready API)
-// - Writes a depth image using reversed-Z (clear=0)
-// - Draw function will be filled in a later step
 class ShadowPass : public IRenderPass
 {
 public:
@@ -19,8 +18,8 @@ public:
 
     const char *getName() const override { return "ShadowMap"; }
 
-    // Register the depth-only pass into the render graph
+    // Register N cascades; one graphics pass per cascade.
-    void register_graph(RenderGraph *graph, RGImageHandle shadowDepth, VkExtent2D extent);
+    void register_graph(RenderGraph *graph, std::span<RGImageHandle> cascades, VkExtent2D extent);
 
 private:
     EngineContext *_context = nullptr;
@@ -29,5 +28,6 @@ private:
                      EngineContext *context,
                      const RGPassResources &resources,
                      RGImageHandle shadowDepth,
-                     VkExtent2D extent) const;
+                     VkExtent2D extent,
+                     uint32_t cascadeIndex) const;
 };

src/scene/vk_scene.cpp

@@ -4,6 +4,7 @@
 
 #include "vk_swapchain.h"
 #include "core/engine_context.h"
+#include "core/config.h"
 #include "glm/gtx/transform.hpp"
 #include <glm/gtc/matrix_transform.hpp>
 
@@ -104,7 +105,9 @@ void SceneManager::update_scene()
     sceneData.viewproj = projection * view;
 
     // Build a simple directional light view-projection (reversed-Z orthographic)
-    // Centered around the camera for now (non-cascaded, non-stabilized)
+    // Centered around the camera for now. For the initial CSM-plumbing test,
+    // duplicate this single shadow matrix across all cascades so we render
+    // four identical shadow maps. This verifies the pass/descriptor wiring.
     {
         const glm::vec3 camPos = glm::vec3(glm::inverse(view)[3]);
         glm::vec3 L = glm::normalize(-glm::vec3(sceneData.sunlightDirection));
@@ -124,11 +127,27 @@ void SceneManager::update_scene()
         const float farDist = 200.0f;
         const glm::vec3 lightPos = camPos - L * 100.0f;
         glm::mat4 viewLight = glm::lookAtRH(lightPos, camPos, up);
-        // Standard RH ZO ortho with near<far, then explicitly flip Z to reversed-Z
+        // Standard RH ZO ortho with near<far (works with our reversed-Z depth setup
+        // as we clamp and bias in shader). We'll stabilize/flip later when CSM lands.
         glm::mat4 projLight = glm::orthoRH_ZO(-orthoRange, orthoRange, -orthoRange, orthoRange,
                                               nearDist, farDist);
 
         sceneData.lightViewProj = projLight * viewLight;
+
+        // Fill cascade arrays with the same matrix for now so the shadow
+        // pass can run four times using identical transforms.
+        for (int c = 0; c < kShadowCascadeCount; ++c)
+        {
+            sceneData.lightViewProjCascades[c] = sceneData.lightViewProj;
+        }
+
+        // Provide a simple increasing split hint (view-space distances).
+        // Not used yet by shaders, but helps when we switch to CSM.
+        const float farView = kShadowCSMFar;
+        sceneData.cascadeSplitsView = glm::vec4(0.1f * farView,
+                                                0.3f * farView,
+                                                0.6f * farView,
+                                                1.0f * farView);
     }
 
     auto end = std::chrono::system_clock::now();