refactor(3d): Split Renderer3D into sub-functionalities

Moved SDF, Mesh, and Skybox logic into separate files to adhere to the 500-line file limit rule.
- src/3d/renderer_sdf.cc
- src/3d/renderer_mesh.cc
- src/3d/renderer_skybox.cc

1 files changed, 202 insertions, 0 deletions

diff --git a/src/3d/renderer_mesh.cc b/src/3d/renderer_mesh.cc
new file mode 100644
index 0000000..97b91d3
--- /dev/null
+++ b/src/3d/renderer_mesh.cc
@@ -0,0 +1,202 @@
+// This file is part of the 64k demo project.
+// It implements mesh-related logic for Renderer3D.
+
+#include "3d/renderer.h"
+#include "generated/assets.h"
+#include "gpu/effects/shader_composer.h"
+#include "util/asset_manager.h"
+#include <cstring>
+#include <vector>
+
+void Renderer3D::create_mesh_pipeline() {
+  std::vector<WGPUBindGroupLayoutEntry> entries;
+
+  // Binding 0: Global Uniforms
+  {
+    WGPUBindGroupLayoutEntry e = {};
+    e.binding = 0;
+    e.visibility = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment;
+    e.buffer.type = WGPUBufferBindingType_Uniform;
+    e.buffer.minBindingSize = sizeof(GlobalUniforms);
+    entries.push_back(e);
+  }
+
+  // Binding 1: Object Data
+  {
+    WGPUBindGroupLayoutEntry e = {};
+    e.binding = 1;
+    e.visibility = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment;
+    e.buffer.type = WGPUBufferBindingType_ReadOnlyStorage;
+    e.buffer.minBindingSize = sizeof(ObjectData) * kMaxObjects;
+    entries.push_back(e);
+  }
+
+  // Binding 2: BVH Nodes (Optional)
+  if (bvh_enabled_) {
+    WGPUBindGroupLayoutEntry e = {};
+    e.binding = 2;
+    e.visibility = WGPUShaderStage_Fragment;
+    e.buffer.type = WGPUBufferBindingType_ReadOnlyStorage;
+    e.buffer.minBindingSize = sizeof(BVHNode) * kMaxObjects * 2;
+    entries.push_back(e);
+  }
+
+  // Binding 3: Noise Texture
+  {
+    WGPUBindGroupLayoutEntry e = {};
+    e.binding = 3;
+    e.visibility = WGPUShaderStage_Fragment;
+    e.texture.sampleType = WGPUTextureSampleType_Float;
+    e.texture.viewDimension = WGPUTextureViewDimension_2D;
+    entries.push_back(e);
+  }
+
+  // Binding 4: Default Sampler
+  {
+    WGPUBindGroupLayoutEntry e = {};
+    e.binding = 4;
+    e.visibility = WGPUShaderStage_Fragment;
+    e.sampler.type = WGPUSamplerBindingType_Filtering;
+    entries.push_back(e);
+  }
+
+  // Binding 5: Sky Texture
+  {
+    WGPUBindGroupLayoutEntry e = {};
+    e.binding = 5;
+    e.visibility = WGPUShaderStage_Fragment;
+    e.texture.sampleType = WGPUTextureSampleType_Float;
+    e.texture.viewDimension = WGPUTextureViewDimension_2D;
+    entries.push_back(e);
+  }
+
+  WGPUBindGroupLayoutDescriptor bgl_desc = {};
+  bgl_desc.entryCount = (uint32_t)entries.size();
+  bgl_desc.entries = entries.data();
+  WGPUBindGroupLayout bgl = wgpuDeviceCreateBindGroupLayout(device_, &bgl_desc);
+
+  WGPUPipelineLayoutDescriptor pl_desc = {};
+  pl_desc.bindGroupLayoutCount = 1;
+  pl_desc.bindGroupLayouts = &bgl;
+  WGPUPipelineLayout pipeline_layout =
+      wgpuDeviceCreatePipelineLayout(device_, &pl_desc);
+
+  const char* shader_code_asset = (const char*)GetAsset(AssetId::ASSET_SHADER_MESH);
+  
+  ShaderComposer::CompositionMap composition_map;
+  if (bvh_enabled_) {
+    composition_map["render/scene_query_mode"] = "render/scene_query_bvh";
+  } else {
+    composition_map["render/scene_query_mode"] = "render/scene_query_linear";
+  }
+  std::string shader_source = ShaderComposer::Get().Compose({}, shader_code_asset, composition_map);
+
+#if defined(DEMO_CROSS_COMPILE_WIN32)
+  WGPUShaderModuleWGSLDescriptor wgsl_desc = {};
+  wgsl_desc.chain.sType = WGPUSType_ShaderModuleWGSLDescriptor;
+  wgsl_desc.code = shader_source.c_str();
+  WGPUShaderModuleDescriptor shader_desc = {};
+  shader_desc.nextInChain = (const WGPUChainedStruct*)&wgsl_desc.chain;
+#else
+  WGPUShaderSourceWGSL wgsl_desc = {};
+  wgsl_desc.chain.sType = WGPUSType_ShaderSourceWGSL;
+  wgsl_desc.code = str_view(shader_source.c_str());
+  WGPUShaderModuleDescriptor shader_desc = {};
+  shader_desc.nextInChain = (const WGPUChainedStruct*)&wgsl_desc.chain;
+#endif
+  WGPUShaderModule shader_module =
+      wgpuDeviceCreateShaderModule(device_, &shader_desc);
+
+  WGPUVertexAttribute vert_attrs[3] = {};
+  // pos
+  vert_attrs[0].format = WGPUVertexFormat_Float32x3;
+  vert_attrs[0].offset = offsetof(MeshVertex, p);
+  vert_attrs[0].shaderLocation = 0;
+  // norm
+  vert_attrs[1].format = WGPUVertexFormat_Float32x3;
+  vert_attrs[1].offset = offsetof(MeshVertex, n);
+  vert_attrs[1].shaderLocation = 1;
+  // uv
+  vert_attrs[2].format = WGPUVertexFormat_Float32x2;
+  vert_attrs[2].offset = offsetof(MeshVertex, u);
+  vert_attrs[2].shaderLocation = 2;
+
+  WGPUVertexBufferLayout vert_layout = {};
+  vert_layout.arrayStride = sizeof(MeshVertex);
+  vert_layout.stepMode = WGPUVertexStepMode_Vertex;
+  vert_layout.attributeCount = 3;
+  vert_layout.attributes = vert_attrs;
+
+  WGPURenderPipelineDescriptor desc = {};
+  desc.layout = pipeline_layout;
+  desc.vertex.module = shader_module;
+#if defined(DEMO_CROSS_COMPILE_WIN32)
+  desc.vertex.entryPoint = "vs_main";
+#else
+  desc.vertex.entryPoint = {"vs_main", 7};
+#endif
+  desc.vertex.bufferCount = 1;
+  desc.vertex.buffers = &vert_layout;
+
+  WGPUColorTargetState color_target = {};
+  color_target.format = format_;
+  color_target.writeMask = WGPUColorWriteMask_All;
+  WGPUFragmentState fragment = {};
+  fragment.module = shader_module;
+#if defined(DEMO_CROSS_COMPILE_WIN32)
+  fragment.entryPoint = "fs_main";
+#else
+  fragment.entryPoint = {"fs_main", 7};
+#endif
+  fragment.targetCount = 1;
+  fragment.targets = &color_target;
+  desc.fragment = &fragment;
+
+  desc.primitive.topology = WGPUPrimitiveTopology_TriangleList;
+  desc.primitive.cullMode = WGPUCullMode_Back;
+  desc.primitive.frontFace = WGPUFrontFace_CCW;
+
+  WGPUDepthStencilState depth_stencil = {};
+  depth_stencil.format = WGPUTextureFormat_Depth24Plus;
+  depth_stencil.depthWriteEnabled = WGPUOptionalBool_True;
+  depth_stencil.depthCompare = WGPUCompareFunction_Less;
+  desc.depthStencil = &depth_stencil;
+
+  desc.multisample.count = 1;
+  desc.multisample.mask = 0xFFFFFFFF;
+
+  mesh_pipeline_ = wgpuDeviceCreateRenderPipeline(device_, &desc);
+  wgpuBindGroupLayoutRelease(bgl);
+  wgpuPipelineLayoutRelease(pipeline_layout);
+  wgpuShaderModuleRelease(shader_module);
+}
+
+const Renderer3D::MeshGpuData*
+Renderer3D::get_or_create_mesh(AssetId asset_id) {
+  auto it = mesh_cache_.find(asset_id);
+  if (it != mesh_cache_.end()) {
+    return &it->second;
+  }
+
+  MeshAsset asset = GetMeshAsset(asset_id);
+  if (!asset.vertices || asset.num_vertices == 0) {
+    return nullptr;
+  }
+
+  MeshGpuData data;
+  data.num_indices = asset.num_indices;
+
+  data.vertex_buffer =
+      gpu_create_buffer(device_, asset.num_vertices * sizeof(MeshVertex),
+                        WGPUBufferUsage_Vertex | WGPUBufferUsage_CopyDst,
+                        asset.vertices)
+          .buffer;
+  data.index_buffer =
+      gpu_create_buffer(device_, asset.num_indices * sizeof(uint32_t),
+                        WGPUBufferUsage_Index | WGPUBufferUsage_CopyDst,
+                        asset.indices)
+          .buffer;
+
+  mesh_cache_[asset_id] = data;
+  return &mesh_cache_[asset_id];
+}