feat: Implement 3D system and procedural texture manager

- Extended mini_math.h with mat4 multiplication and affine transforms.
- Implemented TextureManager for runtime procedural texture generation and GPU upload.
- Added 3D system components: Camera, Object, Scene, and Renderer3D.
- Created test_3d_render mini-demo for interactive 3D verification.
- Fixed WebGPU validation errors regarding depthSlice and unimplemented WaitAny.

1 files changed, 107 insertions, 0 deletions

diff --git a/src/gpu/texture_manager.cc b/src/gpu/texture_manager.cc
new file mode 100644
index 0000000..7c314d2
--- /dev/null
+++ b/src/gpu/texture_manager.cc
@@ -0,0 +1,107 @@
+// This file is part of the 64k demo project.
+// It implements the TextureManager.
+
+#include "gpu/texture_manager.h"
+#include <iostream>
+#include <vector>
+
+#if defined(DEMO_CROSS_COMPILE_WIN32)
+// Old API
+#define WGPU_TEX_COPY_INFO WGPUImageCopyTexture
+#define WGPU_TEX_DATA_LAYOUT WGPUTextureDataLayout
+#else
+// New API
+#define WGPU_TEX_COPY_INFO WGPUTexelCopyTextureInfo
+#define WGPU_TEX_DATA_LAYOUT WGPUTexelCopyBufferLayout
+#endif
+
+void TextureManager::init(WGPUDevice device, WGPUQueue queue) {
+  device_ = device;
+  queue_ = queue;
+}
+
+void TextureManager::shutdown() {
+  for (auto& pair : textures_) {
+    wgpuTextureViewRelease(pair.second.view);
+    wgpuTextureRelease(pair.second.texture);
+  }
+  textures_.clear();
+}
+
+void TextureManager::create_procedural_texture(
+    const std::string& name, const ProceduralTextureDef& def) {
+  // 1. Generate Data on CPU
+  std::vector<uint8_t> pixel_data;
+  pixel_data.resize(def.width * def.height * 4);
+  def.gen_func(pixel_data.data(), def.width, def.height, def.params.data(),
+               (int)def.params.size());
+
+  WGPUExtent3D tex_size = {(uint32_t)def.width, (uint32_t)def.height, 1};
+
+  // 2. Create GPU Texture
+  WGPUTextureDescriptor tex_desc = {};
+  tex_desc.usage =
+      WGPUTextureUsage_TextureBinding | WGPUTextureUsage_CopyDst;
+  tex_desc.dimension = WGPUTextureDimension_2D;
+  tex_desc.size = tex_size;
+  tex_desc.format = WGPUTextureFormat_RGBA8Unorm;
+  tex_desc.mipLevelCount = 1;
+  tex_desc.sampleCount = 1;
+#if defined(DEMO_CROSS_COMPILE_WIN32)
+  tex_desc.label = nullptr;
+#else
+  tex_desc.label = {nullptr, 0};
+#endif
+
+  WGPUTexture texture = wgpuDeviceCreateTexture(device_, &tex_desc);
+
+  // 3. Upload Data
+  WGPU_TEX_COPY_INFO destination = {};
+  destination.texture = texture;
+  destination.mipLevel = 0;
+  destination.origin = {0, 0, 0};
+  destination.aspect = WGPUTextureAspect_All;
+
+  WGPU_TEX_DATA_LAYOUT source_layout = {};
+  source_layout.offset = 0;
+  source_layout.bytesPerRow = def.width * 4;
+  source_layout.rowsPerImage = def.height;
+
+  wgpuQueueWriteTexture(queue_, &destination, pixel_data.data(),
+                        pixel_data.size(), &source_layout, &tex_size);
+
+
+  // 4. Create View
+  WGPUTextureViewDescriptor view_desc = {};
+  view_desc.format = WGPUTextureFormat_RGBA8Unorm;
+  view_desc.dimension = WGPUTextureViewDimension_2D;
+  view_desc.baseMipLevel = 0;
+  view_desc.mipLevelCount = 1;
+  view_desc.baseArrayLayer = 0;
+  view_desc.arrayLayerCount = 1;
+  view_desc.aspect = WGPUTextureAspect_All;
+
+  WGPUTextureView view = wgpuTextureCreateView(texture, &view_desc);
+
+  // 5. Store
+  GpuTexture gpu_tex;
+  gpu_tex.texture = texture;
+  gpu_tex.view = view;
+  gpu_tex.width = def.width;
+  gpu_tex.height = def.height;
+  
+  textures_[name] = gpu_tex;
+
+#if !defined(STRIP_ALL)
+  std::cout << "Generated procedural texture: " << name << " (" << def.width
+            << "x" << def.height << ")" << std::endl;
+#endif
+}
+
+WGPUTextureView TextureManager::get_texture_view(const std::string& name) {
+  auto it = textures_.find(name);
+  if (it != textures_.end()) {
+    return it->second.view;
+  }
+  return nullptr;
+}