Refactor: factorize common WGPU patterns into helper functions

Add texture creation helpers (gpu_create_texture_2d, gpu_create_storage_texture_2d,
gpu_create_mip_view) and extend BindGroupLayoutBuilder with uint_texture and
storage_texture methods.

Refactored files:
- cnn_v2_effect.cc: Use texture helpers (~70% code reduction in create_textures)
- rotating_cube_effect.cc: Use BindGroupLayoutBuilder and texture helpers
- circle_mask_effect.cc: Use BindGroupBuilder

Benefits:
- Improved code readability
- Reduced boilerplate for texture/bind group creation
- Consistent patterns across effects

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

1 files changed, 47 insertions, 0 deletions

diff --git a/src/gpu/gpu.cc b/src/gpu/gpu.cc
index 41f5bcf..cf5d85d 100644
--- a/src/gpu/gpu.cc
+++ b/src/gpu/gpu.cc
@@ -51,6 +51,53 @@ GpuBuffer gpu_create_buffer(WGPUDevice device, size_t size, uint32_t usage,
   return {buffer, size};
 }
 
+TextureWithView gpu_create_texture_2d(WGPUDevice device, uint32_t width,
+                                      uint32_t height, WGPUTextureFormat format,
+                                      WGPUTextureUsage usage,
+                                      uint32_t mip_levels) {
+  WGPUTextureDescriptor desc = {};
+  desc.usage = usage;
+  desc.dimension = WGPUTextureDimension_2D;
+  desc.size = {width, height, 1};
+  desc.format = format;
+  desc.mipLevelCount = mip_levels;
+  desc.sampleCount = 1;
+
+  WGPUTexture texture = wgpuDeviceCreateTexture(device, &desc);
+
+  WGPUTextureViewDescriptor view_desc = {};
+  view_desc.format = format;
+  view_desc.dimension = WGPUTextureViewDimension_2D;
+  view_desc.mipLevelCount = mip_levels;
+  view_desc.arrayLayerCount = 1;
+
+  WGPUTextureView view = wgpuTextureCreateView(texture, &view_desc);
+
+  return {texture, view};
+}
+
+TextureWithView gpu_create_storage_texture_2d(WGPUDevice device, uint32_t width,
+                                              uint32_t height,
+                                              WGPUTextureFormat format) {
+  return gpu_create_texture_2d(
+      device, width, height, format,
+      WGPUTextureUsage_StorageBinding | WGPUTextureUsage_TextureBinding, 1);
+}
+
+WGPUTextureView gpu_create_mip_view(WGPUTexture texture,
+                                    WGPUTextureFormat format,
+                                    uint32_t mip_level) {
+  WGPUTextureViewDescriptor view_desc = {};
+  view_desc.format = format;
+  view_desc.dimension = WGPUTextureViewDimension_2D;
+  view_desc.baseMipLevel = mip_level;
+  view_desc.mipLevelCount = 1;
+  view_desc.baseArrayLayer = 0;
+  view_desc.arrayLayerCount = 1;
+
+  return wgpuTextureCreateView(texture, &view_desc);
+}
+
 RenderPass gpu_create_render_pass(WGPUDevice device, WGPUTextureFormat format,
                                   const char* shader_code,
                                   ResourceBinding* bindings, int num_bindings) {