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, 15 insertions, 0 deletions

diff --git a/src/gpu/gpu.h b/src/gpu/gpu.h
index c7ee89f..b52d6ab 100644
--- a/src/gpu/gpu.h
+++ b/src/gpu/gpu.h
@@ -82,8 +82,23 @@ inline void gpu_init_color_attachment(WGPURenderPassColorAttachment& attachment,
 #endif
 }
 
+// Texture creation helper
+struct TextureWithView {
+  WGPUTexture texture;
+  WGPUTextureView view;
+};
+
 GpuBuffer gpu_create_buffer(WGPUDevice device, size_t size, uint32_t usage,
                             const void* data = nullptr);
+TextureWithView gpu_create_texture_2d(WGPUDevice device, uint32_t width,
+                                      uint32_t height, WGPUTextureFormat format,
+                                      WGPUTextureUsage usage,
+                                      uint32_t mip_levels = 1);
+TextureWithView gpu_create_storage_texture_2d(WGPUDevice device, uint32_t width,
+                                              uint32_t height,
+                                              WGPUTextureFormat format);
+WGPUTextureView gpu_create_mip_view(WGPUTexture texture,
+                                    WGPUTextureFormat format, uint32_t mip_level);
 ComputePass gpu_create_compute_pass(WGPUDevice device, const char* shader_code,
                                     ResourceBinding* bindings,
                                     int num_bindings);