CNN v2: storage buffer architecture foundation

- Add binary weight format (header + layer info + packed f16)
- New export_cnn_v2_weights.py for binary weight export
- Single cnn_v2_compute.wgsl shader with storage buffer
- Load weights in CNNv2Effect::load_weights()
- Create layer compute pipeline with 5 bindings
- Fast training config: 100 epochs, 3×3 kernels, 8→4→4 channels

Next: Complete bind group creation and multi-layer compute execution

1 files changed, 25 insertions, 5 deletions

diff --git a/src/gpu/effects/cnn_v2_effect.h b/src/gpu/effects/cnn_v2_effect.h
index facf4c3..6005cf5 100644
--- a/src/gpu/effects/cnn_v2_effect.h
+++ b/src/gpu/effects/cnn_v2_effect.h
@@ -19,8 +19,25 @@ public:
   void update_bind_group(WGPUTextureView input_view) override;
 
 private:
+  struct LayerInfo {
+    uint32_t kernel_size;
+    uint32_t in_channels;
+    uint32_t out_channels;
+    uint32_t weight_offset;
+    uint32_t weight_count;
+  };
+
+  struct LayerParams {
+    uint32_t kernel_size;
+    uint32_t in_channels;
+    uint32_t out_channels;
+    uint32_t weight_offset;
+    uint32_t is_output_layer;
+  };
+
   void create_textures();
   void create_pipelines();
+  void load_weights();
   void cleanup();
 
   // Static features compute
@@ -29,16 +46,19 @@ private:
   WGPUTexture static_features_tex_;
   WGPUTextureView static_features_view_;
 
-  // CNN layers (opaque implementation)
-  std::vector<WGPUComputePipeline> layer_pipelines_;
-  std::vector<WGPUBindGroup> layer_bind_groups_;
-  std::vector<WGPUTexture> layer_textures_;
+  // CNN layers (storage buffer architecture)
+  WGPUComputePipeline layer_pipeline_;      // Single pipeline for all layers
+  WGPUBuffer weights_buffer_;               // Storage buffer for weights
+  WGPUBuffer layer_params_buffer_;          // Uniform buffer for per-layer params
+  std::vector<LayerInfo> layer_info_;       // Layer metadata
+  std::vector<WGPUBindGroup> layer_bind_groups_;  // Per-layer bind groups
+  std::vector<WGPUTexture> layer_textures_;       // Ping-pong buffers
   std::vector<WGPUTextureView> layer_views_;
 
   // Input mips
   WGPUTexture input_mip_tex_;
   WGPUTextureView input_mip_view_[3];
-  WGPUTextureView current_input_view_;  // Cached input from update_bind_group
+  WGPUTextureView current_input_view_;
 
   bool initialized_;
 };