test_demo: Add beat-synchronized CNN post-processing with version selection

- Add --cnn-version <1|2> flag to select between CNN v1 and v2
- Implement beat_phase modulation for dynamic blend in both CNN effects
- Fix CNN v2 per-layer uniform buffer sharing (each layer needs own buffer)
- Fix CNN v2 y-axis orientation to match render pass convention
- Add Scene1Effect as base visual layer to test_demo timeline
- Reorganize CNN v2 shaders into cnn_v2/ subdirectory
- Update asset paths and documentation for new shader organization

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

1 files changed, 15 insertions, 1 deletions

diff --git a/src/gpu/effects/cnn_v2_effect.h b/src/gpu/effects/cnn_v2_effect.h
index 6005cf5..4389e4f 100644
--- a/src/gpu/effects/cnn_v2_effect.h
+++ b/src/gpu/effects/cnn_v2_effect.h
@@ -5,9 +5,14 @@
 #include "gpu/effect.h"
 #include <vector>
 
+struct CNNv2EffectParams {
+  float blend_amount = 1.0f;
+};
+
 class CNNv2Effect : public PostProcessEffect {
 public:
   explicit CNNv2Effect(const GpuContext& ctx);
+  explicit CNNv2Effect(const GpuContext& ctx, const CNNv2EffectParams& params);
   ~CNNv2Effect();
 
   void init(MainSequence* demo) override;
@@ -18,6 +23,11 @@ public:
               const CommonPostProcessUniforms& uniforms) override;
   void update_bind_group(WGPUTextureView input_view) override;
 
+  void set_beat_modulation(bool enabled, float scale = 1.0f) {
+    beat_modulated_ = enabled;
+    beat_scale_ = scale;
+  }
+
 private:
   struct LayerInfo {
     uint32_t kernel_size;
@@ -33,6 +43,7 @@ private:
     uint32_t out_channels;
     uint32_t weight_offset;
     uint32_t is_output_layer;
+    float blend_amount;
   };
 
   void create_textures();
@@ -49,7 +60,7 @@ private:
   // 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<WGPUBuffer> layer_params_buffers_;  // Uniform buffers (one per layer)
   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
@@ -60,5 +71,8 @@ private:
   WGPUTextureView input_mip_view_[3];
   WGPUTextureView current_input_view_;
 
+  float blend_amount_ = 1.0f;
+  bool beat_modulated_ = false;
+  float beat_scale_ = 1.0f;
   bool initialized_;
 };