1 files changed, 131 insertions, 0 deletions
diff --git a/src/gpu/sequence.h b/src/gpu/sequence.h
new file mode 100644
index 0000000..a33dedb
--- /dev/null
+++ b/src/gpu/sequence.h
@@ -0,0 +1,131 @@
+// Sequence: Explicit node system with DAG effect routing
+// DAG-based effect routing with ping-pong optimization
+
+#ifndef SEQUENCE_H
+#define SEQUENCE_H
+#pragma once
+
+#include "gpu/gpu.h"
+#include "gpu/uniform_helper.h"
+#include "util/mini_math.h"
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+class Effect;
+
+enum class NodeType {
+  U8X4_NORM,   // RGBAu8 normalized (0-1) - default Source/Sink
+  F32X4,       // RGBA float32
+  F16X8,       // 8-channel float16
+  DEPTH24,     // Depth buffer
+  COMPUTE_F32, // Compute buffer
+};
+
+struct Node {
+  NodeType type;
+  int width;
+  int height;
+  WGPUTexture texture;
+  WGPUTextureView view;
+  std::vector<WGPUTextureView> mip_views; // For multi-target render
+};
+
+struct UniformsSequenceParams {
+  vec2 resolution;
+  float aspect_ratio;
+  float time;           // Per-sequence relative time
+  float beat_time;      // Musical beats
+  float beat_phase;     // Fractional beat 0.0-1.0
+  float audio_intensity;
+  float _pad;
+};
+static_assert(sizeof(UniformsSequenceParams) == 32,
+              "UniformsSequenceParams must be 32 bytes for WGSL alignment");
+
+class NodeRegistry {
+ public:
+  NodeRegistry(WGPUDevice device, int default_width, int default_height);
+  ~NodeRegistry();
+
+  // Declare new node with explicit type/dimensions
+  void declare_node(const std::string& name, NodeType type, int width,
+                    int height);
+
+  // Declare aliased node (ping-pong optimization)
+  void declare_aliased_node(const std::string& name,
+                            const std::string& alias_of);
+
+  // Retrieve views
+  WGPUTextureView get_view(const std::string& name);
+  std::vector<WGPUTextureView>
+  get_output_views(const std::vector<std::string>& names);
+
+  // Resize all nodes
+  void resize(int width, int height);
+
+  // Check if node exists
+  bool has_node(const std::string& name) const;
+
+  // Register external view (for source/sink managed externally)
+  void set_external_view(const std::string& name, WGPUTextureView view);
+
+ private:
+  WGPUDevice device_;
+  int default_width_;
+  int default_height_;
+  std::map<std::string, Node> nodes_;
+  std::map<std::string, std::string> aliases_; // name -> backing node name
+
+  void create_texture(Node& node);
+};
+
+struct EffectDAGNode {
+  std::shared_ptr<Effect> effect;
+  std::vector<std::string> input_nodes;
+  std::vector<std::string> output_nodes;
+  int execution_order; // Topologically sorted
+};
+
+class Sequence {
+ public:
+  Sequence(const GpuContext& ctx, int width, int height);
+  virtual ~Sequence() = default;
+
+  // Virtual methods (most sequences use defaults)
+  virtual void preprocess(float seq_time, float beat_time, float beat_phase,
+                          float audio_intensity);
+  virtual void postprocess(WGPUCommandEncoder encoder);
+  virtual void render_effects(WGPUCommandEncoder encoder);
+
+  void resize(int width, int height);
+
+  // Initialize effect nodes (call at end of subclass constructor)
+  void init_effect_nodes();
+
+  // Set surface texture view for rendering (sink node)
+  void set_sink_view(WGPUTextureView view) {
+    nodes_.set_external_view("sink", view);
+  }
+
+  // Set source texture view (input framebuffer)
+  void set_source_view(WGPUTextureView view) {
+    nodes_.set_external_view("source", view);
+  }
+
+  // Test accessor
+  const std::vector<EffectDAGNode>& get_effect_dag() const {
+    return effect_dag_;
+  }
+
+ protected:
+  const GpuContext& ctx_;
+  int width_;
+  int height_;
+  NodeRegistry nodes_;
+  std::vector<EffectDAGNode> effect_dag_;
+  UniformsSequenceParams params_;
+  UniformBuffer<UniformsSequenceParams> uniforms_buffer_;
+};
+#endif // SEQUENCE_H