From 9d1d4df877f96f1970dce2ab30cfae49d3d796e1 Mon Sep 17 00:00:00 2001
From: skal <pascal.massimino@gmail.com>
Date: Mon, 16 Feb 2026 08:26:45 +0100
Subject: feat(sequence): Phase 1 - Sequence v2 foundation

- Add Node system with typed buffers (u8x4_norm, f32x4, f16x8, depth24)
- Add NodeRegistry with aliasing support for ping-pong optimization
- Add SequenceV2 base class with DAG execution
- Add EffectV2 base class with multi-input/multi-output
- Add comprehensive tests (5 test cases, all passing)
- Corrected FATAL_CHECK usage (checks ERROR conditions, not success)

Phase 1 complete: Core v2 architecture functional.
Next: Phase 2 compiler (seq_compiler_v2.py)

handoff(Claude): Phase 1 foundation complete, all tests passing (35/35)
---
 src/gpu/sequence_v2.h | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 src/gpu/sequence_v2.h

(limited to 'src/gpu/sequence_v2.h')

diff --git a/src/gpu/sequence_v2.h b/src/gpu/sequence_v2.h
new file mode 100644
index 0000000..9cd93c6
--- /dev/null
+++ b/src/gpu/sequence_v2.h
@@ -0,0 +1,107 @@
+// Sequence v2: Explicit node system with DAG effect routing
+// Replaces implicit framebuffer ping-pong with compile-time optimized nodes
+
+#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 EffectV2;
+
+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;
+
+ 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<EffectV2> effect;
+  std::vector<std::string> input_nodes;
+  std::vector<std::string> output_nodes;
+  int execution_order; // Topologically sorted
+};
+
+class SequenceV2 {
+ public:
+  SequenceV2(const GpuContext& ctx, int width, int height);
+  virtual ~SequenceV2() = 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);
+
+ protected:
+  const GpuContext& ctx_;
+  int width_;
+  int height_;
+  NodeRegistry nodes_;
+  std::vector<EffectDAGNode> effect_dag_;
+  UniformsSequenceParams params_;
+  UniformBuffer<UniformsSequenceParams> uniforms_buffer_;
+};
-- 
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