feat: Implement Sequence and Effect system for demo choreography

Refactors the rendering pipeline into a modular Sequence/Effect system. 'MainSequence' manages the final frame rendering and a list of 'Sequence' layers. 'Sequence' manages a timeline of 'Effect' objects (start/end/priority). Concrete effects (Heptagon, Particles) are moved to 'demo_effects.cc'. Updates main loop to pass beat and aspect ratio.

1 files changed, 40 insertions, 0 deletions

diff --git a/src/gpu/demo_effects.h b/src/gpu/demo_effects.h
new file mode 100644
index 0000000..81321d9
--- /dev/null
+++ b/src/gpu/demo_effects.h
@@ -0,0 +1,40 @@
+// This file is part of the 64k demo project.
+// It declares the concrete effects used in the demo.
+
+#pragma once
+#include "effect.h"
+#include "gpu.h"
+#include <memory>
+
+class HeptagonEffect : public Effect {
+public:
+  HeptagonEffect(WGPUDevice device, WGPUQueue queue, WGPUTextureFormat format);
+  void render(WGPURenderPassEncoder pass, float time, float beat,
+              float intensity, float aspect_ratio) override;
+
+private:
+  WGPUQueue queue_;
+  RenderPass pass_;
+  GpuBuffer uniforms_;
+};
+
+class ParticlesEffect : public Effect {
+public:
+  ParticlesEffect(WGPUDevice device, WGPUQueue queue, WGPUTextureFormat format);
+  void compute(WGPUCommandEncoder encoder, float time, float beat,
+               float intensity, float aspect_ratio) override;
+  void render(WGPURenderPassEncoder pass, float time, float beat,
+              float intensity, float aspect_ratio) override;
+
+private:
+  WGPUQueue queue_;
+  ComputePass compute_pass_;
+  RenderPass render_pass_;
+  GpuBuffer particles_buffer_;
+  GpuBuffer uniforms_;
+};
+
+// Factory
+std::shared_ptr<Sequence> create_demo_sequence(WGPUDevice device,
+                                               WGPUQueue queue,
+                                               WGPUTextureFormat format);