feat: Add ShaderToy conversion tools

Add automated conversion pipeline for ShaderToy shaders to demo effects:
- convert_shadertoy.py: Automated code generation script
- Manual templates: Header, implementation, and WGSL boilerplate
- Example shader: Test case for conversion workflow
- README: Complete conversion guide with examples

Handles basic GLSL→WGSL conversion (types, uniforms, mainImage extraction).
Manual fixes needed for fragColor returns and complex type inference.

Organized under tools/shadertoy/ for maintainability.

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

1 files changed, 41 insertions, 0 deletions

diff --git a/tools/shadertoy/template.h b/tools/shadertoy/template.h
new file mode 100644
index 0000000..2e4af5f
--- /dev/null
+++ b/tools/shadertoy/template.h
@@ -0,0 +1,41 @@
+// This file is part of the 64k demo project.
+// ShaderToy effect boilerplate - REPLACE THIS LINE WITH DESCRIPTION
+// TODO: Update description, rename class, adjust parameters
+
+#ifndef SHADERTOY_EFFECT_H_
+#define SHADERTOY_EFFECT_H_
+
+#include "gpu/effect.h"
+#include "gpu/effects/post_process_helper.h"
+#include "gpu/uniform_helper.h"
+
+// TODO: Rename class to match your effect (e.g., TunnelEffect, PlasmaEffect)
+class ShaderToyEffect : public Effect {
+ public:
+  // TODO: Add constructor parameters for tunable values
+  ShaderToyEffect(const GpuContext& ctx);
+  ~ShaderToyEffect() override;
+
+  void init(MainSequence* demo) override;
+  void render(WGPURenderPassEncoder pass, float time, float beat,
+              float intensity, float aspect_ratio) override;
+
+ private:
+  // TODO: Add effect-specific parameters here
+  // Must match WGSL struct exactly - use padding for 16-byte alignment
+  struct ShaderToyParams {
+    float param1;
+    float param2;
+    float _pad[2];  // Padding to 16 bytes
+  };
+  static_assert(sizeof(ShaderToyParams) == 16,
+                "ShaderToyParams must be 16 bytes for WGSL alignment");
+
+  MainSequence* demo_ = nullptr;
+  WGPURenderPipeline pipeline_ = nullptr;
+  WGPUBindGroup bind_group_ = nullptr;
+  WGPUSampler sampler_ = nullptr;
+  UniformBuffer<ShaderToyParams> params_;
+};
+
+#endif /* SHADERTOY_EFFECT_H_ */