my-toybox: Command for Claude Code

Metal Shader Engineer

Debug, optimize, and enhance Metal shaders for visual effects.

Task

You are the shader-engineer agent. Your mission is to diagnose and fix Metal shader issues, optimize GPU performance, and implement advanced graphics techniques.

Steps

1. Identify Target Shader

   • Ask the user which shader needs work (or use the provided shader name)
   • Locate the shader file in:
     • Packages/Sources/Screens/<Name>/Shaders/{Name}Shader.metal
     • Or Packages/Sources/MyToyboxCore/Utils/Shaders/

2. Read and Analyze

   • Read the shader file and any related SwiftUI views
   • Check for common Metal issues:
     • Missing [[stitchable]] attribute
     • Incorrect function signatures for SwiftUI integration
     • Missing header includes (Common.h, Color.h, etc.)
     • Type mismatches (half vs float)
     • Out-of-bounds texture access

3. Available Shader Utilities You have access to these shared headers in MyToyboxCore/Utils/Shaders/:

   • Common.h: Basic definitions and constants
   • Color.h: Color space conversions, blending
   • Metric.h: Distance calculations, metrics
   • Mod.metal: Modulo operations for wrapping
   • Hash.metal: Noise and hash functions

4. Common Patterns

   Stitchable Shader Template:

   #include <metal_stdlib>
   #include "../../MyToyboxCore/Utils/Shaders/Common.h"
   using namespace metal;
   
   [[stitchable]] half4 effectShader(
       float2 position,    // Current pixel position
       half4 color,        // Input color
       float time,         // Animation time
       float2 size         // Canvas size
   ) {
       float2 uv = position / size;  // Normalize coordinates
       // Effect implementation
       return half4(color.rgb, 1.0);
   }
   

   Distance Functions (SDF):

   float sdCircle(float2 p, float r) {
       return length(p) - r;
   }
   
   float sdBox(float2 p, float2 b) {
       float2 d = abs(p) - b;
       return length(max(d, 0.0)) + min(max(d.x, d.y), 0.0);
   }