AgentSkillsCN

Td Glsl

Td GLSL。

SKILL.md

TouchDesigner GLSL Coding Skill

This skill defines best practices for writing GLSL code within TouchDesigner projects.

Documentation Reference

Best Practices

Framework Specifics

  • •There are specific framework-provided uniforms like vUV.
  • •The main() function has no argument.
  • •The final pixel color in a fragment shader is set with fragColor = TDOutputSwizzle(vec4()).
  • •Input textures are sampled by referencing sTD2DInputs[0] instead of iChannel0.
  • •If there's a Noise function or a noise texture lookup in the original code, replace it with TouchDesigner's built-in noise function: TDSimplexNoise(vec2 v).
  • •If there's a Random function or a random texture lookup in the original code, replace it with TouchDesigner's built-in random texture: sampler2D sTDNoiseMap.
  • •If there's a uTime uniform, please replace with iTime.
  • •Don't specify uniform sampler2D sTD2DInputs or in vec2 vUV as they are provided by the TouchDesigner framework.

Code Style & Readability

  • •Clean and Readable: Avoid ultra-compact "code golf" style GLSL. Expand complex one-liners into multiple lines with meaningful variable names.
  • •Comments: Add comments to explain the logic, especially for complex math or algorithms.
  • •Formatting: Use consistent indentation and spacing to make the code visually appealing and easy to scan.
  • •Uniforms: Use meaningful variable names, prefixed with u.

Built-in Uniforms & Functions

From: https://docs.derivative.ca/Write_a_GLSL_TOP

glsl
// Helpers
uniform sampler2D sTDNoiseMap;  // A 256x256 8-bit Red-only channel texture that has random data.
uniform sampler1D sTDSineLookup; // A Red-only texture that goes from 0 to 1 in a sine shape.

// Noise functions
float TDPerlinNoise(vec2 v);
float TDPerlinNoise(vec3 v);
float TDPerlinNoise(vec4 v);
float TDSimplexNoise(vec2 v);
float TDSimplexNoise(vec3 v);
float TDSimplexNoise(vec4 v);

// Information about the textures
TDTexInfo uTDOutputInfo; // The current texture context
TDTexInfo uTD2DInfos[]; // only exists if inputs are connected 

// Converts between RGB and HSV color space
vec3 TDHSVToRGB(vec3 c);
vec3 TDRGBToHSV(vec3 c);

// Applies a small random noise to the color to help avoid banding in some cases.
vec4 TDDither(vec4 color);

Common Snippets

Constants

glsl
#define PI     3.14159265358
#define TWO_PI 6.28318530718

Correct Aspect Ratio

glsl
float width = 1./uTDOutputInfo.res.z;
float height = 1./uTDOutputInfo.res.w;
vec2 aspect = width * uTDOutputInfo.res.wz; // swizzle height/width
vec2 p = vUV.xy / aspect;

Center Coordinate System

glsl
vec2 p = (vUV.st - vec2(0.5)) / aspect;