glsl-luma

Get the luma (brightness) of an RGB color in GLSL. Useful for converting images to greyscale.

Usage

float value = luma(vec3 rgb)

float value = luma(vec4 rgba)

Takes a vec3 or vec4 color as input, returning the luma as a float.

precision mediump float;
 
uniform sampler2D uTexture;
varying vec2 vUv;
 
#pragma glslify: luma = require(glsl-luma) 
 
void main() {
  vec4 color = texture2D(uTexture, vUv);
  float brightness = luma(color);
 
  gl_FragColor = vec4(vec3(brightness), 1.0);
}

License

MIT. See LICENSE.md for details.