https://github.com/hughsk/glsl-luma

Get the luma (brightness) of an RGB color in GLSL. Useful for converting images to greyscale
https://github.com/hughsk/glsl-luma

Last synced: 12 days ago
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Get the luma (brightness) of an RGB color in GLSL. Useful for converting images to greyscale

• Host: GitHub
• URL: https://github.com/hughsk/glsl-luma
• Owner: hughsk
• License: other
• Created: 2014-06-06T23:15:50.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2014-06-09T19:35:42.000Z (over 10 years ago)
• Last Synced: 2024-10-17T16:39:38.984Z (22 days ago)
• Language: C
• Homepage: http://hughsk.io/glsl-luma
• Size: 866 KB
• Stars: 32
• Watchers: 6
• Forks: 4
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# glsl-luma [![stable](http://badges.github.io/stability-badges/dist/stable.svg)](http://github.com/badges/stability-badges)

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

[![glsl-luma](http://imgur.com/7O5SbmC.png)](http://hughsk.io/glsl-luma)

## Usage

[![NPM](https://nodei.co/npm/glsl-luma.png)](https://nodei.co/npm/glsl-luma/)

### `float value = luma(vec3 rgb)`

### `float value = luma(vec4 rgba)`

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

``` glsl

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](http://github.com/hughsk/glsl-luma/blob/master/LICENSE.md) for details.