experience-monks / rgba-to-float

packs a RGBA color into a single float

rgba-to-float

Packs a RGBA color into an ABGR-encoded float. This is useful in WebGL to interleave color data into a Float32Array, but only using a single float for RGBA.

var pack = require('rgba-to-float')

//packs RGBA into a float,
var color = pack(0, 255, 128, 127)

This will only work in browsers that implement typed arrays correctly.

precision

This masks high bits to avoid NaN values, and has a slight amount of precision loss. In the vertex shader you may want to bias it so that 0.0 and 1.0 alpha produces expected results.

attribute vec4 color;
varying vec4 v_color;

void main() {
    v_color = color;
    v_color.a = color.a * (255.0/254.0);
    //...
}

Usage

color = pack(r, g, b, a)

Packs the red, green, blue and alpha channels (0 - 255) into a single float, encoded as ABGR.

License

MIT, see LICENSE.md for details.