isabella232 / glsl-blend-overlay

blend mode 'overlay' for GLSL

glsl-blend-overlay

(click for demo)

Photoshop-like "overlay" blend mode for GLSL.

#pragma glslify: blend = require(../)

void main() {
  vec4 bgColor = texture2D(bg, vUv);
  vec4 fgColor = texture2D(foreground, vUv);

  vec3 color = blend(bgColor.rgb, fgColor.rgb);
  gl_FragColor = vec4(color, 1.0);
}

Usage

blend(vec3 background, vec3 foreground)

Blends background and foreground with an "overlay" blend mode. The algorithm for each channel is as follows:

bg < 0.5 ? (2.0 * bg * fg) : (1.0 - 2.0 * (1.0 - bg) * (1.0 - fg))

Contributing

See stackgl/contributing.

License

MIT. See LICENSE.md for details.