glsl-sh

Get color from spherical harmonic coefficients and normals.

Installation

$ npm i -S glsl-sh

Usage

In order do use this you need spherical harmonics coefficients. You can generate them with the cubemap-sh module which goes hand-in-hand with this module. A shader to calculate the color would look like this:

precision mediump float;
#pragma glslify: sh = require('glsl-sh') // import using glslify
varying vec3 vWorldNormal;
uniform vec3 c[9]; // this is what you get from the cubemap-sh module
uniform vec3 color;
void main() {
  vec3 n = normalize(vWorldNormal);
  vec3 shColor = sh(c, n) * color; // here we get diffuse light calculated by the sperhical harmonics multiplied by the color of the mesh
  gl_FragColor = vec4(shColor, 1.0);
  gl_FragColor.rgb = pow(gl_FragColor.rgb, vec3(1.0 / 2.2)); // gamma correction
}

Please note this example uses glslify.

Please see the cubemap-sh repo for a complete example.

API

#pragma glslify: sh = require('glsl-sh')

sh(vec3[9] c, vec3 worldNormal)

• c: spherical harmonics coefficients
• normal: the world normal

returns vec3, the calculated color

License

MIT