shaders/noise.glsl

   1 uniform sampler2D uTexNoise;
   2
   3 float noise( vec3 x )
   4 {
   5   vec3 i = floor(x);
   6   vec3 f = fract(x);
   7   f = f*f*(3.0-2.0*f);
   8   vec2 uv = (i.xy+vec2(37.0,17.0)*i.z) + f.xy;
   9   vec2 rg = texture( uTexNoise, (uv+0.5)/256.0).yx;
  10   return mix( rg.x, rg.y, f.z );
  11 }
  12
  13 const mat3 m = mat3( 0.00,  0.80,  0.60,
  14                     -0.80,  0.36, -0.48,
  15                     -0.60, -0.48,  0.64 );
  16
  17 float fractalNoise( vec3 x )
  18 {
  19   vec3 q = 8.0*x;
  20   float f;
  21   f  = 0.5000*noise( q ); q = m*q*2.01;
  22   f += 0.2500*noise( q ); q = m*q*2.02;
  23   f += 0.1250*noise( q ); q = m*q*2.03;
  24   f += 0.0625*noise( q ); q = m*q*2.01;
  25   return f;
  26 }