builtin_data/_pbr_prefilter.glsl

   1 uniform PrecalcParams
   2 {
   3         int n_samples;
   4         float roughness;
   5 };
   6
   7 uniform samplerCube environment_map;
   8
   9 vec2 hammersley(int i, int count)
  10 {
  11         float y = bitfieldReverse(uint(i))*2.3283064e-10;
  12         return vec2(float(i)/count, y);
  13 }
  14
  15 vec3 uv_to_hemisphere(float u, float v)
  16 {
  17         float phi = u*2.0*PI;
  18         float r = sqrt(1.0-v*v);
  19         return vec3(cos(phi)*r, sin(phi)*r, v);
  20 }
  21
  22 vec3 ndist_ggxtr_importance_sample(vec2 uv, float roughness)
  23 {
  24         float rough_q = roughness*roughness;
  25         rough_q *= rough_q;
  26         float v = sqrt((1.0-uv.y)/(1.0+(rough_q-1.0)*uv.y));
  27         return uv_to_hemisphere(uv.x, v);
  28 }