src/Shaders/PBRIllumination.glsl

   1 //! Calculates direct illumination using Cook-Torrance BRDF.
   2 vec3 occPBRIllumination (in vec3  theView,
   3                          in vec3  theLight,
   4                          in vec3  theNormal,
   5                          in vec4  theBaseColor,
   6                          in float theMetallic,
   7                          in float theRoughness,
   8                          in float theIOR,
   9                          in vec3  theLightColor,
  10                          in float theLightIntensity)
  11 {
  12   vec3 aHalf = normalize (theView + theLight);
  13   float aCosVH = max(dot(theView, aHalf), 0.0);
  14   vec3 aFresnel = occPBRFresnel (theBaseColor.rgb, theMetallic, theIOR, aCosVH);
  15   vec3 aSpecular = occPBRCookTorrance (theView,
  16                                        theLight,
  17                                        theNormal,
  18                                        theBaseColor.rgb,
  19                                        theMetallic,
  20                                        theRoughness,
  21                                        theIOR);
  22   vec3 aDiffuse = vec3(1.0) - aFresnel;
  23   aDiffuse *= 1.0 - theMetallic;
  24   aDiffuse *= INV_PI;
  25   aDiffuse *= theBaseColor.rgb;
  26   aDiffuse = mix (vec3(0.0), aDiffuse, theBaseColor.a);
  27   return (aDiffuse + aSpecular) * theLightColor * theLightIntensity * max(0.0, dot(theLight, theNormal));
  28 }