New version of the samples and tutorials based on KHR_ray_tracing

ray_tracing__advance/shaders/wavefront.glsl

@@ -0,0 +1,57 @@
+struct Vertex
+{
+  vec3 pos;
+  vec3 nrm;
+  vec3 color;
+  vec2 texCoord;
+};
+
+struct WaveFrontMaterial
+{
+  vec3  ambient;
+  vec3  diffuse;
+  vec3  specular;
+  vec3  transmittance;
+  vec3  emission;
+  float shininess;
+  float ior;       // index of refraction
+  float dissolve;  // 1 == opaque; 0 == fully transparent
+  int   illum;     // illumination model (see http://www.fileformat.info/format/material/)
+  int   textureId;
+};
+
+struct sceneDesc
+{
+  int  objId;
+  int  txtOffset;
+  mat4 transfo;
+  mat4 transfoIT;
+};
+
+
+vec3 computeDiffuse(WaveFrontMaterial mat, vec3 lightDir, vec3 normal)
+{
+  // Lambertian
+  float dotNL = max(dot(normal, lightDir), 0.0);
+  vec3  c     = mat.diffuse * dotNL;
+  if(mat.illum >= 1)
+    return c + mat.ambient;
+}
+
+vec3 computeSpecular(WaveFrontMaterial mat, vec3 viewDir, vec3 lightDir, vec3 normal)
+{
+  if(mat.illum < 2)
+    return vec3(0);
+
+  // Compute specular only if not in shadow
+  const float kPi        = 3.14159265;
+  const float kShininess = max(mat.shininess, 4.0);
+
+  // Specular
+  const float kEnergyConservation = (2.0 + kShininess) / (2.0 * kPi);
+  vec3        V                   = normalize(-viewDir);
+  vec3        R                   = reflect(-lightDir, normal);
+  float       specular            = kEnergyConservation * pow(max(dot(V, R), 0.0), kShininess);
+
+  return vec3(mat.specular * specular);
+}