frag.glsl

varying vec3 vN;
varying vec3 v;
#define MAX_LIGHTS 2
void main (void)
{
   vec3 N = normalize(vN);
   vec4 finalColor = vec4(0.0, 0.0, 0.0, 0.0);

   for (int i=0;i<MAX_LIGHTS;i++)
   {
      vec3 L = normalize(gl_LightSource[i].position.xyz - v);
      vec3 E = normalize(-v); // we are in Eye Coordinates, so EyePos is (0,0,0)
      vec3 R = normalize(-reflect(L,N));

      //calculate Ambient Term:
      vec4 Iamb = gl_FrontLightProduct[i].ambient;
      //calculate Diffuse Term:
      vec4 Idiff = gl_FrontLightProduct[i].diffuse * max(dot(N,L), 0.0);
      Idiff = clamp(Idiff, 0.0, 1.0);

      // calculate Specular Term:
      vec4 Ispec = gl_FrontLightProduct[i].specular
             * pow(max(dot(R,E),0.0),0.3*gl_FrontMaterial.shininess);
      Ispec = clamp(Ispec, 0.0, 1.0);

      finalColor += Iamb + Idiff + Ispec;
   }

   // write Total Color:
   gl_FragColor = gl_FrontLightModelProduct.sceneColor + finalColor;
}