perfragment.frag

GLSL tutorial with sourcecode

/*
    OGLSL Implementation: Per Fragment Lighting
                          uses 1st OpenGL light source

    (c) 2004 by Martin Christen. All Rights Reserved.
*/

varying vec3 L;
varying vec3 N;
varying vec3 P;

void main (void)
{ 
  vec3 E = normalize(-P);
  vec3 R = normalize(-reflect(L,N));

  vec4 Iamb = gl_FrontLightProduct[0].ambient; 
  vec4 Idiff = gl_FrontLightProduct[0].diffuse * max(dot(N,L), 0.0);
  vec4 Ispec = gl_FrontLightProduct[0].specular * pow(max(dot(R,E),0.0),0.3 * gl_FrontMaterial.shininess);

  gl_FragColor =  gl_FrontLightModelProduct.sceneColor + Iamb + Idiff + Ispec;
}