#version 120

varying vec3  vertex;
varying vec3  normal;
varying vec3  lightDirection;

uniform vec3  lightColor;
uniform vec3  lightPosition;
uniform float materialKind;
uniform vec3  materialColor;

void main()
{
  vec3 Eye       = normalize(-vertex);
  vec3 Reflected = normalize(reflect( -lightPosition, normal));

  vec3 IAmbient  = vec3(0.05f);

  if (materialKind == 6) {
      // sun: shines by itself
      gl_FragColor = vec4(materialColor, 1.0);
      return;
  }

    // TODO: add noise texture
  vec3 IDiffuse  = vec3(materialColor) * lightColor * max(dot(normal, lightDirection), 0.0);

  // TODO make instensity/exponent as parameter
  //vec3 ISpecular = lightColor * 5.0 * pow(max(dot(Reflected, Eye), 0.0), 2.0);
  vec3 ISpecular = lightColor * pow(max(dot(Reflected, Eye), 0.0), 2.0);

  if (dot(lightDirection, normal) <= 0.0) {
      ISpecular = vec3(0.0, 0.0, 0.0);
  }

    // p: point of the fragment on the surface
    //vec3 v_eye = normalize(pos_eye - pos_space); // point from p to eye
    //vec3 v_sun = normalize(sun_light_dir); // points from p to the sun

    //float specular = spec_int * pow(
    //    clamp(dot((v_eye + v_sun)/2.0, normal), 0.0, 1.0),
    //    2.0*specular_exponent);

    //ISpecular = vec3(1.0, 0.0, 0.0) * specular;

  //gl_FragColor = vec4(ISpecular, 1.0);
  gl_FragColor   = vec4((IAmbient + IDiffuse) + ISpecular, 1.0);
  //gl_FragColor = vec4(0.5+0.5*normal, 1.0);
}