#version 440

in vec3 f_color;
out vec4 FragColors;

uniform vec3 Kd;
uniform vec3 Ka;
uniform vec3 Ks;
uniform float Shininess;

uniform int LightCount;

struct LightInfo {
  vec4 Position; 
  vec3 Intensity; 
};

uniform LightInfo Light[64];

in vec3 fNormal;
in vec3 pos;

void main()
{ 

	vec3 finalColor;
	vec3 ambient;

	ambient = Ka * Light[0].Intensity;
	for (int i=0; i< LightCount; i++) 
	{   
    vec3 L = normalize(Light[i].Position.xyz - pos);
	vec3 N = fNormal;
	vec3 V = normalize(-pos);	
	//vec3 R = normalize(reflect(-L, N));
	vec3 H = normalize(V + L);

	vec3 diffuse = Kd * Light[i].Intensity * max(dot(L, N), 0.0);	
	vec3 specular = Ks * Light[i].Intensity * pow(max(dot(H, N), 0.0), Shininess);	
	finalColor = finalColor + diffuse + specular;
    }
	
  finalColor = finalColor + ambient;

   //fog calculus
   float z = abs(pos.z);   
   float f = (30 - z) / (30 - 1);
   vec3 fogColor = vec3(1, 1, 1);
   f = clamp(f, 0.0, 1.0);
   finalColor = mix(fogColor, finalColor, f);  

   FragColors = vec4(finalColor, 1);   
}