#version 440

in vec3 f_color;
out vec4 FragColors;

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

struct LightInfo {
  vec4 Position; 
  vec3 Intensity;
  float SpotCutoff;
  float SpotInnerCutoff;
  float SpotExponent;
  vec3 SpotDirection;  
};

uniform LightInfo Light[64];
uniform int LightCount;

in vec3 fNormal;
in vec3 pos;

in vec2 texCoord;
uniform sampler2D tex1;

void main()
{ 

	vec3 finalColor;
	vec3 diffuse_sum;
	vec3 specular_sum;
	vec3 ambient;
	float D;
	float attenuation;

	D = distance(Light[0].Position.xyz, pos);
	attenuation = 1 / (1 + 0.01 * D + 0.001 * D * D);
	ambient = Ka * Light[0].Intensity * attenuation;	
	for (int i=0; i<LightCount; i++) 
	{
		D = distance(Light[i].Position.xyz, pos);
		attenuation = 1 / (1 + 0.01 * D + 0.001 * D * D);
		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) * attenuation;	
		vec3 specular = Ks * Light[i].Intensity * pow(max(dot(H, N), 0.0), Shininess) * attenuation;	

		diffuse_sum += diffuse;
		specular_sum += specular;
    }

      FragColors = vec4(diffuse_sum + specular_sum + ambient, 1);   
}