#version 330

out vec4 FragColor;

in vec2 TexCoords;

uniform sampler2D gPosition;
uniform sampler2D gNormal;
uniform sampler2D gAlbedoSpec;

struct Light {
    vec3 Position;
    vec3 Color;
};

const int NR_LIGHTS = 32;
uniform Light lights[NR_LIGHTS];
uniform vec3 viewPos;

void main()
{
    // retrieve data from G-buffer
    vec3 FragPos = texture(gPosition, TexCoords).rgb;
    vec3 Normal = texture(gNormal, TexCoords).rgb;
    vec3 Albedo = texture(gAlbedoSpec, TexCoords).rgb;
    float Specular = texture(gAlbedoSpec, TexCoords).a;

    // then calculate lighting as usual
    vec3 lighting = Albedo * 0.1; // hard-coded ambient component
    vec3 viewDir = normalize(viewPos - FragPos);
    for(int i = 0; i < NR_LIGHTS; ++i)
    {
	// diffuse
	vec3 lightDir = normalize(lights[i].Position - FragPos);
	vec3 diffuse = max(dot(Normal, lightDir), 0.0) * Albedo * lights[i].Color;
	lighting += diffuse;
    }
    FragColor = vec4(lighting, 1.0);
}