/*

 Copyright (C) 2015 Apple Inc. All Rights Reserved.

 See LICENSE.txt for this sample’s licensing information

 Abstract:

 The application delegate.

 */

#version 150

uniform sampler2D normalTex, posTex, colorTex;

uniform vec3 light1Pos;

uniform vec3 light1Color;

uniform vec3 light2Pos;

uniform vec3 light2Color;

uniform vec3 light3Pos;

uniform vec3 light3Color;

uniform vec3 light4Pos;

uniform vec3 light4Color;

in vec3 texCoord;

out vec4 fragColor;

void main()

{

    vec4 color = texture(colorTex, texCoord.xy);

    //drop out early if there's nothing to draw

    if(color.a < 0.00001)

    {

        discard;

    }

    //pull normal x and y from texture

    vec2 norm = texture(normalTex, texCoord.xy).xy;

    //reconstruct the normal

    vec3 normal = vec3(norm.xy, 0.0);

    normal.z = sqrt(1.0 - norm.x*norm.x-norm.y*norm.y);

    //pull out the position

    vec3 position = texture(posTex,texCoord.xy).xyz;

    vec3 view = normalize(-position);

    //light 1

    vec3 L = normalize(light1Pos-position);

    float attenuation1 = max(0.0, dot(L, normal));

    //specular

    vec3 reflectvec = normalize(reflect(-L, normal));

    float spec = max(dot(reflectvec, view),0.0);

    //light 2

    vec3 L2 = normalize(light2Pos-position);

    float attenuation2 = max(0.0, dot(L2, normal));

    //specular

    vec3 reflectvec2 = normalize(reflect(-L2, normal));

    float spec2 = max(dot(reflectvec2, view),0.0);

    vec3 L3 = normalize(light3Pos-position);

    float attenuation3 = max(0.0, dot(L3, normal));

    //specular

    vec3 reflectvec3 = normalize(reflect(-L3, normal));

    float spec3 = max(dot(reflectvec3, view),0.0);

    //light 4

    vec3 L4 = normalize(light4Pos-position);

    float attenuation4 = max(0.0, dot(L4, normal));

    //specular

    vec3 reflectvec4 = normalize(reflect(-L4, normal));

    float spec4 = max(dot(reflectvec4, view),0.0);

    fragColor = color +

                    (vec4(min(pow(spec, 32.0)+attenuation1*light1Color, 1.0), 1)+

                    vec4(min(pow(spec2, 32.0)+attenuation2*light2Color, 1.0), 1)+

                    vec4(min(pow(spec3, 32.0)+attenuation3*light3Color, 1.0), 1)+

                    vec4(min(pow(spec4, 32.0)+attenuation4*light4Color, 1.0), 1));

}