#version 430 core

float AMBIENT = 0.05;

uniform sampler2D colorTexture;

uniform vec3 color;
uniform vec3 lightPos;
uniform vec3 lightColor;

uniform vec3 cameraPos;

uniform bool atmosphereCheck;

in vec3 vecNormal;
in vec3 worldPos;
in vec2 vtc;

out vec4 outColor;

vec3 toneMapping(vec3 color)
{
	float exposure = 0.06;
	vec3 mapped = 1 - exp(-color * exposure);
	return mapped;
}

void main()
{
	vec3 normal = normalize(vecNormal);
    vec3 viewDir = normalize(cameraPos - worldPos);
	vec3 lightDir = normalize(lightPos - worldPos);

	float diffuse = max(0, dot(normal, lightDir));

    vec4 textureColor = texture2D(colorTexture, vtc);

	float atmosphereDot = dot(normal, viewDir);
    vec3 atmosphereColor = vec3(0.04, 0.2, 1.0);

    if (atmosphereCheck)
        textureColor = mix(textureColor, vec4(atmosphereColor / atmosphereDot, 1.0), 0.05);

	vec3 distance = lightColor / pow(length(lightPos - worldPos), 2.0) * 10000;
    vec3 toneMappedColor = toneMapping(vec3(textureColor) * min(1, AMBIENT + diffuse) * distance);
    //gamma correction
    //toneMappedColor = pow(toneMappedColor, vec3(1.0/2.2)); 

	outColor = vec4(toneMappedColor, 1);
}