#version 450 core

out vec4 FragColor;

in vec2 TexCoords;

uniform sampler2D gBaseColor;
uniform sampler2D gDebug;
uniform float exposure = 1;
uniform bool showDebug = false;

vec3 ACESToneMapping(vec3 color)
{
    const float A = 2.51;
    const float B = 0.03;
    const float C = 2.43;
    const float D = 0.59;
    const float E = 0.14;
    return (color * (A * color + B)) / (color * (C * color + D) + E);
}

void main()
{       
	vec4 rgbm = texture(gBaseColor, TexCoords);
	vec4 debug = texture(gDebug, TexCoords);
	if(rgbm.a==0 && (showDebug ? debug.a==0 : true))
	{
		//FragColor = vec4(1,0,0,1);
		//return;
		discard;
	}
	vec3 color = 8 * rgbm.rgb * rgbm.a;

	color *= exposure;
	color = ACESToneMapping(color);

	//color = color / (color + vec3(1.0));
	color = pow(color, vec3(1.0/2.2));  
	FragColor = vec4(color, 1.0);
	if(showDebug)
		FragColor = mix(FragColor, debug, debug.a);
}