composite.fsh

#version 120

//FXAA shader by kool_Kat

uniform sampler2D gcolor;
uniform sampler2D gdepth;

uniform float viewHeight;
uniform float viewWidth;

varying vec4 texcoord;


vec4 fxaa() {
    float pw = 1.0 / viewWidth;
    float ph = 1.0 / viewHeight;

    vec3 rgbNW = texture2D(gcolor, texcoord.xy + vec2(-pw,-ph)).xyz;
    vec3 rgbNE = texture2D(gcolor, texcoord.xy + vec2(pw,-ph)).xyz;
    vec3 rgbSW = texture2D(gcolor, texcoord.xy + vec2(-pw,ph)).xyz;
    vec3 rgbSE = texture2D(gcolor, texcoord.xy + vec2(pw,ph)).xyz;
    vec3 rgbM =  texture2D(gcolor, texcoord.xy).xyz;

    vec3 luma = vec3(0.299, 0.587, 0.114);
    float lumaNW = dot(rgbNW, luma);
    float lumaNE = dot(rgbNE, luma);
    float lumaSW = dot(rgbSW, luma);
    float lumaSE = dot(rgbSE, luma);
    float lumaM = dot(rgbM, luma);

    float lumaMin = min(lumaM, min(min(lumaNW,lumaNE),min(lumaSW,lumaSE)));
    float lumaMax = max(lumaM, max(max(lumaNW,lumaNE),max(lumaSW,lumaSE)));

    vec2 dir;
    dir.x = -((lumaNW + lumaNE) - (lumaSW + lumaSE));
    dir.y = ((lumaNW + lumaSW) - (lumaNE + lumaSE));

    float dirReduce = max((lumaNW + lumaNE + lumaSW + lumaSE) * (0.25 * 1.0/8.0), 1.0/128.0);

    float rcpDirMin = 1.0 /(min(abs(dir.x), abs(dir.y)) + dirReduce);

    dir = min(vec2(4.0,4.0),max(vec2(-4.0,-4.0),dir * rcpDirMin)) * vec2(pw,ph);

    vec3 rgbA = (1.0/2.0) * (texture2D(gcolor, texcoord.xy + dir * (1.0/3,0 - 0.5)).xyz +
                            texture2D(gcolor, texcoord.xy + dir * (2.0/3.0 - 0.5)).xyz);

    vec3 rgbB = rgbA * (1.0/2.0) + (1.0/4.0) * (texture2D(gcolor, texcoord.xy + dir * (0.0/3.0 - 0.5)).xyz +
                                                texture2D(gcolor, texcoord.xy + dir * (3.0/3.0 - 0.5)).xyz);

    float lumaB = dot(rgbB, luma);

    if((lumaB < lumaMin) || (lumaB > lumaMax)) {
        return vec4(rgbA , 1.0);
    }
    return vec4(rgbB, 1.0);
}

void main() {
    gl_FragData[0] = texture2D(gcolor, texcoord.st);
    gl_FragData[1] = texture2D(gdepth, texcoord.st);
    gl_FragData[3] = fxaa();
}