68 lines
2.6 KiB
GLSL
68 lines
2.6 KiB
GLSL
// FXAA fragment shader by Timothy Lottes (public domain)
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// http://timothylottes.blogspot.com/
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uniform sampler2D tex;
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float FXAA_SUBPIX_SHIFT = 1.0/4.0;
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// posPos: Output of FxaaVertexShader interpolated across screen.
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// tex: Input texture.
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// rcpFrame: const vec2(1.0/frameWidth, 1.0/frameHeight).
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vec3 FxaaPixelShader(vec4 posPos, sampler2D tex, vec2 rcpFrame) {
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#define FXAA_REDUCE_MIN (1.0/128.0)
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#define FXAA_REDUCE_MUL (1.0/8.0)
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#define FXAA_SPAN_MAX 8.0
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vec3 rgbNW = texture2DLod(tex, posPos.zw, 0.0).xyz;
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vec3 rgbNE = texture2DLod(tex, posPos.zw + vec2(1.0,0.0)*rcpFrame.xy, 0.0).xyz;
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vec3 rgbSW = texture2DLod(tex, posPos.zw + vec2(0.0,1.0)*rcpFrame.xy, 0.0).xyz;
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vec3 rgbSE = texture2DLod(tex, posPos.zw + vec2(1.0,1.0)*rcpFrame.xy, 0.0).xyz;
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vec3 rgbM = texture2DLod(tex, posPos.xy,0.0).xyz;
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vec3 luma = vec3(0.299, 0.587, 0.114);
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float lumaNW = dot(rgbNW, luma);
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float lumaNE = dot(rgbNE, luma);
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float lumaSW = dot(rgbSW, luma);
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float lumaSE = dot(rgbSE, luma);
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float lumaM = dot(rgbM, luma);
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float lumaMin = min(lumaM, min(min(lumaNW, lumaNE), min(lumaSW, lumaSE)));
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float lumaMax = max(lumaM, max(max(lumaNW, lumaNE), max(lumaSW, lumaSE)));
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vec2 dir;
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dir.x = -((lumaNW + lumaNE) - (lumaSW + lumaSE));
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dir.y = ((lumaNW + lumaSW) - (lumaNE + lumaSE));
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float dirReduce = max(
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(lumaNW + lumaNE + lumaSW + lumaSE) * (0.25 * FXAA_REDUCE_MUL),
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FXAA_REDUCE_MIN);
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float rcpDirMin = 1.0/(min(abs(dir.x), abs(dir.y)) + dirReduce);
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dir = min(vec2( FXAA_SPAN_MAX, FXAA_SPAN_MAX),
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max(vec2(-FXAA_SPAN_MAX, -FXAA_SPAN_MAX),
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dir * rcpDirMin)) * rcpFrame.xy;
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vec3 rgbA = (1.0/2.0) * (
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texture2DLod(tex, posPos.xy + dir * (1.0/3.0 - 0.5),0.0).xyz +
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texture2DLod(tex, posPos.xy + dir * (2.0/3.0 - 0.5),0.0).xyz);
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vec3 rgbB = rgbA * (1.0/2.0) + (1.0/4.0) * (
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texture2DLod(tex, posPos.xy + dir * (0.0/3.0 - 0.5),0.0).xyz +
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texture2DLod(tex, posPos.xy + dir * (3.0/3.0 - 0.5),0.0).xyz);
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float lumaB = dot(rgbB, luma);
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if((lumaB < lumaMin) || (lumaB > lumaMax)) return rgbA;
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return rgbB;
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}
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vec4 FXAA(sampler2D tex, vec2 uv) {
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vec2 rcpFrame = vec2(1.0/iWidth, 1.0/iHeight);
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vec4 posPos = vec4(texcoord.st,texcoord.st -(rcpFrame * (0.5 + FXAA_SUBPIX_SHIFT)));
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vec4 c = vec4(0.0);
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c.rgb = FxaaPixelShader(posPos, tex, rcpFrame);
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// c.rgb = texture2D(tex, posPos.xy).rgb - c.rgb; // debug
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c.a = texture2D(tex, posPos.xy).a;
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return c;
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}
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void main() {
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FRAGCOLOR = FXAA(iChannel0, texcoord.st);
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}
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