38 lines
995 B
GLSL
38 lines
995 B
GLSL
/**
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* Simple down-sample shader. Takes the average of the 4 texels of lower mip.
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*/
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uniform sampler2D source;
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uniform float fireflyFactor;
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out vec4 FragColor;
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float brightness(vec3 c)
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{
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return max(max(c.r, c.g), c.b);
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}
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void main()
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{
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#if 0
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/* Reconstructing Target uvs like this avoid missing pixels if NPO2 */
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vec2 uvs = gl_FragCoord.xy * 2.0 / vec2(textureSize(source, 0));
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FragColor = textureLod(source, uvs, 0.0);
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#else
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vec2 texel_size = 1.0 / vec2(textureSize(source, 0));
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vec2 uvs = gl_FragCoord.xy * 2.0 * texel_size;
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vec4 ofs = texel_size.xyxy * vec4(0.75, 0.75, -0.75, -0.75);
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FragColor = textureLod(source, uvs + ofs.xy, 0.0);
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FragColor += textureLod(source, uvs + ofs.xw, 0.0);
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FragColor += textureLod(source, uvs + ofs.zy, 0.0);
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FragColor += textureLod(source, uvs + ofs.zw, 0.0);
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FragColor *= 0.25;
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/* Clamped brightness. */
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float luma = max(1e-8, brightness(FragColor.rgb));
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FragColor *= 1.0 - max(0.0, luma - fireflyFactor) / luma;
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#endif
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}
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