28 lines
753 B
GLSL
28 lines
753 B
GLSL
#version 330 core
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uniform sampler2DRect minMaxMeanSampler;
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uniform int width;
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uniform int height;
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layout(location = 0)out vec3 outValues;
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void main(void) {
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vec3 val[3];
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ivec2 pos = ivec2(gl_FragCoord.xy)*2;
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// fetching 4 texels
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outValues = texelFetch(minMaxMeanSampler, pos).xyz;
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val[0] = texelFetch(minMaxMeanSampler, pos + ivec2(1, 0)).xyz;
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val[1] = texelFetch(minMaxMeanSampler, pos + ivec2(0, 1)).xyz;
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val[2] = texelFetch(minMaxMeanSampler, pos + ivec2(1, 1)).xyz;
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// computing min, max, and mean for these 4 texels
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for(int i=0; i<3; ++i)
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{
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outValues.x = min(outValues.x, val[i].x);
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outValues.y = max(outValues.y, val[i].y);
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outValues.z += val[i].z;
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}
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outValues.z /= 4;
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}
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