fb74671204
- compare both textures with the same side up - load target from the filename passed to the function
42 lines
1.3 KiB
GLSL
42 lines
1.3 KiB
GLSL
// Compute the pixelwise diff between two textures, one row at a time.
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// Assumes both images are not transparent.
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// Warning: Only works on rows <= 65793
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// Formula for max pixels per row: (256^3)/255
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uniform vec2 size;
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uniform bool horizontal;
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uniform sampler2D base;
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uniform sampler2D curr;
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void main(void)
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{
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// calculate total diff of row in either direction
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float total = 0.0;
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if (horizontal) {
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float posy = gl_FragCoord.y/size.y;
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for (float x=0.0; x<=1.0; x+=(1.0/size.x)) {
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vec4 color = texture2D(curr, vec2(x, posy));
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vec4 basecolor = texture2D(base, vec2(x, posy));
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color.rgb = abs(color.rgb - basecolor.rgb);
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total = total + color.r + color.g + color.b;
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}
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} else {
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float posx = gl_FragCoord.x/size.x;
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for (float y=0.0; y<=1.0; y+=(1.0/size.y)) {
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vec4 color = texture2D(curr, vec2(posx, y));
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vec4 basecolor = texture2D(base, vec2(posx, y));
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color.rgb = abs(color.rgb - basecolor.rgb);
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total = total + color.r + color.g + color.b;
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}
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}
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// encode to rgba channels in current pixel
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vec4 col = vec4(0.0, 0.0, 0.0, 1.0);
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col.r = floor(mod(total*255.0, 256.0))/255.0;
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col.g = floor(mod(total*255.0/256.0, 256.0))/255.0;
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col.b = floor(mod(total*255.0/65536.0, 256.0))/255.0;
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gl_FragColor = col;
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}
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