0c80ac3296
Sampling at the edge between texels causes one or the other to be chosen semi-randomly, depending on rounding errors. Add half a pixel so they sample at texel centers instead.
16 lines
655 B
GLSL
16 lines
655 B
GLSL
vec4 scale(sampler2D image)
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{
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vec2 texCoord = vec2(gl_FragCoord.x, uResolution.y - gl_FragCoord.y) / uResolution;
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vec2 pixel = texCoord * textureDimensions - vec2(0.5, 0.5);
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vec4 q11 = texture(image, (floor(pixel) + 0.5) / textureDimensions);
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vec4 q12 = texture(image, (vec2(floor(pixel.x), ceil(pixel.y)) + 0.5) / textureDimensions);
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vec4 q21 = texture(image, (vec2(ceil(pixel.x), floor(pixel.y)) + 0.5) / textureDimensions);
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vec4 q22 = texture(image, (ceil(pixel) + 0.5) / textureDimensions);
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vec4 r1 = mix(q11, q21, fract(pixel.x));
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vec4 r2 = mix(q12, q22, fract(pixel.x));
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return mix (r1, r2, fract(pixel.y));
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} |