50 lines
No EOL
1.5 KiB
Text
50 lines
No EOL
1.5 KiB
Text
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/*
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Edge Detection (Sobel Filter and Gaussian Blur) by FencerDevLog, adapted
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original code: https://godotshaders.com/shader/edge-detection-sobel-filter-and-gaussian-blur/
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license of the original code: CC0
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*/
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vec3 _convolution(sampler2D tex, vec2 uv, vec2 pixel_size) {
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vec3 conv = vec3(0.0);
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// Gaussian blur kernel
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float gauss[25] = {
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0.00390625, 0.015625, 0.0234375, 0.015625, 0.00390625,
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0.015625, 0.0625, 0.09375, 0.0625, 0.015625,
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0.0234375, 0.09375, 0.140625, 0.09375, 0.0234375,
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0.015625, 0.0625, 0.09375, 0.0625, 0.015625,
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0.00390625, 0.015625, 0.0234375, 0.015625, 0.00390625
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};
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for (int row = 0; row < 5; row++) {
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for (int col = 0; col < 5; col++) {
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conv += texture(tex, uv + vec2(float(col - 2), float(row - 2)) * pixel_size).rgb * gauss[row * 5 + col];
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}
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}
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return conv;
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}
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vec4 sobel(sampler2D tex, vec2 uv) {
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vec2 pixel_size = 1.0/vec2(textureSize(tex, 0));
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vec3 pixels[9]; // Sobel kernel
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// [0, 1, 2]
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// [3, 4, 5]
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// [6, 7, 8]
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for (int row = 0; row < 3; row++) {
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for (int col = 0; col < 3; col++) {
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vec2 uv_ = uv + vec2(float(col - 1), float(row - 1)) * pixel_size;
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pixels[row * 3 + col] = _convolution(tex, uv_, pixel_size);
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}
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}
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// Sobel operator
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vec3 gx = (
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pixels[0] * -1.0 + pixels[3] * -2.0 + pixels[6] * -1.0
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+ pixels[2] * 1.0 + pixels[5] * 2.0 + pixels[8] * 1.0
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);
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vec3 gy = (
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pixels[0] * -1.0 + pixels[1] * -2.0 + pixels[2] * -1.0
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+ pixels[6] * 1.0 + pixels[7] * 2.0 + pixels[8] * 1.0
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);
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vec3 sobel = sqrt(gx * gx + gy * gy);
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return vec4(sobel, 1.0);
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} |