70 lines
1.9 KiB
GLSL
Executable File
70 lines
1.9 KiB
GLSL
Executable File
uniform sampler2D tex;
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uniform float sigma;
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uniform int dir;
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uniform float brightness;
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uniform float width;
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uniform float height;
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vec4 getTexture(vec2 uv) {
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if (uv.x < 3. / width)
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uv.x = 3. / width;
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if (uv.y < 3. / height)
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uv.y = 3. / height;
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if (uv.x > 1. - 3. / width)
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uv.x = 1. - 3. / width;
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if (uv.y > 1. - 3. / height)
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uv.y = 1. - 3. / height;
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return texture2D(tex, uv);
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}
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void main(void) {
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vec2 uv = cogl_tex_coord_in[0].xy;
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vec2 direction = vec2(dir, (1.0 - dir));
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float pixel_step;
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if (dir == 0)
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pixel_step = 1.0 / height;
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else
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pixel_step = 1.0 / width;
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vec3 gauss_coefficient;
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gauss_coefficient.x = 1.0 / (sqrt(2.0 * 3.14159265) * sigma);
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gauss_coefficient.y = exp(-0.5 / (sigma * sigma));
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gauss_coefficient.z = gauss_coefficient.y * gauss_coefficient.y;
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float gauss_coefficient_total = gauss_coefficient.x;
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vec4 ret = getTexture(uv) * gauss_coefficient.x;
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gauss_coefficient.xy *= gauss_coefficient.yz;
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int n_steps = int(ceil(1.5 * sigma)) * 2;
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for (int i = 1; i <= n_steps; i += 2) {
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float coefficient_subtotal = gauss_coefficient.x;
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gauss_coefficient.xy *= gauss_coefficient.yz;
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coefficient_subtotal += gauss_coefficient.x;
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float gauss_ratio = gauss_coefficient.x / coefficient_subtotal;
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float foffset = float(i) + gauss_ratio;
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vec2 offset = direction * foffset * pixel_step;
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ret += getTexture(uv + offset) * coefficient_subtotal;
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ret += getTexture(uv - offset) * coefficient_subtotal;
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gauss_coefficient_total += 2.0 * coefficient_subtotal;
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gauss_coefficient.xy *= gauss_coefficient.yz;
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}
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vec4 outColor = ret / gauss_coefficient_total;
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// apply brightness on the second pass (dir==0 comes last)
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if (dir == 0) {
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outColor.rgb *= brightness;
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}
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cogl_color_out = outColor;
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} |