137 lines
3.1 KiB
GLSL
137 lines
3.1 KiB
GLSL
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vec3 conv(in sampler2D tex, in vec2 uv, in mat3 ker);
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vec3 edges(in sampler2D tex, in vec2 uv)
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{
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mat3 ker = mat3(
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vec3(-1, -2, -1),
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vec3(-2, 12, -2),
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vec3(-1, -2, -1)
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);
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return conv(tex, uv, ker)+.5;
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}
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// can be used to remove high frequency noise
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vec3 median(in sampler2D tex, in vec2 uv)
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{
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float k = 1./8.;
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mat3 ker = mat3(
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vec3(k, k, k),
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vec3(k, 0, k),
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vec3(k, k, k)
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);
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return conv(tex, uv, ker);
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}
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// sharpen filter including diagonals
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vec3 laplace(in sampler2D tex, in vec2 uv, in float strength)
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{
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float k = -strength;
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mat3 ker = mat3(
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vec3(k, k, k),
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vec3(k, 8.*strength+1., k),
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vec3(k, k, k)
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);
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return conv(tex, uv, ker);
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}
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// subtracts high frequency edges from the source image
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vec3 unsharp(in sampler2D tex, in vec2 uv)
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{
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float k = 1./9.;
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mat3 ker = mat3(
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vec3(k, k, k),
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vec3(k, k, k),
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vec3(k, k, k)
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);
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vec3 blurred = conv(tex, uv, ker);
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return texture(iChannel0, uv).rgb - (texture(iChannel0, uv).rgb - blurred);
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}
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vec3 emboss(in sampler2D tex, in vec2 uv, in float theta)
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{
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// init kernel
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mat3 ker = mat3(
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vec3(0),
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vec3(0),
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vec3(0)
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);
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// direction of edge detection
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vec2 dir = vec2(sin(theta), cos(theta));
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// fill kernel with values
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for (int x = -1; x < 2; x++)
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for (int y = -1; y < 2; y++)
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ker[x+1][y+1] = dot(dir, vec2(x,y));
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return conv(tex, uv, ker)+.5;
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}
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vec3 sobelFeldmann(in sampler2D tex, in vec2 uv)
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{
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// init horizontal kernel
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mat3 ker0 = mat3(
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vec3(1, 0, -1),
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vec3(2, 0, -2),
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vec3(1, 0, -1)
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);
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// init vertical kernel
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mat3 ker1 = mat3(
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vec3(1, 2, 1),
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vec3(0, 0, 0),
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vec3(-1, -2, -1)
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);
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vec3 c0 = conv(tex, uv, ker0);// convolute horizontal
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vec3 c1 = conv(tex, uv, ker1);// convolute vertical
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// pythagoras
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return sqrt(c0*c0+c1*c1);
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}
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vec3 conv(in sampler2D tex, in vec2 uv, in mat3 ker)
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{
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vec3 sum = vec3(0);
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for (int x = 0; x < 3; x++)
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for (int y = 0; y < 3; y++)
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{
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vec2 off = (vec2(x,y)*.3333-.5)/iResolution.xy;
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sum += texture(tex, uv + off).rgb * ker[x][y];
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}
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return sum;
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}
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bool sector(in vec2 uv, in vec2 hor, in vec2 ver)
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{
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vec2 delta = 1./vec2(hor[1], ver[1]);
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vec2 low = delta * vec2(hor[0], ver[0]);
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vec2 high = low + delta;
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return low.x < uv.x && low.y < uv.y && high.x > uv.x && high.y > uv.y;
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}
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void mainImage( out vec4 fragColor, in vec2 fragCoord )
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{
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vec2 uv = fragCoord/iResolution.xy;
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vec3 col = texture(iChannel0, uv).rgb;
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if (sector(uv, vec2(0,4), vec2(1,2))) col = unsharp(iChannel0, uv);
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if (sector(uv, vec2(1,4), vec2(0,2))) col = laplace(iChannel0, uv, 2.0);
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if (sector(uv, vec2(1,2), vec2(0,2))) col = emboss(iChannel0, uv, iTime);
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if (sector(uv, vec2(1,2), vec2(1,2))) col = sobelFeldmann(iChannel0, uv);
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if (sector(uv, vec2(1,4), vec2(1,2))) col = median(iChannel0, uv);
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if (sector(uv, vec2(1,4), vec2(1,2))) col = edges(iChannel0, uv);
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fragColor = vec4(col,1.0);
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} |