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updated dilation and erosion

This commit is contained in:
Sven Vogel 2023-08-07 19:20:59 +02:00
parent 8ebb7b181a
commit eed7f3ce21
2 changed files with 45 additions and 27 deletions
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51
Image-Filtering/Dilation-Erosion/Image.glsl
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@ -1,35 +1,43 @@
//#define DIAMOND_KERNEL
#define CIRCULAR_KERNEL
float lum(in vec3 rgb)
float luminance(in vec3 rgb)
{
return dot(rgb, vec3(0.21, 0.72, 0.07));
}
/**
* Intensifies the brightest pixels of the applied kernel based on the luminance() function
*/
vec3 dilate(in sampler2D tex, in vec2 uv, in int size, in float sep, in float minb, in float maxb)
{
vec3 cc = texture(tex, uv).rgb;
vec3 tc = cc;
float cl = lum(cc);
float cl = luminance(cc);
vec2 texSize = sep/vec2(textureSize(tex, 0));
for (int x = -size; x <= size; ++x)
for (int y = -size; y <= size; ++y)
{
// default kernel is box shaped
#ifdef DIAMOND_KERNEL
// diamond shaped kernel (45° rotated square)
#if defined(DIAMOND_KERNEL)
if (abs(x) > size - abs(y))
continue;
#else
#elif defined(CIRCULAR_KERNEL)
if (distance(vec2(x, y), vec2(0, 0)) > float(size))
continue;
#endif
vec3 s = texture(tex, uv + vec2(x,y)/iResolution.xy*sep).rgb;
float b = lum(s);
vec3 s = texture(tex, uv + vec2(x,y)*texSize).rgb;
float b = luminance(s);
if (cl < b)
{
@ -41,30 +49,37 @@ vec3 dilate(in sampler2D tex, in vec2 uv, in int size, in float sep, in float mi
return mix(cc, tc, smoothstep(minb, maxb, cl));
}
/**
* Intensifies the darkest pixels of the applied kernel based on the luminance() function
*/
vec3 erode(in sampler2D tex, in vec2 uv, in int size, in float sep, in float minb, in float maxb)
{
vec3 cc = texture(tex, uv).rgb;
vec3 tc = cc;
float cl = lum(cc);
float cl = luminance(cc);
vec2 texSize = sep/vec2(textureSize(tex, 0));
for (int x = -size; x <= size; ++x)
for (int y = -size; y <= size; ++y)
{
// default kernel is box shaped
#ifdef DIAMOND_KERNEL
// diamond shaped kernel (45° rotated square)
#if defined(DIAMOND_KERNEL)
if (abs(x) > size - abs(y))
continue;
#else
#elif defined(CIRCULAR_KERNEL)
if (distance(vec2(x, y), vec2(0, 0)) > float(size))
continue;
#endif
vec3 s = texture(tex, uv + vec2(x,y)/iResolution.xy*sep).rgb;
float b = lum(s);
vec3 s = texture(tex, uv + vec2(x,y)*texSize).rgb;
float b = luminance(s);
if (cl > b)
{
@ -76,16 +91,16 @@ vec3 erode(in sampler2D tex, in vec2 uv, in int size, in float sep, in float min
return mix(tc, cc, smoothstep(minb, maxb, cl));
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
// Normalized pixel coordinates (from 0 to 1)
vec2 uv = fragCoord/iResolution.xy;
vec2 uv = (fragCoord-0.5*iResolution.xy)/iResolution.y;
vec3 dil = dilate(iChannel0, uv, 12, (uv.x-.5)*3., 0.0, 1.0);
vec3 er = erode(iChannel0, uv, 12, (uv.x-.5)*3., 0.0, 1.0);
float separation = (uv.x)*1.5;
vec3 col = uv.x > 0.5 ? er : dil;
vec3 dilation = dilate(iChannel0, uv, 16, separation, 0.0, 1.0);
vec3 erosion = erode (iChannel0, uv, 16, separation, 0.0, 1.0);
vec3 col = uv.x > 0.0 ? erosion : dilation;
// Output to screen
fragColor = vec4(col,1.0);
}

3
Image-Filtering/Dilation-Erosion/README.md
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@ -2,3 +2,6 @@
![overview.png](https://git.teridax.de/teridax/Shadertoy-Shaders/raw/branch/main/Image-Filtering/Dilation-Erosion/overview.png)
Dilation is the process of intesifying the brightessed pixel of a kernel, where as erosion intesifies the darkesed pixel of a kernel.
## Demo
<iframe width="640" height="360" frameborder="0" src="https://www.shadertoy.com/embed/dljcRz?gui=true&t=10&paused=true&muted=false" allowfullscreen></iframe>