added dilation and erosion to image filter

Image-Filtering/Dilation-Erosion/Image.glsl

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+
+//#define DIAMOND_KERNEL
+
+float lum(in vec3 rgb)
+{
+    return dot(rgb, vec3(0.21, 0.72, 0.07));
+}
+
+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);
+
+    for (int x = -size; x <= size; ++x)
+    for (int y = -size; y <= size; ++y)
+    {
+    
+        #ifdef DIAMOND_KERNEL
+        
+        if (abs(x) > size - abs(y))
+            continue;
+            
+        #else
+            
+        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);
+        
+        if (cl < b)
+        {
+            cl = b;
+            tc = s;
+        }
+    }
+    
+    return mix(cc, tc, smoothstep(minb, maxb, cl));
+}
+
+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);
+
+    for (int x = -size; x <= size; ++x)
+    for (int y = -size; y <= size; ++y)
+    {
+    
+        #ifdef DIAMOND_KERNEL
+        
+        if (abs(x) > size - abs(y))
+            continue;
+            
+        #else
+            
+        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);
+        
+        if (cl > b)
+        {
+            cl = b;
+            tc = s;
+        }
+    }
+    
+    return mix(tc, cc, smoothstep(minb, maxb, cl));
+}
+
+void mainImage( out vec4 fragColor, in vec2 fragCoord )
+{
+    // Normalized pixel coordinates (from 0 to 1)
+    vec2 uv = fragCoord/iResolution.xy;
+
+    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);
+    
+    vec3 col = uv.x > 0.5 ? er : dil;
+    
+    // Output to screen
+    fragColor = vec4(col,1.0);
+}

Image-Filtering/Dilation-Erosion/README.md

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+# Dilation / Erosion filter
+![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.