From 062e8357fa5860a072b45c9966fcb0acecaebd2a Mon Sep 17 00:00:00 2001
From: Bruno Herbelin <bruno.herbelin@gmail.com>
Date: Sun, 15 May 2022 23:34:09 +0200
Subject: [PATCH] Fixing morphological shaders code

---
 rsc/shaders/filters/dilation.glsl |  9 +++++----
 rsc/shaders/filters/erosion.glsl  |  9 +++++----
 rsc/shaders/filters/kuwahara.glsl | 25 +++++++++++++++----------
 3 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/rsc/shaders/filters/dilation.glsl b/rsc/shaders/filters/dilation.glsl
index d0d095c..7196bac 100644
--- a/rsc/shaders/filters/dilation.glsl
+++ b/rsc/shaders/filters/dilation.glsl
@@ -1,14 +1,15 @@
 uniform float Radius;
 #define MAX_SIZE 5
 
-vec3 dilation (sampler2D source, vec2 uv, vec2 uv_step, float R) {
+vec3 dilation (sampler2D source, vec2 uv, vec2 uv_step, float rad) {
     
     vec3 maxValue = vec3(0.0);
-    float D = length(vec2( R / 2.));
+    float R = length(vec2(rad)) ;
+    float D = rad;
 
-    for (float i=-R; i <= R; ++i)
+    for (float i=-rad; i <= rad; ++i)
     {
-        for (float j=-R; j <= R; ++j)
+        for (float j=-rad; j <= rad; ++j)
         {
             vec2 delta = vec2(i, j);
             maxValue = max(texture(source, uv + delta * smoothstep(R, D, length(delta)) * uv_step ).rgb, maxValue); 
diff --git a/rsc/shaders/filters/erosion.glsl b/rsc/shaders/filters/erosion.glsl
index 994c1e3..3993964 100644
--- a/rsc/shaders/filters/erosion.glsl
+++ b/rsc/shaders/filters/erosion.glsl
@@ -1,14 +1,15 @@
 uniform float Radius;
 #define MAX_SIZE 5
 
-vec3 erosion (sampler2D source, vec2 uv, vec2 uv_step, float R) 
+vec3 erosion (sampler2D source, vec2 uv, vec2 uv_step, float rad) 
 {
     vec3 minValue = vec3(1.0);  
-    float D = length(vec2( R / 2.));
+    float R = length(vec2(rad)) ;
+    float D = rad;
 
-    for (float i=-R; i <= R; ++i)
+    for (float i=-rad; i <= rad; ++i)
     {
-        for (float j=-R; j <= R; ++j)
+        for (float j=-rad; j <= rad; ++j)
         {
             vec2 delta = vec2(i, j);
             minValue = min(texture(source, uv + delta * smoothstep(R, D, length(delta)) * uv_step ).rgb, minValue); 
diff --git a/rsc/shaders/filters/kuwahara.glsl b/rsc/shaders/filters/kuwahara.glsl
index c6acc7f..f706ab5 100644
--- a/rsc/shaders/filters/kuwahara.glsl
+++ b/rsc/shaders/filters/kuwahara.glsl
@@ -14,31 +14,31 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
 
     int rad = int(Radius * 10.0);
 
-    vec2 src_size = iResolution.xy;
+    vec2 uv_step = 1.0 / iResolution.xy;
     vec2 uv = fragCoord.xy / iResolution.xy;
     float n = float((rad + 1) * (rad + 1));
 
     ////////////////////////////////////////////////////////////////////////////////
     // Bilateral difference-check, to speed up the processing of large flat areas //
     ////////////////////////////////////////////////////////////////////////////////
-    vec3 compare = texture(iChannel0, uv / src_size).rgb;
+    vec3 compare = texture(iChannel0, uv).rgb;
     bool diffpix = false;
     for (int j = -rad; j <= rad; ++j) {
-        if (texture(iChannel0, uv + vec2(0,j) / src_size).rgb != compare) {
+        if (texture(iChannel0, uv + vec2(0,j) * uv_step).rgb != compare) {
             diffpix = true;
             break;
         }
     }
     if (!diffpix) {
         for (int i = -rad; i <= rad; ++i) {
-            if (texture(iChannel0, uv + vec2(i,0) / src_size).rgb != compare) {
+            if (texture(iChannel0, uv + vec2(i,0) * uv_step).rgb != compare) {
                 diffpix = true;
                 break;
             }
         }
     }
     if (!diffpix) {
-        outpix = vec4( texture(iChannel0, uv / src_size).rgb, 1.0);
+        outpix = vec4( texture(iChannel0, uv).rgb, 1.0);
     }
     ////////////////////////////////////////////////////////////////////////////////
     ////////////////////////////////////////////////////////////////////////////////
@@ -49,10 +49,13 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
 	        m[k] = vec3(0.0);
 	        s[k] = vec3(0.0);
 	    }
+	    float R = 0.1;
+    	float D = length(vec2(rad));
 	
 	    for (int j = -rad; j <= 0; ++j)  {
 	        for (int i = -rad; i <= 0; ++i)  {
-	            vec3 c = texture(iChannel0, uv + vec2(i,j) / src_size).rgb;
+                vec2 delta = vec2(i, j);
+	            vec3 c = texture(iChannel0, uv + delta * smoothstep(R, D, length(delta)) * uv_step).rgb;
 	            m[0] += c;
 	            s[0] += c * c;
 	        }
@@ -60,7 +63,8 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
 	
 	    for (int j = -rad; j <= 0; ++j)  {
 	        for (int i = 0; i <= rad; ++i)  {
-	            vec3 c = texture(iChannel0, uv + vec2(i,j) / src_size).rgb;
+                vec2 delta = vec2(i, j);
+	            vec3 c = texture(iChannel0, uv + delta * smoothstep(R, D, length(delta)) * uv_step).rgb;
 	            m[1] += c;
 	            s[1] += c * c;
 	        }
@@ -68,7 +72,8 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
 	
 	    for (int j = 0; j <= rad; ++j)  {
 	        for (int i = 0; i <= rad; ++i)  {
-	            vec3 c = texture(iChannel0, uv + vec2(i,j) / src_size).rgb;
+                vec2 delta = vec2(i, j);
+	            vec3 c = texture(iChannel0, uv + delta * smoothstep(R, D, length(delta)) * uv_step).rgb;
 	            m[2] += c;
 	            s[2] += c * c;
 	        }
@@ -76,7 +81,8 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
 	
 	    for (int j = 0; j <= rad; ++j)  {
 	        for (int i = -rad; i <= 0; ++i)  {
-	            vec3 c = texture(iChannel0, uv + vec2(i,j) / src_size).rgb;
+                vec2 delta = vec2(i, j);
+	            vec3 c = texture(iChannel0, uv + delta * smoothstep(R, D, length(delta)) * uv_step).rgb;
 	            m[3] += c;
 	            s[3] += c * c;
 	        }
@@ -97,4 +103,3 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
     fragColor = outpix;
 }
 
-