Create KuwaharaFilter.frag

shader_experiments/KuwaharaFilter.frag

@@ -0,0 +1,93 @@
+//  KuwaharaFilter.cpp
+//  filterSandbox
+//
+// Originally Created by Matthew Fargo on 2014/06/23.
+//
+
+  uniform sampler2D inputImageTexture;
+  uniform float u_x0;
+
+  const vec2 src_size = vec2 (1.0 / 680.0, 1.0 / 1024.0);
+
+  void main (void) {
+      highp int index = int(u_x0 * 10.0);
+      vec2 uv = gl_TexCoord[0].xy;
+
+      vec4 textureColor = texture2D(inputImageTexture, uv);
+
+      float n = float((radius + 1) * (radius + 1));
+      int i; int j;
+      vec3 m0 = vec3(0.0); vec3 m1 = vec3(0.0); vec3 m2 = vec3(0.0); vec3 m3 = vec3(0.0);
+      vec3 s0 = vec3(0.0); vec3 s1 = vec3(0.0); vec3 s2 = vec3(0.0); vec3 s3 = vec3(0.0);
+      vec3 c;
+
+      for (j = -radius; j <= 0; ++j)  {
+          for (i = -radius; i <= 0; ++i)  {
+              c = texture2D(inputImageTexture, uv + vec2(i,j) * src_size).rgb;
+              m0 += c;
+              s0 += c * c;
+          }
+      }
+
+      for (j = -radius; j <= 0; ++j)  {
+          for (i = 0; i <= radius; ++i)  {
+              c = texture2D(inputImageTexture, uv + vec2(i,j) * src_size).rgb;
+              m1 += c;
+              s1 += c * c;
+          }
+      }
+
+      for (j = 0; j <= radius; ++j)  {
+          for (i = 0; i <= radius; ++i)  {
+              c = texture2D(inputImageTexture, uv + vec2(i,j) * src_size).rgb;
+              m2 += c;
+              s2 += c * c;
+          }
+      }
+
+      for (j = 0; j <= radius; ++j)  {
+          for (i = -radius; i <= 0; ++i)  {
+              c = texture2D(inputImageTexture, uv + vec2(i,j) * src_size).rgb;
+              m3 += c;
+              s3 += c * c;
+          }
+      }
+
+
+      float min_sigma2 = 1e+2;
+      m0 /= n;
+      s0 = abs(s0 / n - m0 * m0);
+
+      float sigma2 = s0.r + s0.g + s0.b;
+      if (sigma2 < min_sigma2) {
+          min_sigma2 = sigma2;
+          gl_FragColor = vec4(m0, textureColor.a);
+      }
+
+      m1 /= n;
+      s1 = abs(s1 / n - m1 * m1);
+
+      sigma2 = s1.r + s1.g + s1.b;
+      if (sigma2 < min_sigma2) {
+          min_sigma2 = sigma2;
+          gl_FragColor = vec4(m1, textureColor.a);
+      }
+
+      m2 /= n;
+      s2 = abs(s2 / n - m2 * m2);
+
+      sigma2 = s2.r + s2.g + s2.b;
+      if (sigma2 < min_sigma2) {
+          min_sigma2 = sigma2;
+          gl_FragColor = vec4(m2, textureColor.a);
+      }
+
+      m3 /= n;
+      s3 = abs(s3 / n - m3 * m3);
+
+      sigma2 = s3.r + s3.g + s3.b;
+      if (sigma2 < min_sigma2) {
+          min_sigma2 = sigma2;
+          gl_FragColor = vec4(m3, textureColor.a);
+      }
+  }