1 files changed, 24 insertions, 0 deletions
diff --git a/source/blender/compositor/realtime_compositor/shaders/compositor_morphological_distance.glsl b/source/blender/compositor/realtime_compositor/shaders/compositor_morphological_distance.glsl
new file mode 100644
index 00000000000..09f896b7a9d
--- /dev/null
+++ b/source/blender/compositor/realtime_compositor/shaders/compositor_morphological_distance.glsl
@@ -0,0 +1,24 @@
+#pragma BLENDER_REQUIRE(common_math_lib.glsl)
+#pragma BLENDER_REQUIRE(gpu_shader_compositor_texture_utilities.glsl)
+
+void main()
+{
+  ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
+
+  /* Find the minimum/maximum value in the circular window of the given radius around the pixel. By
+   * circular window, we mean that pixels in the window whose distance to the center of window is
+   * larger than the given radius are skipped and not considered. Consequently, the dilation or
+   * erosion that take place produces round results as opposed to squarish ones. This is
+   * essentially a morphological operator with a circular structuring element. The LIMIT value
+   * should be FLT_MAX if OPERATOR is min and FLT_MIN if OPERATOR is max. */
+  float value = LIMIT;
+  for (int y = -radius; y <= radius; y++) {
+    for (int x = -radius; x <= radius; x++) {
+      if (x * x + y * y <= radius * radius) {
+        value = OPERATOR(value, texture_load(input_tx, texel + ivec2(x, y), vec4(LIMIT)).x);
+      }
+    }
+  }
+
+  imageStore(output_img, texel, vec4(value));
+}