1 files changed, 53 insertions, 0 deletions
diff --git a/source/blender/compositor/realtime_compositor/shaders/compositor_symmetric_separable_blur.glsl b/source/blender/compositor/realtime_compositor/shaders/compositor_symmetric_separable_blur.glsl
new file mode 100644
index 00000000000..ab0c7baa787
--- /dev/null
+++ b/source/blender/compositor/realtime_compositor/shaders/compositor_symmetric_separable_blur.glsl
@@ -0,0 +1,53 @@
+#pragma BLENDER_REQUIRE(gpu_shader_compositor_blur_common.glsl)
+#pragma BLENDER_REQUIRE(gpu_shader_compositor_texture_utilities.glsl)
+
+vec4 load_input(ivec2 texel)
+{
+  vec4 color;
+  if (extend_bounds) {
+    /* If bounds are extended, then we treat the input as padded by a radius amount of pixels. So
+     * we load the input with an offset by the radius amount and fallback to a transparent color if
+     * it is out of bounds. Notice that we subtract 1 because the weights texture have an extra
+     * center weight, see the SymmetricSeparableBlurWeights for more information. */
+    int blur_size = texture_size(weights_tx) - 1;
+    color = texture_load(input_tx, texel - ivec2(blur_size, 0), vec4(0.0));
+  }
+  else {
+    color = texture_load(input_tx, texel);
+  }
+
+  if (gamma_correct_input) {
+    color = gamma_correct_blur_input(color);
+  }
+
+  return color;
+}
+
+void main()
+{
+  ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
+
+  vec4 accumulated_color = vec4(0.0);
+
+  /* First, compute the contribution of the center pixel. */
+  vec4 center_color = load_input(texel);
+  accumulated_color += center_color * texture_load(weights_tx, 0).x;
+
+  /* Then, compute the contributions of the pixel to the right and left, noting that the
+   * weights texture only stores the weights for the positive half, but since the filter is
+   * symmetric, the same weight is used for the negative half and we add both of their
+   * contributions. */
+  for (int i = 1; i < texture_size(weights_tx); i++) {
+    float weight = texture_load(weights_tx, i).x;
+    accumulated_color += load_input(texel + ivec2(i, 0)) * weight;
+    accumulated_color += load_input(texel + ivec2(-i, 0)) * weight;
+  }
+
+  if (gamma_uncorrect_output) {
+    accumulated_color = gamma_uncorrect_blur_output(accumulated_color);
+  }
+
+  /* Write the color using the transposed texel. See the execute_separable_blur_horizontal_pass
+   * method for more information on the rational behind this. */
+  imageStore(output_img, texel.yx, accumulated_color);
+}