From 885e7abed13b204a701466a203f6d96773de902a Mon Sep 17 00:00:00 2001
From: Omar Emara <mail@OmarEmara.dev>
Date: Thu, 18 Aug 2022 17:14:29 +0200
Subject: Realtime Compositor: Implement bilateral blur node

This patch implements the bilateral blur node for the realtime compositor.

Differential Revision: https://developer.blender.org/D15674

Reviewed By: Clement Foucault
---
 .../compositor/compositor_bilateral_blur.glsl      | 31 ++++++++++++++++++++++
 .../infos/compositor_bilateral_blur_info.hh        | 13 +++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 source/blender/gpu/shaders/compositor/compositor_bilateral_blur.glsl
 create mode 100644 source/blender/gpu/shaders/compositor/infos/compositor_bilateral_blur_info.hh

(limited to 'source/blender/gpu/shaders')

diff --git a/source/blender/gpu/shaders/compositor/compositor_bilateral_blur.glsl b/source/blender/gpu/shaders/compositor/compositor_bilateral_blur.glsl
new file mode 100644
index 00000000000..c7c5ada7a9f
--- /dev/null
+++ b/source/blender/gpu/shaders/compositor/compositor_bilateral_blur.glsl
@@ -0,0 +1,31 @@
+#pragma BLENDER_REQUIRE(gpu_shader_compositor_texture_utilities.glsl)
+
+void main()
+{
+  ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
+
+  vec4 center_determinator = texture_load(determinator_tx, texel);
+
+  /* Go over the pixels in the blur window of the specified radius around the center pixel, and for
+   * pixels whose determinator is close enough to the determinator of the center pixel, accumulate
+   * their color as well as their weights. */
+  float accumulated_weight = 0.0;
+  vec4 accumulated_color = vec4(0.0);
+  for (int y = -radius; y <= radius; y++) {
+    for (int x = -radius; x <= radius; x++) {
+      vec4 determinator = texture_load(determinator_tx, texel + ivec2(x, y));
+      float difference = dot(abs(center_determinator - determinator).rgb, vec3(1.0));
+
+      if (difference < threshold) {
+        accumulated_weight += 1.0;
+        accumulated_color += texture_load(input_tx, texel + ivec2(x, y));
+      }
+    }
+  }
+
+  /* Write the accumulated color divided by the accumulated weight if any pixel in the window was
+   * accumulated, otherwise, write a fallback black color. */
+  vec4 fallback = vec4(vec3(0.0), 1.0);
+  vec4 color = (accumulated_weight != 0.0) ? (accumulated_color / accumulated_weight) : fallback;
+  imageStore(output_img, texel, color);
+}
diff --git a/source/blender/gpu/shaders/compositor/infos/compositor_bilateral_blur_info.hh b/source/blender/gpu/shaders/compositor/infos/compositor_bilateral_blur_info.hh
new file mode 100644
index 00000000000..301cd6acd9e
--- /dev/null
+++ b/source/blender/gpu/shaders/compositor/infos/compositor_bilateral_blur_info.hh
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "gpu_shader_create_info.hh"
+
+GPU_SHADER_CREATE_INFO(compositor_bilateral_blur)
+    .local_group_size(16, 16)
+    .push_constant(Type::INT, "radius")
+    .push_constant(Type::FLOAT, "threshold")
+    .sampler(0, ImageType::FLOAT_2D, "input_tx")
+    .sampler(1, ImageType::FLOAT_2D, "determinator_tx")
+    .image(0, GPU_RGBA16F, Qualifier::WRITE, ImageType::FLOAT_2D, "output_img")
+    .compute_source("compositor_bilateral_blur.glsl")
+    .do_static_compilation(true);
-- 
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