Realtime Compositor: Implement directional blur node

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

Differential Revision: https://developer.blender.org/D15672

Reviewed By: Clement Foucault

3 files changed, 35 insertions, 0 deletions

diff --git a/source/blender/gpu/CMakeLists.txt b/source/blender/gpu/CMakeLists.txt
index 33a0ccec24b..fd732a09e08 100644
--- a/source/blender/gpu/CMakeLists.txt
+++ b/source/blender/gpu/CMakeLists.txt
@@ -318,6 +318,7 @@ set(GLSL_SRC
   shaders/compositor/compositor_bokeh_image.glsl
   shaders/compositor/compositor_box_mask.glsl
   shaders/compositor/compositor_convert.glsl
+  shaders/compositor/compositor_directional_blur.glsl
   shaders/compositor/compositor_edge_filter.glsl
   shaders/compositor/compositor_ellipse_mask.glsl
   shaders/compositor/compositor_filter.glsl
@@ -567,6 +568,7 @@ set(SRC_SHADER_CREATE_INFOS
   shaders/compositor/infos/compositor_bokeh_image_info.hh
   shaders/compositor/infos/compositor_box_mask_info.hh
   shaders/compositor/infos/compositor_convert_info.hh
+  shaders/compositor/infos/compositor_directional_blur_info.hh
   shaders/compositor/infos/compositor_edge_filter_info.hh
   shaders/compositor/infos/compositor_ellipse_mask_info.hh
   shaders/compositor/infos/compositor_filter_info.hh
diff --git a/source/blender/gpu/shaders/compositor/compositor_directional_blur.glsl b/source/blender/gpu/shaders/compositor/compositor_directional_blur.glsl
new file mode 100644
index 00000000000..1805cb5a7f5
--- /dev/null
+++ b/source/blender/gpu/shaders/compositor/compositor_directional_blur.glsl
@@ -0,0 +1,21 @@
+#pragma BLENDER_REQUIRE(gpu_shader_compositor_texture_utilities.glsl)
+
+void main()
+{
+  ivec2 texel = ivec2(gl_GlobalInvocationID.xy);
+  ivec2 input_size = texture_size(input_tx);
+
+  /* Add 0.5 to evaluate the input sampler at the center of the pixel. */
+  vec2 coordinates = vec2(texel) + vec2(0.5);
+
+  /* For each iteration, accumulate the input at the normalize coordinates, hence the divide by
+   * input size, then transform the coordinates for the next iteration. */
+  vec4 accumulated_color = vec4(0.0);
+  for (int i = 0; i < iterations; i++) {
+    accumulated_color += texture(input_tx, coordinates / input_size);
+    coordinates = (mat3(inverse_transformation) * vec3(coordinates, 1.0)).xy;
+  }
+
+  /* Write the accumulated color divided by the number of iterations. */
+  imageStore(output_img, texel, accumulated_color / iterations);
+}
diff --git a/source/blender/gpu/shaders/compositor/infos/compositor_directional_blur_info.hh b/source/blender/gpu/shaders/compositor/infos/compositor_directional_blur_info.hh
new file mode 100644
index 00000000000..bb9199dcd26
--- /dev/null
+++ b/source/blender/gpu/shaders/compositor/infos/compositor_directional_blur_info.hh
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include "gpu_shader_create_info.hh"
+
+GPU_SHADER_CREATE_INFO(compositor_directional_blur)
+    .local_group_size(16, 16)
+    .push_constant(Type::INT, "iterations")
+    .push_constant(Type::MAT4, "inverse_transformation")
+    .sampler(0, ImageType::FLOAT_2D, "input_tx")
+    .image(0, GPU_RGBA16F, Qualifier::WRITE, ImageType::FLOAT_2D, "output_img")
+    .compute_source("compositor_directional_blur.glsl")
+    .do_static_compilation(true);