Workbench: Background Dithering

Background dithering was introduced to solve banding issues on gradient backgrounds.
This patch will enable dithering based on the texture that is used for drawing.
Only when using a GPU_RGBA8 texture the dithering will be enabled.

This disables dithering for final rendering, vertex and texture paint modes.

Reviewed By: fclem

Differential Revision: https://developer.blender.org/D6056

1 files changed, 8 insertions, 1 deletions

diff --git a/source/blender/draw/engines/workbench/workbench_private.h b/source/blender/draw/engines/workbench/workbench_private.h
index 252be3570d7..f28cf12405e 100644
--- a/source/blender/draw/engines/workbench/workbench_private.h
+++ b/source/blender/draw/engines/workbench/workbench_private.h
@@ -194,7 +194,8 @@ typedef struct WORKBENCH_UBO_World {
   float background_alpha;
   float curvature_ridge;
   float curvature_valley;
-  int pad[3];
+  float background_dither_factor;
+  int pad[2];
 } WORKBENCH_UBO_World;
 BLI_STATIC_ASSERT_ALIGN(WORKBENCH_UBO_World, 16)
 
@@ -406,6 +407,12 @@ BLI_INLINE eGPUTextureFormat workbench_color_texture_format(const WORKBENCH_Priv
   return result;
 }
 
+BLI_INLINE bool workbench_background_dither_factor(const WORKBENCH_PrivateData *wpd) {
+  /* Only apply dithering when rendering on a RGBA8 texture.
+   * The dithering will remove banding when using a gradient as background */
+  return workbench_color_texture_format(wpd) == GPU_RGBA8;
+}
+
 /* workbench_deferred.c */
 void workbench_deferred_engine_init(WORKBENCH_Data *vedata);
 void workbench_deferred_engine_free(void);