EEVEE: Motion Blur: Add shutter position option

This makes it easier to generate motion trail effect with EEVEE.

This just mimics the cycles option as described here:
https://docs.blender.org/manual/en/latest/render/cycles/render_settings/motion_blur.html

This fix T80070

1 files changed, 20 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index b909885b006..24cff501b59 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -6851,6 +6851,17 @@ static void rna_def_scene_eevee(BlenderRNA *brna)
       {0, NULL, 0, NULL, NULL},
   };
 
+  static const EnumPropertyItem eevee_motion_blur_position_items[] = {
+      {SCE_EEVEE_MB_START, "START", 0, "Start on Frame", "The shutter opens at the current frame"},
+      {SCE_EEVEE_MB_CENTER,
+       "CENTER",
+       0,
+       "Center on Frame",
+       "The shutter is open during the current frame"},
+      {SCE_EEVEE_MB_END, "END", 0, "End on Frame", "The shutter closes at the current frame"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
   srna = RNA_def_struct(brna, "SceneEEVEE", NULL);
   RNA_def_struct_path_func(srna, "rna_SceneEEVEE_path");
   RNA_def_struct_ui_text(srna, "Scene Display", "Scene display settings for 3d viewport");
@@ -7240,6 +7251,15 @@ static void rna_def_scene_eevee(BlenderRNA *brna)
   RNA_def_property_override_flag(prop, PROPOVERRIDE_OVERRIDABLE_LIBRARY);
   RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
 
+  prop = RNA_def_property(srna, "motion_blur_position", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_items(prop, eevee_motion_blur_position_items);
+  RNA_def_property_ui_text(prop,
+                           "Motion Blur Position",
+                           "Offset for the shutter's time interval, "
+                           "allows to change the motion blur trails");
+  RNA_def_property_override_flag(prop, PROPOVERRIDE_OVERRIDABLE_LIBRARY);
+  RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
+
   /* Shadows */
   prop = RNA_def_property(srna, "shadow_cube_size", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_items(prop, eevee_shadow_size_items);