[Bf-blender-cvs] [a6b7f321120] blender-v3.0-release: Fix T93297: incorrect eevee motion blur with geometry instances

[Jacques Lucke]

Commit: a6b7f3211205032b0b35bac489127d38ca6f004e
Author: Jacques Lucke
Date:   Tue Nov 23 16:40:21 2021 +0100
Branches: blender-v3.0-release
https://developer.blender.org/rBa6b7f3211205032b0b35bac489127d38ca6f004e

Fix T93297: incorrect eevee motion blur with geometry instances

This disables motion blur for geometry instances in eevee, which did
not work correctly anyway. See code comment for more details.

Differential Revision: https://developer.blender.org/D13334

===================================================================

M	source/blender/draw/engines/eevee/eevee_motion_blur.c

===================================================================

diff --git a/source/blender/draw/engines/eevee/eevee_motion_blur.c b/source/blender/draw/engines/eevee/eevee_motion_blur.c
index 1eff2a3af24..703518a32ec 100644
--- a/source/blender/draw/engines/eevee/eevee_motion_blur.c
+++ b/source/blender/draw/engines/eevee/eevee_motion_blur.c
@@ -29,6 +29,7 @@
 
 #include "BKE_animsys.h"
 #include "BKE_camera.h"
+#include "BKE_duplilist.h"
 #include "BKE_object.h"
 #include "BKE_screen.h"
 
@@ -318,6 +319,14 @@ void EEVEE_motion_blur_cache_populate(EEVEE_ViewLayerData *UNUSED(sldata),
     return;
   }
 
+  const DupliObject *dup = DRW_object_get_dupli(ob);
+  if (dup != NULL && dup->ob->data != dup->ob_data) {
+    /* Geometry instances do not support motion blur correctly yet. The #key used in
+     * #motion_blur_deform_data_get has to take ids of instances (#DupliObject.persistent_id) into
+     * account. Otherwise it can't find matching geometry instances at different points in time. */
+    return;
+  }
+
   EEVEE_ObjectMotionData *mb_data = EEVEE_motion_blur_object_data_get(
       &effects->motion_blur, ob, false);