[Bf-blender-cvs] [2c427d594f3] master: Fix T83638: mirror modifier with mirror object renders wrong motion blur

[Jishan Singh]

Commit: 2c427d594f37d47b469ffac514b6ecd247ad9305
Author: Jishan Singh
Date:   Mon Mar 22 16:55:37 2021 +0100
Branches: master
https://developer.blender.org/rB2c427d594f37d47b469ffac514b6ecd247ad9305

Fix T83638: mirror modifier with mirror object renders wrong motion blur

In this case both the mirror object and object itself moving in time may
change the geometry and must be checked.

Differential Revision: https://developer.blender.org/D10757

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

M	source/blender/blenkernel/intern/object.c

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

diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index 704d6d1cf4f..76c96ec9603 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -4885,7 +4885,7 @@ static bool object_deforms_in_time(Object *object)
   return object_moves_in_time(object);
 }
 
-static bool constructive_modifier_is_deform_modified(ModifierData *md)
+static bool constructive_modifier_is_deform_modified(Object *ob, ModifierData *md)
 {
   /* TODO(sergey): Consider generalizing this a bit so all modifier logic
    * is concentrated in MOD_{modifier}.c file,
@@ -4900,7 +4900,8 @@ static bool constructive_modifier_is_deform_modified(ModifierData *md)
   }
   if (md->type == eModifierType_Mirror) {
     MirrorModifierData *mmd = (MirrorModifierData *)md;
-    return mmd->mirror_ob != NULL && object_moves_in_time(mmd->mirror_ob);
+    return mmd->mirror_ob != NULL &&
+           (object_moves_in_time(mmd->mirror_ob) || object_moves_in_time(ob));
   }
   if (md->type == eModifierType_Screw) {
     ScrewModifierData *smd = (ScrewModifierData *)md;
@@ -4984,7 +4985,7 @@ int BKE_object_is_deform_modified(Scene *scene, Object *ob)
     bool can_deform = mti->type == eModifierTypeType_OnlyDeform || is_modifier_animated;
 
     if (!can_deform) {
-      can_deform = constructive_modifier_is_deform_modified(md);
+      can_deform = constructive_modifier_is_deform_modified(ob, md);
     }
 
     if (can_deform) {