VSE: Fix slow prefetching when strips are animated

Issue was caused by anim handle being reset by
`DEG_evaluate_on_framechange()`

Preserve anim handle by backing it up in
`blender::deg::SequenceBackup`

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D11059

2 files changed, 8 insertions, 1 deletions

diff --git a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.cc b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.cc
index 35720140f97..d481e0c39a8 100644
--- a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.cc
+++ b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.cc
@@ -35,24 +35,28 @@ SequenceBackup::SequenceBackup(const Depsgraph * /*depsgraph*/)
 void SequenceBackup::reset()
 {
   scene_sound = nullptr;
+  BLI_listbase_clear(&anims);
 }
 
 void SequenceBackup::init_from_sequence(Sequence *sequence)
 {
   scene_sound = sequence->scene_sound;
+  anims = sequence->anims;
 
   sequence->scene_sound = nullptr;
+  BLI_listbase_clear(&sequence->anims);
 }
 
 void SequenceBackup::restore_to_sequence(Sequence *sequence)
 {
   sequence->scene_sound = scene_sound;
+  sequence->anims = anims;
   reset();
 }
 
 bool SequenceBackup::isEmpty() const
 {
-  return (scene_sound == nullptr);
+  return (scene_sound == nullptr) && BLI_listbase_is_empty(&anims);
 }
 
 }  // namespace blender::deg
diff --git a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.h b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.h
index eb38dc3dc5b..3b3aa496496 100644
--- a/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.h
+++ b/source/blender/depsgraph/intern/eval/deg_eval_runtime_backup_sequence.h
@@ -23,6 +23,8 @@
 
 #pragma once
 
+#include "BLI_listbase.h"
+
 struct Sequence;
 
 namespace blender {
@@ -43,6 +45,7 @@ class SequenceBackup {
   bool isEmpty() const;
 
   void *scene_sound;
+  ListBase anims;
 };
 
 }  // namespace deg