Fix slow tracking of long sequences

The performance issue was noticeable when tracking a lot of tracks
which are using keyframe pattern matching. What was happening is that
at some cache gets filled in and the furthest away frame gets removed
from the cache: the frame at marker's keyframe gets removed and needs
to be re-read from disk on the next tracking step.

This change makes it so frames at markers' keyframes are not removed
from cache during tracking.

Steps to easily reproduce:
- Set cache size to 512 Mb.
- Open image sequence in clip editor
- Detect features
- Track all markers

Originally was reported by Rik, thanks!

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_tracking.h b/source/blender/blenkernel/BKE_tracking.h
index 8cac196accc..29eb180a2ab 100644
--- a/source/blender/blenkernel/BKE_tracking.h
+++ b/source/blender/blenkernel/BKE_tracking.h
@@ -510,6 +510,7 @@ void BKE_tracking_refine_marker(struct MovieClip *clip,
 struct AutoTrackContext *BKE_autotrack_context_new(struct MovieClip *clip,
                                                    struct MovieClipUser *user,
                                                    bool is_backwards);
+void BKE_autotrack_context_start(struct AutoTrackContext *context);
 bool BKE_autotrack_context_step(struct AutoTrackContext *context);
 void BKE_autotrack_context_sync(struct AutoTrackContext *context);
 void BKE_autotrack_context_sync_user(struct AutoTrackContext *context, struct MovieClipUser *user);