Tracking: Re-write marker request function

There are two main things.

First, remove the marker index caching. Thins makes it possible to
safely use function from a threaded environment.

Second, replace linear search with binary search, which speeds up
random lookup.

There is no measurable difference in the stabilization which had a
comment about caching nature of track lookup. The random lookup
complexity changed from O(N) to O(log N). In practice this also
unlikely to be measurable, but thread-safety worth it.

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/makesdna/DNA_tracking_types.h b/source/blender/makesdna/DNA_tracking_types.h
index 908b06da2ce..5a8bbdc08a1 100644
--- a/source/blender/makesdna/DNA_tracking_types.h
+++ b/source/blender/makesdna/DNA_tracking_types.h
@@ -141,7 +141,7 @@ typedef struct MovieTrackingTrack {
   /** Count of markers in track. */
   int markersnr;
   /** Most recently used marker. */
-  int last_marker;
+  int _pad;
   /** Markers in track. */
   MovieTrackingMarker *markers;