Fix T68700: Incorrect 'absolute' timing of animated masks in the Video

Sequence Editor

Code in 'seq_render_mask' will effectively do
BKE_mask_evaluate(mask_temp, mask->sfra + (cfra - fra_offset), true)
where 'fra_offset' is zero for absolute and seq->start for relative.

If we really want the scene's current frame (as advertised) if Mask Time
is set to Absolute (effectively ignoring the Mask Settings start/end) we
need to change the fra_offset from zero to mask->sfra.

Also BKE_animsys_evaluate_animdata should take mask->sfra into account
as well (otherwise mask animation [points] and other animation [e.g.
opacity] will run out of sync)

Reviewers: campbellbarton, ISS

Maniphest Tasks: T68700

Differential Revision: https://developer.blender.org/D5495

1 files changed, 2 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/seqmodifier.c b/source/blender/blenkernel/intern/seqmodifier.c
index a7543881dad..57b8c92de3e 100644
--- a/source/blender/blenkernel/intern/seqmodifier.c
+++ b/source/blender/blenkernel/intern/seqmodifier.c
@@ -34,6 +34,7 @@
 
 #include "BLT_translation.h"
 
+#include "DNA_mask_types.h"
 #include "DNA_sequence_types.h"
 #include "DNA_scene_types.h"
 
@@ -1044,7 +1045,7 @@ ImBuf *BKE_sequence_modifier_apply_stack(const SeqRenderData *context,
         frame_offset = seq->start;
       }
       else /*if (smd->mask_time == SEQUENCE_MASK_TIME_ABSOLUTE)*/ {
-        frame_offset = 0;
+        frame_offset = ((Mask *)smd->mask_id)->sfra;
       }
 
       ImBuf *mask = modifier_mask_get(smd, context, cfra, frame_offset, ibuf->rect_float != NULL);