Implement a new automatic handle algorithm to produce smooth F-Curves.

The legacy algorithm only considers two adjacent points when computing
the bezier handles, which cannot produce satisfactory results. Animators
are often forced to manually adjust all curves.

The new approach instead solves a system of equations to trace a cubic spline
with continuous second derivative through the whole segment of auto points,
delimited at ends by keyframes with handles set by other requirements.

This algorithm also adjusts Vector handles that face ordinary bezier keyframes
to achieve zero acceleration at the Vector keyframe, instead of simply pointing
it at the adjacent point.

Original idea and implementation by Benoit Bolsee <benoit.bolsee@online.be>;
code mostly rewritten to improve code clarity and extensibility.

Reviewers: aligorith

Differential Revision: https://developer.blender.org/D2884

1 files changed, 3 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/mask.c b/source/blender/blenkernel/intern/mask.c
index 8b8b48db279..b8a241ed956 100644
--- a/source/blender/blenkernel/intern/mask.c
+++ b/source/blender/blenkernel/intern/mask.c
@@ -1196,14 +1196,14 @@ static void mask_calc_point_handle(MaskSplinePoint *point, MaskSplinePoint *poin
 
 #if 1
 	if (bezt_prev || bezt_next) {
-		BKE_nurb_handle_calc(bezt, bezt_prev, bezt_next, 0);
+		BKE_nurb_handle_calc(bezt, bezt_prev, bezt_next, 0, 0);
 	}
 #else
 	if (handle_type == HD_VECT) {
-		BKE_nurb_handle_calc(bezt, bezt_prev, bezt_next, 0);
+		BKE_nurb_handle_calc(bezt, bezt_prev, bezt_next, 0, 0);
 	}
 	else if (handle_type == HD_AUTO) {
-		BKE_nurb_handle_calc(bezt, bezt_prev, bezt_next, 0);
+		BKE_nurb_handle_calc(bezt, bezt_prev, bezt_next, 0, 0);
 	}
 	else if (handle_type == HD_ALIGN || handle_type == HD_ALIGN_DOUBLESIDE) {
 		float v1[3], v2[3];