Fix for bug #1756

This was caused by a very primitive method of interpolating quaternions.
It was converting quats to mat and back to quat, and then just doing
a linear interpolation. That whilst quaternions are renowned for having
good interpolation possible.

I've experimented with 2 quaternion interpolation methods, and can only
get one to work correctly... the "official" version from Watt brothers
I can't get working, both are in arithb.c now.

Will arrange *close* review with experienced NLAers for it! But testing
here gives fully predictable results.

Also changed;
- added pointer check in drawaction
- changed puldown menu for correct hotkeys for move NLA strips up/down

1 files changed, 9 insertions, 8 deletions

diff --git a/source/blender/src/drawaction.c b/source/blender/src/drawaction.c
index 402f7684215..278be07b65b 100644
--- a/source/blender/src/drawaction.c
+++ b/source/blender/src/drawaction.c
@@ -877,15 +877,16 @@ static BezTriple **action_to_keylist(bAction *act, int flags, int *totvert)
 		/* Count required keys */
 		for (achan=act->chanbase.first; achan; achan=achan->next){
 			/* Count transformation keys */
-			for (icu=achan->ipo->curve.first; icu; icu=icu->next)
-				count+=icu->totvert;
-			
-			/* Count constraint keys */
-			for (conchan=achan->constraintChannels.first; conchan; conchan=conchan->next)
-				for (icu=conchan->ipo->curve.first; icu; icu=icu->next)
+			if(achan->ipo) {
+				for (icu=achan->ipo->curve.first; icu; icu=icu->next)
 					count+=icu->totvert;
-			
-
+				
+				/* Count constraint keys */
+				for (conchan=achan->constraintChannels.first; conchan; conchan=conchan->next)
+					for (icu=conchan->ipo->curve.first; icu; icu=icu->next)
+						count+=icu->totvert;
+				
+			}
 		}
 		
 		/* Build the list */