Fix T48234: Glitch w/ action constraints sharing an action

FCurve evaluation depended on FCurve.curval, which isn't threadsafe.
Now only use this value for debug display,
and pass the value instead of storing in the FCurve for all but debug-display.

1 files changed, 7 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/fcurve.c b/source/blender/blenkernel/intern/fcurve.c
index a2b5a05feac..395161aa6ed 100644
--- a/source/blender/blenkernel/intern/fcurve.c
+++ b/source/blender/blenkernel/intern/fcurve.c
@@ -2671,7 +2671,7 @@ float evaluate_fcurve(FCurve *fcu, float evaltime)
 }
 
 /* Calculate the value of the given F-Curve at the given frame, and set its curval */
-void calculate_fcurve(FCurve *fcu, float ctime)
+float calculate_fcurve(FCurve *fcu, float evaltime)
 {
 	/* only calculate + set curval (overriding the existing value) if curve has 
 	 * any data which warrants this...
@@ -2680,7 +2680,12 @@ void calculate_fcurve(FCurve *fcu, float ctime)
 	    list_has_suitable_fmodifier(&fcu->modifiers, 0, FMI_TYPE_GENERATE_CURVE))
 	{
 		/* calculate and set curval (evaluates driver too if necessary) */
-		fcu->curval = evaluate_fcurve(fcu, ctime);
+		float curval = evaluate_fcurve(fcu, evaltime);
+		fcu->curval = curval;  /* debug display only, not thread safe! */
+		return curval;
+	}
+	else {
+		return 0.0f;
 	}
 }