Fix T59237: Instancing on a path doesn't do anything

This commit makes it so curve path parent solving accepts an explicit
arguments for both time and curve speed flag, making it so we don't
have to mock around with scene's frame.

One unfortunate issue still is that if the instancing object is used
for something else, we might be running into a threading conflict.
Possible solution would be to create a temp copy of an object, but
then it will be an issue of preventing drivers from modifying other
datablocks.

At least the original issue is fixed now, and things behave same as
in older Blender version. Additionally, the global variable which
was defining curve speed flag behavior is gone now!

1 files changed, 9 insertions, 18 deletions

diff --git a/source/blender/blenkernel/intern/object_dupli.c b/source/blender/blenkernel/intern/object_dupli.c
index 882ec07f56a..6cd0f412d06 100644
--- a/source/blender/blenkernel/intern/object_dupli.c
+++ b/source/blender/blenkernel/intern/object_dupli.c
@@ -317,9 +317,7 @@ static void make_duplis_frames(const DupliContext *ctx)
 	Depsgraph *depsgraph = ctx->depsgraph;
 	Scene *scene = ctx->scene;
 	Object *ob = ctx->object;
-	extern int enable_cu_speed; /* object.c */
 	Object copyob;
-	int cfrao = scene->r.cfra;
 	int dupend = ob->dupend;
 
 	/* dupliframes not supported inside collections */
@@ -339,16 +337,15 @@ static void make_duplis_frames(const DupliContext *ctx)
 	copyob = *ob;
 
 	/* duplicate over the required range */
-	if (ob->transflag & OB_DUPLINOSPEED) enable_cu_speed = 0;
-
-	for (scene->r.cfra = ob->dupsta; scene->r.cfra <= dupend; scene->r.cfra++) {
+	const int dupli_transflag = (ob->transflag & OB_DUPLINOSPEED);
+	for (int frame = ob->dupsta; frame <= dupend; frame++) {
 		int ok = 1;
 
 		/* - dupoff = how often a frames within the range shouldn't be made into duplis
 		 * - dupon = the length of each "skipping" block in frames
 		 */
 		if (ob->dupoff) {
-			ok = scene->r.cfra - ob->dupsta;
+			ok = frame - ob->dupsta;
 			ok = ok % (ob->dupon + ob->dupoff);
 			ok = (ok < ob->dupon);
 		}
@@ -359,23 +356,17 @@ static void make_duplis_frames(const DupliContext *ctx)
 			 * However, this has always been the way that this worked (i.e. pre 2.5), so I guess that it'll be fine!
 			 */
 			/* ob-eval will do drivers, so we don't need to do them */
-			BKE_animsys_evaluate_animdata(depsgraph, scene, &ob->id, ob->adt, (float)scene->r.cfra, ADT_RECALC_ANIM);
-			BKE_object_where_is_calc_time(depsgraph, scene, ob, (float)scene->r.cfra);
+			BKE_animsys_evaluate_animdata(depsgraph, scene, &ob->id, ob->adt, (float)frame, ADT_RECALC_ANIM);
+			BKE_object_where_is_calc_time_for_dupli(depsgraph, scene, ob, (float)frame, dupli_transflag);
 
-			make_dupli(ctx, ob, ob->obmat, scene->r.cfra);
+			make_dupli(ctx, ob, ob->obmat, frame);
 		}
 	}
 
-	enable_cu_speed = 1;
-
-	/* reset frame to original frame, then re-evaluate animation as above
-	 * as 2.5 animation data may have far-reaching consequences
-	 */
-	scene->r.cfra = cfrao;
-
 	/* ob-eval will do drivers, so we don't need to do them */
-	BKE_animsys_evaluate_animdata(depsgraph, scene, &ob->id, ob->adt, (float)scene->r.cfra, ADT_RECALC_ANIM);
-	BKE_object_where_is_calc_time(depsgraph, scene, ob, (float)scene->r.cfra);
+	const float original_ctime = DEG_get_ctime(depsgraph);
+	BKE_animsys_evaluate_animdata(depsgraph, scene, &ob->id, ob->adt, original_ctime, ADT_RECALC_ANIM);
+	BKE_object_where_is_calc_time(depsgraph, scene, ob, original_ctime);
 
 	/* but, to make sure unkeyed object transforms are still sane,
 	 * let's copy object's original data back over