Fix T50745: Shape key editing on bezier objects broken with Rendered Viewport Shading

So... Curve+shapekey was even more broken than it looked, this report was
actually a nice crasher (immediate crash in an ASAN build when trying to
edit a curve shapekey with some viewport rendering enabled).

There were actually two different issues here.

I) The less critical: rB6f1493f68fe was not fully fixing issues from
T50614. More specifically, if you updated obdata from editnurb
*without* freeing editnurb afterwards, you had a 'restored' (to
original curve) editnurb, without the edited shapekey modifications
anymore. This was fixed by tweaking again `calc_shapeKeys()` behavior in
`ED_curve_editnurb_load()`.

II) The crasher: in `ED_curve_editnurb_make()`, the call to
`init_editNurb_keyIndex()` was directly storing pointers of obdata
nurbs. Since those get freed every time `ED_curve_editnurb_load()` is
executed, it easily ended up being pointers to freed memory. This was
fixed by copying those data, which implied more complex handling code
for editnurbs->keyindex, and some reshuffling of a few functions to
avoid duplicating things between editor's editcurve.c and BKE's curve.c

Note that the separation of functions between editors and BKE area for
curve could use a serious update, it's currently messy to say the least.
Then again, that area is due to rework since a long time now... :/

Finally, aligned 'for_render' curve evaluation to mesh one - now
editing a shapekey will show in rendered viewports, if it does have some
weight (exactly as with shapekeys of meshes).

1 files changed, 18 insertions, 5 deletions

diff --git a/source/blender/blenkernel/intern/curve.c b/source/blender/blenkernel/intern/curve.c
index 90a514781d7..439abb1d593 100644
--- a/source/blender/blenkernel/intern/curve.c
+++ b/source/blender/blenkernel/intern/curve.c
@@ -89,20 +89,33 @@ void BKE_curve_editfont_free(Curve *cu)
 	}
 }
 
-void BKE_curve_editNurb_keyIndex_free(EditNurb *editnurb)
+static void curve_editNurb_keyIndex_cv_free_cb(void *val)
 {
-	if (!editnurb->keyindex) {
+	CVKeyIndex *index = val;
+	MEM_freeN(index->orig_cv);
+	MEM_freeN(val);
+}
+
+void BKE_curve_editNurb_keyIndex_delCV(GHash *keyindex, const void *cv)
+{
+	BLI_assert(keyindex != NULL);
+	BLI_ghash_remove(keyindex, cv, NULL, curve_editNurb_keyIndex_cv_free_cb);
+}
+
+void BKE_curve_editNurb_keyIndex_free(GHash **keyindex)
+{
+	if (!(*keyindex)) {
 		return;
 	}
-	BLI_ghash_free(editnurb->keyindex, NULL, MEM_freeN);
-	editnurb->keyindex = NULL;
+	BLI_ghash_free(*keyindex, NULL, curve_editNurb_keyIndex_cv_free_cb);
+	*keyindex = NULL;
 }
 
 void BKE_curve_editNurb_free(Curve *cu)
 {
 	if (cu->editnurb) {
 		BKE_nurbList_free(&cu->editnurb->nurbs);
-		BKE_curve_editNurb_keyIndex_free(cu->editnurb);
+		BKE_curve_editNurb_keyIndex_free(&cu->editnurb->keyindex);
 		MEM_freeN(cu->editnurb);
 		cu->editnurb = NULL;
 	}