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, 10 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_curve.h b/source/blender/blenkernel/BKE_curve.h
index 5558786d254..e111bd0e16b 100644
--- a/source/blender/blenkernel/BKE_curve.h
+++ b/source/blender/blenkernel/BKE_curve.h
@@ -36,6 +36,7 @@
 struct BezTriple;
 struct Curve;
 struct EditNurb;
+struct GHash;
 struct ListBase;
 struct Main;
 struct Nurb;
@@ -52,6 +53,13 @@ typedef struct CurveCache {
 	struct Path *path;
 } CurveCache;
 
+/* Definitions needed for shape keys */
+typedef struct CVKeyIndex {
+	void *orig_cv;
+	int key_index, nu_index, pt_index, vertex_index;
+	bool switched;
+} CVKeyIndex;
+
 #define KNOTSU(nu)      ( (nu)->orderu + (nu)->pntsu + (((nu)->flagu & CU_NURB_CYCLIC) ? ((nu)->orderu - 1) : 0) )
 #define KNOTSV(nu)      ( (nu)->orderv + (nu)->pntsv + (((nu)->flagv & CU_NURB_CYCLIC) ? ((nu)->orderv - 1) : 0) )
 
@@ -108,7 +116,8 @@ void BK_curve_nurbs_vertexCos_apply(struct ListBase *lb, float (*vertexCos)[3]);
 float (*BKE_curve_nurbs_keyVertexCos_get(struct ListBase *lb, float *key))[3];
 void BKE_curve_nurbs_keyVertexTilts_apply(struct ListBase *lb, float *key);
 
-void BKE_curve_editNurb_keyIndex_free(struct EditNurb *editnurb);
+void BKE_curve_editNurb_keyIndex_delCV(struct GHash *keyindex, const void *cv);
+void BKE_curve_editNurb_keyIndex_free(struct GHash **keyindex);
 void BKE_curve_editNurb_free(struct Curve *cu);
 struct ListBase *BKE_curve_editNurbs_get(struct Curve *cu);