Cleanup/refactor binding code for MeshDeform modifier.

We had two different ways of doing it, SurfaceDeform and LaplacianDeform
would do it through a special modifier stack evaluation triggered from
binding operator, while MeshDeform would do it through a regular
depsgraph update/eval (also triggered from its binding op).

This enforces the later to search back for orig modifier data inside
modifier code (to apply binding on that one, and not on useless CoW
one).

Besides the question of safety about modifying orig data from threaded
despgraph (that was *probably* OK, but think it's bad idea in general),
it's much better to have a common way of doing that kind of things.

For now it remains rather dodgy, but at least it's reasonably consistent
and safe now.

This commit also fixes a potential memleak from binding process of
MeshDeform, and does some general cleanup a bit.

3 files changed, 22 insertions, 34 deletions

diff --git a/source/blender/editors/armature/meshlaplacian.c b/source/blender/editors/armature/meshlaplacian.c
index 001c8ce215f..96799304845 100644
--- a/source/blender/editors/armature/meshlaplacian.c
+++ b/source/blender/editors/armature/meshlaplacian.c
@@ -1427,7 +1427,7 @@ static void meshdeform_matrix_solve(MeshDeformModifierData *mmd, MeshDeformBind
 	EIG_linear_solver_delete(context);
 }
 
-static void harmonic_coordinates_bind(Scene *UNUSED(scene), MeshDeformModifierData *mmd, MeshDeformBind *mdb)
+static void harmonic_coordinates_bind(MeshDeformModifierData *mmd, MeshDeformBind *mdb)
 {
 	MDefBindInfluence *inf;
 	MDefInfluence *mdinf;
@@ -1578,7 +1578,7 @@ static void harmonic_coordinates_bind(Scene *UNUSED(scene), MeshDeformModifierDa
 }
 
 void ED_mesh_deform_bind_callback(
-        Scene *scene, MeshDeformModifierData *mmd, Mesh *cagemesh,
+        MeshDeformModifierData *mmd, Mesh *cagemesh,
         float *vertexcos, int totvert, float cagemat[4][4])
 {
 	MeshDeformBind mdb;
@@ -1606,7 +1606,7 @@ void ED_mesh_deform_bind_callback(
 		mul_v3_m4v3(mdb.vertexcos[a], mdb.cagemat, vertexcos + a * 3);
 
 	/* solve */
-	harmonic_coordinates_bind(scene, mmd, &mdb);
+	harmonic_coordinates_bind(mmd, &mdb);
 
 	/* assign bind variables */
 	mmd->bindcagecos = (float *)mdb.cagecos;
diff --git a/source/blender/editors/include/ED_armature.h b/source/blender/editors/include/ED_armature.h
index d5698ecadf7..3131e5221d8 100644
--- a/source/blender/editors/include/ED_armature.h
+++ b/source/blender/editors/include/ED_armature.h
@@ -238,7 +238,6 @@ struct Object *ED_pose_object_from_context(struct bContext *C);
 
 /* meshlaplacian.c */
 void ED_mesh_deform_bind_callback(
-        struct Scene *scene,
         struct MeshDeformModifierData *mmd,
         struct Mesh *cagemesh,
         float *vertexcos, int totvert, float cagemat[4][4]);
diff --git a/source/blender/editors/object/object_modifier.c b/source/blender/editors/object/object_modifier.c
index 7b4fba23551..200ff1ab0d6 100644
--- a/source/blender/editors/object/object_modifier.c
+++ b/source/blender/editors/object/object_modifier.c
@@ -1944,52 +1944,41 @@ static bool meshdeform_poll(bContext *C)
 
 static int meshdeform_bind_exec(bContext *C, wmOperator *op)
 {
-	Main *bmain = CTX_data_main(C);
 	Depsgraph *depsgraph = CTX_data_depsgraph(C);
+	Scene *scene = CTX_data_scene(C);
 	Object *ob = ED_object_active_context(C);
 	MeshDeformModifierData *mmd = (MeshDeformModifierData *)edit_modifier_property_get(op, ob, eModifierType_MeshDeform);
 
-	if (!mmd)
+	if (mmd == NULL) {
 		return OPERATOR_CANCELLED;
+	}
 
-	if (mmd->bindcagecos) {
-		MEM_freeN(mmd->bindcagecos);
-		if (mmd->dyngrid) MEM_freeN(mmd->dyngrid);
-		if (mmd->dyninfluences) MEM_freeN(mmd->dyninfluences);
-		if (mmd->bindinfluences) MEM_freeN(mmd->bindinfluences);
-		if (mmd->bindoffsets) MEM_freeN(mmd->bindoffsets);
-		if (mmd->dynverts) MEM_freeN(mmd->dynverts);
-		if (mmd->bindweights) MEM_freeN(mmd->bindweights);  /* deprecated */
-		if (mmd->bindcos) MEM_freeN(mmd->bindcos);  /* deprecated */
-
-		mmd->bindcagecos = NULL;
-		mmd->dyngrid = NULL;
-		mmd->dyninfluences = NULL;
-		mmd->bindinfluences = NULL;
-		mmd->bindoffsets = NULL;
-		mmd->dynverts = NULL;
-		mmd->bindweights = NULL; /* deprecated */
-		mmd->bindcos = NULL; /* deprecated */
+	if (mmd->bindcagecos != NULL) {
+		MEM_SAFE_FREE(mmd->bindcagecos);
+		MEM_SAFE_FREE(mmd->dyngrid);
+		MEM_SAFE_FREE(mmd->dyninfluences);
+		MEM_SAFE_FREE(mmd->bindinfluences);
+		MEM_SAFE_FREE(mmd->bindoffsets);
+		MEM_SAFE_FREE(mmd->dynverts);
+		MEM_SAFE_FREE(mmd->bindweights);  /* Deprecated */
+		MEM_SAFE_FREE(mmd->bindcos);  /* Deprecated */
 		mmd->totvert = 0;
 		mmd->totcagevert = 0;
 		mmd->totinfluence = 0;
 	}
 	else {
-		int mode = mmd->modifier.mode;
-		mmd->bindfunc = ED_mesh_deform_bind_callback;
+		/* Force modifier to run, it will call binding routine (this has to happen outside of depsgraph evaluation). */
+		const int mode = mmd->modifier.mode;
 		mmd->modifier.mode |= eModifierMode_Realtime;
-
-		/* Force depsgraph update, this will do binding. */
-		DEG_id_tag_update(&ob->id, OB_RECALC_DATA);
-		BKE_scene_graph_update_tagged(depsgraph, bmain);
-
-		mmd->bindfunc = NULL;
+		mmd->bindfunc = ED_mesh_deform_bind_callback;
+		object_force_modifier_update_for_bind(depsgraph, scene, ob);
 		mmd->modifier.mode = mode;
+		mmd->bindfunc = NULL;
 	}
 
-	DEG_id_tag_update(&ob->id, OB_RECALC_DATA);
+	/* We need DEG_TAG_COPY_ON_WRITE to ensure (un)binding is flushed to CoW copies of the object... */
+	DEG_id_tag_update(&ob->id, DEG_TAG_GEOMETRY | DEG_TAG_COPY_ON_WRITE);
 	WM_event_add_notifier(C, NC_OBJECT | ND_MODIFIER, ob);
-
 	return OPERATOR_FINISHED;
 }