vgroup_modifiers: coded a way to test whether the dm needs to be copied (i.e. if the affected cdata layer is or not the original one).

However, as this piece of code tends to slow down things (see e.g. scene 5 of WeightVG test blend file), I deactivated it for now...

1 files changed, 39 insertions, 15 deletions

diff --git a/source/blender/modifiers/intern/MOD_weightvgedit.c b/source/blender/modifiers/intern/MOD_weightvgedit.c
index c8d7ab52ce8..e84ecffa74b 100644
--- a/source/blender/modifiers/intern/MOD_weightvgedit.c
+++ b/source/blender/modifiers/intern/MOD_weightvgedit.c
@@ -190,8 +190,8 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob, DerivedMesh *der
                                   int UNUSED(useRenderParams), int UNUSED(isFinalCalc))
 {
 	WeightVGEditModifierData *wmd = (WeightVGEditModifierData*) md;
-	DerivedMesh *dm = derivedData;
-	DerivedMesh *ret;
+	DerivedMesh *dm = derivedData, *ret = NULL;
+	Mesh *ob_m = NULL;
 	MDeformVert *dvert = NULL;
 	float *org_w = NULL; /* Array original weights. */
 	float *new_w = NULL; /* Array new weights. */
@@ -217,30 +217,54 @@ static DerivedMesh *applyModifier(ModifierData *md, Object *ob, DerivedMesh *der
 	if ((numVerts == 0) || (ob->defbase.first == NULL))
 		return dm;
 
-	/* Create a copy of our dmesh.
-	 * TODO: This should be done only if needed, i.e. if dm has the org data !
+	/* Get vgroup idx from its name. */
+	defgrp_idx = defgroup_name_index(ob, wmd->defgrp_name);
+	if (defgrp_idx < 0)
+		return dm;
+
+	/* XXX All this to avoid copying dm when not needed… However, it nearly doubles compute
+	 *     time! See scene 5 of the WeighVG test file…
 	 */
-	if (1) {
-		/* XXX Seems to create problems with weightpaint mode... */
+#if 0
+	/* Get actual dverts (ie vertex group data). */
+	dvert = dm->getVertDataArray(dm, CD_MDEFORMVERT);
+	/* If no dverts, return unmodified data… */
+	if (dvert == NULL)
+		return dm;
+
+	/* Get org mesh, only to test whether affected cdata layer has already been copied
+	 * somewhere up in the modifiers stack.
+	 */
+	ob_m = get_mesh(ob);
+	if (ob_m == NULL)
+		return dm;
+
+	/* Create a copy of our dmesh, only if our affected cdata layer is the same as org mesh. */
+	if (dvert == CustomData_get_layer(&ob_m->vdata, CD_MDEFORMVERT)) {
+		/* XXX Seems to create problems with weightpaint mode???
+		 *     I’m missing something here, I guess…
+		 */
 //		DM_set_only_copy(dm, CD_MASK_MDEFORMVERT); /* Only copy defgroup layer. */
 		ret = CDDM_copy(dm);
+		dvert = ret->getVertDataArray(ret, CD_MDEFORMVERT);
+		if (dvert == NULL) {
+			ret->release(ret);
+			return dm;
+		}
 		rel_ret = 1;
 	}
 	else
 		ret = dm;
-
-	/* Get vgroup idx from its name. */
-	defgrp_idx = defgroup_name_index(ob, wmd->defgrp_name);
-
-	/* Get actual dverts (ie vertex group data). */
-	if (defgrp_idx >= 0)
-		dvert = ret->getVertDataArray(ret, CD_MDEFORMVERT);
-	/* If no dverts, return unmodified data… */
-	if ((defgrp_idx < 0) || (dvert == NULL)) {
+#else
+	ret = CDDM_copy(dm);
+	rel_ret = 1;
+	dvert = ret->getVertDataArray(ret, CD_MDEFORMVERT);
+	if (dvert == NULL) {
 		if (rel_ret)
 			ret->release(ret);
 		return dm;
 	}
+#endif
 
 	/* Get org weights, assuming 0.0 for vertices not in given vgroup. */
 	org_w = MEM_mallocN(sizeof(float) * numVerts, "WeightVGEdit Modifier, org_w");