Fix T53206: Array modifier doesn't merge vgroups

Vertex group remapping utility function,
now shared between object join and array modifier cap-ends.

Weights which don't exist are removed.

D3092 by @Foaly

1 files changed, 29 insertions, 3 deletions

diff --git a/source/blender/modifiers/intern/MOD_array.c b/source/blender/modifiers/intern/MOD_array.c
index 053957d89e2..b781c47ac56 100644
--- a/source/blender/modifiers/intern/MOD_array.c
+++ b/source/blender/modifiers/intern/MOD_array.c
@@ -51,6 +51,7 @@
 #include "BKE_library_query.h"
 #include "BKE_modifier.h"
 #include "BKE_mesh.h"
+#include "BKE_object_deform.h"
 
 #include "MOD_util.h"
 
@@ -312,7 +313,7 @@ static void dm_mvert_map_doubles(
 static void dm_merge_transform(
         DerivedMesh *result, DerivedMesh *cap_dm, float cap_offset[4][4],
         unsigned int cap_verts_index, unsigned int cap_edges_index, int cap_loops_index, int cap_polys_index,
-        int cap_nverts, int cap_nedges, int cap_nloops, int cap_npolys)
+        int cap_nverts, int cap_nedges, int cap_nloops, int cap_npolys, int *remap, int remap_len)
 {
 	int *index_orig;
 	int i;
@@ -320,6 +321,7 @@ static void dm_merge_transform(
 	MEdge *me;
 	MLoop *ml;
 	MPoly *mp;
+	MDeformVert *dvert;
 
 	/* needed for subsurf so arrays are allocated */
 	cap_dm->getVertArray(cap_dm);
@@ -340,6 +342,12 @@ static void dm_merge_transform(
 		mv->flag = mv->bweight = 0;
 	}
 
+	/* remap the vertex groups if necessary */
+	dvert = DM_get_vert_data(result, cap_verts_index, CD_MDEFORMVERT);
+	if (dvert != NULL) {
+		BKE_object_defgroup_index_map_apply(dvert, cap_nverts, remap, remap_len);
+	}
+
 	/* adjust cap edge vertex indices */
 	me = CDDM_get_edges(result) + cap_edges_index;
 	for (i = 0; i < cap_nedges; i++, me++) {
@@ -417,6 +425,11 @@ static DerivedMesh *arrayModifier_doArray(
 
 	DerivedMesh *result, *start_cap_dm = NULL, *end_cap_dm = NULL;
 
+	int *vgroup_start_cap_remap = NULL;
+	int vgroup_start_cap_remap_len = 0;
+	int *vgroup_end_cap_remap = NULL;
+	int vgroup_end_cap_remap_len = 0;
+
 	chunk_nverts = dm->getNumVerts(dm);
 	chunk_nedges = dm->getNumEdges(dm);
 	chunk_nloops = dm->getNumLoops(dm);
@@ -425,6 +438,8 @@ static DerivedMesh *arrayModifier_doArray(
 	count = amd->count;
 
 	if (amd->start_cap && amd->start_cap != ob && amd->start_cap->type == OB_MESH) {
+		vgroup_start_cap_remap = BKE_object_defgroup_index_map_create(amd->start_cap, ob, &vgroup_start_cap_remap_len);
+
 		start_cap_dm = get_dm_for_modifier(amd->start_cap, flag);
 		if (start_cap_dm) {
 			start_cap_nverts = start_cap_dm->getNumVerts(start_cap_dm);
@@ -434,6 +449,8 @@ static DerivedMesh *arrayModifier_doArray(
 		}
 	}
 	if (amd->end_cap && amd->end_cap != ob && amd->end_cap->type == OB_MESH) {
+		vgroup_end_cap_remap = BKE_object_defgroup_index_map_create(amd->end_cap, ob, &vgroup_end_cap_remap_len);
+
 		end_cap_dm = get_dm_for_modifier(amd->end_cap, flag);
 		if (end_cap_dm) {
 			end_cap_nverts = end_cap_dm->getNumVerts(end_cap_dm);
@@ -696,7 +713,8 @@ static DerivedMesh *arrayModifier_doArray(
 		        result_nedges - start_cap_nedges - end_cap_nedges,
 		        result_nloops - start_cap_nloops - end_cap_nloops,
 		        result_npolys - start_cap_npolys - end_cap_npolys,
-		        start_cap_nverts, start_cap_nedges, start_cap_nloops, start_cap_npolys);
+		        start_cap_nverts, start_cap_nedges, start_cap_nloops, start_cap_npolys,
+		        vgroup_start_cap_remap, vgroup_start_cap_remap_len);
 		/* Identify doubles with first chunk */
 		if (use_merge) {
 			dm_mvert_map_doubles(
@@ -720,7 +738,8 @@ static DerivedMesh *arrayModifier_doArray(
 		        result_nedges - end_cap_nedges,
 		        result_nloops - end_cap_nloops,
 		        result_npolys - end_cap_npolys,
-		        end_cap_nverts, end_cap_nedges, end_cap_nloops, end_cap_npolys);
+		        end_cap_nverts, end_cap_nedges, end_cap_nloops, end_cap_npolys,
+		        vgroup_end_cap_remap, vgroup_end_cap_remap_len);
 		/* Identify doubles with last chunk */
 		if (use_merge) {
 			dm_mvert_map_doubles(
@@ -768,6 +787,13 @@ static DerivedMesh *arrayModifier_doArray(
 		result->dirty |= DM_DIRTY_NORMALS;
 	}
 
+	if (vgroup_start_cap_remap) {
+		MEM_freeN(vgroup_start_cap_remap);
+	}
+	if (vgroup_end_cap_remap) {
+		MEM_freeN(vgroup_end_cap_remap);
+	}
+
 	return result;
 }