1 files changed, 14 insertions, 17 deletions

diff --git a/source/blender/blenkernel/intern/pbvh.c b/source/blender/blenkernel/intern/pbvh.c
index 24f3097f9e3..1c6274ef35e 100644
--- a/source/blender/blenkernel/intern/pbvh.c
+++ b/source/blender/blenkernel/intern/pbvh.c
@@ -145,9 +145,14 @@ static void update_node_vb(PBVH *pbvh, PBVHNode *node)
 //  BB_expand(&node->vb, co);
 //}
 
-static bool face_materials_match(const MPoly *f1, const MPoly *f2)
+static bool face_materials_match(const PBVH *pbvh, const int a, const int b)
 {
-  return ((f1->flag & ME_SMOOTH) == (f2->flag & ME_SMOOTH) && (f1->mat_nr == f2->mat_nr));
+  if (pbvh->material_indices) {
+    if (pbvh->material_indices[a] != pbvh->material_indices[b]) {
+      return false;
+    }
+  }
+  return (pbvh->mpoly[a].flag & ME_SMOOTH) == (pbvh->mpoly[b].flag & ME_SMOOTH);
 }
 
 static bool grid_materials_match(const DMFlagMat *f1, const DMFlagMat *f2)
@@ -180,30 +185,23 @@ static int partition_indices(int *prim_indices, int lo, int hi, int axis, float
 /* Returns the index of the first element on the right of the partition */
 static int partition_indices_material(PBVH *pbvh, int lo, int hi)
 {
-  const MPoly *mpoly = pbvh->mpoly;
   const MLoopTri *looptri = pbvh->looptri;
   const DMFlagMat *flagmats = pbvh->grid_flag_mats;
   const int *indices = pbvh->prim_indices;
-  const void *first;
   int i = lo, j = hi;
 
-  if (pbvh->looptri) {
-    first = &mpoly[looptri[pbvh->prim_indices[lo]].poly];
-  }
-  else {
-    first = &flagmats[pbvh->prim_indices[lo]];
-  }
-
   for (;;) {
     if (pbvh->looptri) {
-      for (; face_materials_match(first, &mpoly[looptri[indices[i]].poly]); i++) {
+      const int first = looptri[pbvh->prim_indices[lo]].poly;
+      for (; face_materials_match(pbvh, first, looptri[indices[i]].poly); i++) {
         /* pass */
       }
-      for (; !face_materials_match(first, &mpoly[looptri[indices[j]].poly]); j--) {
+      for (; !face_materials_match(pbvh, first, looptri[indices[j]].poly); j--) {
         /* pass */
       }
     }
     else {
+      const DMFlagMat *first = &flagmats[pbvh->prim_indices[lo]];
       for (; grid_materials_match(first, &flagmats[indices[i]]); i++) {
         /* pass */
       }
@@ -424,12 +422,9 @@ static bool leaf_needs_material_split(PBVH *pbvh, int offset, int count)
 
   if (pbvh->looptri) {
     const MLoopTri *first = &pbvh->looptri[pbvh->prim_indices[offset]];
-    const MPoly *mp = &pbvh->mpoly[first->poly];
-
     for (int i = offset + count - 1; i > offset; i--) {
       int prim = pbvh->prim_indices[i];
-      const MPoly *mp_other = &pbvh->mpoly[pbvh->looptri[prim].poly];
-      if (!face_materials_match(mp, mp_other)) {
+      if (!face_materials_match(pbvh, first->poly, pbvh->looptri[prim].poly)) {
         return true;
       }
     }
@@ -557,6 +552,8 @@ void BKE_pbvh_build_mesh(PBVH *pbvh,
   pbvh->mesh = mesh;
   pbvh->header.type = PBVH_FACES;
   pbvh->mpoly = mpoly;
+  pbvh->material_indices = (const int *)CustomData_get_layer_named(
+      &mesh->pdata, CD_PROP_INT32, "material_index");
   pbvh->mloop = mloop;
   pbvh->looptri = looptri;
   pbvh->verts = verts;