Fix loading external MDisps, BMesh merge bug.

* When converting mfaces to mpolys, load external MDisp data in, add
  CustomDataExternal struct to loopdata if needed.

* Fix multires modifier's filepath RNA functions to use ldata rather
  than fdata.

3 files changed, 18 insertions, 3 deletions

diff --git a/source/blender/blenkernel/intern/mesh.c b/source/blender/blenkernel/intern/mesh.c
index bcb95211bcc..9a10a00bf45 100644
--- a/source/blender/blenkernel/intern/mesh.c
+++ b/source/blender/blenkernel/intern/mesh.c
@@ -1978,6 +1978,11 @@ static void bm_corners_to_loops(Mesh *me, int findex, int loopstart, int numTex,
 		float (*disps)[3] = fd->disps;
 		int i, tot = mf->v4 ? 4 : 3;
 		int side, corners;
+
+		if (CustomData_external_test(&me->fdata, CD_MDISPS)) {
+			CustomData_external_add(&me->ldata, &me->id, CD_MDISPS,
+									me->totloop, me->fdata.external->filename);
+		}
 		
 		corners = multires_mdisp_corners(fd);
 		
@@ -2042,6 +2047,9 @@ void BKE_mesh_convert_mfaces_to_mpolys(Mesh *mesh)
 	CustomData_to_bmeshpoly(&mesh->fdata, &mesh->pdata, &mesh->ldata,
 		mesh->totloop, mesh->totpoly);
 
+	/* ensure external data is transferred */
+	CustomData_external_read(&mesh->fdata, &mesh->id, CD_MASK_MDISPS, mesh->totface);
+
 	eh = BLI_edgehash_new();
 
 	/*build edge hash*/
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 60f4f3c0f31..e9a5dada044 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -3708,7 +3708,14 @@ static void lib_link_mesh(FileData *fd, Main *main)
 
 			/*check if we need to convert mfaces to mpolys*/
 			if (me->totface && !me->totpoly) {
+				/* temporarily switch main so that reading from
+				   external CustomData works */
+				Main *gmain = G.main;
+				G.main = main;
+				
 				BKE_mesh_convert_mfaces_to_mpolys(me);
+
+				G.main = gmain;
 			}
 			
 			/*
diff --git a/source/blender/makesrna/intern/rna_modifier.c b/source/blender/makesrna/intern/rna_modifier.c
index 11c58139630..42849fbfa16 100644
--- a/source/blender/makesrna/intern/rna_modifier.c
+++ b/source/blender/makesrna/intern/rna_modifier.c
@@ -490,7 +490,7 @@ static int rna_MultiresModifier_external_get(PointerRNA *ptr)
 static void rna_MultiresModifier_filepath_get(PointerRNA *ptr, char *value)
 {
 	Object *ob = (Object*)ptr->id.data;
-	CustomDataExternal *external = ((Mesh*)ob->data)->fdata.external;
+	CustomDataExternal *external = ((Mesh*)ob->data)->ldata.external;
 
 	BLI_strncpy(value, (external)? external->filename: "", sizeof(external->filename));
 }
@@ -498,7 +498,7 @@ static void rna_MultiresModifier_filepath_get(PointerRNA *ptr, char *value)
 static void rna_MultiresModifier_filepath_set(PointerRNA *ptr, const char *value)
 {
 	Object *ob = (Object*)ptr->id.data;
-	CustomDataExternal *external = ((Mesh*)ob->data)->fdata.external;
+	CustomDataExternal *external = ((Mesh*)ob->data)->ldata.external;
 
 	if (external && strcmp(external->filename, value)) {
 		BLI_strncpy(external->filename, value, sizeof(external->filename));
@@ -509,7 +509,7 @@ static void rna_MultiresModifier_filepath_set(PointerRNA *ptr, const char *value
 static int rna_MultiresModifier_filepath_length(PointerRNA *ptr)
 {
 	Object *ob = (Object*)ptr->id.data;
-	CustomDataExternal *external = ((Mesh*)ob->data)->fdata.external;
+	CustomDataExternal *external = ((Mesh*)ob->data)->ldata.external;
 
 	return strlen((external)? external->filename: "");
 }