Fix T45184: OBJ importer would add UV or clnor layers to all objects in split-import case.

In case some parts have UVs and others not, when doing split import we have to
avoid creating empty dummy UV layers for meshes that have no 'tex' data in .obj.
Same goes for clnors.

2 files changed, 38 insertions, 15 deletions

diff --git a/io_scene_obj/__init__.py b/io_scene_obj/__init__.py
index 17ef0f48..e6452eb9 100644
--- a/io_scene_obj/__init__.py
+++ b/io_scene_obj/__init__.py
@@ -21,7 +21,7 @@
 bl_info = {
     "name": "Wavefront OBJ format",
     "author": "Campbell Barton, Bastien Montagne",
-    "version": (2, 1, 1),
+    "version": (2, 1, 2),
     "blender": (2, 74, 0),
     "location": "File > Import-Export",
     "description": "Import-Export OBJ, Import OBJ mesh, UV's, "
diff --git a/io_scene_obj/import_obj.py b/io_scene_obj/import_obj.py
index 330e0694..458a73a6 100644
--- a/io_scene_obj/import_obj.py
+++ b/io_scene_obj/import_obj.py
@@ -369,7 +369,7 @@ def split_mesh(verts_loc, faces, unique_materials, filepath, SPLIT_OB_OR_GROUP):
 
     if not SPLIT_OB_OR_GROUP or not faces:
         # use the filename for the object name since we aren't chopping up the mesh.
-        return [(verts_loc, faces, unique_materials, filename)]
+        return [(verts_loc, faces, unique_materials, filename, bool(verts_nor), bool(verts_tex))]
 
     def key_to_name(key):
         # if the key is a tuple, join it to make a string
@@ -388,12 +388,19 @@ def split_mesh(verts_loc, faces, unique_materials, filepath, SPLIT_OB_OR_GROUP):
 
         if oldkey != key:
             # Check the key has changed.
-            (verts_split, faces_split,
-             unique_materials_split, vert_remap) = face_split_dict.setdefault(key, ([], [], {}, {}))
+            (verts_split, faces_split, unique_materials_split, vert_remap,
+             use_verts_nor, use_verts_tex) = face_split_dict.setdefault(key, ([], [], {}, {}, [], []))
             oldkey = key
 
         face_vert_loc_indices = face[0]
 
+        # In case a face only uses zero indices for vnors/vtex (aka UV), we assume it actually does not use those...
+        if not use_verts_nor and face[1]:
+            use_verts_nor.append(True)
+
+        if not use_verts_tex and face[2]:
+            use_verts_tex.append(True)
+
         # Remap verts to new vert list and add where needed
         for enum, i in enumerate(face_vert_loc_indices):
             map_index = vert_remap.get(i)
@@ -411,8 +418,9 @@ def split_mesh(verts_loc, faces, unique_materials, filepath, SPLIT_OB_OR_GROUP):
         faces_split.append(face)
 
     # remove one of the items and reorder
-    return [(verts_split, faces_split, unique_materials_split, key_to_name(key))
-            for key, (verts_split, faces_split, unique_materials_split, _) in face_split_dict.items()]
+    return [(verts_split, faces_split, unique_materials_split, key_to_name(key), bool(use_vnor), bool(use_vtex))
+            for key, (verts_split, faces_split, unique_materials_split, _, use_vnor, use_vtex)
+            in face_split_dict.items()]
 
 
 def create_mesh(new_objects,
@@ -459,7 +467,8 @@ def create_mesh(new_objects,
         if len_face_vert_loc_indices == 1:
             faces.pop(f_idx)  # cant add single vert faces
 
-        elif not face_vert_tex_indices or len_face_vert_loc_indices == 2:  # faces that have no texture coords are lines
+        # Face with a single item in face_vert_nor_indices is actually a polyline!
+        elif len(face_vert_nor_indices) == 1 or len_face_vert_loc_indices == 2:
             if use_edges:
                 edges.extend((face_vert_loc_indices[i], face_vert_loc_indices[i + 1])
                              for i in range(len_face_vert_loc_indices - 1))
@@ -490,11 +499,11 @@ def create_mesh(new_objects,
                                [face_vert_nor_indices[ngon[0]],
                                 face_vert_nor_indices[ngon[1]],
                                 face_vert_nor_indices[ngon[2]],
-                                ],
+                                ] if face_vert_nor_indices else [],
                                [face_vert_tex_indices[ngon[0]],
                                 face_vert_tex_indices[ngon[1]],
                                 face_vert_tex_indices[ngon[2]],
-                                ],
+                                ] if face_vert_tex_indices else [],
                                context_material,
                                context_smooth_group,
                                context_object,
@@ -600,11 +609,11 @@ def create_mesh(new_objects,
                 context_material_old = context_material
             blen_poly.material_index = mat
 
-        if verts_nor:
+        if verts_nor and face_vert_nor_indices:
             for face_noidx, lidx in zip(face_vert_nor_indices, blen_poly.loop_indices):
                 me.loops[lidx].normal[:] = verts_nor[face_noidx]
 
-        if verts_tex:
+        if verts_tex and face_vert_tex_indices:
             if context_material:
                 image = unique_material_images[context_material]
                 if image:  # Can be none if the material dosnt have an image.
@@ -865,6 +874,7 @@ def load(operator, context, filepath,
     face_vert_loc_indices = None
     face_vert_nor_indices = None
     face_vert_tex_indices = None
+    face_vert_nor_valid = face_vert_tex_valid = False
     face_items_usage = set()
     face_invalid_blenpoly = None
     prev_vidx = None
@@ -930,6 +940,7 @@ def load(operator, context, filepath,
                 if len(obj_vert) > 1 and obj_vert[1]:
                     idx = int(obj_vert[1]) - 1
                     face_vert_tex_indices.append((idx + len(verts_tex) + 1) if (idx < 0) else idx)
+                    face_vert_tex_valid = True
                 else:
                     # dummy
                     face_vert_tex_indices.append(0)
@@ -937,11 +948,19 @@ def load(operator, context, filepath,
                 if len(obj_vert) > 2 and obj_vert[2]:
                     idx = int(obj_vert[2]) - 1
                     face_vert_nor_indices.append((idx + len(verts_nor) + 1) if (idx < 0) else idx)
+                    face_vert_nor_valid = True
                 else:
                     # dummy
                     face_vert_nor_indices.append(0)
 
             if not context_multi_line:
+                # Clear nor/tex indices in case we had none defined for this face.
+                if not face_vert_nor_valid:
+                    face_vert_nor_indices.clear()
+                if not face_vert_tex_valid:
+                    face_vert_tex_indices.clear()
+                face_vert_nor_valid = face_vert_tex_valid = False
+
                 # Means we have finished a face, we have to do final check if ngon is suspected to be blender-invalid...
                 if face_invalid_blenpoly:
                     face_invalid_blenpoly.clear()
@@ -962,8 +981,11 @@ def load(operator, context, filepath,
                 # Instantiate a face
                 face = create_face(context_material, context_smooth_group, context_object)
                 face_vert_loc_indices = face[0]
+                # XXX A bit hackish, we use special 'value' of face_vert_nor_indices (a single True item) to tag this
+                #     as a polyline, and not a regular face...
+                face[1][:] = [True]
                 faces.append(face)
-            # Else, use face_vert_loc_indices and face_vert_tex_indices previously defined and used the obj_face
+            # Else, use face_vert_loc_indices previously defined and used the obj_face
 
             context_multi_line = b'l' if strip_slash(line_split) else b''
 
@@ -1087,13 +1109,14 @@ def load(operator, context, filepath,
     SPLIT_OB_OR_GROUP = bool(use_split_objects or use_split_groups)
 
     for data in split_mesh(verts_loc, faces, unique_materials, filepath, SPLIT_OB_OR_GROUP):
-        verts_loc_split, faces_split, unique_materials_split, dataname = data
+        verts_loc_split, faces_split, unique_materials_split, dataname, use_vnor, use_vtex = data
         # Create meshes from the data, warning 'vertex_groups' wont support splitting
+        #~ print(dataname, use_vnor, use_vtex)
         create_mesh(new_objects,
                     use_edges,
                     verts_loc_split,
-                    verts_nor,
-                    verts_tex,
+                    verts_nor if use_vnor else [],
+                    verts_tex if use_vtex else [],
                     faces_split,
                     unique_materials_split,
                     unique_material_images,