glTF importer: performance improvement importing meshes & normals

3 files changed, 23 insertions, 25 deletions

diff --git a/io_scene_gltf2/__init__.py b/io_scene_gltf2/__init__.py
index f051b08e..9410cd1d 100755
--- a/io_scene_gltf2/__init__.py
+++ b/io_scene_gltf2/__init__.py
@@ -15,7 +15,7 @@
 bl_info = {
     'name': 'glTF 2.0 format',
     'author': 'Julien Duroure, Norbert Nopper, Urs Hanselmann, Moritz Becher, Benjamin Schmithüsen, Jim Eckerlein, and many external contributors',
-    "version": (1, 2, 5),
+    "version": (1, 2, 6),
     'blender': (2, 81, 6),
     'location': 'File > Import-Export',
     'description': 'Import-Export as glTF 2.0',
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_mesh.py b/io_scene_gltf2/blender/imp/gltf2_blender_mesh.py
index e069069e..05a443a7 100755
--- a/io_scene_gltf2/blender/imp/gltf2_blender_mesh.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_mesh.py
@@ -124,19 +124,14 @@ class BlenderMesh():
         if gltf.import_settings['import_shading'] == "NORMALS":
             mesh.create_normals_split()
 
-        # use_smooth for faces
+        use_smooths = []  # whether to smooth for each poly
         face_idx = 0
         for prim in pymesh.primitives:
-            if 'NORMAL' not in prim.attributes:
-                face_idx += prim.num_faces
-                continue
-
-            if gltf.import_settings['import_shading'] == "FLAT":
-                for fi in range(face_idx, face_idx + prim.num_faces):
-                    mesh.polygons[fi].use_smooth = False
+            if gltf.import_settings['import_shading'] == "FLAT" or \
+                    'NORMAL' not in prim.attributes:
+                use_smooths += [False] * prim.num_faces
             elif gltf.import_settings['import_shading'] == "SMOOTH":
-                for fi in range(face_idx, face_idx + prim.num_faces):
-                    mesh.polygons[fi].use_smooth = True
+                use_smooths += [True] * prim.num_faces
             elif gltf.import_settings['import_shading'] == "NORMALS":
                 mesh_loops = mesh.loops
                 for fi in range(face_idx, face_idx + prim.num_faces):
@@ -146,14 +141,16 @@ class BlenderMesh():
                     for loop_idx in range(poly.loop_start, poly.loop_start + poly.loop_total):
                         vi = mesh_loops[loop_idx].vertex_index
                         if poly.normal.dot(bme.verts[vi].normal) <= 0.9999999:
-                            poly.use_smooth = True
+                            use_smooths.append(True)
                             break
-
+                    else:
+                        use_smooths.append(False)
             else:
                 # shouldn't happen
-                pass
+                assert False
 
             face_idx += prim.num_faces
+        mesh.polygons.foreach_set('use_smooth', use_smooths)
 
         # Custom normals, now that every update is done
         if gltf.import_settings['import_shading'] == "NORMALS":
diff --git a/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py b/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py
index a046204b..ff654f18 100755
--- a/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py
+++ b/io_scene_gltf2/blender/imp/gltf2_blender_primitive.py
@@ -155,9 +155,10 @@ class BlenderPrimitive():
         pyprimitive.num_faces = 0
         for face in faces:
             try:
-                face = bme_faces.new(tuple(
-                    bme_verts[pidx_to_bidx[i]]
-                    for i in face
+                face = bme_faces.new((
+                    bme_verts[pidx_to_bidx[face[0]]],
+                    bme_verts[pidx_to_bidx[face[1]]],
+                    bme_verts[pidx_to_bidx[face[2]]],
                 ))
 
                 if material_index is not None:
@@ -204,15 +205,15 @@ class BlenderPrimitive():
                 )
 
             for bidx, pidx in vert_idxs:
+                color = colors[pidx]
+                col = (
+                    color_linear_to_srgb(color[0]),
+                    color_linear_to_srgb(color[1]),
+                    color_linear_to_srgb(color[2]),
+                    color[3] if is_rgba else 1.0,
+                )[:blender_num_components]
                 for loop in bme_verts[bidx].link_loops:
-                    color = colors[pidx]
-                    col = (
-                        color_linear_to_srgb(color[0]),
-                        color_linear_to_srgb(color[1]),
-                        color_linear_to_srgb(color[2]),
-                        color[3] if is_rgba else 1.0,
-                    )
-                    loop[layer] = col[:blender_num_components]
+                    loop[layer] = col
 
             set_num += 1