glTF importer/exporter: Draco decoder + encoder fixes

We can now read Draco compressed files.
This also fix exporting vertex color Draco compressed files. Fix #T75550

1 files changed, 64 insertions, 0 deletions

diff --git a/io_scene_gltf2/io/com/gltf2_io_draco_compression_extension.py b/io_scene_gltf2/io/com/gltf2_io_draco_compression_extension.py
new file mode 100644
index 00000000..51359f82
--- /dev/null
+++ b/io_scene_gltf2/io/com/gltf2_io_draco_compression_extension.py
@@ -0,0 +1,64 @@
+# Copyright 2018-2019 The glTF-Blender-IO authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import sys
+from pathlib import Path
+import bpy
+
+from ...io.com.gltf2_io_debug import print_console
+
+
+def dll_path() -> Path:
+    """
+    Get the DLL path depending on the underlying platform.
+    :return: DLL path.
+    """
+    lib_name = 'extern_draco'
+    blender_root = Path(bpy.app.binary_path).parent
+    python_lib = Path('{v[0]}.{v[1]}/python/lib'.format(v=bpy.app.version))
+    python_version = 'python{v[0]}.{v[1]}'.format(v=sys.version_info)
+
+    path = os.environ.get('BLENDER_EXTERN_DRACO_LIBRARY_PATH')
+    if path is None:
+        path = {
+            'win32': blender_root / python_lib / 'site-packages',
+            'linux': blender_root / python_lib / python_version / 'site-packages',
+            'darwin': blender_root.parent / 'Resources' / python_lib / python_version / 'site-packages'
+        }.get(sys.platform)
+    else:
+        path = Path(path)
+    
+    library_name = {
+        'win32': '{}.dll'.format(lib_name),
+        'linux': 'lib{}.so'.format(lib_name),
+        'darwin': 'lib{}.dylib'.format(lib_name)
+    }.get(sys.platform)
+
+    if path is None or library_name is None:
+        print_console('WARNING', 'Unsupported platform {}, Draco mesh compression is unavailable'.format(sys.platform))
+
+    return path / library_name
+
+
+def dll_exists(quiet=False) -> bool:
+    """
+    Checks whether the DLL path exists.
+    :return: True if the DLL exists.
+    """
+    exists = dll_path().exists()
+    if quiet is False:
+        print("'{}' ".format(dll_path().absolute()) + ("exists, draco mesh compression is available" if exists else
+                                                       "does not exist, draco mesh compression not available"))
+    return exists