See https://github.com/NixOS/nixpkgs/issues/217921
Blender sets WITH_DRACO=OFF if WITH_PYTHON_INSTALL=OFF, however that’s
not totally necessary. Removing that forced-set then builds with
WITH_DRACO=ON, however Blender fails to launch because this creates
e.g. `share/blender/3.6/python`, and Blender then sets this as Python’s
home dir, so Python fails to init since it expects Python core to be
there (and it’s not). I couldn’t figure out how Blender sets Python’s
home dir, and explicitly setting PYTHONHOME in the env didn’t have any
effect. So instead just rename that dir to python-ext to avoid this
behavior. All that is left then is to adjust where Blender is looking
for the Draco lib.
This functionality may be verified by:
1. Visiting File → Export → glTF 2.0
2. In the right side panel (press the gear icon in top-right if not
visible), expanding “Data”
3. Enabling “Compression”
4. Press “Export glTF 2.0”
5. Verify:
- Blender stdout+stderr shows “Draco mesh compression is available”
- no error or warning message
- exported file exists
f1468a9946