Add gsplat version number to build directory.

[keunhong]

This ensures that the extension is compiled when the library is upgraded.

Resolves #318.

[liruilong940607]

Did you encounter this problem in an actual run?

This feels a bit strange because JIT build does on-the-fly comparison on the hashing of the files and if any file changes it will trigger rebuild during JIT load():

gsplat/gsplat/cuda/_backend.py

Line 38 in 7816033

return load(

Code reference in torch:

https://github.com/pytorch/pytorch/blob/40ce0a53bb4dd4e5e8aa886fb29334f981595023/torch/utils/cpp_extension.py#L1680

I would be curious to look into it if you have this problem in an actual run.

[liruilong940607]

I did a test on this. It seems like at least in the latest release it will trigger the rebuilt if you upgrade it with pip, which is as expected. So I'm closing this for now. Feel free to reopen it if this is not the case.

# install v1.1.0
pip install gsplat==1.1.0
python -c "from gsplat.cuda._backend import _C; print(_C)"

# replace v1.1.0 with v1.3.0
pip install gsplat==1.3.0
python -c "from gsplat.cuda._backend import _C; print(_C)"