BugFix: Manually specify directory to load nvrtc dll on pyflamegpu import.

[Robadob]

Required for some Windows installs where Python >=3.8.

Have tested it with Python 3.7.x and 3.9.x locally, however I could never reproduce the original bug.

Fix inspired by @zeyus

Closes #450

[Robadob]

I'd appreciate it if you can confirm this solves it for you @zeyus (GitHub doesn't seem to allow me to invite you to review the PR)

It's a bit more complicated than your proposed solution, but I think it should hopefully work for users with many verisons of CUDA installed. I don't believe python actually wipes the path variable, hence where should allow us to find the preferred copy of the dll.

[Robadob]

cc @jcbpyle This may also be relevant to you. If you're still affected by the issue can you test this too?

[jcbpyle]

Works on a fresh build for me, all cmake config/generation/ vstudio building worked without a problem. The venv environment needed a few packages installing (numpy and deap which I use in an experiment generator module when doing boids stuff, so probably unrelated) and it didn't like 'python3 -m ...' but after installing those packages and using 'python -m ...' all worked fine.

[Robadob]

Great, those things should be unrelated to this change. Will get it merged once @ptheywood has confirmed he's happy with it.

[zeyus]

I'd appreciate it if you can confirm this solves it for you @zeyus (GitHub doesn't seem to allow me to invite you to review the PR)

Huh, strange, maybe I have to be a collaborator or something. I'll pull the changes and build it now :) thanks

[Robadob]

Huh, strange, maybe I have to be a collaborator or something. I'll pull the changes and build it now :) thanks

Probably, I think non-collaborators can still review though (they just get a grey tick, rather than a green tick). Last year we had an issue where some bot kept approving a temporarily inactive PR for no reason.

[zeyus]

UPDATE:

I ran the dependency tree again, and it turns out this is not the same issue, rather, libpng16.dll was not found (I guess my compiled version is not in the bin / path).

Your update / fix works fine :) 👍

So, @Robadob, this doesn't introduce any new bugs, but for some reason it doesn't actually fix the importerror, which might indicate a restriction on a module's ability to use os.add_dll_directory ?

[Robadob]

Iirc, libpng is an optional dependency of the visualiser. CMake only builds with it if it can find it on your system, so it's probably not in the pre-built binaries from CI.

It's possible this is the same bug for a different dll, would just need to add logic for that too. I will add a note to the closed issue. Although, it probably has a more permissive license that would allow us to package it's dll like we do SDL2.

Thanks for your input, has been very useful.

[zeyus]

That's fair, I did have libpng with vcpkg, but the vcpkg bin path is definitely not in my PATH variable.

Yeah I think that makes sense, and no probs happy to help, I'll definitely raise any issues I bump into along the way, this seems like a great ABM tool, and I'm going to be implementing it for one of my exam papers, thanks for the awesome support.