Memory Leak with the Phong Renderer from PySixd

[Arka161]

Hello there,

I have noticed that there's a major memory leak in the repository when we use the Phong renderer, and try to render multiple images (eg: On datasets such as T-LESS PBR, referenced in the BOP Challenge and Cosypose).

Steps to repro:

• Just run a for loop over a few epochs and try to get the rgb and depth using the Phong renderer for a loaded Mesh + Image configuration.
• The memory would gradually be increased till it crashes the RAM.

Let me know if you need any further details or code snippets related to the bug.

[Arka161]

Just to clarify, this error doesn't hit normally, as the error seems to be on the GL/C++ end of PySixd.

The reasons generate_batches directly won't cause the bug, is because Python clears the memory when the program exits. But if in the same code you call render_phong multiple times in a loop (it is useful when you try to load up a custom dataset), the memory leak is very stark.

Are there are reference repos where I can mention this to the PySixd Devs? I also realized that the fix isn't super trivial as calling a gc() wouldn't work as the leak is associated with C++ objects.

Thank you so much