[alejo7797]

This change fixes an issue with loading PNG files in ImageBasedTexture.

png.Reader.asRGBA8() got removed from pypng: https://gitlab.com/drj11/pypng/-/commit/85479eaf5d6152afcfc4d0f3de4188a2174bdf8a This commit hasn't made it to the pypng wheel on PyPI (still at version 0.20220715.0) which is why I assume maybe it's hard to run into.

But the removal is present in this release (version 0.20250521.0) which is what distributions seem to be packaging (Debian, Arch Linux and Nixpkgs at least).

This causes the following:

In[1]: M = Manifold('4_1')

In[2]: M.inside_view()
Warning could not read texture {{prefix}}/lib/python3.14/site-packages/snappy/raytracing/shaders/NonGeometric.png
'Reader' object has no attribute 'asRGBA8'
Warning could not read texture {{prefix}}/lib/python3.14/site-packages/snappy/raytracing/shaders/Eye.png
'Reader' object has no attribute 'asRGBA8'

Out[2]: New window: Inside view of 4_1

and the eyeball texture not to render when selected:

---

So I replaced the call to .asRGBA8() with one to .asRGBA() and added a check that the bitdepth of the PNG texture file is 8. This is the case for Eye.png andNonGeometric.png, which from what I can tell are the only PNG texture files used within SnapPy.

Happy eyeballs: