[WIP] v0.5.0

[dvicini]

This PR updates the plugin to use the latest Mitsuba APIs. Mainly, the Properties API has been slightly modified.

Moreover, it improves the testing scripts to better support local runs of unit tests.

(work in progress, not yet ready to merge. This will require a Mitsuba release to use the latest APIs)

[dvicini]

At the moment, there appears to be an issue with Mitsuba picking up Blender's embree library (version 4). I can work around by running with LD_PRELOAD, but probably that's not ideal:

LD_PRELOAD=~/code/mitsuba3/build/blender-dbg/libembree3.so $BLENDER -b -noaudio --factory-startup --python scripts/run_tests.py --mitsuba ~/code/mitsuba3/build/blender-dbg/ -- -v --cov=mitsuba-blender

@bathal1 How come this wasn't an issue in the past? Any idea?

[dvicini]

The embree symbol issue was now fixed in Mitsuba itself: mitsuba-renderer/mitsuba3#1663

[bathal1]

I'll be pushing some commits to prepare for the next release of the add-on here @dvicini.

Regarding testing, it would be nice to add more extensive round-trip tests. IIRC we also only test one round-trip, but two might pose an issue. For example, exporting a scene from blender will wrap all BSDFs into twosided Mitsuba plugins, but when re-importing that scene, this will create additional nodes in the shader graph for each material to emulate that plugin. This is not necessary and may pose issue when exporting once again.

[dvicini]

Sounds good! I don't have local changes, feel free to use this branch. We can later maybe cleanup the history a bit and squash some of my earlier commits into fewer ones.

For testing: Not just round trip tests, but it would also be good to more rigorously test that the renderings match. For example, Blender at some point changed its definition of the light source intensities, which leads to very different outputs if not handled correctly. My suggestion would be to test some of those things by programmatically creating simple blender scenes, rendering them, exporting, and rendering with Mitsuba and comparing final images.

[merlinND]

By the way, is #105 (same title) deprecated or should it be combined with this PR?