Renderer modernization effort on FreeCAD's Coin fork

[Lgt2x]

Hello @VolkerEnderlein @veelo ,

We wanted to let you know that the FreeCAD project is starting an effort to modernize Coin's rendering stack and improve its performance. This work is happening on our experimental Coin fork that is now integrated to FreeCAD as a submodule. You can see the progress of this effort here: https://github.com/FreeCAD/coin/pulls?q=is%3Apr+author%3Atritao

Would you be willing to help us integrate this to the official Coin distribution?

[VolkerEnderlein]

Sure, I'll support the integration.

[Lgt2x]

Sweet!

A first wave of various fixes coming from our fork is already submitted:

• Add pick layer to SoPickStyle for ordered on-top picking #633
• tidbits: use C++ cmath functions #638
• ci: enforce warning-clean builds #640

A second wave (pending internal review, testing & merging) prepares the openGL modernization:

• build: establish profile-aware OpenGL headers FreeCAD/coin#11
• egl: preserve caller state and support surfaceless offscreen contexts FreeCAD/coin#12
• shaders: migrate GLSL to profile-neutral dispatch FreeCAD/coin#14
• shaders: improve GLSL diagnostics and source attribution FreeCAD/coin#22
• rendering: make shared GL infrastructure profile-safe FreeCAD/coin#15
• gl: make shared OpenGL infrastructure profile-safe FreeCAD/coin#16
• build: add platform GL header plumbing FreeCAD/coin#19
• ci: validate installed packages and final profiles FreeCAD/coin#17

The patch introducing a new faster draw-list API is work-in-progress here: FreeCAD#7 . These patches are not expected to break retro-compatibility, and will add testing.

[tritao]

@VolkerEnderlein If you would like to provide some feedback at this stage, before we merge the PRs into FreeCAD Coin, it would be very welcome and appreciated, we can also schedule a call if you would like to go over the design and implementation.

Additionally to the PRs that @Lgt2x linked above, a lot more PRs have been opened up, if you open any of them, they are now linked as a Github stacked PR, so you can navigate across the whole stack.

@Lgt2x has also raised an interesting question, do we need to follow the Kongsberg copyright for new files? Can we instead assign copyright to the FreeCAD contributors, like it's usually done in FreeCAD?

[VolkerEnderlein]

@tritao I'll have a look onto the outstanding PRs. Give me a few days to provide sound feedback.

As far as I know we do not need to add the Kongsberg copyright notice to new files. Assigning copyright to the contributors seems the right way to do.

[tritao]

A summary of the work has now been posted, it has some benchmark numbers which might be interesting to review.

FreeCAD/FPA-grant-proposals#35 (comment)
FreeCAD/FPA-grant-proposals#35 (comment)