On Friday, 9 September 2022 at 03:19:40 UTC+1 Gonzalo wrote:
Yes, that's exactly what I was trying to do. On Linux and Windows this
works, but on macOS, as Manolo said, it does not, as it does not allow
mixing OpenGL2 and OpenGL3+ calls. That sucks, as I was now relying on
that feature for my program. It is a pity as the video library I am now
using requires OpenGL4.1, while FLTK is still stuck on GL2.
Oh well... one more thing the new rewrite of my program won't support.
Bother - apologies if two versions of this reply appear. This is my second try; the web interface appears to have dropped my first (longer and more rambling) attempt somewhere...
Anyway, the crux of my replay was that FLTK needs to use GL2 as that is the only API that we know is exposed by default on WIN32 and most X11/Wayland systems, and that is also available on macOS.
Further, to get "higher" GL API than 2.1, on WIN32 and most X11/Wayland systems you need to use an "extension wrangler" such as GLEW.
If we switch FLTK to use, say, GL3 as the default then that impacts a lot of use cases, and we'd need to look at bundling GLEW or a similar extension wrangler, at least for the Win32 usage. And that might not work as there are a lot of desktop systems that have really ancient GL driver support...
But *generally* this does not matter, since GL contexts are *generally* "backwards compatible" - on Win32 or X11 a GL4 context can still do GL2-ish things.
Apple seem to have contrived to make that not work. (At this point in the lost post I implied this was related to Apple being down on GL and trying to force people to use their proprietary API.)
So... I'm not convinced this is a problem of FLTKs making, or one that we can readily fix. Perhaps Apple will fix it...
