Clarification on getting OpenGL running

[TechdudeGames]

I've been able to compile DirectFB2. but I have had trouble getting OpenGL to work with it. I have tried using instructions from here to build IDirectFBGL, but that seems to not work as all OpenGL applications just produce a black screen or crash. Is there a different set of instructions I need to follow to get OpenGL to work with DirectFB2? I am interested in using it for one of my projects on an embedded system but I need to figure out how to get OpenGL to work.

[caramelli]

Hi,

Yes, it can be tricky to have a Mesa version correctly built to work with DirectFB.

Keep in mind that you have 2 options for OpenGL rendering:

• DirectFBGL (the one you are trying to use with SDL2)
• EGL for the DirectFB platform

It would be easier if DirectFBGL was still maintained in Mesa (its support has been removed since version 7.8): https://gitlab.freedesktop.org/mesa/mesa/-/commits/4387580e50f49d642160982208c807da858cd1ab
For EGL, patches never merged into Mesa can be applied: https://lists.freedesktop.org/archives/mesa-dev/2013-April/037768.html

But for both DirectFBGL and EGL, it relies on a software implementation!
Some embedded systems have a GPU with a proprietary implementation for OpenGL rendering with DirectFB, which is better for hardware acceleration. For example, on some ARM embedded systems with a Mali or Vivante GPU.

I also recommend checking OpenGL rendering with https://github.com/caramelli/yagears before trying to run higher level applications (like with SDL2).

It would be nice to have DirectFB support in Mesa again, it's on my TODO list, and any help making it is welcome!