[Mesa-dev] How MESA display image in case of use full software rendering?

[Nathan Kidd]

On 2019-12-23 6:01 a.m., Oleg Gavrilchenko wrote:
> I can ask. How MESA display image in case of use full software
> rendering? What does interface it use?
> It use /dev/fbX, drm or otherwise method?

[Disclaimer: I have very limited experience with this, but hope some
hint is better than none.]

The software renderers obviously output to internal system memory
buffers.  You need to pick a mechanism to blit those bits to your own
output buffer for scanout (or otherwise display).  As one example, look
at the X server's glx/glxdriswrast.c:__glXDRIscreenProbe() where you can
trace down how the DRI mechanism connects swrast output images to X
drawable memory. (It is quite convoluted, likely there are better
examples than that mechanism, but I don't know them.)

-Nathan