Am Sat, 31 Oct 2020 08:49:39 +0100
schrieb Thomas Huth <th.huth@xxxxxxxxx>:
Am Sat, 31 Oct 2020 07:55:28 +0100
schrieb Jens Guenther <dbotw@xxxxxxx>:
Hi,
while discussing an issue with the Tandy TRS-80 emulator SDL2TRS in
the RetroPie-Forum (1) regarding KMS/DRM with SDL2 on the Raspberry
Pi 4 and Wayland, it turns out that the patch also fixes it for
Hatari ...
Interesting ... we removed that call three years ago, after deciding
that it is not necessary, see:
https://git.tuxfamily.org/hatari/hatari.git/commit/?id=5a59019da3e
and the related discussion:
https://listengine.tuxfamily.org/lists.tuxfamily.org/hatari-devel/2017/02/msg00144.html
Why is the call necessary with KMS/DRM and Wayland? Does it have any
side effects there beside clearing the surface?
So in case we have to include this again, do we have to do it on each
frame? Or would it be ok to only call it e.g. only on every 50th frame
to avoid the speed penality of the unnecessary screen clear?
Ok, I've found some more information here:
https://wiki.libsdl.org/SDL_RenderPresent
Citing: "You are strongly encouraged to call SDL_RenderClear() to
initialize the backbuffer before starting each new frame's drawing,
even if you plan to overwrite every pixel."
... so I assume we should simply add the SDL_RenderClear() again, to be
on the safe side? Nicolas, what do you think?