Looks like the channel type of your screen is not handled by the SDL2
port, which would explain why it works in drawterm (which probably
sets it to a generic RGB24 or XRGB32 or whatever).

Could you, in npe/libnpe_sdl2/sdl2.c, at the start of the chan2mask
function just before the switch, add something along the lines of
fprint(2, "--- my channel: %08x ---\n", chan); and then mk install
npe, mk clean and mk install uxn, and see what uxnemu prints out
before crashing on the assert? We could then try to add your channel
to the switch in chan2mask and set the masks appropriately.

(For example, on my machine the number printed out is 68081828, which
means XRGB32, based on the definitions in /sys/include/draw.h)

On Mon Nov 25, 2024 at 13:24 CET, Karol Belina wrote:
> Looks like the channel type of your screen is not handled by the SDL2
> port, which would explain why it works in drawterm (which probably
> sets it to a generic RGB24 or XRGB32 or whatever).
>
> Could you, in npe/libnpe_sdl2/sdl2.c, at the start of the chan2mask
> function just before the switch, add something along the lines of
> fprint(2, "--- my channel: %08x ---\n", chan); and then mk install
> npe, mk clean and mk install uxn, and see what uxnemu prints out
> before crashing on the assert? We could then try to add your channel
> to the switch in chan2mask and set the masks appropriately.
>
> (For example, on my machine the number printed out is 68081828, which
> means XRGB32, based on the definitions in /sys/include/draw.h)
The channel reported on a QEMU VM as well as an old laptop with to my
knowledge WVGA is 00051625

Right, so RGB16 (also known as RGB565). I gave the implementation a go
and experimented with the source code of libnpe_sdl2 for a bit, but I
couldn't get it fully working. Maybe you could contact Sigrid? She
made the SDL2 port and could help you out for sure.