Touch input causes pointer to jump around erratically

[rsn8887]

Tested on Steamdeck desktop mode and game mode, using latest Retroarch flatpak 1.17.0 with SDL2 input and SDL2 controller drivers, and ozone menu.

Any touchscreen input with fingers cause the mouse pointer to jump around erratically. Touch input is unusable because of this.

On the Steam store version of Retroarch, touch works fine.

Maybe it has to do with the bundled SDL2 library version in flatpak?

[AlexFolland]

Is it mapped such that touching near the top maps to the left and touching near the bottom maps to the right? That's what I would expect because the Steam Deck's screen is sideways. I think RetroArch would need to handle screen orientation metadata from the OS properly to resolve this.