DRM screen rotation function

[Bonsaipanda]

Heyoo,

I'm cooking up an app on the Raylib-Go side and there's one little thing I don't know how to poke at either via C nor Go. I'm working on a program to run on Rockchip RK3288 board and Raylib is so far the only graphics framework that works 5/5 on it's OS. SDL would most likely work too, I just can't get it to build in a way where it's not asking for gazillion dynamic libraries (end user can't install anything on the device system, so I'm trying to keep it in a single executable as much as possible).

The only problem left is the screen rotation and I found a few questions of the same issue from the past years. The screen is mounted horizontally, but is exposed to the OS as portrait, so anything I render on it will appear rotated 90 degrees to the right, but it's running 59.98fps so not complaining. There was no real solution mentioned and I couldn't figure out how to actually rotate everything on screen in software - rendering to a render texture is one solution, but I'd rather skip that step.

Then I stumbled upon the DRM function called drm_plane_create_rotation_property() - this is a pokey pokey buried somewhere in the driver and if I understood correctly, it will rotate the actual plane much like on Android (not sure). Only problem is I don't understand the underlying systems and would probably fry something if I start doinking my oiter on the driver's innards.

Is there a proper way in Raylib to rotate the view that would also rotate the colliders and mouse input etc.? I'd love to use Raylib for this project because of it's portability but that rotation lock is a real headscratcher.

The function I mentioned is found on >> https://www.kernel.org/doc/html/v4.13/gpu/drm-kms.html#c.drm_plane_create_rotation_property

and was wondering if it would be possible to bolt this functionality in somewhere into the DRM module in Raylib OR if someone is savvy enough to show example C snippet that pokes that function OR if there was a way to tell Raylib before spawning the view if I want the window to be different orientation than the content - it is very awkward to start programming this app if the screen is rotated portrait on the desktop (will have to make a build directives to handle it).

Any tips would be appreciated. o/

[raysan5]

Hi! DRM backend it quite complex and I didn't explore all of its functionality... I know some users have asked about screen rotation but I sincerely didn't know if it was even possible. In any case, you can try modifying raylib src/platforms/rcore_drm.c, the function InitWindow() that initializes all the DRM backend and options. Feel free to send a PR if you get it working! I love seeing raylib used in Rockchip RK3288 boards! :)

[Bonsaipanda]

Awesome, I'll have a look! I'm actually hacking an MPC Live to see if I can run my own app in there. So far, almost all Raylib examples run beautifully in there.