No Wayland support

[ribosomerocker]

Hello! I have been trying to get a program I've written to work in Wayland by setting the environment variable
export SDL_VIDEODRIVER=wayland
but I get this error:
SDLCallFailed {sdlExceptionCaller = "SDL.Init.init", sdlFunction = "SDL_Init", sdlExceptionError = "wayland not available"}

From what I know, SDL2 already supports Wayland at this point; so I am rather confused how it doesn't work with sdl2.

[ocharles]

I think it would help to see a C sample that works for you on Wayland. Next, we can see if we can get it working in Haskell.

[ribosomerocker]

https://bpa.st/USTA
This is a very {bad,small} example. It creates a white window. If I run it with SDL_VIDEODRIVER=wayland, then it uses Wayland instead of XWayland. But if I try any Haskell sdl2 project with that environment variable, I get the aforementioned error.

[ribosomerocker]

Oh, sorry. Misclicked!

[ribosomerocker]

I think I figured out the issue. When this didn't work, I was using surfaces. But in the meantime I've switched to textures; and they seem to work for Wayland. I'll do some testing.

[ocharles]

I'm afraid I don't think anyone is actively looking at this at the moment.

[ocharles]

What would help would be to have a reproducible example in Haskell that mimics the C you provided

[ribosomerocker]

This doesn't quite mimic the C, but it does most of it: https://bpa.st/ZCXQ
So, here's the conclusion I've arrived at: In haskell sdl2, surfaces are not Wayland compatible. But textures are.

Maybe you should encourage the usage of textures instead of surfaces?

[dpwiz]

The bpa.st links are all 404d out )=

[coder3112]

@MonAaraj can you please either

1. Revive the links you gave
2. Post the minimal, reproducible example in the comments themselves so that they are (more) permanent.
   Thanks!

[ribosomerocker]

I can't exactly revive them, but I can give you a """minimal""" reproducible example.

Main.hs

#!/usr/bin/env cabal
{-# LANGUAGE OverloadedStrings #-}

{- cabal:
build-depends: base, sdl2, text, linear
-}

import SDL
import Linear (V4(..))
import Control.Monad (unless)

main :: IO ()
main = do
  initializeAll
  window <- createWindow "My SDL Application" defaultWindow
  renderer <- createRenderer window (-1) defaultRenderer
  screen <- getWindowSurface window
  appLoop renderer
  destroyWindow window

appLoop :: Renderer -> IO ()
appLoop renderer = do
  events <- pollEvents
  let eventIsQPress event =
        case eventPayload event of
          KeyboardEvent keyboardEvent ->
            keyboardEventKeyMotion keyboardEvent == Pressed &&
            keysymKeycode (keyboardEventKeysym keyboardEvent) == KeycodeQ
          _ -> False
      qPressed = any eventIsQPress events
  rendererDrawColor renderer $= V4 0 0 255 255
  clear renderer
  present renderer
  unless qPressed (appLoop renderer)

As mentioned earlier, if you run this with SDL_VIDEODRIVER=wayland, then it says:
script: SDLCallFailed {sdlExceptionCaller = "SDL.Video.getWindowSurface", sdlFunction = "SDL_GetWindowSurface", sdlExceptionError = "No hardware accelerated renderers available"}

But, if I don't use surfaces at all, instead only textures, then it works fine for Wayland.

[hanst99]

@MonAaraj Using a screen surface together with the SDL_Renderer API like you're doing here is not supported by SDL itself: see documention. This API is mostly outmoded anyway, it's more useful as a temporary utility for porting SDL1.x code. Using a screen surface by its nature keeps you from using hardware accelerated rendering, which is not what you want because software rendering is somewhere on the order to thousands to millions of times slower than accelerated, depending on what exactly you're doing.

[ribosomerocker]

Alright, thank you very much. I will be closing this issue.

[dpwiz]

I wonder what would be a correct place to put the wayland/texture notice. Should the entire Surface block get a heads-up / deprecation notice? 🤔