Bug#1124335: domino-chain: strobes between two frames when using Wayland

[Simon McVittie]

On Tue, 30 Dec 2025 at 23:53:58 +0000, Simon McVittie wrote:
>On Tue, 30 Dec 2025 at 19:51:36 +0000, Simon McVittie wrote:
>>Actual result with Wayland: A black window. If I press Escape, I get
>>what appears to be the expected window on every 2nd frame, and a black
>>screen on the remaining frames.
>
>This seems to be the same thing that was reported upstream as 
><https://gitlab.com/domino-chain/domino-chain.gitlab.io/-/issues/20>.
>
>See also <https://github.com/libsdl-org/sdl2-compat/issues/569> 
>looking at this from the SDL side.

According to SDL upstream, this is a game bug in domino-chain: it's 
assuming that the backbuffer contents from each frame are preserved 
after the frame is presented, but this is undefined behaviour in OpenGL 
and Vulkan: with some platform/driver combinations it happens, but with 
some it does not.

SDL's rendering API never guaranteed this either, but in practice it 
usually worked in the past. Newer versions of sdl2-compat will work 
around this by forcing use of SDL's software renderer for domino-chain, 
which does have the backbuffer-preserving behaviour.

Reference: https://github.com/libsdl-org/sdl2-compat/commit/61789ee297b0dd0fae298fb4fd8c86afff933c08

     smcv