I have a Radeon x1250 graphics card and I am using Devuan Freia.  I compiled xroar from source.  Xroar is an emulator that uses sdl.  The problem is xroar runs painfully slow.  It runs fine when it is in a small window.  But when I enlarge the window or make it full screen it is painfully slow.  I tried running glxgears and it shows gears moving.  I am wondering if I am missing some library that allows sdl to use graphics acceleration.  Youtube videos run fine.  Any suggestion would be appreciated.