Notice to Retina-screen Mac (MBPr) owners.

[ellmo]

Hey there!
Anyone who bought a Retina-screen Mac recently might encounter abysmal performance with ALL source ports when they run them in windowed mode. I myself experienced it with Eternity, ZDoom, GZDoom, Chocolate and PRBoom. None of those were compiled, I used generally availbe OSX packages and installers.

It turns out to be a simple HiDPI / Retina issue, so don't worry, it's not your brand new, shiny Mac that blows this hard, your OS and hardware are ok - you just have to force the application to open in low-resolution mode.

Locate the engine's *.app package with your Finder (most probably in /Applications/), right click, select Get Info and on the info panel tick Open in Low Resolution.

Et voila