While I was working on the DosBox sources and reading a few forums to get some clues I came across a patch for libSDL called OpenGL-HQ. OpenGL-HQ is a video “driver” for SDL that uses your graphics hardware to scale the output to any size you want. It was originally written for 2D games/emulators like dosbox, scummvm or exult.

If you take a look at the screenshot here you will see why I was keen on getting this to work in my DosBox build. Unfortunately this meant to recompile libSDL from scratch. But I took the chance and did an optimized build using the compiler switches that should give best results on a Core2Duo INTeL Mac: -march=nocona -mtune=pentium-m -msse3

There is also a little patch in the OpenGL-HQ distribution that must be run against the dosbox 0.65 sources. This one fails but I was able to include the changes by hand. Download the binary here:

DosBox-065CVS_OpenGL-HQ_Core2Duo_INTeL_static_no-X11.zip

Usage:

export SDL_OPENGLHQ_WINRES=800x600
export SDL_VIDEODRIVER=openglhq

And within the DOSBox Preferences set output=openglhq output=surface.

Now for the bad news: the new mode isn't working (at least here on my machine). I always get errors like these:

CONFIG:Loading primary settings from config file /Users/rhoenie/Library/Preferences/DOSBox Preferences
2006-11-23 22:27:30.437 DosBox[18724] ** _NSAutoreleaseNoPool(): Object 0x26dc8a0 of class NSMutableParagraphStyle autoreleased with no pool in place - just leaking
2006-11-23 22:27:30.437 DosBox[18724] ** _NSAutoreleaseNoPool(): Object 0x26dca20 of class NSCFDictionary autoreleased with no pool in place - just leaking

Maybe one has to find the right set of configuration options - maybe its just an issue with my machine. If you find a way to run the OpenGL-HQ mode properly then please tell me so.

Update:
Never run it in fullscreen=true mode! You won't be able to get back to your normal desktop, once it crashed (just as I had to learn right now - had to poweroff the beauty).

Update:
I just got informed by the author of the opengl-hq patch that he fixed the issues on OSX and that there will be a new release soon. As soon as I get the sources I will put a new build up here. So stay tuned.