you could try these examples below
[1]
install virtual pc on a serious grunt mac with a decent video card and win98se or win2k /XP installed with directx.
[2]
wait for the darwine project to be more compatible with its port of emulating windows on the mac os x environment.
[3]
there are some projects on the internet that will take c++ direct x code and do a rough conversion of it to opengl, these programs would take a lot of knowledge in both 3d rendering methods for any real success, you could then recompile it on mac with xtools or metrowerks.
[4]
beg lee to export your final darkbasic syntax into C++ or find someone who has a similar tool and recompile the code to openGL by hand
[5]
port your project to java so compiling for both machines is relatively straight forward.
but there is issues with each language if you access the languages
http://www.starfireresearch.com/services/java3d/java3d-OpenGLvsDirectX.html
[6]
using X11 and wine to emulate windows but it would be safer and less mind boggling to wait for the darwine project above.
[7]
REALBASIC looks like a good cross platform package but i think its lacks a real 3d engine so you would have to create your own and that can get messy inside another language thats not closer to machine code etc..
[8]
METALBASIC is a free mac basic game creation language you can try for 2d based games but you have to write your own 3d engine, its really good for accessing quicktime components and mac based features within the languages native syntax. you could also wait for the the newer version of metal.
[9]
here is something i just found but havent tested
http://www.v3x.net/directx/
[*]
this is a good real world article regarding someone who has been through the process of porting over
http://www.altsoftware.com/company/media_center/presentations/mac-os-game-porting.pdf
[*]
oblivion a guru coder from way back, had an example of using darkbasic but using opengl, unfortunately this doesnt escape the requirement of directx
for me im waiting for darwine to shape up as i have other stuff to do before i die
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