|> Looking for information about incompatibilities between SGI GL and
|> the RS/6000 version and how to fix them, when porting an SGI programm
|> to RS/6000.
If you are concerned about the bare functionality of the program,
the portability is pretty good in my opinion. The IBM version may
have something missing here and there, but the most important calls
However, as soon as you consider the performance arena, you may
find HUGE differences, in particular if the IBM models are of the
cheap 8-bit graphics variety. I found programs with reasonable
(say 2-3 frames per second) animation performance on an R3k Indigo
to drop by an order of magnitude on IBM 320s, to the point of
being barely usable. On a machine I used, the doublebuffer/swapbuffer
calls were "fake" (that is, the system was clearly using a single
buffer, ignoring the buffer selection calls made by the program).
Moreover, the integration of GL with the graphicsl user interface
(X, Motif, etc) is ridiculously bad on 8-bit IBMs. To see the colors
right on the GL window, all the colors on the rest of the screen
will be screwed up, sometimes resulting in illegible text.
Since porting itself is easy, I suggest you to get a loaner
machine for a week, try out your application and see if you
can live with it.
Of course, beating IBM RISCs in linear algebra calculations
is really tough, and RS/6000s here are all over the place
doing numerical work.