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From: jdb@reef.cis.ufl.edu (Brian K. W. Hook)
Newsgroups: rec.games.programmer,comp.os.msdos.programmer,comp.graphics
Subject: Need hard core help doing some 3d optimizations
Message-ID: <27979@uflorida.cis.ufl.EDU>
Date: 12 Apr 91 00:07:59 GMT
Sender: news@uflorida.cis.ufl.EDU
Organization: UF CIS Dept.
Lines: 36


I just ran Turbo Profiler on some code of mine, and it looks like roughly
90% of my CPU time is being shoved into one function.  Any help on the
optimizations would be really appreciated.

E-mail would be preferred, however posts are fine too.

void Calc3D ( int WorldX, int WorldY, int WorldZ,
	      int MX, int MY, int MZ,
	      int *DisplayX, int *DisplayY)
{
float xa, ya, za;

   WorldX=-WorldX;
   xa=_yawCosFactor*WorldX-_yawSinFactor*WorldZ;
   za=_yawSinFactor*WorldX+_yawCosFactor*WorldZ;
   WorldX=_rollCosFactor*xa+_rollSinFactor*WY;
   ya=_rollCosFactor*WorldY-_rollSinFactor*xa;
   WorldZ=_pitchCosFactor*za-_pitchSinFactor*ya;
   WorldY=_pitchSinFactor*za+_pitchCosFactor*ya;
   WorldX+=MX;
   WorldY+=MY;
   WorldZ+=MZ;
   *DisplayX=AngPerspFactor*WorldX/WorldZ;
   *DisplayY=AngPerspFactor*WorldY/WorldZ;
}

AngPerspFactor is a float, as are the assorted factors.  I have already
used a COS and SIN lookup table in another part of the module to expedite
things, but this is really slowing things down considerably.

Any help is appreciated.

Brian