Re: optimization of movable parts

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Jim Helman (jimh++at++surreal)
Thu, 03 Nov 94 18:24:43 -0800


> what method to generate the cosines and sines?

Use pfSinCos; it's fast. According to the current author
dog/flight, it beats some table lookup code.

> Also, I could use pfMakeRotMat if I know the axis of rotation.

pfMakeRotMat is not as fast as it should be for special axis cases
(better in 2.0). Better to use pfMakeEulerMat where possible,
since it does well with the special cases.

> BTW, am I right in remembering the degree fidelity in GL and thus Performer
> is 1/10 of a degree (thus the .05 for smooth transitions between tenths
> of degrees)?

Hmmm... just because the old integer rotate(3G) still exists?

The gfx pipe's accuracy is effectively that of the single
precision float that is used in the load/multmatrix(3G) or
rot(3G) and should be better than 1/1000 degree. pfSinCos has
similar accuracy.

rgds,

-jim helman

jimh++at++surreal.asd.sgi.com
415/390-1151


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