Steve Baker (sbaker++at++link.com)
Thu, 11 Jun 1998 05:47:26 -0500 (CDT)
> THE PROBLEM:
>
> Everything is almost de same,
> BUT,
> in Perfly the drawing performance for an object depends on how much
> portion of the screen this objects is taken.
> While in ours the performance still the same.
>
> THE TEST CASE:
>
> The test case is simple you only have to run:
> perfly cow.obj
> and change FOV to a big field of view,
> The performance will change: from 4.2 to 2.5 ms.
>
> THE QUESTION:
>
> The question is, WHERE, is defined in perfly such behavior.
There are two possibilities that I can think of:
1) You are probably pixel-fill limited. Increasing the
screen area covered by the object increases the number
of pixels - decreasing the speed *if* that is the
limiting factor on performance.
2) (Long-shot) Performer can automagically adjust the
level of detail of objects depending on field of
view and screen resolution. It's *just* possible
that the level of detail has been cranked up when
the FOV is resized such that a bunch more polygons
are being drawn.
I very much doubt that it's (2).
So, why does Perfly do this and not your application?
Well, perhaps your application chooses a different (and
perhaps faster) pixel format - such that even with the
larger screen, you are still not fill limited.
What are the timings from your application in the
wide and narrow FOV cases?
Steve Baker (817)619-8776 (Vox/Vox-Mail)
Raytheon Systems Inc. (817)619-4028 (Fax)
Work: SBaker++at++link.com http://www.hti.com
Home: SJBaker1++at++airmail.net http://web2.airmail.net/sjbaker1
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