Bill Storma (BILLS++at++p3.enzian.com)
Thu, 26 Sep 1996 18:41:03 EST
I am trying to understand the interaction between the app, cull, draw
times in a performer scene and how the screen resolution affects the
performance data. The machine I am using is a 3 pipe RE2, with 2
RM4's per pipe, running Performer 2.0 and IRIX 5.3. All testing is
being performed at root level.
As I understand the process from the SGI technical manuals, the cull
process determines what information is to be drawn into a channel
(pipe). The draw process then determines which polygons are affected
and then forwards this list to the graphics pipe. Therefore, if I
run an application at 1280x1024 vice 1024x768, with the same frustrum
looking at the same scene, the app and draw times should be the same
for both programs. The screen resolution should only come into play
inside the graphics pipe, where the tri's are scanned into pixels.
I have setup this exact scenario, and have noticed that the app and
draw times are longer for the higher resolution screen. If the
cull is forwarding the same frustrum data to the draw process and
the draw is processing the same number of polygons in the scene,
why are the process times higher with a higher resolution screen ?
Have I missed something in understanding how the system flows
information from one process to the next ? Can someone explain
exactly why the app and draw times are affected by the screen
resolution ?
Thanks
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Bill Storma Phone: 407-282-1884
Enzian Technology FAX: 407-282-3013
Orlando, Fl. 32817 e-mail: bills++at++p3.enzian.com
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