From: K. Chugh (chugh++at++buffalo.edu)
Date: 05/09/2001 07:19:57
hi- i have a quick question about pfSync. does it just wait until the
other processes are finished for the given cycle, or does it also
somehow synchronize app, cull and draw to the monitor refresh rate. or
maybe the question is moot as i think about an example.
suppose your cull process takes 2 cycles. does pfSync just sit and wait
until An and Cn (app at time step n and cull at time step n) are
finished before starting Dn? if so, then how does Performer know to
draw the frame at time step n-1 during n? here's some ascii art:
cycles: |-----|-----|-----|-----|-----|
process: |-An|
|------Cn--|
|--Dn|
|Dn-2-|Dn-1-|Dn-1-|
now, i'm not using the time connotation in the traditional sense for
draw- Dn here doens't mean "the draw process at
time n", rather it means "Send the image created from cycle n to the
monitor. So, my question is, does pfSync simply
do the waiting part, or is it also responsible for telling the hardware
to draw the old frame buffer since the new one isn't
ready yet? not sure if my question is clear- what i'm asking basically
is- does pfSync perform 2 roles (sleeping AND telling
the hardware to draw the old framebuffer if the new one isn't ready) or
just one (sleeping until app and cull are done)?
thanks,
kevin
-- Kevin P. Chugh, Ph.D. Research Associate NYSCEDII New York State Center for Engineering Design and Industral Innovation http://www.nyscedii.buffalo.edu E-mail: chugh++at++buffalo.edu Postal Mail: 5 Norton Hall SUNY at Buffalo Amherst, NY 14260 Phone: (716) 645-2685 ext. 104 Fax: (716) 645-2684
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