Jude Anthony (jude++at++p3.enzian.com)
Fri, 10 Jan 1997 10:12:41 EST
Our TTPRR requires that we render, at 30Hz, a scene with:
150 tris, 101x101
1350 tris, 51x51
1500 tris, 10x10
We're not getting 30Hz at 1024x768.
When we bought the Onyx/RE2, we had 1 RM4. The salesman looked at our
screen size, projected depth complexity, and iteration rate, and told us we'd
need to upgrade to 2 RM4s to get the job done.
Our average depth complexity for the scene is somewhere between 3.31 and
3.33. My manager tells me the threshold was around 3.1.
The rated pixel fill rate for 2 RM4s is 110Mpix/sec. Our scene contains:
150 x 101 x 101 / 2 = 765,075
+ 1350 x 51 x 51 / 2 = 1,755,675
+ 1500 x 10 x 10 / 2 = 75,000
--------------------------------
2,595,750 pixels.
At 30Hz, that makes 2,595,750 * 30 = 77,872,500pix/sec.
77,872,500pix/sec is below the rated pixel fill rate. It's even below the
90Mpix/sec conservative fill rate on the salesman's sheets.
The problem is to increase the iteration rate to 30Hz. My manager has me
shifting polygons around, trying to decrease the depth complexity. I'm
making the attempt, but my experience with renderers tells me this is not
going to work; the depth complexity is calculated, and is only useful for
culling and pixel fill estimates. Is this the case, or am I working with a
different beast?
The current thinking is that there is some Performer bottleneck. Any ideas
on how to bring the iteration rate up?
The scene is composed of strips of polygons. Perfly shows me that all the
strips are meshed, all at more than 14 tris/strip. The strips are offset in
such a way that no more than 6 are ever layered. Each strip is a different
color than the one above it, so as to facilitate counting (6 colors total).
There are no textures. The whole thing eventually runs as a vega app.
Any help would be greatly appreciated.
Thanks,
Jude Anthony
jude++at++p3.enzian.com
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