Simon Bennett (simonb++at++wormald.com.au)
Mon, 6 Nov 1995 11:45:41 +1100 (EST)
> I have an application in which I turn on a big bunch of pfLightPoints
> (the usual runway lights, etc.). These points render as expected on
> a PowerIndigo 2 Extreme, and a few Onyces I have tried it on. These
> Onyces always have more than 1 RM4. The application messes up in a
> big way on the single-RM4 Onyx on which I need to run (adding an RM4
> makes everything work great again, so I think I have narrowed this
> problem down to the single RM4).
> Instead of light points I get huge rectangles (spanning some 80%
> of the visual field) and performance goes to hell (0.5 frames per
> second appx. compared to 30 fps even on the extreme).
Is this Performer 2.0 or 1.2 application?
I know why your lightpoints have become square, but if you're a Performer 1.2
application I'm not exactly sure why they've become so large (unless of course
you're playing with pntsize() or pntsizef() somewhere else in your
application).
Performer uses a "magic" backdoor method for drawing fast-high-quality round
lightpoints while multisampling - which, if you look carefully, directly
contradicts what's written in the "Graphics Library Programming Guide Volume II
Section 15.5.3 pg: 15.43" - but I digress, they're round, they're excellent and
they work well, the only problem I have with them is that they don't get any
bigger than ~ 3.5 pixels.
> My question is 2-fold:
> 1) what do pfLightPoints use the RM4 for?
Drawing the magic multisampled lightpoints! If you're running at 1280x1024
with 1 RM you can no longer multi-sample. Which means you can't draw "magic"
lightpoints anymore - which means they come out square! You can disable this
magic by calling glcompat(1011,0) which should give similar results on 2 amd 4
RM machines to the 1RM machine...
> 2) is there any way I can maybe give up some rendering beauty for
> the light points and run my app anyway with 1 RM4? (the quality
> of the light points is much better on the stuffed Onyces, but the
> quality of the Extreme light points is perfectly adequate for my
> purposes).
There are a couple of things you can try.
1) Drop the VOF res to 960x680 (or lower) and you again be able to
multi-sample. Lightpoints should then return to normal. An added bonus is
that you get your full screen anti-aliasing back! ... and if you were fill
limited, your application will go faster!!
2) The only reason I can think that your lightpoints are sooooo big (remember
that the "magic" points don't get any bigger than ~ 3.5 pixels) is that
you've set their size somehow either throught a pntsize() or pntsizef() call
or directly on the node (assuming Performer 1.2) using pfLPointSize(). Try
setting them all to 2.0 pixels and see how it looks (they'll still be square
thou...).
3) If you still want round lightpoints and can't drop your VOF look into
pntsmooth().
+----------------------------------------------------------------------------+
Simon Bennett simonb++at++wormald.com.au
Wormald Technology Advanced Systems Engineering Ph: +61 2 9981 0611 (x512)
Meeting - an event where you take minutes and waste hours.
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