[Opengc-devel] performance addendum

[Damion S. <da...@op...>]

A few additional thoughts:

I just ran a frame rate test on my Mac laptop (1Ghz G4) and I'm seeing 
about 60-70 FPS in stand alone mode. Is the frame rate you're reporting 
in a test "stand-alone" mode (i.e. without being connected to a data 
source) or while connected to a sim? This is probably obvious, but all 
sim connections are limited by the server side frame rate. Regardless 
of how fast the client (OpenGC) is trying to render data, it only 
visually updates the gauges at the frame rate provided by the sim.

Unfortunately the initial frame rate test function does not work on 
Windows, and I'm not sure why; this is the easiest way to verify that 
you're getting adequate performance, since it runs through 200 
rendering frames by applying sin and cos functions to a few of the data 
source parameters. This test completes in approximately 3 seconds on my 
laptop, and I'd be extremely surprised if a modern Windows or Linux 
machine was slower.

One final note: the font rendering in OpenGC is surprisingly graphics 
intensive. Gauges which use a large number of fonts (the nav gauge is 
currently by far the worst offender) are slower than you'd probably 
expect. Font rendering could be greatly accelerated by caching bitmaps 
of each font rather than using vector rendering, but that would be at 
the expense of scale independence.

Cheers,
-Damion-


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Damion Shelton
Carnegie Mellon University, Robotics Institute
A408-o Newell Simon Hall
412.268.3866 (office)
412.818.8829 (cell)
412.268.6436 (fax)
http://www.cs.cmu.edu/~beowulf
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