feedback() limitations?

[DanKarron at UCBVAX.BERKELEY.EDU]

My understanding from TFM and sgi is that they don't want people using the
feedback buffer. I had major problems migrating from 2400, 3000 class machines
to the risc machine because I used the geometry pipeline to overcome
cpu bottlenecks. I would now use another cpu thread before I would use
the pipeline. Besides, you have to wait for the answer from the
pipeline, and that ruins any parallelism you might get from the pipeline.

If you are doing picking and pruning, what we need is a "parallel non screen"
geometry pipeline. What I mean is a process running on another threaded cpu
to do the same geometry operations on your data stream (matrix xformation and
picking/pruning). The output would not go to the video processor, but would
return values about visibility. This would be really nice for robotics app's
where you need to know if there is a line of sight between two points
on arbitrary shapes in arbitrary orientations. Eventually, we will need
one cpu for each point to scan w/r/t the rest of the domain of points.

Cheers!

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