[comp.graphics] region filling a quadtree?

gleicher@APPLE.COM (Michael Gleicher) (06/21/91)

I was hoping someone could help me with a reference or some other ideas on an
algorithm for the following problem:

I have a quadtree with some squares "colored". 

What I need is to take this tree and an uncolored square, and get the
region which can be reached from this square without going through a
colored square. Sortof a floodfill, but on a quadtree instead of a
grid. 

I would greatly appreciate any references or algorithm ideas. Do
either of Samet's books (??? of Spatial Data Structures) have anything
like this? (These books are on my shelf at school, which doesn't help
me this summer)

In case you're curious: the quadtree represents the u,v plane of a
parametric surface, the colored squares are a trimming curve (found by
subdivision) and I need to region fill so I can chop up objects (eg:
cut things away).

Thanks,
	Mike

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