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- > Hi John,
- >
- > I know I'll forget to tell you this if I don't write it right now....
- >
- > >(2) How is the receiving geometry for the shadow decided?
- >
- > I wrote about an LSS-test but actually performing a new VFC test (from the
- > light's view) is the same. In both cases, here's a trick to take advantage
- > of temporal coherence : test the world against a slightly larger than
- > necessary LSS or frustum. Keep the list of touched surfaces. Then next
- > frame, if the new volume is still contained within the previous one used
- for
- > the query, you can reuse the same list immediately. Actually it's a bit
- > similar to what you did in your sphere-tree, I think. Anyway, now the
- O(log
- > N) VFC is O(1) for some frames. It's not worth it for the "real" VFC, but
- > when you have N virtual frustum to test to drop N shadows, that's another
- > story.
- >
- > Two downsides:
- > - You need more ram to keep track of one list of meshes / shadow, but
- > usually it's not a lot.
- > - By using a larger volume for the query you possibly touch more
- > faces/surfaces, which will be rendered in the shadow pass. Usually it's
- not
- > a problem either since rendering is simply faster than geometric queries
- > those days. But of course, "your mileage may vary".
- >
- > Happy new year !
- >
- > Pierre
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