newest:
[ ] 0) go with pure d20
[ ] 1) use the inside-thresholds to determin the double-cover status
[ ] 3) that is all
old-new:
[ ] 0) See the old-new.
[ ] 1) instead of saying it's visible if _one_ of the vectors can get there
[ ] instead, only use them for cover calc
[ ] 2) use center to center for visicalc
(must read phb/dmg to determine if this is correct, cuz the mess in ~/www/marked/ isn't.)
Old-new LoS strategy:
[x] 1. Find all the possible closed {od} between C0 and C1 as vectors.
[x] 2. Find all 16 vectors from C0 corners to C1 corners.
[x] 3. See which of the corner vectors have a projections onto the solid {od} vectors.
[x] a. projections is false, we need the intersection
[x] b. see http://perlmonks.org/?node_id=253983
[x] 4. Conclusions
[x] a. If there's at least one corner vector without a projection, there's an LoS
[x] b. If any set of 4 C0 vectors have no projection, there's no cover
[x] Also, the LoS scores should be like so, to reflect increasing scores:
0 LOS_NO
1 LOS_COVER
2 LOS_IGNORABLE_COVER
3 LOS_YES