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Ingy döt Net 2013-04-10 23:57:08 -07:00
parent 47bf37c096
commit b83f433714
12433 changed files with 156208 additions and 123 deletions
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Task/Ray-casting-algorithm/J/ray-casting-algorithm-1.j Normal file
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NB.*crossPnP v point in closed polygon, crossing number
NB. bool=. points crossPnP polygon
crossPnP=: 4 : 0"2
'X Y'=. |:x
'x0 y0 x1 y1'=. |:2 ,/\^:(2={:@$@]) y
p1=. ((y0<:/Y)*. y1>/Y) +. (y0>/Y)*. y1<:/Y
p2=. (x0-/X) < (x0-x1) * (y0-/Y) % (y0 - y1)
2|+/ p1*.p2
)