pointInPolygon?()

Synopsis

Returns True if pt lies inside the polygon described by the point list poly.

Polygons are represented in a "lightweight" way by a list of points. The first three non-colinear points define the "plane" of the polygon, and even if the rest of the points do not lie in that plane, they will be projected onto that plane for all computations.

Syntax

pointInPolygon? ( pt As Point, _
                  poly As List ) As Boolean 

Example 1

Intent >pointInPolygon?(point(1,1,0), {Point(0,0,0), Point(2,0,0), Point(1,2,0)}) 
--> True 

Example 2

Intent >pointInPolygon?(point(2,1,0), {Point(0,0,0), Point(2,0,0), Point(1,2,0)}) 
--> False 

Example 3

Points lying ON the polygon boundary are ambiguous; they are sometimes reported as out, and sometimes in, depending on the particular numbers involved. True implies "inside or on", but False does not imply "not on" the boundary.

Intent >pointInPolygon?(point(1,0,0), {Point(0,0,0), Point(2,0,0), Point(1,2,0)}) 
--> True