How to detect point on border as insided one.

[joonhwan]

For a given rect like

(-1, -1), (-1, 1), (1, 1), (1, -1)

the point (0,1) is not detected as inside of polygon.
How to detect it as insid of polygon?

[sromku]

The used algorithm here is Ray casting algorithm. If the test point is on the border of the polygon, this algorithm will deliver unpredictable results; i.e. the result may be “inside” or “outside”. In general it depends on ray creation with respect to the coordinate system.

From wiki:
Unfortunately, this method won't work if the point is on the edge of the polygon.

For example, in polygon (-1, -1), (-1, 1), (1, 1), (1, -1):

• This is outside: (0,1)
• This is inside: (-1,0)

[sromku]

You can see the new added test to showcase this issue. e5717ff