How can I determine whether a 2D Point is within a Polygon?

Question

I\'m trying to create a fast 2D point inside polygon algorithm, for use in hit-testing (e.g. Polygon.contains(p:Point)). Suggestions for effective tech

Answer 1

Compute the oriented sum of angles between the point p and each of the polygon apices. If the total oriented angle is 360 degrees, the point is inside. If the total is 0, the point is outside.

I like this method better because it is more robust and less dependent on numerical precision.

Methods that compute evenness of number of intersections are limited because you can 'hit' an apex during the computation of the number of intersections.

EDIT: By The Way, this method works with concave and convex polygons.

EDIT: I recently found a whole Wikipedia article on the topic.