javascript polygon intersection

Question

I have used the code in the following : http://www.amphibian.com/blogstuff/collision.html. in the html test file I have changed the the first triangle to

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Answer 1

Here is my not too complicated implementation of finding the intersection polygon of two polygons.

It works for convex and concave polygons, but not for complex (self-intersecting) polygons. Algorithm is fairly similar to the one presented in Margalit & Knott.

Its complexity is about 4*n1*n2, where n1 and n2 are numbers of vertices in polygons whose intersection is being calculated.

It is a single standalone .js file. A 'Polygon' is regarded any javascript array of 2D Points. A 'Point' is any javascript object with x and y numeric properties.

Implementing the Union functionality on top of existing one should not be a problem and I will do it probably soon.

Intersection of 2D polygons