Here’s my Java port, dodging the error condition when the determinant disappears with a very elegant IllegalArgumentException, my approach to coping with the “points are two far apart” or “points lie on a line” conditions. Also, this computes the radius (and copes with exceptional conditions) which your intersecting-slopes approach will not do. public class CircleThree … Read more
The ordering if the segments change only at intersection points, and only for the segments that do intersect at the given point. This can be implemented by removing the intersecting segments and inserting them again. The ordering function is by y coordinate, and when ys are equal, by the slope. The intersecting segments will then … Read more
Edit As of 2013, most links below are not functional anymore. However, I’ve found the cited paper, algorithm included, still available at this (very slow) server. Here you can find a project dealing exactly with your issues. Although it works primarily with an area “filled” by points, you can set it to work with a … Read more
Have a look at Wykobi. It is a templated library and you can template the dimension as 2D. It is distributed under the MIT License.
Two circles intersect if, and only if, the distance between their centers is between the sum and the difference of their radii. Given two circles (x0, y0, R0) and (x1, y1, R1), the formula is as follows: ABS(R0 – R1) <= SQRT((x0 – x1)^2 + (y0 – y1)^2) <= (R0 + R1) Squaring both sides … Read more
Update in July 2016: Thanks to a number of volunteers (especially Nikolai Nowaczyk and I), there is now far more robust / correct code for handling Voronoi diagrams on the surface of a sphere in Python. This is officially available as scipy.spatial.SphericalVoronoi from version 0.18 of scipy onwards. There’s a working example of usage and … Read more
I solved the equations for you: k = ((y2-y1) * (x3-x1) – (x2-x1) * (y3-y1)) / ((y2-y1)^2 + (x2-x1)^2) x4 = x3 – k * (y2-y1) y4 = y3 + k * (x2-x1) Where ^2 means squared
One very simple option would be to use a standard algorithm for checking whether two line segments intersect to check whether the line segments intersects any of the four line segments that make up the corners of the box. It’s computationally very efficient to check if two line segments intersect, so I would expect that … Read more
I took @MitchWheat and @templatetypedef’s idea of sampling points on a circle and took it a bit farther. In my application I need to be able to control how weird the polygons are, ie start with regular polygons and as I crank up the parameters they get increasingly chaotic. The basic idea is as stated … Read more
You may organize your points in an Octree. Then you only need to search a small subset. A Octree is a fairly simple data structure you can implement yourself (which would be a valuable learning experience), or you may find some helpful libraries to get you going.