This web content explains the algorithms behind collisions in games and user interfaces. It covers collisions between points, circles, rectangles, lines, polygons, and triangles. The examples are designed to be easily understood and there is minimal math involved. The content includes interactive examples built using processing.js and the source code for all examples and the book itself can be found on GitHub. The author notes that the examples may not work well on mobile devices and recommends using a computer instead. The content does not cover three-dimensional space or ellipses, but welcomes suggestions and contributions from readers. Any issues with the code, explanations, or typos should be reported on the GitHub repository. The navigation instructions are provided at the end of the content to move to the next chapter or back to the table of contents.
https://www.jeffreythompson.org/collision-detection/index.php