Port of Grant Schindler's concise "Ray Tracing and Photon Mapping" to JS for educational purposes. Ported almost line by line from Processing to JS, in order to preserve the original intent with the source. Complemented with a small gfx library to port Processings's drawing capabilitities to HTML5 Canvas.
https://erlandranvinge.github.io/photons/
Use the mouse to move the spheres and/or light source.