I’m trying to render a 2D image something like this:
…where an arbitrary shape has its border illuminated by a line in a relatively physically accurate way, i.e. with less illumination reaching the shape at points that the line is farther away from. I’m generally familiar with some of the existing approximations in 3D, e.g. linearly transformed cosines; as far as I can tell, though, there’s no literature on ways to do the same in 2D. It seems like there might even be a way to solve the actual integral analytically, but I’m not sure where to start. Any ideas?