Mesh-tracing
I roughly implemented the mesh-tracing method that calculates the acoustic impulse responses of the room, which is presented in the paper Real-time Acoustics Simulation using Mesh-Tracing, Schiettecatte et al. 2003, in 2D space.
Here's the C++ source code for my mesh-tracing implementation. It should, I believe, contain bugs and errors and my misinterpretations.