Ray casting is quite old technique, that was heavily used in the early days of game development in a lot of games to create illusion of 3D space. Most known example, and perhaps first widely successful game that used this technique, was Wolfenstein 3D, made by ID Software in 1992.
At the end of the Part 2 I’ve mentioned that quasiquoting was problematic in GRScheme, due to some of the internal representations and algorithms, but now it is not an issue (I hope). I’ve figured out correct way to maintain list invariant, splice one tree into another tree, and so on.
Good things happened since my previous post! I’ve finished rewriting of interpreter from recursive to iterative, which means that there will be no stack overflows when traversing deep trees. I’ve also simplified name binding and lookup systems, added support for arbitrary-sized integers, fractions, and 64-bit floating point numbers, but most importantly figured out tail call elimination and closures.
At the end of my previous post I’ve mentioned that I will write more about GRScheme - language that I’m working on. As of this moment I’m rewriting it to be more robust and to fix some design flaws that make it impossible to do such things as tail call elimination.