[cyberax]

It doesn't. Doom uses BSP to precisely determine which columns of textures it needs to render.

It's faster than raycasting, so this was even used in Wolf3D port to GBA.

[eumenides1]

Yeah is fast and cheap because the BSP tree is created after the level mapped out. It's also why "Will it run DOOM?!" is a thing.

For further reading: https://en.wikipedia.org/wiki/Doom_engine#Binary_space_parti... https://en.wikipedia.org/wiki/Binary_space_partitioning#Appl...