Also compare this: https://lodev.org/cgtutor/raycasting.html https://lodev.org/cgtutor/raycasting.html It's a bit old but also explains a lot of the underlying

Also compare this: https://lodev.org/cgtutor/raycasting.html https://lodev.org/cgtutor/raycasting.html It's a bit old but also explains a lot of the underlying logic. And it's not written in javascript so it may be more readable to some.