Editing Ray casting (section)

===''Wolfenstein 3D''===

The video game ''[[Wolfenstein 3D]]'' was built from a square based grid of uniform height walls meeting solid-colored floors and ceilings. In order to draw the world, a single ray was traced for every column of screen [[pixel]]s and a vertical slice of wall [[Texture mapping|texture]] was selected and scaled according to where in the world the ray hits a wall and how far it travels before doing so.<ref>[http://www.permadi.com/tutorial/raycast/ Wolfenstein-style ray casting tutorial] by F. Permadi</ref>

The purpose of the grid based levels was twofold — ray-wall collisions can be found more quickly since the potential hits become more predictable and memory overhead is reduced. However, encoding wide-open areas takes extra space.