Comment by Jarb

I'm simplifying, but Wolfenstein's technique is called Ray Casting, which calculated the player's view by drawing lines from the player's "eye" to objects and walls in the field of view and use that information to calculate distance and perspective. Ray tracing has been around for forever, but was too resource-intensive to use in real-time until recently. It calculates the path a pixel/light source takes, allowing for realistic lighting (including bouncing off of surfaces) and perfect reflections.