EDIT : I would say the number of dimensions is roughly the number of coordinates you need to store the position of a sprit in the game. (In this sens, Wolf3D is not real 3D since the third dimension (up-down) is just "emulated".)
EDIT : I would say the number of dimensions is roughly the number of coordinates you need to store the position of a sprit in the game. (In this sens, Wolf3D is not real 3D since the third dimension (up-down) is just "emulated".)