One omission from that book that would have been nice to have been included is an explanation of how the 3D scenes are drawn in those games. In one of the quoted passages, Carmack states that it is something other than the raycasting used in Wolf3D, with the added disadvantage of not being correct in every case.
From personal observation, the perspective looks strange in those games (no consistent single vanishing point). However, maybe this can be fixed by tweaking a few variables. Supposedly Catacomb and Hovertank have much higher frame rates that Wolf3D on old computers.
(another omission is that it doesn't completely explain the theory behind linear feedback shift registers, necessitating further research on the part of the reader to understand them).
Just to clarify: the question regarding LFSRs is not in how to implement them (which I think was described adequately), but how to determine what their orbit is upon repeated application, and how to choose one that generates a complete permutation when this is done. And furthermore, how was the particular one used in Wolf3D found. Was 100% Psyched to hear how the screen could be efficiently cleared pixel-by-pixel seemingly at random, but ultimately was left in the dark on this specific question.
>Hovertank and Catacomb
One omission from that book that would have been nice to have been included is an explanation of how the 3D scenes are drawn in those games. In one of the quoted passages, Carmack states that it is something other than the raycasting used in Wolf3D, with the added disadvantage of not being correct in every case.
From personal observation, the perspective looks strange in those games (no consistent single vanishing point). However, maybe this can be fixed by tweaking a few variables. Supposedly Catacomb and Hovertank have much higher frame rates that Wolf3D on old computers.
(another omission is that it doesn't completely explain the theory behind linear feedback shift registers, necessitating further research on the part of the reader to understand them).