[sfn42]

The original doom wasn't even proper 3d. It was a sort of 2,5d.

And sure you can do 3d rendering on modern CPUs. It's just better on GPUs. Like thousands of times better.

[alxmdev]

Someone always points out how Doom wasn't "real 3D" like it's some sort of gotcha. Games are smoke and mirrors, it's all a 2D grid of pixels at the end.

[sfn42]

Well yeah, a 2d grid of pixels also describes the result of rendering a 2d game. It matters how you arrive at that 2d grid of pixels, that's why you can't render Crysis on just a CPU. At least not in real time.

[Flamingoat]

The main limitation of the engine is you couldn't have room over room. There is definitely three dimensions when playing the game.