[codeflo]

Exactly, straight lines on a texture should obey perspective (think rows of bricks on a wall). I think this wasn't as widely understood back then, but notably, id software already got it right a few years earlier in the original Wolfenstein.

Great link. The artifacts are especially apparent when the walls are near the camera, for example at this timestamp: https://www.youtube.com/watch?v=VutzIK3DqZE&t=398s And note that here, the seemingly flat walls are already heavily subdivided into smaller polygons to lessen the impact of the problem. (Why they wouldn't then make use of those additional polygons to include more geometry details for free is beyond me, however.)

[AnIdiotOnTheNet]

The way you've worded this makes it sound as though programmers of the era were somehow unaware of perspective mapping, which I can assure you is not the case at all. Affine texturing was a tradeoff of performance, nothing more.

Wolfenstein's correct texture mapping is due to it using raycasting in a 2D plane and rendering scaled vertical strips of texture, which just happens to be perspective correct because you only ever have surfaces at 90deg angles in the vertical.

As to why those extra triangles weren't used for detailing, it's likely because that would take up extra level data. Tessellation of an existing triangle into smaller triangles doesn't.

[rasz]

From the horses mouths (minus Abrash/Carmack) 'HandmadeCon 2016 - History of Software Texture Mapping in Games' https://www.youtube.com/watch?v=xn76r0JxqNM

Wolfenstein and Doom are 100% correct because Carmack 'cheated' by deciding to never look down/up or draw slopes :-) so whole game is drawn with 'lines of constant Z'. Or as they put it

Chris Hecker (Microsoft/Maxis/etc): that's a classic Carmack thing which is like Fuck those general problems, Im gonna solve this other problem perfectly

John Miles (ORIGIN/Miles Design/etc): Its all about not doing the math, we were still at a point in time when you won by not doing the math