Interestingly, even the depth buffer is wrong if you interpolate Z linearly, but it's such a subtle effect, it's almost imperceptible. IIRC games back then als

Interestingly, even the depth buffer is wrong if you interpolate Z linearly, but it's such a subtle effect, it's almost imperceptible. IIRC games back then also used to do perspective-correct interpolation every 8 or 16 pixels, and linearly in between, which is a good compromise (you always have to interpolate U and V, what they wanted to avoid was the division, which is more expensive). I've written about this here, https://gabrielgambetta.com/computer-graphics-from-scratch/12-hidden-surface-removal.html#why-1z-instead-of-z https://gabrielgambetta.com/computer-graphics-from-scratch/1..., including some detailed examples of how the math works. Very fun topic :)