I believe it was mentioned in class that the pixels at the infinite edges should be gray.

However, in practice, do we ever need to deal with the infinite edge situations? I remember there's a limit to determine how far do we want to render these triangles, and outside that limit we just throw them away. In that case the color will just be black.

@ethanyanjiali, good question. If we think about a game like flying simulator, I wonder how they express the far horizon line with the far frustum plane. Assuming the horizon line is drawn by triangles like here, the far plane should be pretty far out to draw the horizon, and this jaggies might show up I guess.

Can someone explain exactly how this phenomenon occurs again? The other sampling examples make sense to me, but this one doesn't quite.