Few months ago I had an argue with a colleague of mine of whether we still will be using triangles in 10 (or 15) years. While I naturally opposed the idea, I feel there is something into it. So why are we using triangles, really?
Saving by calculating in VS and interpolating in PS
In fact, this is less and less is a viable argument. Nowadays characters already feature near-to-one-pixel triangles. We are actually LOOSING in this case: we get 4-fold PS cost and even rasterizer choking on some architectures. Besides, one modern architectures VS parameter cache is a bottleneck, so it is even less expensive to recompute a view position in a PS, than calculate it in VS and interpolate.
To match DCC tools
It is actually quite awkward to model your characters with triangles - a lot of artists use tools like ZBrush where they sculpt with spheres instead.
Once again - it is not really optimal when you triangles become very tiny. Besides, one might use bounding volumes for other representations to clip invisible surface.
I probably see how one can gain benefit for fx/billboards - but that's quite a specific case. Again, overdraw due to unused space on those is a big issue.
All in all, to support triangles we now have a lot of overhead - VS, sometimes tessellation, rasterization - while sometimes they are nearly equivalent to final pixels (and this trend seem to continue).
I am curious to hear your opinions and rationales guys. Will triangles live forever or will be replaced with something else (voxels? splats?) in a decade or two?