Comment by ralferoo

I'm not sure I understand the problem you're having.

Obviously, if you have translucent, then you need to be doing those objects last, but if you're using the half line method, then two triangles that share an edge will follow the same edge exactly if you're using fixed point math (and doing it properly, I guess!) A pixel will either be in one or the other, not both.

The only issue would be if you're wanted to do MSAA, then yes it gets more complicated, but I'd say it's conceptually simpler to have a 2x resolution and then downsample later. I didn't attempt to tackle MSAA, but one optimisation would be to write 2x2 from a single calculated pixel and but do the half line equation at the finer resolution to determine which of the 2x2 pixels receive the contribution. And then after you render everything, do a 2x2 downsample on the final image.