Getting edge equations done right / consistently is certainly important. That's not actually a floating point vs fixed point argument though. There's always go

Getting edge equations done right / consistently is certainly important. That's not actually a floating point vs fixed point argument though. There's always going to be rounding and clamping. With fixed point code or fixed-function hardware it's obvious and explicit. You can do all the same range reduction work in fp32. Modern rasterizers have been outputting "24-bit Z" aka the equivalent of [-0.5, 0.5] in fp32 forever. Said another way: fp32 hardware perfectly implements a signed 23-bit fixed point :).