There are rational geometry libraries which are precise (edit: I mean that answers are "exact"): http://www.algorithmic-solutions.info/leda_guide/Geometry.html

There are rational geometry libraries which are precise (edit: I mean that answers are "exact"): http://www.algorithmic-solutions.info/leda_guide/Geometry.html http://www.algorithmic-solutions.info/leda_guide/Geometry.ht... Quilez's concern with how the number fits into 32 or 64 bits may be necessary for performance, but using arbitrary precision numerators and denominators is the only way to achieve the robustness he was initially pursuing.