Well, Floating Points are a Binary Number System used to represent decimal points... there are a number of different precision versions. There's a "Half" it's a 16 bit floating point that has up to ~3 decimal points, a "Float" has about ~7 decimal points, and used 32 bits, and there's a "Double" it's 64 bits and has ~16…
My bet is that this render engine uses float variables to represent colors, instead of 8 bit unsigned integers. Another possibility is that the depth buffer uses floats for better depth decisions. Perhaps it would help if you tell us more about this render engine. Is it a hardware render engine (GPU) or a software render…
Disclaimer: While I'm a programmer, I haven't written a "proper" render engine. Some of what I say is from my own experience, and therefore may be less than 100% true. With that said... First off, one thing that we should be clear on with half/float/doubles are approximations of decimal numbers. Computers don't really have…