gnu@l5.uucp (John Gilmore) (12/08/85)
One application that rarely requires double precision is graphics. All the math required to scale and render graphical/geometric objects can be done in single precision without a problem, since the resolution of the final output is going to be like 10 bits (1024 bit wide screen). Even for a laser printer, add 3 or 4 bits. You're still well within single precision. I think Lucasfilm was trying movies at 4096 or 8192 points, still fine. When Sun recompiled its SunCore libraries to use single precision internally (including in function arguments), using unsupported compiler options, it sped up a *lot*, and gave the same results on the screen. [For calculating the math that *generates* the figures you are going to display, you might need doubles. But not to go from "world coordinates" to "screen coordinates" and render them on the screen.]