The GL must perform a number of floating-point operations during
the course of its operation. We do not specify how floating-
point numbers are to be represented or how operations on them
are to be performed. We require simply that numbers' floating-
point parts contain enough bits and that their exponent fields
are large enough so that individual results of floating-point
operations are accurate to about 1 part in . The maximum
representable magnitude of a floating-point number used to
represent positional or normal coordinates must be at least ;
the maximum representable magnitude for colors or texture
coordinates must be at least . The maximum representable
magnitude for all other floating-point values must be at least .
for any non-infinite and non-NaN x. . x + 0 = 0 + x = x. .
(Occasionally further requirements will be specified.) Most
single-precision floating-point formats meet these requirements.
Any representable floating-point value is legal as input to a GL
command that requires floating-point data.