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Floating-Point Computation
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 Any representable floating-point value is legal as input to a GL command that requires floating-point data. The result of providing a value that is not a floating-point number to such a command is unspecified, but must not lead to GL interruption or termination. In IEEE arithmetic, for example, providing a negative zero or a denormalized number to a GL command yields predictable results, while providing a NaN or an infinity yields unspecified results. Some calculations require division. In such cases (including implied divisions required by vector normalizations), a division by zero produces an unspecified result but must not lead to GL interruption or termination.
David Blythe Sat Mar 29 02:23:21 PST 1997
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