Native bindings to the GLX_EXT_fbconfig_packed_float extension.

This extension adds a new 3-component floating-point texture format that fits within a single 32-bit word. This format stores 5 bits of biased exponent per component in the same manner as 16-bit floating-point formats, but rather than 10 mantissa bits, the red, green, and blue components have 6, 6, and 5 bits respectively. Each mantissa is assumed to have an implied leading one except in the denorm exponent case. There is no sign bit so only non-negative values can be represented. Positive infinity, positive denorms, and positive NaN values are representable. The value of the fourth component returned by a texture fetch is always 1.0.

This extension also provides support for rendering into an unsigned floating-point rendering format with the assumption that the texture format described above could also be advertised as an unsigned floating-point format for rendering.

The extension also provides a pixel external format for specifying packed float values directly.

Requires GLX 1.3.