function rad2degf( x ) {
	return float64ToFloat32( float64ToFloat32( x ) * CONST_180_DIV_PI );
}
Converts an angle from radians to degrees (single-precision).

@param {number} x - angle in radians
@returns {number} angle in degrees

@example
var d = rad2degf( 3.141592653589793 / 2.0 );
// returns 90.0

@example
var d = rad2degf( -3.141592653589793 / 4.0 );
// returns -45.0

@example
var d = rad2degf( NaN );
// returns NaN