Using GLKMath from GLKit in Swift

Question

So I\'m using a book called iOS Games by tutorials from Ray Wenderlich and trying to utilize some of the objective-C code found there to make the accelerometer control of a

Answer 1

Swift has added union support in version 1.2. The fields in imported unions are read-only, even if declared with var, but can be passed to and from C functions as necessary.

The release notes for Swift 1.2 imply that the fields may not be accessible at all, but they are still readable for at least the GLKit types:

Swift can now partially import C aggregates containing unions, bitfields, SIMD vector types, and other C language features that are not natively supported in Swift. The unsupported fields will not be accessible from Swift, but C and Objective-C APIs that have arguments and return values of these types can be used in Swift. This includes the Foundation NSDecimal type and the GLKit GLKVector and GLKMatrix types, among others.