sdlGetRelativeMouseState function
Retrieve the relative state of the mouse.
The current button state is returned as a button bitmask, which can be
tested using the SDL_BUTTON(X) macros (where X is generally 1 for the
left, 2 for middle, 3 for the right button), and x and y are set to the
mouse deltas since the last call to SDL_GetRelativeMouseState() or since
event initialization. You can pass NULL for either x or y.
\param x a pointer filled with the last recorded x coordinate of the mouse \param y a pointer filled with the last recorded y coordinate of the mouse \returns a 32-bit button bitmask of the relative button state.
\since This function is available since SDL 2.0.0.
\sa SDL_GetMouseState
extern DECLSPEC Uint32 SDLCALL SDL_GetRelativeMouseState(int *x, int *y)
Implementation
int sdlGetRelativeMouseState(Pointer<Int32> x, Pointer<Int32> y) {
  final sdlGetRelativeMouseStateLookupFunction = libSdl2.lookupFunction<
      Uint32 Function(Pointer<Int32> x, Pointer<Int32> y),
      int Function(
          Pointer<Int32> x, Pointer<Int32> y)>('SDL_GetRelativeMouseState');
  return sdlGetRelativeMouseStateLookupFunction(x, y);
}