union method

Implementation

math.Rectangle<double> union(math.Rectangle<double> b) {
  var aPointer = callocInt();
  var bPointer = b.callocInt();
  var resultPointer = ffi.calloc<SdlRect>();
  aPointer.union(bPointer, resultPointer);
  var result = resultPointer.create();
  ffi.calloc.free(aPointer);
  ffi.calloc.free(bPointer);
  ffi.calloc.free(resultPointer);
  return result;
}