case UIDeviceOrientation.PortraitUpsideDown:
trans.Rotate(FloatMath.PI);
break;
case UIDeviceOrientation.LandscapeLeft:
landscape = true;
trans.Rotate(FloatMath.PI / 2);
break;
case UIDeviceOrientation.LandscapeRight:
landscape = true;
trans.Rotate(-FloatMath.PI / 2);
break;