Since 4.22 we have implemented multi-viewport functionality within single app instance. However, specifying a unique camera per viewport and specifying its offset for proper stereoscopic configuration is only going to be available in 4.23.
Since 4.22 we have implemented multi-viewport functionality within single app instance. However, specifying a unique camera per viewport and specifying its offset for proper stereoscopic configuration is only going to be available in 4.23.