When running on iPad Pro 11’ inch on simulator (I don’t own the device) game is letterboxed in old iPad (3:2) aspect ratio, namely 1024x768 (in points). Usually this is caused by missing launch image, but there aren’t any new to add in assets editor in Xcode. I even tried an empty project and couldn’t do it. It only worked fine If I used LaunchScreen made in storyboard.
You aren’t getting the right size in the simulator? Is there anything out of the ordinary in your AppDelegate? I also think you can do this without storyboards using launch images.
I can try it for you. I got the iPad Pro 11.
I have an iPad Pro 2 12.9 if you ever need anything.
This isn’t really problem cocos2d-x itself, I think, but from the other hand everyone will probably face this, unless it’s just a simulator issue, which I doubt is.
Can you run an empty iOS project (Single Page) with added launch images? (be sure to remove LaunchScreen.storyboard) and print the size of it?