I ve done plenty of test and some reading of the BitMapText code. If the string is big enough it will show up.
From my point of view something is wrong with the boundary. I can’t tell what but it seem to move when you move a viewport. Even if the view port is set to be (0.0f, 0.3f, 0.3f, 0.7f). I think you should try by your self if you have the time.
I think it would be the CullHint base off the camera location. I think the formula is base on the Main viewport and then if you generate a viewport base off a camera with a smaller view it would automatically cull anything considered outside in the second viewport.
If you want i can try to find the problem, but i think it s in the core, the reason my chat background is not cull would be it s in a certain region it can be seen. If i move the view port a little more higher it will cull everything.<<<<(tested and it does cull my chat if i set the viewport location > 1f to 2f)
And if you wonder why i am not setting the viewport with a camera the same size as my Main viewport, The reason is simple, it would be way to complicated to calculate the size of each picture and to make a ratio out of it base on a 1920x1080 view or anything else. Since many people have many different ratio it would be a pain to fit the viewport.
Still i think it was not working either. I can test this again just to make sure but i think the text was cull again <<< (tested the exact same bug the text is cull) so something is wrong with the (cullhint).
I m sorry if it s unreadable, I have a hard time to explain complex stuff in English since it s my second language. I apologize for any rudeness of my part, I only want to help so the engine work as it should.
The same problem seem to apply to anything inside the viewport. Even if the viewport is visible in the screen, if it reach a location higher then the double of the camera size of the viewport(same viewport) it will cull anything inside.
(this text was written in many part.)
Thank you for your time. (if anyone know about this lets me know)
PS: i though it was the bitmaptext but i think its the thing that cull the stuff.