iOS - UMG widgets render errors on Metal with Scroll Box
We are currently running on UE 4.12.4 and we have an issue in one of our UMG Blueprint Screens where at randomly times when we scroll through our screen, certain widgets both inside the scroll box and outside of it, seem to get their rendering information broken for a single frame, causing them to be drawn over most of the screen in a distorted triangle.
For instance we have a button located in the top right of the screen and sometimes as we scroll, it suddenly get rendered from its anchor point, to near the opposite side of the screen, but as a triangle instead of its square size.
This behaviour does not occur every time we scroll, but when it does occur it seems to happen no matter how fast we are scrolling.
I was thinking it might be related to this bug https://answers.unrealengine.com/questions/413842/why-do-umg-widgets-flicker-on-ioswhy-are-pictures.html
This only occurs on Metal, as our project is setup not to run without metal. The widget itself consists of a few buttons that lie outside the scroll box, and then a scroll box which takes up about 66% of the screen, which contains a Uniform Grid Panel, which then contains a whole number of Vertical Boxes, each containing an image and text.
Like the other bug we do use the Canvas HUD system as well. I will try and get a video of the bug itself, as capturing it in a screenshot is next to impossible.
My first question is did the first bug in question get fixed and is it possible to try that? What else can I provide to help track this down, as it is a bug which is holding back our release and Apple really want it fixed.
Edit: I have only managed to repro this very very rarely in a new project. It could be that the lower the frame rate is, the more often it occurs. I created a HUD which just draws a texture, and then a umg widget with a scrollbox which contains about 30-40 image widgets in a 4 column uniform grid layout. With this I can get it to happen only once after launch, on the first scroll only. It doesn't happen 100%. I am going to do some more experimentation.
I was able to reproduce this issue on our end with the project provided. I have written up a report and I have submitted it to the developers for further consideration. I have also provided a link to the public tracker. Please feel free to visit the provided thread for future updates.
Make it a great day
answered Aug 03 '16 at 08:47 PM
Rudy Q ♦♦ STAFF
only because this thread is almost 3 months old now.
We experience flickering textures on 4.13.1 with an animated UMG. Our App has a blue background with 4 cloud png's, which are animated moving from left to right. On iOS with metal forward rendering activated the menu is flickering while the clouds are moving. If we deactivated the metal forward rendering it works without flickering.
As i said only to notice that others have this problem too.
Kind regards, Marcel / pyr0t0n
answered Oct 26 '16 at 06:10 AM
Same problem here! did you guy find a way to fix it? or minimize the glitching?
answered Apr 25 '17 at 10:54 PM
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