Absolute world position appears to be returning a constant per pass or fixating on a particular pixel’s world position when called from a post-process shader.
The shader utilizes this value to normalize a pixel position to a UV for line of site and fog of war masks. This worked quite well for UE4.24 and does not work in 4.25.x
As I move the character around the map the pixels are all tinted the same amount which indicates the value from the world position is the same for the whole pass. Also, the tint may change based on zoom level indicating that there may be a particular pixel location for which the absolute world position is calculated for the whole pass. Also, a minimap is still working that uses the fog of war mask and the line of site masks, so I know that those masks are constructing properly.
This does not work properly even when using the ES3.1 PIE emulator in 4.25.while it worked in the emulator in 4.24. It also worked directly on my LG V30 phone in 4.24.
Please let me know how I can further clarify my issue.
Edited to add that this may be related to UE-95120.
Edit 2 to add that a simplified project was submitted to create UE-98089 in the title.
Note: The shader works correctly in 4.25 when the standard play in editor for the desktop is run, but the shader fails when using the ES3.1 PIE. That does not seem clear in the issue synopsis.
I’m experiencing the same issue. In my case, the angle of the camera used for rendering is causing a fog of war to shift incorrectly in the screen’s (not world’s) y axis which similarly seems like a scene depth issue. If I set the camera to face directly down (no y axis movement, no scene depth change with camera panning as in an isometric perspective) then the fog of war renders correctly. I believe 95120 is the root cause but I’m not sure. Regardless, ABS WP seems to be borked in UE4 for mobile.
I did run a test recently in a preview build for 4.26 (and just did in Preview 7)and my test project works properly there, so whenever they release 4.26 the issue should be resolved. I won’t mark this as resolved until the official release of 4.26 comes out with the issue resolved.