Ambient occlusion darkens image depending on the value of camera FOV

[CobaltUDK]

I have a problem with the ambient occlusion, which darkens the image but only with certain values in the camera FOV.

In the video I show how changing the FOV with some values will darken the image, also using some AO presets including SSAO.

The problem is that the game can change the FOV depending on the weapon in use, and in the player sprints, so that a flicker occurs during the interpolation, when those FOV values darken the image.

This is the AO configuration from the preset "Contrast 2", show in the video.



Is there any way to fix this problem?

[CobaltUDK]

I forgot to say that the more far you are from the center of the map (10x10 km), more noticeable is the problem, and the FOV values which darkens or lightens, are different.

[Nathaniel3W]

Wow. That's a really strange bug. I would be surprised if there were anything you could do to fix this. If you're just using UDK's out-of-the-box ambient occlusion, then the problem is surely buried somewhere in the native UDK code. I'm guessing the best you could do is a workaround: find ambient occlusion settings that don't flip out when the FOV changes, or don't use ambient occlusion. Sorry I don't have more for you.

[CobaltUDK]

Umm... "safe" values for FOV are not always the same. With a resolution of 1650x1080 are different than using 1280x720. And on the north side of the map are different than on the south side.

In the center of the map are not appreciable, but when goes far from center, the dark are bigger.

So the only thing I can do of is to use low values for AO and enable an option for the player to change the FOV to find safe values.

[CobaltUDK]

I have found some safe values for common screens resolutions:

1280x720 = FOV 59.1
1280x768 = FOV 59.9
1280x800 = FOV 60.1
1680x1050 = FOV 60.1

In the editor window, 59.5 (window resolution is 1608x932)

also works in the first person view with an increment of 30 in the FOV (around 90).

I have tested in different locations on the map and works fine in all, but the map is big and I need to test more locations.
And I need to test it in others machines and in 1920x1080 res.

The only problem is the interpolation when changing the FOV, in sprints and when aiming. The initial and final FOV works fine, but in the middle there are some flickering when the FOV takes some values that darken the image. I did a list of numbers for bad FOVs, to no use them during the interpolation. Works well, but I need to do a list for each screen resolution.

Perhaps there are a relation between aspect ratio and fov, any idea how to calculate?