SSAO doesn't work when the camera is in orthogonal mode

[websterek]

Godot version:
3.X.X branch

OS/device including version:
Windows, but probably it's global issue

Issue description:
Ssao is not working with camera in orthogonal mode

Steps to reproduce:
Add WorldEnviroment with Ssao turned on and switch camera between projection modes

Screens:

[Calinou]

I can confirm this on Godot 3.2.2beta4 as well as ec1bf96 (Vulkan).

[foxid-gamedev]

Still an issue in the current 4.2 version

SSAO seams to be disabled / not working when switching to orthographic camera. That's sad. Does this have a technical background? Any limitation of world environments?

[Calinou]

Please upload a minimal reproduction project¹ to make this easier to troubleshoot.

Footnotes

1. A small Godot project which reproduces the issue, with no unnecessary files included. Be sure to not include the .godot folder in the archive (but keep project.godot).
   
   Drag and drop a ZIP archive to upload it. Do not select another field until the project is done uploading.
   
   Note for C# users: If your issue is not Mono-specific, please upload a minimal reproduction project written in GDScript or VisualScript. This will make it easier for contributors to reproduce the issue locally as not everyone has a Mono setup available. ↩

[Flarkk]

From what I've seen while testing PR #99755 for non-regression, SSAO seems to work as expected with orthogonal cameras in 4.x (see the screenshots and the test project).

Unless the issue happens under specific conditions and a MRP is provided, I suggest to refocus this issue to branch 3.x (if the issue is reproduced - I couldn't test).

[tetrapod00]

From quick testing in 4.3, SSAO does indeed work with an orthogonal camera, in Forward+. However, when the editor viewport camera is set to Orthogonal, the SSAO doesn't seem to show up by default.

The relevant factor might might be the camera's distance from the objects - from brief testing with an ingame camera, the amount of SSAO in orthogonal mode still reacts to how far the camera is from objects.

I think it is reasonable to try to track the 4.x issue separately, since the 4.x issue is certainly not "confirmed" any more, and it may not have the same root cause as the 3.x version.