CMCL-1436: Integration with the new Cameras Overlay in 23.2

[thomas-tu]

Purpose of this PR

Jira ticket: CST-1310

This PR adds allows the new Cameras Overlay to take control of Cinemachine Cameras, which is an Editor only feature. In summary:

• Cinemachine Cameras are visible and selectable from the Cameras Overlay.
• Selected Cinemachine Camera will have a preview shown on the Overlay.
• Users can look through the selected Cinemachine Camera within the SceneView.

This implementation doesn't take constraints into account.

Minimal supported version: Unity 23.2.0a14.

Testing status

[Explanation of what’s tested, how tested and existing or new automation tests. Can include manual testing by self and/or QA. Specify test plans. Rarely acceptable to have no testing.]

• Added an automated test
• Passed all automated tests
• Manually tested

Documentation status

[Overview of how documentation is affected by this change. If there is no effect on documentation, explain why. Otherwise, state which sections are changed and why.]

• Updated CHANGELOG
• Updated README (if applicable)
• Commented all public classes, properties, and methods
• Updated user documentation

Technical risk

Low. It's scoped to the Cameras Overlay and the Scene View.

Package version

[Justification for updating either the patch, minor, or major version according to the semantic versioning rules]

• Updated package version

[glabute]

LGTM, although I can't test it until the appropriate Unity version becomes available

[gaborkb]

I just finished building trunk unity, I am going to test it today or tomorrow.

[glabute]

There are some interesting edge-cases to look at.

For example, what if I have a vcam with no procedural motion on Position (allowing the scene-view camera to drag it), but has a rotation tracking enabled? I would expect to be able to drag the camera's position, but while it's dragging the rotation should update so that it's always looking at the thing I'm tracking. Currently, that doesn't happen, and I have to wait for a refresh after I stop dragging to get the updated rotation.

[codecov-commenter]

Codecov Report

Attention: 45 lines in your changes are missing coverage. Please review.

Comparison is base (9e2d555) 21.02% compared to head (7104141) 20.98%.

Files	Patch %	Lines
...ine/Editor/SceneView/CinemachineCameraViewpoint.cs	0.00%	45 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #854      +/-   ##
==========================================
- Coverage   21.02%   20.98%   -0.04%     
==========================================
  Files         244      245       +1     
  Lines       27482    27527      +45     
==========================================
  Hits         5777     5777              
- Misses      21705    21750      +45     

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[glabute]

Thomas, what are the controls to change the FOV and other lens properties via screen view? I can't figure it out

[glabute]

It seems that this can be called with a negative number, resulting in negative FOV. In the inspector, this is protected against by calls to Validate() whenever the user changes something. Should the infrastructure be calling Validate() here? Or should the client (i.e. this code) be responsible for it?

Note: If we push a negative value and then undo/redo, Validate() does get called.