Replay renderer partial deletion

[0mdc]

Motivation and Context

The batch renderer can only delete full scenes - it cannot delete single objects.

To circumvent this, deletions are processed as such:

1. Latest transforms are cached.
2. All instances are deleted.
3. Remaining instances are re-created.
4. Latest transforms are re-applied.

How Has This Been Tested

Tested locally on PPO training and added a unit test.

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have completed my CLA (see CONTRIBUTING)
• I have added tests to cover my changes.
• All new and existing tests passed.

[eundersander]

I left some comments. Let me know when I should take another look!

[eundersander]

Can you add a unit test that will trigger this code? BatchReplayRendererTest::testIntegration is close but it doesn't do any deletions.

[eundersander]

LGTM!

[eundersander]

I assume this code was moved from BatchReplayRenderer.cpp without changes so I'm not looking closely at this file.