Clipping texture plumbing

[mzschwartz5]

Description

This is the third step in reimplementing Clipping Polygons on top of the vector data pipeline -- specifically, for terrain. In steps one and two, I introduced the machinery for vector-clipping. Now that we have the necessary APIs to create vector-clipping textures, this PR calls them to create and update / manage the lifecycle of these textures (for terrain; models to follow).

Issue number and link

https://github.com/iTwin/cesiumjs-web3d-internal/issues/33

Testing plan

Once again, no external / behavioral changes here. Clipping is still using the SDF path at this point. Regression testing with sandcastle (plus, since changes to Globe classes were made, general regression testing on globe rendering isn't a bad idea).

Author checklist

• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

AI acknowledgment

• I used AI to generate content in this PR
• If yes, I have reviewed the AI-generated content before submitting

If yes, I used the following Tools(s) and/or Service(s):

If yes, I used the following Model(s):

PR Dependency Tree

• PR Clipping polygon buffer migration #13623
  • PR Vector Textures for Polygon Clipping #13635
    • PR Clipping texture plumbing #13636 👈
      • PR Shader rework for terrain polygon clipping #13637
        • PR Remove SDF polygon clipping from Globe #13638
          • PR Model clipping rework foundation #13641
            • PR Model polygon clipping shader impl #13647
              • PR Remove polygon clipping sdf path #13654
                • PR Clipping Polygon Holes #13660
                  • PR ClippingPolygon immutable positions (performance) #13665

This tree was auto-generated by Charcoal

[github-actions]

Thank you for the pull request, @mzschwartz5!

✅ We can confirm we have a CLA on file for you.

[mzschwartz5]

Note: I used a slightly different dirty mechanism than vector tiles uses. Rather than having a "clipping polygons dirty" flag on every terrain tile, I just have one on the clipping polygon collection. When the flag is set, I clear the clipping vector data on all tiles - which tells GlobeSurfaceTileProvider to recreate that data next time the tile is rendered.

The reasons for this choice were partly for memory reasons (fewer dirty flags), and also because of how ClippingPolygonCollection is structured differently from VectorProvider (and how it needs to serve both terrain and 3d tiles / models).