Fix #15595 - Stop caching TileRepresentation based on source key and use interimTile until tiles are loaded.

[sweepline]

Fixes #15595 by stopping caching TileRepresentation based on source key and use interimTile until tiles are loaded.

I am new to contributing to this project so im not sure if this is the best way to fix the underlying issue. I think the main aspects are correct. For example I could not find a way to keep using isDrawableTile_, but the current way its used in WebGLBaseTileLayerRenderer is also causing issues.

[github-actions]

📦 Preview the website for this branch here: https://deploy-preview-15596--ol-site.netlify.app/.

[sweepline]

Is there anything else I need to do to get a rerun of the workflow / get assigned a reviewer. I could not read anything in DEVELOPING.md or CONTRIBUTING.md about the review process other than I need to pass the CI tests. The ones failing on my local machine also fails on master so I think I need to run them in CI.

[ahocevar]

@sweepline Thanks for your contribution. You have correctly followed the process, and the reason why you haven't gotten a review yet is simply that none of the potential reviewers (@tschaub in this case) has found time to look at it yet.

I have triggered a CI run, and the result looks good.

[tschaub]

Thanks for putting time into diagnosing this issue and proposing a fix, @sweepline.

I have been working on another change that will let us remove interim tiles altogether (see #15568). The goal there is to still use previously loaded cached tiles, but to do so without the current interim tile chain handling. That is a breaking change, and will require discussion with (and likely assistance from) others if we are to get it in. If the new tile source changes don't make it in, we can revisit these changes, but I'd like to give that a chance first. In either case, the example you add here will provide a useful case for the behavior we want to retain (and in both cases, we need to decide what to do with the isDrawableTile_ function).

[sweepline]

Thanks for looking at it @tschaub. At SCALGO we are already running a patched version of Openlayers with this PR in it as we are using a slider to change dimension of a DataTileSource with a custom WebGL renderer.
The patch works well for our use-case but we will keep an eye on #15568.