Support multiple ClippingPolygons with mixed inverse-settings

[mborjesson-bentley]

Feature

We need to create scenes that have multiple ClippingPolygons that can have mixed inverse-settings.

An example use-case would be to have a ClippingPolygon on a globe and/or 3DTiles-tileset that defines an area of interest, clipping away everything outside of it (inverse = true). Then there'd be ClippingPolygons used to create holes in the visible part of the tileset (inverse = false).

It could look something like this, where the purple polygon would be used to clip a hole:

It does not looks like this is possible, since the inverse-setting is set on the ClippingPolygonCollection and there can be only one collection on the globe/3DTiles-tileset.

Sandcastle

[mzschwartz5]

Hi @mborjesson-bentley, this seems like a reasonable and useful feature request to me. I'm not intimately familiar with how clipping polygons work, but it does look like it would be a non-trivial change.

Looking at the original PR by @ggetz, this feature was mentioned but deemed out of scope. But from Gabby's description, it sounds very much possible.

[r-veenstra]

An example of needing this in a highway project use case

These are the types of holes one might be expecting to fill with the existing context