Feature request:
Add some way to provide a list of NavMeshBuildSource during CollectSources phase in NavMeshSurface. Can be either a separate component, or a new method in NavMeshModifier.
Also, I geuss can make CollectSources virtual and let us modify it in child classes.
Lore:
Before NavMeshSurface became an official package, we modified it a bit to be able to provide list of custom
NavMeshBuildSource from components. It is similar to NavMeshModifier, but it just provides list of sources directly.
The reason for it is that we mostly work with sprites and tiles in our projects, and NavMesh can only build based on mesh data. NavMeshModifiers can provide some extra data, but each of them require separate game object, which will result in a big performance cost since we need thousands of those.
So, we have some grid-based data in our scenes: 2d grids, tiles, non-mesh-based obstacles. And we use custom NavMeshBuildSource provider to build the NavMesh based on those.