3D Tiles show through the globe

[lilleyse]

If a tile's geometric error is sufficiently large to be visible at global scale, it will show through the opposite side of the globe.

This happens due to rendering the depth plane after 3D Tiles, which was done to fix a separate set of bugs - the classification and picking bugs below. It only happens when globe.depthTestAgainstTerrain is false so once terrain is on by default none of these problems will happen.

Tileset showing through globe - Sandcastle code - when the depth plane is rendered after 3D Tiles.

Classification bug - Sandcastle code - when the depth plane is rendered before 3D Tiles and the depth plane offset is not applied.

Picking bug - Sandcastle code - when the depth plane is rendered before 3D Tiles and the depth plane offset is applied.