Raw vs Smooth Depth

[alcooper91]

Devices can support either raw depth textures, "smoothed" depth textures, or both. The Spec is ~roughly silent on which types of textures we should return. I've had some developer interest in being able to choose which type they can receive, as they have different uses for different benefits.

In exposing raw depth, it is likely we may want to expose a confidence as well.

/agenda