* Provides mid-range stable AO for dynamic rigid meshes
* Movable sky lights are now supported, and distance field AO is used for shadowing Movable sky lighting from dynamic scenes
* Static meshes are preprocessed into signed distance field volumes at mesh build time when the r.AllowMeshDistanceFieldRepresentations project setting is enabled
* Non-uniform scaling does not work with this method (mirroring is fine), animating through world position offset also causes artifacts as the two representations diverge
* Occlusion is computed along cones to reduce over-shadowing, object distance fields are operated on directly (no hierarchy) to obtain enough resolution to prevent leaking, visibility traces are done with cone stepping to allow better parallelization, and shading is done adaptively in space and time using the surface cache.
[CL 2093556 by Daniel Wright in Main branch]
#proj core
#branch UE4
#summary Moved global variables to statics in FApp. Removed unused GUnclampedDeltaTime.
#codereview robert.manuszewski
[CL 2043034 by Mikolaj Sieluzycki in Main branch]
