* SDFs are now generated, allocated from the atlas and uploaded in 8^3 bricks (7^3 unique data, half voxel padding).
* Tracing must load the brick index from the indirection table, and only bricks near the surface are stored
* 3 mips are now generated, with the lowest resolution always loaded and the other 2 streamed
* SDFs are now G8 narrow band. Lower resolution mips must be traversed when querying distance to nearest surface far away from the surface
* The Distance Field Brick Atlas is now stored for each FScene and dynamically resized based on needs with a GPU memcopy
* Brick atlas uses a 1d pooled allocator which has no fragmentation and greatly reduces packing waste over the 3d allocator
* Added new indirection for Distance Field Asset data, so that only a single entry needs to be updated when a mip is streamed in or out in scenes with millions of instances
* Compute shaders operating on distance field instances generate streaming requests, which are async read back to CPU, turned into IO requests, which are polled and when complete uploaded to atlases
* Any mesh instance inside the Global SDF extent (200m) requests mip1, and at 50m requests mip2
* Now using a batched compute scatter to upload to the distance field atlas instead of RHIUpdateTexture3d, to bypass alignment restrictions and per-upload overhead
* Distance Field streaming uses an async task to move Memcpy and IO request overhead off of the Rendering Thread
* Distance Field Visualization now computes a normal from the SDF gradient and does simple lighting to better visualize the scene representation
* Increased r.DistanceFields.MaxPerMeshResolution from 128 to 512, to better represent large objects
* Mesh SDF generation now uses an Embree point query to calculate closest unsigned distance, and then a much smaller set of rays to count backfaces for negative region determination, for a 11x speedup
* Upgraded mesh utilities to Embree 3.12.2 to get point queries
* Fixed wrong transform used for SDF normals in Lumen, causing non-uniformly scaled meshes to have incorrect Surface Cache interpolation
* Fixed Static Mesh materials not getting PostLoaded before SDF build, causing their blend modes to be wrong for the build, which corrupts the DDC. Also included those blend modes in the DDC key.
Original costs on 1080 GTX (full updates on everything and no screen traces)
10.60ms UpdateGlobalDistanceField
3.62ms LumenReflectiveTest.DirectionalLight_1 Shadowmap 1
1.73ms VoxelizeCards Clipmaps=[0,1,2,3]
0.38ms TraceCards 1 dispatch 1 groups
0.51ms TraceCards 1 dispatch 1 groups
Sparse SDF costs
12.06ms UpdateGlobalDistanceField
4.35ms LumenReflectiveTest.DirectionalLight_1 Shadowmap 1
2.30ms VoxelizeCards Clipmaps=[0,1,2,3]
0.69ms TraceCards 1 dispatch 1 groups
0.77ms TraceCards 1 dispatch 1 groups
Tested: TopazEntry PC, Reverb PC and PS5, EngineTests, QAGame, Rift, Frosty P_Construct_WP, FortGPUTestbed
#rb Krzysztof.Narkowicz
#ROBOMERGE-OWNER: Daniel.Wright
#ROBOMERGE-AUTHOR: daniel.wright
#ROBOMERGE-SOURCE: CL 15784493 in //UE5/Release-5.0-EarlyAccess/...
#ROBOMERGE-BOT: STARSHIP (Release-5.0-EarlyAccess -> Main) (v783-15756269)
#ROBOMERGE-CONFLICT from-shelf
[CL 15790658 by Daniel Wright in ue5-main branch]
#jira ue-90726
#rb uriel.doyon
#ROBOMERGE-SOURCE: CL 12232768 in //UE4/Release-4.25/... via CL 12232770
#ROBOMERGE-BOT: RELEASE (Release-4.25Plus -> Main) (v664-12234175)
[CL 12234779 by john hable in Main branch]
#rnx
#rb none
#ROBOMERGE-OWNER: ryan.durand
#ROBOMERGE-AUTHOR: ryan.durand
#ROBOMERGE-SOURCE: CL 10869210 via CL 10869511 via CL 10869900
#ROBOMERGE-BOT: (v613-10869866)
[CL 10870549 by ryan durand in Main branch]
