SSAO/SSGI followup tracking issue - Githubissues

bevyengine / bevy

A refreshingly simple data-driven game engine built in Rust

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SSAO/SSGI followup tracking issue #8888

Open JMS55 opened 1 year ago

JMS55 commented 1 year ago

SSAO got merged in #7402, but there's still a lot we can do better.

Performance

[ ] Faster depth->world position (see reverted code)
[ ] Render at half resolution and use a bilateral upsample
[ ] F16 math (missing naga-wgsl support https://github.com/gfx-rs/wgpu/issues/4384)
[ ] Faster depth mipchain creation (https://github.com/GPUOpen-Effects/FidelityFX-SPD) (wgpu/naga does not currently support subgroup ops)

Quality

[ ] Replace the spatial denoiser with a combined spatial+temporal denoiser, similar to bevy_solari's
[ ] Try interleaved gradient noise or tellusim's spatiotemporal blue noise for sampling
[ ] Bent normals
[ ] Better multibounce approximation (https://drive.google.com/file/d/1SyagcEVplIm2KkRD3WQYSO9O0Iyi1hfy/view)
[ ] Configurable parameters/heuristics

Platform Support

[x] SSAO currently does not work on DirectX12 due to issues with wgpu and naga:
- https://github.com/gfx-rs/wgpu/pull/3798
- https://github.com/gfx-rs/naga/pull/2353 (we have a work-around for this issue in the SSAO shaders atm)
[ ] SSAO currently does not work on WebGPU because r16float is not a valid storage texture format https://gpuweb.github.io/gpuweb/wgsl/#storage-texel-formats. We can fix this with a fallback to r32float.

Recent Algorithm Advancements

[x] Visibility bitmask (https://cdrinmatane.github.io/posts/ssaovb-code/, https://link.springer.com/article/10.1007/s00371-022-02703-y, https://cdrinmatane.github.io/posts/cgspotlight-slides/)
[ ] Screen space diffuse lighting (https://github.com/Patapom/GodComplex/blob/master/Tests/TestHBIL/2018%20Mayaux%20-%20Horizon-Based%20Indirect%20Lighting%20(HBIL).pdf)

Elabajaba commented 1 year ago

The wgpu backport was released, so SSAO works on DX12 now!

We can get rid of the manual bitmask packing/unpacking implementations in the next wgpu release, as it should have the naga PR included.

JMS55 commented 1 year ago

Open source reference we can use for visibility bitmasks: https://github.com/4lex4nder/ReshadeEffectShaderToggler-BG3/blob/main/Shaders/bg3_xegtao_gi.fx