JMS55 af9c945f40 Screen Space Ambient Occlusion (SSAO) MVP (#7402) ...  # Objective - Add Screen space ambient occlusion (SSAO). SSAO approximates small-scale, local occlusion of _indirect_ diffuse light between objects. SSAO does not apply to direct lighting, such as point or directional lights. - This darkens creases, e.g. on staircases, and gives nice contact shadows where objects meet, giving entities a more "grounded" feel. - Closes https://github.com/bevyengine/bevy/issues/3632. ## Solution - Implement the GTAO algorithm. - https://www.activision.com/cdn/research/Practical_Real_Time_Strategies_for_Accurate_Indirect_Occlusion_NEW%20VERSION_COLOR.pdf - https://blog.selfshadow.com/publications/s2016-shading-course/activision/s2016_pbs_activision_occlusion.pdf - Source code heavily based on [Intel's XeGTAO](0d177ce06b/Source/Rendering/Shaders/XeGTAO.hlsli). - Add an SSAO bevy example. ## Algorithm Overview * Run a depth and normal prepass * Create downscaled mips of the depth texture (preprocess_depths pass) * GTAO pass - for each pixel, take several random samples from the depth+normal buffers, reconstruct world position, raytrace in screen space to estimate occlusion. Rather then doing completely random samples on a hemisphere, you choose random _slices_ of the hemisphere, and then can analytically compute the full occlusion of that slice. Also compute edges based on depth differences here. * Spatial denoise pass - bilateral blur, using edge detection to not blur over edges. This is the final SSAO result. * Main pass - if SSAO exists, sample the SSAO texture, and set occlusion to be the minimum of ssao/material occlusion. This then feeds into the rest of the PBR shader as normal. --- ## Future Improvements - Maybe remove the low quality preset for now (too noisy) - WebGPU fallback (see below) - Faster depth->world position (see reverted code) - Bent normals - Try interleaved gradient noise or spatiotemporal blue noise - Replace the spatial denoiser with a combined spatial+temporal denoiser - Render at half resolution and use a bilateral upsample - Better multibounce approximation (https://drive.google.com/file/d/1SyagcEVplIm2KkRD3WQYSO9O0Iyi1hfy/view) ## Far-Future Performance Improvements - F16 math (missing naga-wgsl support https://github.com/gfx-rs/naga/issues/1884) - Faster coordinate space conversion for normals - Faster depth mipchain creation (https://github.com/GPUOpen-Effects/FidelityFX-SPD) (wgpu/naga does not currently support subgroup ops) - Deinterleaved SSAO for better cache efficiency (https://developer.nvidia.com/sites/default/files/akamai/gameworks/samples/DeinterleavedTexturing.pdf) ## Other Interesting Papers - Visibility bitmask (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) ## Platform Support * 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 * 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. --- ## Changelog - Added ScreenSpaceAmbientOcclusionSettings, ScreenSpaceAmbientOcclusionQualityLevel, and ScreenSpaceAmbientOcclusionBundle --------- Co-authored-by: IceSentry <c.giguere42@gmail.com> Co-authored-by: IceSentry <IceSentry@users.noreply.github.com> Co-authored-by: Daniel Chia <danstryder@gmail.com> Co-authored-by: Elabajaba <Elabajaba@users.noreply.github.com> Co-authored-by: Robert Swain <robert.swain@gmail.com> Co-authored-by: robtfm <50659922+robtfm@users.noreply.github.com> Co-authored-by: Brandon Dyer <brandondyer64@gmail.com> Co-authored-by: Edgar Geier <geieredgar@gmail.com> Co-authored-by: Nicola Papale <nicopap@users.noreply.github.com> Co-authored-by: Carter Anderson <mcanders1@gmail.com>		2023-06-18 21:05:55 +00:00
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bevy_a11y	Require #[derive(Event)] on all Events (#7086)	2023-06-06 14:44:32 +00:00
bevy_animation	Fixed several missing links in docs. (#8117)	2023-04-23 17:28:36 +00:00
bevy_app	Fix documentation of SubApp extract (#8747)	2023-06-12 19:30:04 +00:00
bevy_asset	Update notify requirement from 5.0.0 to 6.0.0 (#8757)	2023-06-06 21:05:21 +00:00
bevy_audio	reflect: stable type path v2 (#7184)	2023-06-05 20:31:20 +00:00
bevy_core	Add Reflect and FromReflect for AssetPath (#8531)	2023-05-08 19:19:19 +00:00
bevy_core_pipeline	Screen Space Ambient Occlusion (SSAO) MVP (#7402)	2023-06-18 21:05:55 +00:00
bevy_derive	bevy_derive: Add #[deref] attribute (#8552)	2023-05-16 18:29:09 +00:00
bevy_diagnostic	Initialize DiagnosticStore on register_diagnostic if it does not exist (#8819)	2023-06-12 19:40:09 +00:00
bevy_dylib	Suppress the clippy::type_complexity lint (#8313)	2023-04-06 21:27:36 +00:00
bevy_dynamic_plugin	Remove stray boilerplate line in bevy_dynamic_plugin/Cargo.toml (#8830)	2023-06-12 19:10:48 +00:00
bevy_ecs	doc: update a reference from add_system to add_systems (#8881)	2023-06-18 17:17:02 +00:00
bevy_ecs_compile_fail_tests	Resolve clippy issues for rust 1.70.0 (#8738)	2023-06-01 21:05:05 +00:00
bevy_encase_derive	update syn, encase, glam and hexasphere (#8573)	2023-05-16 01:24:17 +00:00
bevy_gilrs	Add gamepad rumble support to bevy_input (#8398)	2023-04-24 15:28:53 +00:00
bevy_gizmos	Instanced line rendering for gizmos based on bevy_polyline (#8427)	2023-06-13 06:49:47 +00:00
bevy_gltf	reflect: stable type path v2 (#7184)	2023-06-05 20:31:20 +00:00
bevy_hierarchy	Rename Command's "write" method to "apply" (#8814)	2023-06-12 17:53:47 +00:00
bevy_input	Add window entity to mouse and keyboard events (#8852)	2023-06-16 13:54:06 +00:00
bevy_internal	Instanced line rendering for gizmos based on bevy_polyline (#8427)	2023-06-13 06:49:47 +00:00
bevy_log	Update android_log-sys requirement from 0.2.0 to 0.3.0 (#7925)	2023-06-01 07:55:33 +00:00
bevy_macro_utils	update syn, encase, glam and hexasphere (#8573)	2023-05-16 01:24:17 +00:00
bevy_macros_compile_fail_tests	bevy_derive: Add #[deref] attribute (#8552)	2023-05-16 18:29:09 +00:00
bevy_math	Add integer equivalents for Rect (#7984)	2023-06-12 19:10:48 +00:00
bevy_mikktspace	update syn, encase, glam and hexasphere (#8573)	2023-05-16 01:24:17 +00:00
bevy_pbr	Screen Space Ambient Occlusion (SSAO) MVP (#7402)	2023-06-18 21:05:55 +00:00
bevy_ptr	Fixed several missing links in docs. (#8117)	2023-04-23 17:28:36 +00:00
bevy_reflect	bevy_reflect: implement Reflect for SmolStr (#8771)	2023-06-08 20:33:21 +00:00
bevy_reflect_compile_fail_tests	reflect: stable type path v2 (#7184)	2023-06-05 20:31:20 +00:00
bevy_render	Screen Space Ambient Occlusion (SSAO) MVP (#7402)	2023-06-18 21:05:55 +00:00
bevy_scene	Rename Command's "write" method to "apply" (#8814)	2023-06-12 17:53:47 +00:00
bevy_sprite	reflect: stable type path v2 (#7184)	2023-06-05 20:31:20 +00:00
bevy_tasks	remove some use of once_cell that can be replace with new std (#8739)	2023-06-01 21:55:18 +00:00
bevy_text	reflect: stable type path v2 (#7184)	2023-06-05 20:31:20 +00:00
bevy_time	Hide naga info logs & Derive PartialEq on Timer and Stopwatch (#8664)	2023-05-24 15:16:15 +00:00
bevy_transform	Rename Command's "write" method to "apply" (#8814)	2023-06-12 17:53:47 +00:00
bevy_ui	Ui Node Borders (#7795)	2023-06-14 22:43:38 +00:00
bevy_utils	Fix all_tuples + added docs. (#8743)	2023-06-02 16:05:27 +00:00
bevy_window	Register a few missed reflect components (#8807)	2023-06-10 23:19:39 +00:00
bevy_winit	Add window entity to mouse and keyboard events (#8852)	2023-06-16 13:54:06 +00:00