Temporal Antialiasing (TAA) (#7291)

![image](https://user-images.githubusercontent.com/47158642/214374911-412f0986-3927-4f7a-9a6c-413bdee6b389.png)

# Objective

- Implement an alternative antialias technique
- TAA scales based off of view resolution, not geometry complexity
- TAA filters textures, firefly pixels, and other aliasing not covered
by MSAA
- TAA additionally will reduce noise / increase quality in future
stochastic rendering techniques
- Closes #3663

## Solution

- Add a temporal jitter component
- Add a motion vector prepass
- Add a TemporalAntialias component and plugin
- Combine existing MSAA and FXAA examples and add TAA

## Followup Work
- Prepass motion vector support for skinned meshes
- Move uniforms needed for motion vectors into a separate bind group,
instead of using different bind group layouts
- Reuse previous frame's GPU view buffer for motion vectors, instead of
recomputing
- Mip biasing for sharper textures, and or unjitter texture UVs
#7323
- Compute shader for better performance
- Investigate FSR techniques
  - Historical depth based disocclusion tests, for geometry disocclusion
  - Historical luminance/hue based tests, for shading disocclusion
- Pixel "locks" to reduce blending rate / revamp history confidence
mechanism
- Orthographic camera support for TemporalJitter
- Figure out COD's 1-tap bicubic filter

---

## Changelog

- Added MotionVectorPrepass and TemporalJitter
- Added TemporalAntialiasPlugin, TemporalAntialiasBundle, and
TemporalAntialiasSettings

---------

Co-authored-by: IceSentry <[email protected]>
Co-authored-by: IceSentry <[email protected]>
Co-authored-by: Robert Swain <[email protected]>
Co-authored-by: Daniel Chia <[email protected]>
Co-authored-by: robtfm <[email protected]>
Co-authored-by: Brandon Dyer <[email protected]>
Co-authored-by: Edgar Geier <[email protected]>

Cargo.toml

@@ -414,6 +414,16 @@ description = "A scene showcasing the built-in 3D shapes"
 category = "3D Rendering"
 wasm = true
 
+[[example]]
+name = "anti_aliasing"
+path = "examples/3d/anti_aliasing.rs"
+
+[package.metadata.example.anti_aliasing]
+name = "Anti-aliasing"
+description = "Compares different anti-aliasing methods"
+category = "3D Rendering"
+wasm = false
+
 [[example]]
 name = "3d_gizmos"
 path = "examples/3d/3d_gizmos.rs"
@@ -515,26 +525,6 @@ description = "Compares tonemapping options"
 category = "3D Rendering"
 wasm = true
 
-[[example]]
-name = "fxaa"
-path = "examples/3d/fxaa.rs"
-
-[package.metadata.example.fxaa]
-name = "FXAA"
-description = "Compares MSAA (Multi-Sample Anti-Aliasing) and FXAA (Fast Approximate Anti-Aliasing)"
-category = "3D Rendering"
-wasm = true
-
-[[example]]
-name = "msaa"
-path = "examples/3d/msaa.rs"
-
-[package.metadata.example.msaa]
-name = "MSAA"
-description = "Configures MSAA (Multi-Sample Anti-Aliasing) for smoother edges"
-category = "3D Rendering"
-wasm = true
-
 [[example]]
 name = "orthographic"
 path = "examples/3d/orthographic.rs"

assets/shaders/show_prepass.wgsl

@@ -5,6 +5,7 @@
 struct ShowPrepassSettings {
  show_depth: u32,
  show_normals: u32,
+ show_motion_vectors: u32,
  padding_1: u32,
  padding_2: u32,
 }
@@ -23,6 +24,9 @@ fn fragment(
  } else if settings.show_normals == 1u {
  let normal = prepass_normal(frag_coord, sample_index);
  return vec4(normal, 1.0);
+ } else if settings.show_motion_vectors == 1u {
+ let motion_vector = prepass_motion_vector(frag_coord, sample_index);
+ return vec4(motion_vector / globals.delta_time, 0.0, 1.0);
  }
 
  return vec4(0.0);

crates/bevy_core_pipeline/Cargo.toml

@@ -21,6 +21,7 @@ tonemapping_luts = []
 # bevy
 bevy_app = { path = "../bevy_app", version = "0.11.0-dev" }
 bevy_asset = { path = "../bevy_asset", version = "0.11.0-dev" }
+bevy_core = { path = "../bevy_core", version = "0.11.0-dev" }
 bevy_derive = { path = "../bevy_derive", version = "0.11.0-dev" }
 bevy_ecs = { path = "../bevy_ecs", version = "0.11.0-dev" }
 bevy_reflect = { path = "../bevy_reflect", version = "0.11.0-dev" }

crates/bevy_core_pipeline/src/bloom/mod.rs

@@ -23,8 +23,6 @@ use bevy_render::{
  view::ViewTarget,
  Render, RenderApp, RenderSet,
 };
-#[cfg(feature = "trace")]
-use bevy_utils::tracing::info_span;
 use downsampling_pipeline::{
  prepare_downsampling_pipeline, BloomDownsamplingPipeline, BloomDownsamplingPipelineIds,
  BloomUniforms,
@@ -150,9 +148,6 @@ impl Node for BloomNode {
  render_context: &mut RenderContext,
  world: &World,
  ) -> Result<(), NodeRunError> {
- #[cfg(feature = "trace")]
- let _bloom_span = info_span!("bloom").entered();
-
  let downsampling_pipeline_res = world.resource::<BloomDownsamplingPipeline>();
  let pipeline_cache = world.resource::<PipelineCache>();
  let uniforms = world.resource::<ComponentUniforms<BloomUniforms>>();

crates/bevy_core_pipeline/src/core_3d/main_pass_3d_node.rs

@@ -1,7 +1,7 @@
 use crate::{
  clear_color::{ClearColor, ClearColorConfig},
  core_3d::{AlphaMask3d, Camera3d, Opaque3d, Transparent3d},
- prepass::{DepthPrepass, NormalPrepass},
+ prepass::{DepthPrepass, MotionVectorPrepass, NormalPrepass},
 };
 use bevy_ecs::prelude::*;
 use bevy_render::{
@@ -29,6 +29,7 @@ pub struct MainPass3dNode {
  &'static ViewDepthTexture,
  Option<&'static DepthPrepass>,
  Option<&'static NormalPrepass>,
+ Option<&'static MotionVectorPrepass>,
  ),
  With<ExtractedView>,
  >,
@@ -64,6 +65,7 @@ impl Node for MainPass3dNode {
  depth,
  depth_prepass,
  normal_prepass,
+ motion_vector_prepass,
  )) = self.query.get_manual(world, view_entity) else {
  // No window
  return Ok(());
@@ -94,7 +96,10 @@ impl Node for MainPass3dNode {
  view: &depth.view,
  // NOTE: The opaque main pass loads the depth buffer and possibly overwrites it
  depth_ops: Some(Operations {
- load: if depth_prepass.is_some() || normal_prepass.is_some() {
+ load: if depth_prepass.is_some()
+ || normal_prepass.is_some()
+ || motion_vector_prepass.is_some()
+ {
  // if any prepass runs, it will generate a depth buffer so we should use it,
  // even if only the normal_prepass is used.
  Camera3dDepthLoadOp::Load

crates/bevy_core_pipeline/src/lib.rs

@@ -7,9 +7,17 @@ pub mod fullscreen_vertex_shader;
 pub mod fxaa;
 pub mod msaa_writeback;
 pub mod prepass;
+mod taa;
 pub mod tonemapping;
 pub mod upscaling;
 
+/// Experimental features that are not yet finished. Please report any issues you encounter!
+pub mod experimental {
+ pub mod taa {
+ pub use crate::taa::*;
+ }
+}
+
 pub mod prelude {
  #[doc(hidden)]
  pub use crate::{

crates/bevy_core_pipeline/src/prepass/mod.rs

@@ -1,4 +1,4 @@
-//! Run a prepass before the main pass to generate depth and/or normals texture, sometimes called a thin g-buffer.
+//! Run a prepass before the main pass to generate depth, normals, and/or motion vectors textures, sometimes called a thin g-buffer.
 //! These textures are useful for various screen-space effects and reducing overdraw in the main pass.
 //!
 //! The prepass only runs for opaque meshes or meshes with an alpha mask. Transparent meshes are ignored.
@@ -7,6 +7,7 @@
 //!
 //! [`DepthPrepass`]
 //! [`NormalPrepass`]
+//! [`MotionVectorPrepass`]
 //!
 //! The textures are automatically added to the default mesh view bindings. You can also get the raw textures
 //! by querying the [`ViewPrepassTextures`] component on any camera with a prepass component.
@@ -15,9 +16,9 @@
 //! to a separate texture unless the [`DepthPrepass`] is activated. This means that if any prepass component is present
 //! it will always create a depth buffer that will be used by the main pass.
 //!
-//! When using the default mesh view bindings you should be able to use `prepass_depth()`
-//! and `prepass_normal()` to load the related textures. These functions are defined in `bevy_pbr::prepass_utils`.
-//! See the `shader_prepass` example that shows how to use it.
+//! When using the default mesh view bindings you should be able to use `prepass_depth()`,
+//! `prepass_normal()`, and `prepass_motion_vector()` to load the related textures.
+//! These functions are defined in `bevy_pbr::prepass_utils`. See the `shader_prepass` example that shows how to use them.
 //!
 //! The prepass runs for each `Material`. You can control if the prepass should run per-material by setting the `prepass_enabled`
 //! flag on the `MaterialPlugin`.
@@ -39,6 +40,7 @@ use bevy_utils::FloatOrd;
 
 pub const DEPTH_PREPASS_FORMAT: TextureFormat = TextureFormat::Depth32Float;
 pub const NORMAL_PREPASS_FORMAT: TextureFormat = TextureFormat::Rgb10a2Unorm;
+pub const MOTION_VECTOR_PREPASS_FORMAT: TextureFormat = TextureFormat::Rg16Float;
 
 /// If added to a [`crate::prelude::Camera3d`] then depth values will be copied to a separate texture available to the main pass.
 #[derive(Component, Default, Reflect)]
@@ -49,6 +51,10 @@ pub struct DepthPrepass;
 #[derive(Component, Default, Reflect)]
 pub struct NormalPrepass;
 
+/// If added to a [`crate::prelude::Camera3d`] then screen space motion vectors will be copied to a separate texture available to the main pass.
+#[derive(Component, Default, Reflect)]
+pub struct MotionVectorPrepass;
+
 /// Textures that are written to by the prepass.
 ///
 /// This component will only be present if any of the relevant prepass components are also present.
@@ -60,6 +66,9 @@ pub struct ViewPrepassTextures {
  /// The normals texture generated by the prepass.
  /// Exists only if [`NormalPrepass`] is added to the `ViewTarget`
  pub normal: Option<CachedTexture>,
+ /// The motion vectors texture generated by the prepass.
+ /// Exists only if [`MotionVectorPrepass`] is added to the `ViewTarget`
+ pub motion_vectors: Option<CachedTexture>,
  /// The size of the textures.
  pub size: Extent3d,
 }

crates/bevy_core_pipeline/src/prepass/node.rs

@@ -64,15 +64,34 @@ impl Node for PrepassNode {
  };
 
  let mut color_attachments = vec![];
- if let Some(view_normals_texture) = &view_prepass_textures.normal {
- color_attachments.push(Some(RenderPassColorAttachment {
- view: &view_normals_texture.default_view,
+ color_attachments.push(
+ view_prepass_textures
+ .normal
+ .as_ref()
+ .map(|view_normals_texture| RenderPassColorAttachment {
+ view: &view_normals_texture.default_view,
+ resolve_target: None,
+ ops: Operations {
+ load: LoadOp::Clear(Color::BLACK.into()),
+ store: true,
+ },
+ }),
+ );
+ color_attachments.push(view_prepass_textures.motion_vectors.as_ref().map(
+ |view_motion_vectors_texture| RenderPassColorAttachment {
+ view: &view_motion_vectors_texture.default_view,
  resolve_target: None,
  ops: Operations {
- load: LoadOp::Clear(Color::BLACK.into()),
+ // Blue channel doesn't matter, but set to 1.0 for possible faster clear
+ // https://gpuopen.com/performance/#clears
+ load: LoadOp::Clear(Color::rgb_linear(1.0, 1.0, 1.0).into()),
  store: true,
  },
- }));
+ },
+ ));
+ if color_attachments.iter().all(Option::is_none) {
+ // all attachments are none: clear the attachment list so that no fragment shader is required
+ color_attachments.clear();
  }
 
  {