# Objective
- Standard Material is starting to run out of samplers (currently uses
13 with no additional features off, I think in 0.13 it was 12).
- This change adds a new feature switch, modelled on the other ones
which add features to Standard Material, to turn off the new anisotropy
feature by default.
## Solution
- feature + texture define
## Testing
- Anisotropy example still works fine
- Other samples work fine
- Standard Material now takes 12 samplers by default on my Mac instead
of 13
## Migration Guide
- Add feature pbr_anisotropy_texture if you are using that texture in
any standard materials.
---------
Co-authored-by: John Payne <20407779+johngpayne@users.noreply.github.com>
# Objective
- Fixes#14059
- `morphed_skinned_mesh_layout` is the same as
`morphed_skinned_motion_mesh_layout` but shouldn't have the skin / morph
from previous frame, as they're used for motion
## Solution
- Remove the extra entries
## Testing
- Run with the glTF file reproducing #14059, it works
As reported in #14004, many third-party plugins, such as Hanabi, enqueue
entities that don't have meshes into render phases. However, the
introduction of indirect mode added a dependency on mesh-specific data,
breaking this workflow. This is because GPU preprocessing requires that
the render phases manage indirect draw parameters, which don't apply to
objects that aren't meshes. The existing code skips over binned entities
that don't have indirect draw parameters, which causes the rendering to
be skipped for such objects.
To support this workflow, this commit adds a new field,
`non_mesh_items`, to `BinnedRenderPhase`. This field contains a simple
list of (bin key, entity) pairs. After drawing batchable and unbatchable
objects, the non-mesh items are drawn one after another. Bevy itself
doesn't enqueue any items into this list; it exists solely for the
application and/or plugins to use.
Additionally, this commit switches the asset ID in the standard bin keys
to be an untyped asset ID rather than that of a mesh. This allows more
flexibility, allowing bins to be keyed off any type of asset.
This patch adds a new example, `custom_phase_item`, which simultaneously
serves to demonstrate how to use this new feature and to act as a
regression test so this doesn't break again.
Fixes#14004.
## Changelog
### Added
* `BinnedRenderPhase` now contains a `non_mesh_items` field for plugins
to add custom items to.
The comment was incorrect - we are already looking at the pyramid
texture so we do not need to transform the size in any way. Doing that
resulted in a mip that was too fine to be selected in certain cases,
which resulted in a 2x2 pixel footprint not actually fully covering the
cluster sphere - sometimes this could lead to a non-conservative depth
value being computed which resulted in the cluster being marked as
invisible incorrectly.
This change updates meshopt-rs to 0.3 to take advantage of the newly
added sparse simplification mode: by default, simplifier assumes that
the entire mesh is simplified and runs a set of calculations that are
O(vertex count), but in our case we simplify many small mesh subsets
which is inefficient.
Sparse mode instead assumes that the simplified subset is only using a
portion of the vertex buffer, and optimizes accordingly. This changes
the meaning of the error (as it becomes relative to the subset, in our
case a meshlet group); to ensure consistent error selection, we also use
the ErrorAbsolute mode which allows us to operate in mesh coordinate
space.
Additionally, meshopt 0.3 runs optimizeMeshlet automatically as part of
`build_meshlets` so we no longer need to call it ourselves.
This reduces the time to build meshlet representation for Stanford Bunny
mesh from ~1.65s to ~0.45s (3.7x) in optimized builds.
This is a followup to https://github.com/bevyengine/bevy/pull/13904
based on the discussion there, and switches two HashMaps that used
meshlet ids as keys to Vec.
In addition to a small further performance boost for `from_mesh` (1.66s
=> 1.60s), this makes processing deterministic modulo threading issues
wrt CRT rand described in the linked PR. This is valuable for debugging,
as you can visually or programmatically inspect the meshlet distribution
before/after making changes that should not change the output, whereas
previously every asset rebuild would change the meshlet structure.
Tested with https://github.com/bevyengine/bevy/pull/13431; after this
change, the visual output of meshlets is consistent between asset
rebuilds, and the MD5 of the output GLB file does not change either,
which was not the case before.
This change reworks `find_connected_meshlets` to scale more linearly
with the mesh size, which significantly reduces the cost of building
meshlet representations. As a small extra complexity reduction, it moves
`simplify_scale` call out of the loop so that it's called once (it only
depends on the vertex data => is safe to cache).
The new implementation of connectivity analysis builds edge=>meshlet
list data structure, which allows us to only iterate through
`tuple_combinations` of a (usually) small list. There is still some
redundancy as if two meshlets share two edges, they will be represented
in the meshlet lists twice, but it's overall much faster.
Since the hash traversal is non-deterministic, to keep this part of the
algorithm deterministic for reproducible results we sort the output
adjacency lists.
Overall this reduces the time to process bunny mesh from ~4.2s to ~1.7s
when using release; in unoptimized builds the delta is even more
significant.
This was tested by using https://github.com/bevyengine/bevy/pull/13431
and:
a) comparing the result of `find_connected_meshlets` using old and new
code; they are equal in all steps of the clustering process
b) comparing the rendered result of the old code vs new code *after*
making the rest of the algorithm deterministic: right now the loop that
iterates through the result of `group_meshlets()` call executes in
different order between program runs. This is orthogonal to this change
and can be fixed separately.
Note: a future change can shrink the processing time further from ~1.7s
to ~0.4s with a small diff but that requires an update to meshopt crate
which is pending in https://github.com/gwihlidal/meshopt-rs/pull/42.
This change is independent.
# Objective
- Fixes#13728
## Solution
- add a new feature `smaa_luts`. if enables, it also enables `ktx2` and
`zstd`. if not, it doesn't load the files but use placeholders instead
- adds all the resources needed in the same places that system that uses
them are added.
# Objective
- Fixes#13811 (probably, I lost my test code...)
## Solution
- Turns out that Queue and PrepareAssets are _not_ ordered. We should
probably either rethink our system sets (again), or improve the
documentation here. For reference, I've included the current ordering
below.
- The `prepare_meshlet_meshes_X` systems need to run after
`prepare_assets::<PreparedMaterial<M>>`, and have also been moved to
QueueMeshes.
```rust
schedule.configure_sets(
(
ExtractCommands,
ManageViews,
Queue,
PhaseSort,
Prepare,
Render,
Cleanup,
)
.chain(),
);
schedule.configure_sets((ExtractCommands, PrepareAssets, Prepare).chain());
schedule.configure_sets(QueueMeshes.in_set(Queue).after(prepare_assets::<GpuMesh>));
schedule.configure_sets(
(PrepareResources, PrepareResourcesFlush, PrepareBindGroups)
.chain()
.in_set(Prepare),
);
```
## Testing
- Ambiguity checker to make sure I don't have ambiguous system ordering
* Fixes https://github.com/bevyengine/bevy/issues/13813
* Fixes https://github.com/bevyengine/bevy/issues/13810
Tested a combined scene with both regular meshes and meshlet meshes
with:
* Regular forward setup
* Forward + normal/motion vector prepasses
* Deferred (with depth prepass since that's required)
* Deferred + depth/normal/motion vector prepasses
Still broken:
* Using meshlet meshes rendering in deferred and regular meshes
rendering in forward + depth/normal prepass. I don't know how to fix
this at the moment, so for now I've just add instructions to not mix
them.
# Objective
Closes#13738
## Solution
Added `from_color` to materials that would support it. Didn't add
`from_color` to `WireframeMaterial` as it doesn't seem we expect users
to be constructing them themselves.
## Testing
None
---
## Changelog
### Added
- `from_color` to `StandardMaterial` so you can construct this material
from any color type.
- `from_color` to `ColorMaterial` so you can construct this material
from any color type.
# Objective
- Mikktspace requires that we normalize world normals/tangents _before_
interpolation across vertices, and then do _not_ normalize after. I had
it backwards.
- We do not (am not supposed to?) need a second set of barycentrics for
motion vectors. If you think about the typical raster pipeline, in the
vertex shader we calculate previous_world_position, and then it gets
interpolated using the current triangle's barycentrics.
## Solution
- Fix normal/tangent processing
- Reuse barycentrics for motion vector calculations
- Not implementing this for 0.14, but long term I aim to remove explicit
vertex tangents and calculate them in the shader on the fly.
## Testing
- I tested out some of the normal maps we have in repo. Didn't seem to
make a difference, but mikktspace is all about correctness across
various baking tools. I probably just didn't have any of the ones that
would cause it to break.
- Didn't test motion vectors as there's a known bug with the depth
buffer and meshlets that I'm waiting on the render graph rewrite to fix.
# Objective
- If the fog is disabled it still generates a useless branch which can
hurt performance
## Solution
- Make the flag a shader_def instead
## Testing
- I tested enabling/disabling fog works as expected per-material in the
fog example
- I also tested that scenes that don't add the FogSettings resource
still work correctly
## Review notes
I'm not sure how to handle the removed material flag. Right now I just
commented it out and added a not to reuse it instead of creating a new
one.
# Objective
One thing missing from the new Color implementation in 0.14 is the
ability to easily convert to a u8 representation of the rgb color.
(note this is a redo of PR https://github.com/bevyengine/bevy/pull/13739
as I needed to move the source branch
## Solution
I have added to_u8_array and to_u8_array_no_alpha to a new trait called
ColorToPacked to mirror the f32 conversions in ColorToComponents and
implemented the new trait for Srgba and LinearRgba.
To go with those I also added matching from_u8... functions and
converted a couple of cases that used ad-hoc implementations of that
conversion to use these.
After discussion on Discord of the experience of using the API I renamed
Color::linear to Color::to_linear, as without that it looks like a
constructor (like Color::rgb).
I also added to_srgba which is the other commonly converted to type of
color (for UI and 2D) to match to_linear.
Removed a redundant extra implementation of to_f32_array for LinearColor
as it is also supplied in ColorToComponents (I'm surprised that's
allowed?)
## Testing
Ran all tests and manually tested.
Added to_and_from_u8 to linear_rgba::tests
## Changelog
visible change is Color::linear becomes Color::to_linear.
---------
Co-authored-by: John Payne <20407779+johngpayne@users.noreply.github.com>
# Objective
- apply_normal_mapping was changed to use TBN but the pbr_prepass was
not updated for that change
## Solution
- Update the pbr_prepass to correctly apply normal mapping
* Rename cull_meshlets -> cull_clusters
* Rename meshlet_visible -> cluster_visible
* Add an if statement around meshlet_second_pass_candidates writes,
maybe a small bit of performance.
We want to use the clustering infrastructure for light probes and decals
as well, not just point lights. This patch builds on top of #13640 and
performs the rename.
To make this series easier to review, this patch makes no code changes.
Only identifiers and comments are modified.
## Migration Guide
* In the PBR shaders, `point_lights` is now known as
`clusterable_objects`, `PointLight` is now known as `ClusterableObject`,
and `cluster_light_index_lists` is now known as
`clusterable_object_index_lists`.
This commit implements support for physically-based anisotropy in Bevy's
`StandardMaterial`, following the specification for the
[`KHR_materials_anisotropy`] glTF extension.
[*Anisotropy*] (not to be confused with [anisotropic filtering]) is a
PBR feature that allows roughness to vary along the tangent and
bitangent directions of a mesh. In effect, this causes the specular
light to stretch out into lines instead of a round lobe. This is useful
for modeling brushed metal, hair, and similar surfaces. Support for
anisotropy is a common feature in major game and graphics engines;
Unity, Unreal, Godot, three.js, and Blender all support it to varying
degrees.
Two new parameters have been added to `StandardMaterial`:
`anisotropy_strength` and `anisotropy_rotation`. Anisotropy strength,
which ranges from 0 to 1, represents how much the roughness differs
between the tangent and the bitangent of the mesh. In effect, it
controls how stretched the specular highlight is. Anisotropy rotation
allows the roughness direction to differ from the tangent of the model.
In addition to these two fixed parameters, an *anisotropy texture* can
be supplied. Such a texture should be a 3-channel RGB texture, where the
red and green values specify a direction vector using the same
conventions as a normal map ([0, 1] color values map to [-1, 1] vector
values), and the the blue value represents the strength. This matches
the format that the [`KHR_materials_anisotropy`] specification requires.
Such textures should be loaded as linear and not sRGB. Note that this
texture does consume one additional texture binding in the standard
material shader.
The glTF loader has been updated to properly parse the
`KHR_materials_anisotropy` extension.
A new example, `anisotropy`, has been added. This example loads and
displays the barn lamp example from the [`glTF-Sample-Assets`]
repository. Note that the textures were rather large, so I shrunk them
down and converted them to a mixture of JPEG and KTX2 format, in the
interests of saving space in the Bevy repository.
[*Anisotropy*]:
https://google.github.io/filament/Filament.md.html#materialsystem/anisotropicmodel
[anisotropic filtering]:
https://en.wikipedia.org/wiki/Anisotropic_filtering
[`KHR_materials_anisotropy`]:
https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_materials_anisotropy/README.md
[`glTF-Sample-Assets`]:
https://github.com/KhronosGroup/glTF-Sample-Assets/
## Changelog
### Added
* Physically-based anisotropy is now available for materials, which
enhances the look of surfaces such as brushed metal or hair. glTF scenes
can use the new feature with the `KHR_materials_anisotropy` extension.
## Screenshots
With anisotropy:
Without anisotropy:
# Objective
- Fixes#10909
- Fixes#8492
## Solution
- Name all matrices `x_from_y`, for example `world_from_view`.
## Testing
- I've tested most of the 3D examples. The `lighting` example
particularly should hit a lot of the changes and appears to run fine.
---
## Changelog
- Renamed matrices across the engine to follow a `y_from_x` naming,
making the space conversion more obvious.
## Migration Guide
- `Frustum`'s `from_view_projection`, `from_view_projection_custom_far`
and `from_view_projection_no_far` were renamed to
`from_clip_from_world`, `from_clip_from_world_custom_far` and
`from_clip_from_world_no_far`.
- `ComputedCameraValues::projection_matrix` was renamed to
`clip_from_view`.
- `CameraProjection::get_projection_matrix` was renamed to
`get_clip_from_view` (this affects implementations on `Projection`,
`PerspectiveProjection` and `OrthographicProjection`).
- `ViewRangefinder3d::from_view_matrix` was renamed to
`from_world_from_view`.
- `PreviousViewData`'s members were renamed to `view_from_world` and
`clip_from_world`.
- `ExtractedView`'s `projection`, `transform` and `view_projection` were
renamed to `clip_from_view`, `world_from_view` and `clip_from_world`.
- `ViewUniform`'s `view_proj`, `unjittered_view_proj`,
`inverse_view_proj`, `view`, `inverse_view`, `projection` and
`inverse_projection` were renamed to `clip_from_world`,
`unjittered_clip_from_world`, `world_from_clip`, `world_from_view`,
`view_from_world`, `clip_from_view` and `view_from_clip`.
- `GpuDirectionalCascade::view_projection` was renamed to
`clip_from_world`.
- `MeshTransforms`' `transform` and `previous_transform` were renamed to
`world_from_local` and `previous_world_from_local`.
- `MeshUniform`'s `transform`, `previous_transform`,
`inverse_transpose_model_a` and `inverse_transpose_model_b` were renamed
to `world_from_local`, `previous_world_from_local`,
`local_from_world_transpose_a` and `local_from_world_transpose_b` (the
`Mesh` type in WGSL mirrors this, however `transform` and
`previous_transform` were named `model` and `previous_model`).
- `Mesh2dTransforms::transform` was renamed to `world_from_local`.
- `Mesh2dUniform`'s `transform`, `inverse_transpose_model_a` and
`inverse_transpose_model_b` were renamed to `world_from_local`,
`local_from_world_transpose_a` and `local_from_world_transpose_b` (the
`Mesh2d` type in WGSL mirrors this).
- In WGSL, in `bevy_pbr::mesh_functions`, `get_model_matrix` and
`get_previous_model_matrix` were renamed to `get_world_from_local` and
`get_previous_world_from_local`.
- In WGSL, `bevy_sprite::mesh2d_functions::get_model_matrix` was renamed
to `get_world_from_local`.
As a prerequisite for decals and clustering of light probes, we want
clustering to operate on objects other than lights. (Currently, it only
operates on point and spot lights.) This necessitates a large
refactoring, so I'm splitting it up into small steps.
The first such step is to separate clustering from lighting by moving
clustering-related types and functions out of lighting and into their
own module subtree within the `bevy_pbr` crate. (Ultimately, we may want
to move it to `bevy_render`, but that requires more work and can be a
followup.)
No code changes have been made other than adjusting import lists and
moving code. This is to make this code easy to review. Ultimately, I
want to rename "light" to "clusterable object" in most cases, but doing
that at the same time as moving the code would make reviewing harder. So
instead I'm moving the code first and will follow this up with renaming.
## Migration Guide
* Clustering-related types and functions (e.g.
`assign_lights_to_clusters`) have moved under `bevy_pbr::cluster`, in
preparation for the ability to cluster objects other than lights.
# Objective
- Using multiple raster passes to generate the depth pyramid is
extremely slow
- Pulling data from the source image is the largest bottleneck, it's
important to sample in a cache-aware pattern
- Barriers and pipeline drain between the raster passes is the second
largest bottleneck
- Each separate RenderPass on the CPU is _really_ expensive
## Solution
- Port [FidelityFX SPD](https://gpuopen.com/fidelityfx-spd) to WGSL,
replacing meshlet's existing multiple raster passes with a ~~single~~
two compute dispatches. Lack of coherent buffers means we have to do the
the last 64x64 tile from mip 7+ in a separate dispatch to ensure the mip
6 writes were flushed :(
- Workgroup shared memory version only at the moment, as the subgroup
operation is blocked by our upgrade to wgpu 0.20 #13186
- Don't enforce a power-of-2 depth pyramid texture size, simply scaling
by 0.5 is fine
# Objective
- Add motion vector support to the skybox
- This fixes the last remaining "gap" to complete the motion blur
feature
## Solution
- Add a pipeline for the skybox to write motion vectors to the prepass
## Testing
- Used examples to test motion vectors using motion blur
https://github.com/bevyengine/bevy/assets/2632925/74c0778a-7e77-4e68-8111-05791e4bfdd2
---------
Co-authored-by: Patrick Walton <pcwalton@mimiga.net>
# Objective
- The current version of the `meshopt` dependency is incorrect, as
`bevy_pbr` uses features introduced in `meshopt` `0.2.1`
- This causes errors like this when only `meshopt` `0.2` is present in
`Cargo.lock`:
```
error[E0432]: unresolved imports
`meshopt::ffi::meshopt_optimizeMeshlet`, `meshopt::simplify_scale`
--> crates\bevy_pbr\src\meshlet\from_mesh.rs:10:27
|
10 | ffi::{meshopt_Bounds, meshopt_optimizeMeshlet},
| ^^^^^^^^^^^^^^^^^^^^^^^
| no `meshopt_optimizeMeshlet` in `ffi`
| help: a similar name exists in the module: `meshopt_optimizeOverdraw`
11 | simplify, simplify_scale, Meshlets, SimplifyOptions,
VertexDataAdapter,
| ^^^^^^^^^^^^^^ no `simplify_scale` in the root
```
## Solution
- Specify the actual minimum version of `meshopt` that `bevy_pbr`
requires
This is a revamped equivalent to #9902, though it shares none of the
code. It handles all special cases that I've tested correctly.
The overall technique consists of double-buffering the joint matrix and
morph weights buffers, as most of the previous attempts to solve this
problem did. The process is generally straightforward. Note that, to
avoid regressing the ability of mesh extraction, skin extraction, and
morph target extraction to run in parallel, I had to add a new system to
rendering, `set_mesh_motion_vector_flags`. The comment there explains
the details; it generally runs very quickly.
I've tested this with modified versions of the `animated_fox`,
`morph_targets`, and `many_foxes` examples that add TAA, and the patch
works. To avoid bloating those examples, I didn't add switches for TAA
to them.
Addresses points (1) and (2) of #8423.
## Changelog
### Fixed
* Motion vectors, and therefore TAA, are now supported for meshes with
skins and/or morph targets.
Fixes#13118
If you use `Sprite` or `Mesh2d` and create `Camera` with
* hdr=false
* any tonemapper
You would get
```
wgpu error: Validation Error
Caused by:
In Device::create_render_pipeline
note: label = `sprite_pipeline`
Error matching ShaderStages(FRAGMENT) shader requirements against the pipeline
Shader global ResourceBinding { group: 0, binding: 19 } is not available in the pipeline layout
Binding is missing from the pipeline layout
```
Because of missing tonemapping LUT bindings
## Solution
Add missing bindings for tonemapping LUT's to `SpritePipeline` &
`Mesh2dPipeline`
## Testing
I checked that
* `tonemapping`
* `color_grading`
* `sprite_animations`
* `2d_shapes`
* `meshlet`
* `deferred_rendering`
examples are still working
2d cases I checked with this code:
```
use bevy::{
color::palettes::css::PURPLE, core_pipeline::tonemapping::Tonemapping, prelude::*,
sprite::MaterialMesh2dBundle,
};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, toggle_tonemapping_method)
.run();
}
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<ColorMaterial>>,
asset_server: Res<AssetServer>,
) {
commands.spawn(Camera2dBundle {
camera: Camera {
hdr: false,
..default()
},
tonemapping: Tonemapping::BlenderFilmic,
..default()
});
commands.spawn(MaterialMesh2dBundle {
mesh: meshes.add(Rectangle::default()).into(),
transform: Transform::default().with_scale(Vec3::splat(128.)),
material: materials.add(Color::from(PURPLE)),
..default()
});
commands.spawn(SpriteBundle {
texture: asset_server.load("asd.png"),
..default()
});
}
fn toggle_tonemapping_method(
keys: Res<ButtonInput<KeyCode>>,
mut tonemapping: Query<&mut Tonemapping>,
) {
let mut method = tonemapping.single_mut();
if keys.just_pressed(KeyCode::Digit1) {
*method = Tonemapping::None;
} else if keys.just_pressed(KeyCode::Digit2) {
*method = Tonemapping::Reinhard;
} else if keys.just_pressed(KeyCode::Digit3) {
*method = Tonemapping::ReinhardLuminance;
} else if keys.just_pressed(KeyCode::Digit4) {
*method = Tonemapping::AcesFitted;
} else if keys.just_pressed(KeyCode::Digit5) {
*method = Tonemapping::AgX;
} else if keys.just_pressed(KeyCode::Digit6) {
*method = Tonemapping::SomewhatBoringDisplayTransform;
} else if keys.just_pressed(KeyCode::Digit7) {
*method = Tonemapping::TonyMcMapface;
} else if keys.just_pressed(KeyCode::Digit8) {
*method = Tonemapping::BlenderFilmic;
}
}
```
---
## Changelog
Fix the bug which led to the crash when user uses any tonemapper without
hdr for rendering sprites and 2d meshes.
# Objective
- Fixes#13521
## Solution
Set `ambient_intensity` to 0.0 in volumetric_fog example.
I chose setting it explicitly over changing the default in order to make
it clear that this needs to be set depending on whether you have an
`EnvironmentMapLight`. See documentation for `ambient_intensity` and
related members.
## Testing
- Run the volumetric_fog example and notice how the light shown in
#13521 is not there anymore, as expected.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- #13418 broke volumetric fog
```
wgpu error: Validation Error
Caused by:
In a RenderPass
note: encoder = `<CommandBuffer-(2, 4, Metal)>`
In a set_bind_group command
note: bind group = `mesh_view_bind_group`
Bind group 0 expects 5 dynamic offsets. However 4 dynamic offsets were provided.
```
## Solution
- add ssr offset to volumetric fog bind group
This commit, a revamp of #12959, implements screen-space reflections
(SSR), which approximate real-time reflections based on raymarching
through the depth buffer and copying samples from the final rendered
frame. This patch is a relatively minimal implementation of SSR, so as
to provide a flexible base on which to customize and build in the
future. However, it's based on the production-quality [raymarching code
by Tomasz
Stachowiak](https://gist.github.com/h3r2tic/9c8356bdaefbe80b1a22ae0aaee192db).
For a general basic overview of screen-space reflections, see
[1](https://lettier.github.io/3d-game-shaders-for-beginners/screen-space-reflection.html).
The raymarching shader uses the basic algorithm of tracing forward in
large steps, refining that trace in smaller increments via binary
search, and then using the secant method. No temporal filtering or
roughness blurring, is performed at all; for this reason, SSR currently
only operates on very shiny surfaces. No acceleration via the
hierarchical Z-buffer is implemented (though note that
https://github.com/bevyengine/bevy/pull/12899 will add the
infrastructure for this). Reflections are traced at full resolution,
which is often considered slow. All of these improvements and more can
be follow-ups.
SSR is built on top of the deferred renderer and is currently only
supported in that mode. Forward screen-space reflections are possible
albeit uncommon (though e.g. *Doom Eternal* uses them); however, they
require tracing from the previous frame, which would add complexity.
This patch leaves the door open to implementing SSR in the forward
rendering path but doesn't itself have such an implementation.
Screen-space reflections aren't supported in WebGL 2, because they
require sampling from the depth buffer, which Naga can't do because of a
bug (`sampler2DShadow` is incorrectly generated instead of `sampler2D`;
this is the same reason why depth of field is disabled on that
platform).
To add screen-space reflections to a camera, use the
`ScreenSpaceReflectionsBundle` bundle or the
`ScreenSpaceReflectionsSettings` component. In addition to
`ScreenSpaceReflectionsSettings`, `DepthPrepass` and `DeferredPrepass`
must also be present for the reflections to show up. The
`ScreenSpaceReflectionsSettings` component contains several settings
that artists can tweak, and also comes with sensible defaults.
A new example, `ssr`, has been added. It's loosely based on the
[three.js ocean
sample](https://threejs.org/examples/webgl_shaders_ocean.html), but all
the assets are original. Note that the three.js demo has no screen-space
reflections and instead renders a mirror world. In contrast to #12959,
this demo tests not only a cube but also a more complex model (the
flight helmet).
## Changelog
### Added
* Screen-space reflections can be enabled for very smooth surfaces by
adding the `ScreenSpaceReflections` component to a camera. Deferred
rendering must be enabled for the reflections to appear.
This commit makes us stop using the render world ECS for
`BinnedRenderPhase` and `SortedRenderPhase` and instead use resources
with `EntityHashMap`s inside. There are three reasons to do this:
1. We can use `clear()` to clear out the render phase collections
instead of recreating the components from scratch, allowing us to reuse
allocations.
2. This is a prerequisite for retained bins, because components can't be
retained from frame to frame in the render world, but resources can.
3. We want to move away from storing anything in components in the
render world ECS, and this is a step in that direction.
This patch results in a small performance benefit, due to point (1)
above.
## Changelog
### Changed
* The `BinnedRenderPhase` and `SortedRenderPhase` render world
components have been replaced with `ViewBinnedRenderPhases` and
`ViewSortedRenderPhases` resources.
## Migration Guide
* The `BinnedRenderPhase` and `SortedRenderPhase` render world
components have been replaced with `ViewBinnedRenderPhases` and
`ViewSortedRenderPhases` resources. Instead of querying for the
components, look the camera entity up in the
`ViewBinnedRenderPhases`/`ViewSortedRenderPhases` tables.
Commit 3f5a090b1b added a reference to
`STANDARD_MATERIAL_FLAGS_BASE_COLOR_UV_BIT`, a nonexistent identifier,
in the alpha discard portion of the prepass shader. Moreover, the logic
didn't make sense to me. I think the code was trying to choose between
the two UV sets depending on which is present, so I made it do that.
I noticed this when trying Bistro with #13277. I'm not sure why this
issue didn't manifest itself before, but it's clearly a bug, so here's a
fix. We should probably merge this before 0.14.
# Objective
- The volumetric fog PR originally needed to be modified to use
`.view_layouts` but that was changed in another PR. The merge with main
still kept those around.
## Solution
- Remove them because they aren't necessary
This commit implements a more physically-accurate, but slower, form of
fog than the `bevy_pbr::fog` module does. Notably, this *volumetric fog*
allows for light beams from directional lights to shine through,
creating what is known as *light shafts* or *god rays*.
To add volumetric fog to a scene, add `VolumetricFogSettings` to the
camera, and add `VolumetricLight` to directional lights that you wish to
be volumetric. `VolumetricFogSettings` has numerous settings that allow
you to define the accuracy of the simulation, as well as the look of the
fog. Currently, only interaction with directional lights that have
shadow maps is supported. Note that the overhead of the effect scales
directly with the number of directional lights in use, so apply
`VolumetricLight` sparingly for the best results.
The overall algorithm, which is implemented as a postprocessing effect,
is a combination of the techniques described in [Scratchapixel] and
[this blog post]. It uses raymarching in screen space, transformed into
shadow map space for sampling and combined with physically-based
modeling of absorption and scattering. Bevy employs the widely-used
[Henyey-Greenstein phase function] to model asymmetry; this essentially
allows light shafts to fade into and out of existence as the user views
them.
Volumetric rendering is a huge subject, and I deliberately kept the
scope of this commit small. Possible follow-ups include:
1. Raymarching at a lower resolution.
2. A post-processing blur (especially useful when combined with (1)).
3. Supporting point lights and spot lights.
4. Supporting lights with no shadow maps.
5. Supporting irradiance volumes and reflection probes.
6. Voxel components that reuse the volumetric fog code to create voxel
shapes.
7. *Horizon: Zero Dawn*-style clouds.
These are all useful, but out of scope of this patch for now, to keep
things tidy and easy to review.
A new example, `volumetric_fog`, has been added to demonstrate the
effect.
## Changelog
### Added
* A new component, `VolumetricFog`, is available, to allow for a more
physically-accurate, but more resource-intensive, form of fog.
* A new component, `VolumetricLight`, can be placed on directional
lights to make them interact with `VolumetricFog`. Notably, this allows
such lights to emit light shafts/god rays.
[Scratchapixel]:
https://www.scratchapixel.com/lessons/3d-basic-rendering/volume-rendering-for-developers/intro-volume-rendering.html
[this blog post]: https://www.alexandre-pestana.com/volumetric-lights/
[Henyey-Greenstein phase function]:
https://www.pbr-book.org/4ed/Volume_Scattering/Phase_Functions#TheHenyeyndashGreensteinPhaseFunction
