Fixes#15834
## Migration Guide
The APIs of `Time`, `Timer` and `Stopwatch` have been cleaned up for
consistency with each other and the standard library's `Duration` type.
The following methods have been renamed:
- `Stowatch::paused` -> `Stopwatch::is_paused`
- `Time::elapsed_seconds` -> `Time::elasped_secs` (including `_f64` and
`_wrapped` variants)
**Ready for review. Examples migration progress: 100%.**
# Objective
- Implement https://github.com/bevyengine/bevy/discussions/15014
## Solution
This implements [cart's
proposal](https://github.com/bevyengine/bevy/discussions/15014#discussioncomment-10574459)
faithfully except for one change. I separated `TextSpan` from
`TextSpan2d` because `TextSpan` needs to require the `GhostNode`
component, which is a `bevy_ui` component only usable by UI.
Extra changes:
- Added `EntityCommands::commands_mut` that returns a mutable reference.
This is a blocker for extension methods that return something other than
`self`. Note that `sickle_ui`'s `UiBuilder::commands` returns a mutable
reference for this reason.
## Testing
- [x] Text examples all work.
---
## Showcase
TODO: showcase-worthy
## Migration Guide
TODO: very breaking
### Accessing text spans by index
Text sections are now text sections on different entities in a
hierarchy, Use the new `TextReader` and `TextWriter` system parameters
to access spans by index.
Before:
```rust
fn refresh_text(mut query: Query<&mut Text, With<TimeText>>, time: Res<Time>) {
let text = query.single_mut();
text.sections[1].value = format_time(time.elapsed());
}
```
After:
```rust
fn refresh_text(
query: Query<Entity, With<TimeText>>,
mut writer: UiTextWriter,
time: Res<Time>
) {
let entity = query.single();
*writer.text(entity, 1) = format_time(time.elapsed());
}
```
### Iterating text spans
Text spans are now entities in a hierarchy, so the new `UiTextReader`
and `UiTextWriter` system parameters provide ways to iterate that
hierarchy. The `UiTextReader::iter` method will give you a normal
iterator over spans, and `UiTextWriter::for_each` lets you visit each of
the spans.
---------
Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
Getting closer to the end! Another part of the required components
migration: reflection probes.
## Solution
As per the [proposal added by
Cart](https://hackmd.io/@bevy/required_components/%2FNmpIh0tGSiayGlswbfcEzw)
(Proposal 2), make `LightProbe` require `Transform` and `Visibility`,
and deprecate `ReflectionProbeBundle`.
Note that this proposal wasn't officially blessed yet, but it is the
only existing one that really works, so I implemented it here for
consideration.
## Testing
I ran the reflection probe example, and it appears to work.
---
## Migration Guide
`ReflectionProbeBundle` has been deprecated in favor of inserting the
`LightProbe` and `EnvironmentMapLight` components directly. Inserting
them will now automatically insert `Transform` and `Visibility`
components.
---------
Co-authored-by: Tim Blackbird <justthecooldude@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Yet another PR for migrating stuff to required components. This time,
cameras!
## Solution
As per the [selected
proposal](https://hackmd.io/tsYID4CGRiWxzsgawzxG_g#Combined-Proposal-1-Selected),
deprecate `Camera2dBundle` and `Camera3dBundle` in favor of `Camera2d`
and `Camera3d`.
Adding a `Camera` without `Camera2d` or `Camera3d` now logs a warning,
as suggested by Cart [on
Discord](https://discord.com/channels/691052431525675048/1264881140007702558/1291506402832945273).
I would personally like cameras to work a bit differently and be split
into a few more components, to avoid some footguns and confusing
semantics, but that is more controversial, and shouldn't block this core
migration.
## Testing
I ran a few 2D and 3D examples, and tried cameras with and without
render graphs.
---
## Migration Guide
`Camera2dBundle` and `Camera3dBundle` have been deprecated in favor of
`Camera2d` and `Camera3d`. Inserting them will now also insert the other
components required by them automatically.
# Objective
A step in the migration to required components: scenes!
## Solution
As per the [selected
proposal](https://hackmd.io/@bevy/required_components/%2FPJtNGVMMQhyM0zIvCJSkbA):
- Deprecate `SceneBundle` and `DynamicSceneBundle`.
- Add `SceneRoot` and `DynamicSceneRoot` components, which wrap a
`Handle<Scene>` and `Handle<DynamicScene>` respectively.
## Migration Guide
Asset handles for scenes and dynamic scenes must now be wrapped in the
`SceneRoot` and `DynamicSceneRoot` components. Raw handles as components
no longer spawn scenes.
Additionally, `SceneBundle` and `DynamicSceneBundle` have been
deprecated. Instead, use the scene components directly.
Previously:
```rust
let model_scene = asset_server.load(GltfAssetLabel::Scene(0).from_asset("model.gltf"));
commands.spawn(SceneBundle {
scene: model_scene,
transform: Transform::from_xyz(-4.0, 0.0, -3.0),
..default()
});
```
Now:
```rust
let model_scene = asset_server.load(GltfAssetLabel::Scene(0).from_asset("model.gltf"));
commands.spawn((
SceneRoot(model_scene),
Transform::from_xyz(-4.0, 0.0, -3.0),
));
```
# Objective
A big step in the migration to required components: meshes and
materials!
## Solution
As per the [selected
proposal](https://hackmd.io/@bevy/required_components/%2Fj9-PnF-2QKK0on1KQ29UWQ):
- Deprecate `MaterialMesh2dBundle`, `MaterialMeshBundle`, and
`PbrBundle`.
- Add `Mesh2d` and `Mesh3d` components, which wrap a `Handle<Mesh>`.
- Add `MeshMaterial2d<M: Material2d>` and `MeshMaterial3d<M: Material>`,
which wrap a `Handle<M>`.
- Meshes *without* a mesh material should be rendered with a default
material. The existence of a material is determined by
`HasMaterial2d`/`HasMaterial3d`, which is required by
`MeshMaterial2d`/`MeshMaterial3d`. This gets around problems with the
generics.
Previously:
```rust
commands.spawn(MaterialMesh2dBundle {
mesh: meshes.add(Circle::new(100.0)).into(),
material: materials.add(Color::srgb(7.5, 0.0, 7.5)),
transform: Transform::from_translation(Vec3::new(-200., 0., 0.)),
..default()
});
```
Now:
```rust
commands.spawn((
Mesh2d(meshes.add(Circle::new(100.0))),
MeshMaterial2d(materials.add(Color::srgb(7.5, 0.0, 7.5))),
Transform::from_translation(Vec3::new(-200., 0., 0.)),
));
```
If the mesh material is missing, previously nothing was rendered. Now,
it renders a white default `ColorMaterial` in 2D and a
`StandardMaterial` in 3D (this can be overridden). Below, only every
other entity has a material:
Why white? This is still open for discussion, but I think white makes
sense for a *default* material, while *invalid* asset handles pointing
to nothing should have something like a pink material to indicate that
something is broken (I don't handle that in this PR yet). This is kind
of a mix of Godot and Unity: Godot just renders a white material for
non-existent materials, while Unity renders nothing when no materials
exist, but renders pink for invalid materials. I can also change the
default material to pink if that is preferable though.
## Testing
I ran some 2D and 3D examples to test if anything changed visually. I
have not tested all examples or features yet however. If anyone wants to
test more extensively, it would be appreciated!
## Implementation Notes
- The relationship between `bevy_render` and `bevy_pbr` is weird here.
`bevy_render` needs `Mesh3d` for its own systems, but `bevy_pbr` has all
of the material logic, and `bevy_render` doesn't depend on it. I feel
like the two crates should be refactored in some way, but I think that's
out of scope for this PR.
- I didn't migrate meshlets to required components yet. That can
probably be done in a follow-up, as this is already a huge PR.
- It is becoming increasingly clear to me that we really, *really* want
to disallow raw asset handles as components. They caused me a *ton* of
headache here already, and it took me a long time to find every place
that queried for them or inserted them directly on entities, since there
were no compiler errors for it. If we don't remove the `Component`
derive, I expect raw asset handles to be a *huge* footgun for users as
we transition to wrapper components, especially as handles as components
have been the norm so far. I personally consider this to be a blocker
for 0.15: we need to migrate to wrapper components for asset handles
everywhere, and remove the `Component` derive. Also see
https://github.com/bevyengine/bevy/issues/14124.
---
## Migration Guide
Asset handles for meshes and mesh materials must now be wrapped in the
`Mesh2d` and `MeshMaterial2d` or `Mesh3d` and `MeshMaterial3d`
components for 2D and 3D respectively. Raw handles as components no
longer render meshes.
Additionally, `MaterialMesh2dBundle`, `MaterialMeshBundle`, and
`PbrBundle` have been deprecated. Instead, use the mesh and material
components directly.
Previously:
```rust
commands.spawn(MaterialMesh2dBundle {
mesh: meshes.add(Circle::new(100.0)).into(),
material: materials.add(Color::srgb(7.5, 0.0, 7.5)),
transform: Transform::from_translation(Vec3::new(-200., 0., 0.)),
..default()
});
```
Now:
```rust
commands.spawn((
Mesh2d(meshes.add(Circle::new(100.0))),
MeshMaterial2d(materials.add(Color::srgb(7.5, 0.0, 7.5))),
Transform::from_translation(Vec3::new(-200., 0., 0.)),
));
```
If the mesh material is missing, a white default material is now used.
Previously, nothing was rendered if the material was missing.
The `WithMesh2d` and `WithMesh3d` query filter type aliases have also
been removed. Simply use `With<Mesh2d>` or `With<Mesh3d>`.
---------
Co-authored-by: Tim Blackbird <justthecooldude@gmail.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Fixes: https://github.com/bevyengine/bevy/issues/14036
## Solution
- Add a world space transformation for the environment sample direction.
## Testing
- I have tested the newly added `transform` field using the newly added
`rotate_environment_map` example.
https://github.com/user-attachments/assets/2de77c65-14bc-48ee-b76a-fb4e9782dbdb
## Migration Guide
- Since we have added a new filed to the `EnvironmentMapLight` struct,
users will need to include `..default()` or some rotation value in their
initialization code.
# Objective
- Fixes https://github.com/bevyengine/bevy/issues/14036
## Solution
- Add a view space transformation for the skybox
## Testing
- I have tested the newly added `transform` field using the `skybox`
example.
```
diff --git a/examples/3d/skybox.rs b/examples/3d/skybox.rs
index beaf5b268..d16cbe988 100644
--- a/examples/3d/skybox.rs
+++ b/examples/3d/skybox.rs
@@ -81,6 +81,7 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
Skybox {
image: skybox_handle.clone(),
brightness: 1000.0,
+ rotation: Quat::from_rotation_x(PI * -0.5),
},
));
```
<img width="1280" alt="image"
src="https://github.com/bevyengine/bevy/assets/6300263/1230a608-58ea-492d-a811-90c54c3b43ef">
## Migration Guide
- Since we have added a new filed to the Skybox struct, users will need
to include `..Default::default()` or some rotation value in their
initialization code.
# Objective
- Followup to #13548
- It added a list of all possible labels to documentation. This seems
hard to keep up and doesn't stop people from making spelling mistake
## Solution
- Add an enum that can create all the labels possible, and encourage its
use rather than manually typed labels
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: Rob Parrett <robparrett@gmail.com>
# Objective
- The default font size is too small to be useful in examples or for
debug text.
- Fixes#13587
## Solution
- Updated the default font size value in `TextStyle` from 12px to 24px.
- Resorted to Text defaults in examples to use the default font size in
most of them.
## Testing
- WIP
---
## Migration Guide
- The default font size has been increased to 24px from 12px. Make sure
you set the font to the appropriate values in places you were using
`Default` text style.
## Objective
Use the "standard" text size / placement for the new text in these
examples.
Continuation of an effort started here:
https://github.com/bevyengine/bevy/pull/8478
This is definitely not comprehensive. I did the ones that were easy to
find and relatively straightforward updates. I meant to just do
`3d_shapes` and `2d_shapes`, but one thing lead to another.
## Solution
Use `font_size: 20.0`, the default (built-in) font, `Color::WHITE`
(default), and `Val::Px(12.)` from the edges of the screen.
There are a few little drive-by cleanups of defaults not being used,
etc.
## Testing
Ran the changed examples, verified that they still look reasonable.
# Objective
- As part of the migration process we need to a) see the end effect of
the migration on user ergonomics b) check for serious perf regressions
c) actually migrate the code
- To accomplish this, I'm going to attempt to migrate all of the
remaining user-facing usages of `LegacyColor` in one PR, being careful
to keep a clean commit history.
- Fixes#12056.
## Solution
I've chosen to use the polymorphic `Color` type as our standard
user-facing API.
- [x] Migrate `bevy_gizmos`.
- [x] Take `impl Into<Color>` in all `bevy_gizmos` APIs
- [x] Migrate sprites
- [x] Migrate UI
- [x] Migrate `ColorMaterial`
- [x] Migrate `MaterialMesh2D`
- [x] Migrate fog
- [x] Migrate lights
- [x] Migrate StandardMaterial
- [x] Migrate wireframes
- [x] Migrate clear color
- [x] Migrate text
- [x] Migrate gltf loader
- [x] Register color types for reflection
- [x] Remove `LegacyColor`
- [x] Make sure CI passes
Incidental improvements to ease migration:
- added `Color::srgba_u8`, `Color::srgba_from_array` and friends
- added `set_alpha`, `is_fully_transparent` and `is_fully_opaque` to the
`Alpha` trait
- add and immediately deprecate (lol) `Color::rgb` and friends in favor
of more explicit and consistent `Color::srgb`
- standardized on white and black for most example text colors
- added vector field traits to `LinearRgba`: ~~`Add`, `Sub`,
`AddAssign`, `SubAssign`,~~ `Mul<f32>` and `Div<f32>`. Multiplications
and divisions do not scale alpha. `Add` and `Sub` have been cut from
this PR.
- added `LinearRgba` and `Srgba` `RED/GREEN/BLUE`
- added `LinearRgba_to_f32_array` and `LinearRgba::to_u32`
## Migration Guide
Bevy's color types have changed! Wherever you used a
`bevy::render::Color`, a `bevy::color::Color` is used instead.
These are quite similar! Both are enums storing a color in a specific
color space (or to be more precise, using a specific color model).
However, each of the different color models now has its own type.
TODO...
- `Color::rgba`, `Color::rgb`, `Color::rbga_u8`, `Color::rgb_u8`,
`Color::rgb_from_array` are now `Color::srgba`, `Color::srgb`,
`Color::srgba_u8`, `Color::srgb_u8` and `Color::srgb_from_array`.
- `Color::set_a` and `Color::a` is now `Color::set_alpha` and
`Color::alpha`. These are part of the `Alpha` trait in `bevy_color`.
- `Color::is_fully_transparent` is now part of the `Alpha` trait in
`bevy_color`
- `Color::r`, `Color::set_r`, `Color::with_r` and the equivalents for
`g`, `b` `h`, `s` and `l` have been removed due to causing silent
relatively expensive conversions. Convert your `Color` into the desired
color space, perform your operations there, and then convert it back
into a polymorphic `Color` enum.
- `Color::hex` is now `Srgba::hex`. Call `.into` or construct a
`Color::Srgba` variant manually to convert it.
- `WireframeMaterial`, `ExtractedUiNode`, `ExtractedDirectionalLight`,
`ExtractedPointLight`, `ExtractedSpotLight` and `ExtractedSprite` now
store a `LinearRgba`, rather than a polymorphic `Color`
- `Color::rgb_linear` and `Color::rgba_linear` are now
`Color::linear_rgb` and `Color::linear_rgba`
- The various CSS color constants are no longer stored directly on
`Color`. Instead, they're defined in the `Srgba` color space, and
accessed via `bevy::color::palettes::css`. Call `.into()` on them to
convert them into a `Color` for quick debugging use, and consider using
the much prettier `tailwind` palette for prototyping.
- The `LIME_GREEN` color has been renamed to `LIMEGREEN` to comply with
the standard naming.
- Vector field arithmetic operations on `Color` (add, subtract, multiply
and divide by a f32) have been removed. Instead, convert your colors
into `LinearRgba` space, and perform your operations explicitly there.
This is particularly relevant when working with emissive or HDR colors,
whose color channel values are routinely outside of the ordinary 0 to 1
range.
- `Color::as_linear_rgba_f32` has been removed. Call
`LinearRgba::to_f32_array` instead, converting if needed.
- `Color::as_linear_rgba_u32` has been removed. Call
`LinearRgba::to_u32` instead, converting if needed.
- Several other color conversion methods to transform LCH or HSL colors
into float arrays or `Vec` types have been removed. Please reimplement
these externally or open a PR to re-add them if you found them
particularly useful.
- Various methods on `Color` such as `rgb` or `hsl` to convert the color
into a specific color space have been removed. Convert into
`LinearRgba`, then to the color space of your choice.
- Various implicitly-converting color value methods on `Color` such as
`r`, `g`, `b` or `h` have been removed. Please convert it into the color
space of your choice, then check these properties.
- `Color` no longer implements `AsBindGroup`. Store a `LinearRgba`
internally instead to avoid conversion costs.
---------
Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
Co-authored-by: Afonso Lage <lage.afonso@gmail.com>
Co-authored-by: Rob Parrett <robparrett@gmail.com>
Co-authored-by: Zachary Harrold <zac@harrold.com.au>
# Objective
`FromWorld` is often used to group loading and creation of assets for
resources.
With this setup, users often end up repetitively calling
`.resource::<AssetServer>` and `.resource_mut::<Assets<T>>`, and may
have difficulties handling lifetimes of the returned references.
## Solution
Add extension methods to `World` to add and load assets, through a new
extension trait defined in `bevy_asset`.
### Other considerations
* This might be a bit too "magic", as it makes implicit the resource
access.
* We could also implement `DirectAssetAccessExt` on `App`, but it didn't
feel necessary, as `FromWorld` is the principal use-case here.
---
## Changelog
* Add the `DirectAssetAccessExt` trait, which adds the `add_asset`,
`load_asset` and `load_asset_with_settings` method to the `World` type.
# Objective
The migration process for `bevy_color` (#12013) will be fairly involved:
there will be hundreds of affected files, and a large number of APIs.
## Solution
To allow us to proceed granularly, we're going to keep both
`bevy_color::Color` (new) and `bevy_render::Color` (old) around until
the migration is complete.
However, simply doing this directly is confusing! They're both called
`Color`, making it very hard to tell when a portion of the code has been
ported.
As discussed in #12056, by renaming the old `Color` type, we can make it
easier to gradually migrate over, one API at a time.
## Migration Guide
THIS MIGRATION GUIDE INTENTIONALLY LEFT BLANK.
This change should not be shipped to end users: delete this section in
the final migration guide!
---------
Co-authored-by: Alice Cecile <alice.i.cecil@gmail.com>
# Objective
- Example reflection_probe is not frame rate independent
## Solution
- Use time delta to rotate the camera, use the same rotation speed as
the load_gltf example
31d7fcd9cb/examples/3d/load_gltf.rs (L63)
---
# Objective
After adding configurable exposure, we set the default ev100 value to
`7` (indoor). This brought us out of sync with Blender's configuration
and defaults. This PR changes the default to `9.7` (bright indoor or
very overcast outdoors), as I calibrated in #11577. This feels like a
very reasonable default.
The other changes generally center around tweaking Bevy's lighting
defaults and examples to play nicely with this number, alongside a few
other tweaks and improvements.
Note that for artistic reasons I have reverted some examples, which
changed to directional lights in #11581, back to point lights.
Fixes#11577
---
## Changelog
- Changed `Exposure::ev100` from `7` to `9.7` to better match Blender
- Renamed `ExposureSettings` to `Exposure`
- `Camera3dBundle` now includes `Exposure` for discoverability
- Bumped `FULL_DAYLIGHT ` and `DIRECT_SUNLIGHT` to represent the
middle-to-top of those ranges instead of near the bottom
- Added new `AMBIENT_DAYLIGHT` constant and set that as the new
`DirectionalLight` default illuminance.
- `PointLight` and `SpotLight` now have a default `intensity` of
1,000,000 lumens. This makes them actually useful in the context of the
new "semi-outdoor" exposure and puts them in the "cinema lighting"
category instead of the "common household light" category. They are also
reasonably close to the Blender default.
- `AmbientLight` default has been bumped from `20` to `80`.
## Migration Guide
- The increased `Exposure::ev100` means that all existing 3D lighting
will need to be adjusted to match (DirectionalLights, PointLights,
SpotLights, EnvironmentMapLights, etc). Or alternatively, you can adjust
the `Exposure::ev100` on your cameras to work nicely with your current
lighting values. If you are currently relying on default intensity
values, you might need to change the intensity to achieve the same
effect. Note that in Bevy 0.12, point/spot lights had a different hard
coded ev100 value than directional lights. In Bevy 0.13, they use the
same ev100, so if you have both in your scene, the _scale_ between these
light types has changed and you will likely need to adjust one or both
of them.
# Objective
Fix https://github.com/bevyengine/bevy/issues/11577.
## Solution
Fix the examples, add a few constants to make setting light values
easier, and change the default lighting settings to be more realistic.
(Now designed for an overcast day instead of an indoor environment)
---
I did not include any example-related changes in here.
## Changelogs (not including breaking changes)
### bevy_pbr
- Added `light_consts` module (included in prelude), which contains
common lux and lumen values for lights.
- Added `AmbientLight::NONE` constant, which is an ambient light with a
brightness of 0.
- Added non-EV100 variants for `ExposureSettings`'s EV100 constants,
which allow easier construction of an `ExposureSettings` from a EV100
constant.
## Breaking changes
### bevy_pbr
The several default lighting values were changed:
- `PointLight`'s default `intensity` is now `2000.0`
- `SpotLight`'s default `intensity` is now `2000.0`
- `DirectionalLight`'s default `illuminance` is now
`light_consts::lux::OVERCAST_DAY` (`1000.`)
- `AmbientLight`'s default `brightness` is now `20.0`
# Objective
#11431 and #11688 implemented meshing support for Bevy's new geometric
primitives. The next step is to deprecate the shapes in
`bevy_render::mesh::shape` and to later remove them completely for 0.14.
## Solution
Deprecate the shapes and reduce code duplication by utilizing the
primitive meshing API for the old shapes where possible.
Note that some shapes have behavior that can't be exactly reproduced
with the new primitives yet:
- `Box` is more of an AABB with min/max extents
- `Plane` supports a subdivision count
- `Quad` has a `flipped` property
These types have not been changed to utilize the new primitives yet.
---
## Changelog
- Deprecated all shapes in `bevy_render::mesh::shape`
- Changed all examples to use new primitives for meshing
## Migration Guide
Bevy has previously used rendering-specific types like `UVSphere` and
`Quad` for primitive mesh shapes. These have now been deprecated to use
the geometric primitives newly introduced in version 0.13.
Some examples:
```rust
let before = meshes.add(shape::Box::new(5.0, 0.15, 5.0));
let after = meshes.add(Cuboid::new(5.0, 0.15, 5.0));
let before = meshes.add(shape::Quad::default());
let after = meshes.add(Rectangle::default());
let before = meshes.add(shape::Plane::from_size(5.0));
// The surface normal can now also be specified when using `new`
let after = meshes.add(Plane3d::default().mesh().size(5.0, 5.0));
let before = meshes.add(
Mesh::try_from(shape::Icosphere {
radius: 0.5,
subdivisions: 5,
})
.unwrap(),
);
let after = meshes.add(Sphere::new(0.5).mesh().ico(5).unwrap());
```
This pull request re-submits #10057, which was backed out for breaking
macOS, iOS, and Android. I've tested this version on macOS and Android
and on the iOS simulator.
# Objective
This pull request implements *reflection probes*, which generalize
environment maps to allow for multiple environment maps in the same
scene, each of which has an axis-aligned bounding box. This is a
standard feature of physically-based renderers and was inspired by [the
corresponding feature in Blender's Eevee renderer].
## Solution
This is a minimal implementation of reflection probes that allows
artists to define cuboid bounding regions associated with environment
maps. For every view, on every frame, a system builds up a list of the
nearest 4 reflection probes that are within the view's frustum and
supplies that list to the shader. The PBR fragment shader searches
through the list, finds the first containing reflection probe, and uses
it for indirect lighting, falling back to the view's environment map if
none is found. Both forward and deferred renderers are fully supported.
A reflection probe is an entity with a pair of components, *LightProbe*
and *EnvironmentMapLight* (as well as the standard *SpatialBundle*, to
position it in the world). The *LightProbe* component (along with the
*Transform*) defines the bounding region, while the
*EnvironmentMapLight* component specifies the associated diffuse and
specular cubemaps.
A frequent question is "why two components instead of just one?" The
advantages of this setup are:
1. It's readily extensible to other types of light probes, in particular
*irradiance volumes* (also known as ambient cubes or voxel global
illumination), which use the same approach of bounding cuboids. With a
single component that applies to both reflection probes and irradiance
volumes, we can share the logic that implements falloff and blending
between multiple light probes between both of those features.
2. It reduces duplication between the existing *EnvironmentMapLight* and
these new reflection probes. Systems can treat environment maps attached
to cameras the same way they treat environment maps applied to
reflection probes if they wish.
Internally, we gather up all environment maps in the scene and place
them in a cubemap array. At present, this means that all environment
maps must have the same size, mipmap count, and texture format. A
warning is emitted if this restriction is violated. We could potentially
relax this in the future as part of the automatic mipmap generation
work, which could easily do texture format conversion as part of its
preprocessing.
An easy way to generate reflection probe cubemaps is to bake them in
Blender and use the `export-blender-gi` tool that's part of the
[`bevy-baked-gi`] project. This tool takes a `.blend` file containing
baked cubemaps as input and exports cubemap images, pre-filtered with an
embedded fork of the [glTF IBL Sampler], alongside a corresponding
`.scn.ron` file that the scene spawner can use to recreate the
reflection probes.
Note that this is intentionally a minimal implementation, to aid
reviewability. Known issues are:
* Reflection probes are basically unsupported on WebGL 2, because WebGL
2 has no cubemap arrays. (Strictly speaking, you can have precisely one
reflection probe in the scene if you have no other cubemaps anywhere,
but this isn't very useful.)
* Reflection probes have no falloff, so reflections will abruptly change
when objects move from one bounding region to another.
* As mentioned before, all cubemaps in the world of a given type
(diffuse or specular) must have the same size, format, and mipmap count.
Future work includes:
* Blending between multiple reflection probes.
* A falloff/fade-out region so that reflected objects disappear
gradually instead of vanishing all at once.
* Irradiance volumes for voxel-based global illumination. This should
reuse much of the reflection probe logic, as they're both GI techniques
based on cuboid bounding regions.
* Support for WebGL 2, by breaking batches when reflection probes are
used.
These issues notwithstanding, I think it's best to land this with
roughly the current set of functionality, because this patch is useful
as is and adding everything above would make the pull request
significantly larger and harder to review.
---
## Changelog
### Added
* A new *LightProbe* component is available that specifies a bounding
region that an *EnvironmentMapLight* applies to. The combination of a
*LightProbe* and an *EnvironmentMapLight* offers *reflection probe*
functionality similar to that available in other engines.
[the corresponding feature in Blender's Eevee renderer]:
https://docs.blender.org/manual/en/latest/render/eevee/light_probes/reflection_cubemaps.html
[`bevy-baked-gi`]: https://github.com/pcwalton/bevy-baked-gi
[glTF IBL Sampler]: https://github.com/KhronosGroup/glTF-IBL-Sampler
# Objective
This pull request implements *reflection probes*, which generalize
environment maps to allow for multiple environment maps in the same
scene, each of which has an axis-aligned bounding box. This is a
standard feature of physically-based renderers and was inspired by [the
corresponding feature in Blender's Eevee renderer].
## Solution
This is a minimal implementation of reflection probes that allows
artists to define cuboid bounding regions associated with environment
maps. For every view, on every frame, a system builds up a list of the
nearest 4 reflection probes that are within the view's frustum and
supplies that list to the shader. The PBR fragment shader searches
through the list, finds the first containing reflection probe, and uses
it for indirect lighting, falling back to the view's environment map if
none is found. Both forward and deferred renderers are fully supported.
A reflection probe is an entity with a pair of components, *LightProbe*
and *EnvironmentMapLight* (as well as the standard *SpatialBundle*, to
position it in the world). The *LightProbe* component (along with the
*Transform*) defines the bounding region, while the
*EnvironmentMapLight* component specifies the associated diffuse and
specular cubemaps.
A frequent question is "why two components instead of just one?" The
advantages of this setup are:
1. It's readily extensible to other types of light probes, in particular
*irradiance volumes* (also known as ambient cubes or voxel global
illumination), which use the same approach of bounding cuboids. With a
single component that applies to both reflection probes and irradiance
volumes, we can share the logic that implements falloff and blending
between multiple light probes between both of those features.
2. It reduces duplication between the existing *EnvironmentMapLight* and
these new reflection probes. Systems can treat environment maps attached
to cameras the same way they treat environment maps applied to
reflection probes if they wish.
Internally, we gather up all environment maps in the scene and place
them in a cubemap array. At present, this means that all environment
maps must have the same size, mipmap count, and texture format. A
warning is emitted if this restriction is violated. We could potentially
relax this in the future as part of the automatic mipmap generation
work, which could easily do texture format conversion as part of its
preprocessing.
An easy way to generate reflection probe cubemaps is to bake them in
Blender and use the `export-blender-gi` tool that's part of the
[`bevy-baked-gi`] project. This tool takes a `.blend` file containing
baked cubemaps as input and exports cubemap images, pre-filtered with an
embedded fork of the [glTF IBL Sampler], alongside a corresponding
`.scn.ron` file that the scene spawner can use to recreate the
reflection probes.
Note that this is intentionally a minimal implementation, to aid
reviewability. Known issues are:
* Reflection probes are basically unsupported on WebGL 2, because WebGL
2 has no cubemap arrays. (Strictly speaking, you can have precisely one
reflection probe in the scene if you have no other cubemaps anywhere,
but this isn't very useful.)
* Reflection probes have no falloff, so reflections will abruptly change
when objects move from one bounding region to another.
* As mentioned before, all cubemaps in the world of a given type
(diffuse or specular) must have the same size, format, and mipmap count.
Future work includes:
* Blending between multiple reflection probes.
* A falloff/fade-out region so that reflected objects disappear
gradually instead of vanishing all at once.
* Irradiance volumes for voxel-based global illumination. This should
reuse much of the reflection probe logic, as they're both GI techniques
based on cuboid bounding regions.
* Support for WebGL 2, by breaking batches when reflection probes are
used.
These issues notwithstanding, I think it's best to land this with
roughly the current set of functionality, because this patch is useful
as is and adding everything above would make the pull request
significantly larger and harder to review.
---
## Changelog
### Added
* A new *LightProbe* component is available that specifies a bounding
region that an *EnvironmentMapLight* applies to. The combination of a
*LightProbe* and an *EnvironmentMapLight* offers *reflection probe*
functionality similar to that available in other engines.
[the corresponding feature in Blender's Eevee renderer]:
https://docs.blender.org/manual/en/latest/render/eevee/light_probes/reflection_cubemaps.html
[`bevy-baked-gi`]: https://github.com/pcwalton/bevy-baked-gi
[glTF IBL Sampler]: https://github.com/KhronosGroup/glTF-IBL-Sampler
