# Add Transform Examples
- Adding examples for moving/rotating entities (with its own section) to resolve#2400
I've stumbled upon this project and been fiddling around a little. Saw the issue and thought I might just add some examples for the proposed transformations.
Mind to check if I got the gist correctly and suggest anything I can improve?
**Problem**
- whenever you want more than one of the builtin cameras (for example multiple windows, split screen, portals), you need to add a render graph node that executes the correct sub graph, extract the camera into the render world and add the correct `RenderPhase<T>` components
- querying for the 3d camera is annoying because you need to compare the camera's name to e.g. `CameraPlugin::CAMERA_3d`
**Solution**
- Introduce the marker types `Camera3d`, `Camera2d` and `CameraUi`
-> `Query<&mut Transform, With<Camera3d>>` works
- `PerspectiveCameraBundle::new_3d()` and `PerspectiveCameraBundle::<Camera3d>::default()` contain the `Camera3d` marker
- `OrthographicCameraBundle::new_3d()` has `Camera3d`, `OrthographicCameraBundle::new_2d()` has `Camera2d`
- remove `ActiveCameras`, `ExtractedCameraNames`
- run 2d, 3d and ui passes for every camera of their respective marker
-> no custom setup for multiple windows example needed
**Open questions**
- do we need a replacement for `ActiveCameras`? What about a component `ActiveCamera { is_active: bool }` similar to `Visibility`?
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Use the low power, reactive rendering settings for UI examples.
- Make the feature more discoverable by using it in an applicable context.
# Objective
Fixes#4036
## Solution
- Use `VertexBufferLayout::from_vertex_formats`
- Actually put a u32 into `ATTRIBUTE_COLOR` and convert it in the shader
I'm not 100% sure about the color stuff. It seems like `ATTRIBUTE_COLOR` has been `Uint32` this whole time, but this example previously worked with `[f32; 4]` somehow, perhaps because the vertex layout was manually specified.
Let me know if that can be improved, or feel free to close for an alternative fix.
# Objective
- Improve documentation.
- Provide helper functions for common uses of `Windows` relating to getting the primary `Window`.
- Reduce repeated `Window` code.
# Solution
- Adds infallible `primary()` and `primary_mut()` functions with standard error text. This replaces the commonly used `get_primary().unwrap()` seen throughout bevy which has inconsistent or nonexistent error messages.
- Adds `scale_factor(WindowId)` to replace repeated code blocks throughout.
# Considerations
- The added functions can panic if the primary window does not exist.
- It is very uncommon for the primary window to not exist, as seen by the regular use of `get_primary().unwrap()`. Most users will have a single window and will need to reference the primary window in their code multiple times.
- The panic provides a consistent error message to make this class of error easy to spot from the panic text.
- This follows the established standard of short names for infallible-but-unlikely-to-panic functions in bevy.
- Removes line noise for common usage of `Windows`.
# Objective
- Reduce power usage for games when not focused.
- Reduce power usage to ~0 when a desktop application is minimized (opt-in).
- Reduce power usage when focused, only updating on a `winit` event, or the user sends a redraw request. (opt-in)
https://user-images.githubusercontent.com/2632925/156904387-ec47d7de-7f06-4c6f-8aaf-1e952c1153a2.mp4
Note resource usage in the Task Manager in the above video.
## Solution
- Added a type `UpdateMode` that allows users to specify how the winit event loop is updated, without exposing winit types.
- Added two fields to `WinitConfig`, both with the `UpdateMode` type. One configures how the application updates when focused, and the other configures how the application behaves when it is not focused. Users can modify this resource manually to set the type of event loop control flow they want.
- For convenience, two functions were added to `WinitConfig`, that provide reasonable presets: `game()` (default) and `desktop_app()`.
- The `game()` preset, which is used by default, is unchanged from current behavior with one exception: when the app is out of focus the app updates at a minimum of 10fps, or every time a winit event is received. This has a huge positive impact on power use and responsiveness on my machine, which will otherwise continue running the app at many hundreds of fps when out of focus or minimized.
- The `desktop_app()` preset is fully reactive, only updating when user input (winit event) is supplied or a `RedrawRequest` event is sent. When the app is out of focus, it only updates on `Window` events - i.e. any winit event that directly interacts with the window. What this means in practice is that the app uses *zero* resources when minimized or not interacted with, but still updates fluidly when the app is out of focus and the user mouses over the application.
- Added a `RedrawRequest` event so users can force an update even if there are no events. This is useful in an application when you want to, say, run an animation even when the user isn't providing input.
- Added an example `low_power` to demonstrate these changes
## Usage
Configuring the event loop:
```rs
use bevy::winit::{WinitConfig};
// ...
.insert_resource(WinitConfig::desktop_app()) // preset
// or
.insert_resource(WinitConfig::game()) // preset
// or
.insert_resource(WinitConfig{ .. }) // manual
```
Requesting a redraw:
```rs
use bevy:🪟:RequestRedraw;
// ...
fn request_redraw(mut event: EventWriter<RequestRedraw>) {
event.send(RequestRedraw);
}
```
## Other details
- Because we have a single event loop for multiple windows, every time I've mentioned "focused" above, I more precisely mean, "if at least one bevy window is focused".
- Due to a platform bug in winit (https://github.com/rust-windowing/winit/issues/1619), we can't simply use `Window::request_redraw()`. As a workaround, this PR will temporarily set the window mode to `Poll` when a redraw is requested. This is then reset to the user's `WinitConfig` setting on the next frame.
# Objective
- Make the many_cubes example more interesting (and look more like many_sprites)
## Solution
- Actually display many cubes
- Move the camera around
Adds a `default()` shorthand for `Default::default()` ... because life is too short to constantly type `Default::default()`.
```rust
use bevy::prelude::*;
#[derive(Default)]
struct Foo {
bar: usize,
baz: usize,
}
// Normally you would do this:
let foo = Foo {
bar: 10,
..Default::default()
};
// But now you can do this:
let foo = Foo {
bar: 10,
..default()
};
```
The examples have been adapted to use `..default()`. I've left internal crates as-is for now because they don't pull in the bevy prelude, and the ergonomics of each case should be considered individually.
# Objective
- Add ways to control how audio is played
## Solution
- playing a sound will return a (weak) handle to an asset that can be used to control playback
- if the asset is dropped, it will detach the sink (same behaviour as now)
# Objective
- In the large majority of cases, users were calling `.unwrap()` immediately after `.get_resource`.
- Attempting to add more helpful error messages here resulted in endless manual boilerplate (see #3899 and the linked PRs).
## Solution
- Add an infallible variant named `.resource` and so on.
- Use these infallible variants over `.get_resource().unwrap()` across the code base.
## Notes
I did not provide equivalent methods on `WorldCell`, in favor of removing it entirely in #3939.
## Migration Guide
Infallible variants of `.get_resource` have been added that implicitly panic, rather than needing to be unwrapped.
Replace `world.get_resource::<Foo>().unwrap()` with `world.resource::<Foo>()`.
## Impact
- `.unwrap` search results before: 1084
- `.unwrap` search results after: 942
- internal `unwrap_or_else` calls added: 4
- trivial unwrap calls removed from tests and code: 146
- uses of the new `try_get_resource` API: 11
- percentage of the time the unwrapping API was used internally: 93%
# Objective
Will fix#3377 and #3254
## Solution
Use an enum to represent either a `WindowId` or `Handle<Image>` in place of `Camera::window`.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- Closes#786
- Closes#2252
- Closes#2588
This PR implements a derive macro that allows users to define their queries as structs with named fields.
## Example
```rust
#[derive(WorldQuery)]
#[world_query(derive(Debug))]
struct NumQuery<'w, T: Component, P: Component> {
entity: Entity,
u: UNumQuery<'w>,
generic: GenericQuery<'w, T, P>,
}
#[derive(WorldQuery)]
#[world_query(derive(Debug))]
struct UNumQuery<'w> {
u_16: &'w u16,
u_32_opt: Option<&'w u32>,
}
#[derive(WorldQuery)]
#[world_query(derive(Debug))]
struct GenericQuery<'w, T: Component, P: Component> {
generic: (&'w T, &'w P),
}
#[derive(WorldQuery)]
#[world_query(filter)]
struct NumQueryFilter<T: Component, P: Component> {
_u_16: With<u16>,
_u_32: With<u32>,
_or: Or<(With<i16>, Changed<u16>, Added<u32>)>,
_generic_tuple: (With<T>, With<P>),
_without: Without<Option<u16>>,
_tp: PhantomData<(T, P)>,
}
fn print_nums_readonly(query: Query<NumQuery<u64, i64>, NumQueryFilter<u64, i64>>) {
for num in query.iter() {
println!("{:#?}", num);
}
}
#[derive(WorldQuery)]
#[world_query(mutable, derive(Debug))]
struct MutNumQuery<'w, T: Component, P: Component> {
i_16: &'w mut i16,
i_32_opt: Option<&'w mut i32>,
}
fn print_nums(mut query: Query<MutNumQuery, NumQueryFilter<u64, i64>>) {
for num in query.iter_mut() {
println!("{:#?}", num);
}
}
```
## TODOs:
- [x] Add support for `&T` and `&mut T`
- [x] Test
- [x] Add support for optional types
- [x] Test
- [x] Add support for `Entity`
- [x] Test
- [x] Add support for nested `WorldQuery`
- [x] Test
- [x] Add support for tuples
- [x] Test
- [x] Add support for generics
- [x] Test
- [x] Add support for query filters
- [x] Test
- [x] Add support for `PhantomData`
- [x] Test
- [x] Refactor `read_world_query_field_type_info`
- [x] Properly document `readonly` attribute for nested queries and the static assertions that guarantee safety
- [x] Test that we never implement `ReadOnlyFetch` for types that need mutable access
- [x] Test that we insert static assertions for nested `WorldQuery` that a user marked as readonly
This PR makes a number of changes to how meshes and vertex attributes are handled, which the goal of enabling easy and flexible custom vertex attributes:
* Reworks the `Mesh` type to use the newly added `VertexAttribute` internally
* `VertexAttribute` defines the name, a unique `VertexAttributeId`, and a `VertexFormat`
* `VertexAttributeId` is used to produce consistent sort orders for vertex buffer generation, replacing the more expensive and often surprising "name based sorting"
* Meshes can be used to generate a `MeshVertexBufferLayout`, which defines the layout of the gpu buffer produced by the mesh. `MeshVertexBufferLayouts` can then be used to generate actual `VertexBufferLayouts` according to the requirements of a specific pipeline. This decoupling of "mesh layout" vs "pipeline vertex buffer layout" is what enables custom attributes. We don't need to standardize _mesh layouts_ or contort meshes to meet the needs of a specific pipeline. As long as the mesh has what the pipeline needs, it will work transparently.
* Mesh-based pipelines now specialize on `&MeshVertexBufferLayout` via the new `SpecializedMeshPipeline` trait (which behaves like `SpecializedPipeline`, but adds `&MeshVertexBufferLayout`). The integrity of the pipeline cache is maintained because the `MeshVertexBufferLayout` is treated as part of the key (which is fully abstracted from implementers of the trait ... no need to add any additional info to the specialization key).
* Hashing `MeshVertexBufferLayout` is too expensive to do for every entity, every frame. To make this scalable, I added a generalized "pre-hashing" solution to `bevy_utils`: `Hashed<T>` keys and `PreHashMap<K, V>` (which uses `Hashed<T>` internally) . Why didn't I just do the quick and dirty in-place "pre-compute hash and use that u64 as a key in a hashmap" that we've done in the past? Because its wrong! Hashes by themselves aren't enough because two different values can produce the same hash. Re-hashing a hash is even worse! I decided to build a generalized solution because this pattern has come up in the past and we've chosen to do the wrong thing. Now we can do the right thing! This did unfortunately require pulling in `hashbrown` and using that in `bevy_utils`, because avoiding re-hashes requires the `raw_entry_mut` api, which isn't stabilized yet (and may never be ... `entry_ref` has favor now, but also isn't available yet). If std's HashMap ever provides the tools we need, we can move back to that. Note that adding `hashbrown` doesn't increase our dependency count because it was already in our tree. I will probably break these changes out into their own PR.
* Specializing on `MeshVertexBufferLayout` has one non-obvious behavior: it can produce identical pipelines for two different MeshVertexBufferLayouts. To optimize the number of active pipelines / reduce re-binds while drawing, I de-duplicate pipelines post-specialization using the final `VertexBufferLayout` as the key. For example, consider a pipeline that needs the layout `(position, normal)` and is specialized using two meshes: `(position, normal, uv)` and `(position, normal, other_vec2)`. If both of these meshes result in `(position, normal)` specializations, we can use the same pipeline! Now we do. Cool!
To briefly illustrate, this is what the relevant section of `MeshPipeline`'s specialization code looks like now:
```rust
impl SpecializedMeshPipeline for MeshPipeline {
type Key = MeshPipelineKey;
fn specialize(
&self,
key: Self::Key,
layout: &MeshVertexBufferLayout,
) -> RenderPipelineDescriptor {
let mut vertex_attributes = vec![
Mesh::ATTRIBUTE_POSITION.at_shader_location(0),
Mesh::ATTRIBUTE_NORMAL.at_shader_location(1),
Mesh::ATTRIBUTE_UV_0.at_shader_location(2),
];
let mut shader_defs = Vec::new();
if layout.contains(Mesh::ATTRIBUTE_TANGENT) {
shader_defs.push(String::from("VERTEX_TANGENTS"));
vertex_attributes.push(Mesh::ATTRIBUTE_TANGENT.at_shader_location(3));
}
let vertex_buffer_layout = layout
.get_layout(&vertex_attributes)
.expect("Mesh is missing a vertex attribute");
```
Notice that this is _much_ simpler than it was before. And now any mesh with any layout can be used with this pipeline, provided it has vertex postions, normals, and uvs. We even got to remove `HAS_TANGENTS` from MeshPipelineKey and `has_tangents` from `GpuMesh`, because that information is redundant with `MeshVertexBufferLayout`.
This is still a draft because I still need to:
* Add more docs
* Experiment with adding error handling to mesh pipeline specialization (which would print errors at runtime when a mesh is missing a vertex attribute required by a pipeline). If it doesn't tank perf, we'll keep it.
* Consider breaking out the PreHash / hashbrown changes into a separate PR.
* Add an example illustrating this change
* Verify that the "mesh-specialized pipeline de-duplication code" works properly
Please dont yell at me for not doing these things yet :) Just trying to get this in peoples' hands asap.
Alternative to #3120Fixes#3030
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- `WgpuOptions` is mutated to be updated with the actual device limits and features, but this information is readily available to both the main and render worlds through the `RenderDevice` which has .limits() and .features() methods
- Information about the adapter in terms of its name, the backend in use, etc were not being exposed but have clear use cases for being used to take decisions about what rendering code to use. For example, if something works well on AMD GPUs but poorly on Intel GPUs. Or perhaps something works well in Vulkan but poorly in DX12.
## Solution
- Stop mutating `WgpuOptions `and don't insert the updated values into the main and render worlds
- Return `AdapterInfo` from `initialize_renderer` and insert it into the main and render worlds
- Use `RenderDevice` limits in the lighting code that was using `WgpuOptions.limits`.
- Renamed `WgpuOptions` to `WgpuSettings`
I wanted to try one of the new examples but it felt so clunky that I wanted to improve it.
It did make me feel like maybe some input axes abstraction like Unity has might be useful.
Also, eating cake should probably be a separate system from movement.
What is says on the tin.
This has got more to do with making `clippy` slightly more *quiet* than it does with changing anything that might greatly impact readability or performance.
that said, deriving `Default` for a couple of structs is a nice easy win
# Objective
My attempt at fixing #2142. My very first attempt at contributing to Bevy so more than open to any feedback.
I borrowed heavily from the [Bevy Cheatbook page](https://bevy-cheatbook.github.io/patterns/generic-systems.html?highlight=generic#generic-systems).
## Solution
Fairly straightforward example using a clean up system to delete entities that are coupled with app state after exiting that state.
Co-authored-by: B-Janson <brandon@canva.com>
# Objective
- Bevy currently has no simple way to make an "empty" Entity work correctly in a Hierachy.
- The current Solution is to insert a Tuple instead:
```rs
.insert_bundle((Transform::default(), GlobalTransform::default()))
```
## Solution
* Add a `TransformBundle` that combines the Components:
```rs
.insert_bundle(TransformBundle::default())
```
* The code is based on #2331, except for missing the more controversial usage of `TransformBundle` as a Sub-bundle in preexisting Bundles.
Co-authored-by: MinerSebas <66798382+MinerSebas@users.noreply.github.com>
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
Add two examples on how to communicate with a task that is running either in another thread or in a thread from `AsyncComputeTaskPool`.
Loosely based on https://github.com/bevyengine/bevy/discussions/1150
# Objective
Enable the user to specify any presentation modes (including `Mailbox`).
Fixes#3807
## Solution
I've added a new `PresentMode` enum in `bevy_window` that mirrors the `wgpu` enum 1:1. Alternatively, I could add a new dependency on `wgpu-types` if that would be preferred.
## Objective
The [`DrawMeshInstanced`] command in the example sets vertex buffer 0 twice, with two identical calls to:
```rs
pass.set_vertex_buffer(0, gpu_mesh.vertex_buffer.slice(..));
```
## Solution
Remove the second call as it is unecessary.
[`DrawMeshInstanced`]: f3de12bc5e/examples/shader/shader_instancing.rs (L217-L258)
# Objective
- `asset_server.watch_for_changes().unwrap()` only watches changes for assets loaded **_after_** that call.
- Technically, the `hot_asset_reloading` example is racey as the watch on the asset path is set up in an async task scheduled from the asset `load()`, but the filesystem watcher is only constructed in a call that comes **_after_** the call to `load()`.
## Solution
- It feels safest to allow enabling watching the filesystem for changes on the asset server from the point of its construction. Therefore, adding such an option to `AssetServerSettings` seemed to be the correct solution.
- Fix `hot_asset_reloading` by inserting the `AssetServerSettings` resource with `watch_for_changes: true` instead of calling `asset_server.watch_for_changes().unwrap()`.
- Document the shortcomings of `.watch_for_changes()`
# Objective
When using empty events, it can feel redundant to have to specify the type of the event when sending it.
## Solution
Add a new `fire()` function that sends the default value of the event. This requires that the event derives Default.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
## Objective
There is no bevy example that shows how to transform a sprite. At least as its singular purpose. This creates an example of how to use transform.translate to move a sprite up and down. The last pull request had issues that I couldn't fix so I created a new one
### Solution
I created move_sprite example.
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
I think the 'collide' function inside the 'bevy/crates/bevy_sprite/src/collide_aabb.rs' file should return 'Some' if the two rectangles are fully overlapping or one is inside the other. This can happen on low-end machines when a lot of time passes between two frames because of a stutter, so a bullet for example gets inside its target. I can also think of situations where this is a valid use case even without stutters.
## Solution
I added an 'Inside' version to the Collision enum declared in the file. And I use it, when the two rectangles are overlapping, but we can't say from which direction it happened. I gave a 'penetration depth' of minus Infinity to these cases, so that this variant only appears, when the two rectangles overlap from each side fully. I am not sure if this is the right thing to do.
Fixes#1980
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
While trying to learn how to use custom shaders, I had difficulty figuring out how to use a vertex shader. My confusion was mostly because all the other shader examples used a custom pipeline, but I didn't want a custom pipeline. After digging around I realised that I simply needed to add a function to the `impl Material` block. I also searched what was the default shader used, because it wasn't obvious to me where to find it.
## Solution
Added a few comments explaining what is going on in the example and a link to the default shader.
# Objective
Some new bevy users are unfamiliar with quaternions and have trouble working with rotations in 2D.
There has been an [issue](https://github.com/bitshifter/glam-rs/issues/226) raised with glam to add helpers to better support these users, however for now I feel could be better to provide examples of how to do this in Bevy as a starting point for new users.
## Solution
I've added a 2d_rotation example which demonstrates 3 different rotation examples to try help get people started:
- Rotating and translating a player ship based on keyboard input
- An enemy ship type that rotates to face the player ship immediately
- An enemy ship type that rotates to face the player at a fixed angular velocity
I also have a standalone version of this example here https://github.com/bitshifter/bevy-2d-rotation-example but I think it would be more discoverable if it's included with Bevy.
# Objective
- Allow opting-out of the built-in frustum culling for cases where its behaviour would be incorrect
- Make use of the this in the shader_instancing example that uses a custom instancing method. The built-in frustum culling breaks the custom instancing in the shader_instancing example if the camera is moved to:
```rust
commands.spawn_bundle(PerspectiveCameraBundle {
transform: Transform::from_xyz(12.0, 0.0, 15.0)
.looking_at(Vec3::new(12.0, 0.0, 0.0), Vec3::Y),
..Default::default()
});
```
...such that the Aabb of the cube Mesh that is at the origin goes completely out of view. This incorrectly (for the purpose of the custom instancing) culls the `Mesh` and so culls all instances even though some may be visible.
## Solution
- Add a `NoFrustumCulling` marker component
- Do not compute and add an `Aabb` to `Mesh` entities without an `Aabb` if they have a `NoFrustumCulling` marker component
- Do not apply frustum culling to entities with the `NoFrustumCulling` marker component
# Objective
- There are wasm specific examples, which is misleading as now it works by default
- I saw a few people on discord trying to work through those examples that are very limited
## Solution
- Remove them and update the instructions
adds an example using UI for something more related to a game than the current UI examples.
Example with a game menu:
* new game - will display settings for 5 seconds before returning to menu
* preferences - can modify the settings, with two sub menus
* quit - will quit the game
I wanted a more complex UI example before starting the UI rewrite to have ground for comparison
Co-authored-by: François <8672791+mockersf@users.noreply.github.com>
# Objective
In this PR I added the ability to opt-out graphical backends. Closes#3155.
## Solution
I turned backends into `Option` ~~and removed panicking sub app API to force users handle the error (was suggested by `@cart`)~~.
# Objective
The current 2d rendering is specialized to render sprites, we need a generic way to render 2d items, using meshes and materials like we have for 3d.
## Solution
I cloned a good part of `bevy_pbr` into `bevy_sprite/src/mesh2d`, removed lighting and pbr itself, adapted it to 2d rendering, added a `ColorMaterial`, and modified the sprite rendering to break batches around 2d meshes.
~~The PR is a bit crude; I tried to change as little as I could in both the parts copied from 3d and the current sprite rendering to make reviewing easier. In the future, I expect we could make the sprite rendering a normal 2d material, cleanly integrated with the rest.~~ _edit: see <https://github.com/bevyengine/bevy/pull/3460#issuecomment-1003605194>_
## Remaining work
- ~~don't require mesh normals~~ _out of scope_
- ~~add an example~~ _done_
- support 2d meshes & materials in the UI?
- bikeshed names (I didn't think hard about naming, please check if it's fine)
## Remaining questions
- ~~should we add a depth buffer to 2d now that there are 2d meshes?~~ _let's revisit that when we have an opaque render phase_
- ~~should we add MSAA support to the sprites, or remove it from the 2d meshes?~~ _I added MSAA to sprites since it's really needed for 2d meshes_
- ~~how to customize vertex attributes?~~ _#3120_
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- More colours
## Solution
- Various changes
- Would have a video here, but don't have an easy way to record one before I go to sleep
- I intend to additionally change the distribution of the satellites, to be more uniform in space.
#3457 adds the `doc_markdown` clippy lint, which checks doc comments to make sure code identifiers are escaped with backticks. This causes a lot of lint errors, so this is one of a number of PR's that will fix those lint errors one crate at a time.
This PR fixes lints in the `examples` folder.
