c2b332f98a
# Objective Update the `calculate_bounds` system to update `Aabb`s for entities who've either: - gotten a new mesh - had their mesh mutated Fixes https://github.com/bevyengine/bevy/issues/4294. ## Solution There are two commits here to address the two issues above: ### Commit 1 **This Commit** Updates the `calculate_bounds` system to operate not only on entities without `Aabb`s but also on entities whose `Handle<Mesh>` has changed. **Why?** So if an entity gets a new mesh, its associated `Aabb` is properly recalculated. **Questions** - This type is getting pretty gnarly - should I extract some types? - This system is public - should I add some quick docs while I'm here? ### Commit 2 **This Commit** Updates `calculate_bounds` to update `Aabb`s of entities whose meshes have been directly mutated. **Why?** So if an entity's mesh gets updated, its associated `Aabb` is properly recalculated. **Questions** - I think we should be using `ahash`. Do we want to do that with a direct `hashbrown` dependency or an `ahash` dependency that we configure the `HashMap` with? - There is an edge case of duplicates with `Vec<Entity>` in the `HashMap`. If an entity gets its mesh handle changed and changed back again it'll be added to the list twice. Do we want to use a `HashSet` to avoid that? Or do a check in the list first (assuming iterating over the `Vec` is faster and this edge case is rare)? - There is an edge case where, if an entity gets a new mesh handle and then its old mesh is updated, we'll update the entity's `Aabb` to the new geometry of the _old_ mesh. Do we want to remove items from the `Local<HashMap>` when handles change? Does the `Changed` event give us the old mesh handle? If not we might need to have a `HashMap<Entity, Handle<Mesh>>` or something so we can unlink entities from mesh handles when the handle changes. - I did the `zip()` with the two `HashMap` gets assuming those would be faster than calculating the Aabb of the mesh (otherwise we could do `meshes.get(mesh_handle).and_then(Mesh::compute_aabb).zip(entity_mesh_map...)` or something). Is that assumption way off? ## Testing I originally tried testing this with `bevy_mod_raycast` as mentioned in the original issue but it seemed to work (maybe they are currently manually updating the Aabbs?). I then tried doing it in 2D but it looks like `Handle<Mesh>` is just for 3D. So I took [this example](https://github.com/bevyengine/bevy/blob/main/examples/3d/pbr.rs) and added some systems to mutate/assign meshes: <details> <summary>Test Script</summary> ```rust use bevy::prelude::*; use bevy::render:📷:ScalingMode; use bevy::render::primitives::Aabb; /// Make sure we only mutate one mesh once. #[derive(Eq, PartialEq, Clone, Debug, Default)] struct MutateMeshState(bool); /// Let's have a few global meshes that we can cycle between. /// This way we can be assigned a new mesh, mutate the old one, and then get the old one assigned. #[derive(Eq, PartialEq, Clone, Debug, Default)] struct Meshes(Vec<Handle<Mesh>>); fn main() { App::new() .add_plugins(DefaultPlugins) .init_resource::<MutateMeshState>() .init_resource::<Meshes>() .add_startup_system(setup) .add_system(assign_new_mesh) .add_system(show_aabbs.after(assign_new_mesh)) .add_system(mutate_meshes.after(show_aabbs)) .run(); } fn setup( mut commands: Commands, mut meshes: ResMut<Assets<Mesh>>, mut global_meshes: ResMut<Meshes>, mut materials: ResMut<Assets<StandardMaterial>>, ) { let m1 = meshes.add(Mesh::from(shape::Icosphere::default())); let m2 = meshes.add(Mesh::from(shape::Icosphere { radius: 0.90, ..Default::default() })); let m3 = meshes.add(Mesh::from(shape::Icosphere { radius: 0.80, ..Default::default() })); global_meshes.0.push(m1.clone()); global_meshes.0.push(m2); global_meshes.0.push(m3); // add entities to the world // sphere commands.spawn_bundle(PbrBundle { mesh: m1, material: materials.add(StandardMaterial { base_color: Color::hex("ffd891").unwrap(), ..default() }), ..default() }); // new 3d camera commands.spawn_bundle(Camera3dBundle { projection: OrthographicProjection { scale: 3.0, scaling_mode: ScalingMode::FixedVertical(1.0), ..default() } .into(), ..default() }); // old 3d camera // commands.spawn_bundle(OrthographicCameraBundle { // transform: Transform::from_xyz(0.0, 0.0, 8.0).looking_at(Vec3::default(), Vec3::Y), // orthographic_projection: OrthographicProjection { // scale: 0.01, // ..default() // }, // ..OrthographicCameraBundle::new_3d() // }); } fn show_aabbs(query: Query<(Entity, &Handle<Mesh>, &Aabb)>) { for thing in query.iter() { println!("{thing:?}"); } } /// For testing the second part - mutating a mesh. /// /// Without the fix we should see this mutate an old mesh and it affects the new mesh that the /// entity currently has. /// With the fix, the mutation doesn't affect anything until the entity is reassigned the old mesh. fn mutate_meshes( mut meshes: ResMut<Assets<Mesh>>, time: Res<Time>, global_meshes: Res<Meshes>, mut mutate_mesh_state: ResMut<MutateMeshState>, ) { let mutated = mutate_mesh_state.0; if time.seconds_since_startup() > 4.5 && !mutated { println!("Mutating {:?}", global_meshes.0[0]); let m = meshes.get_mut(&global_meshes.0[0]).unwrap(); let mut p = m.attribute(Mesh::ATTRIBUTE_POSITION).unwrap().clone(); use bevy::render::mesh::VertexAttributeValues; match &mut p { VertexAttributeValues::Float32x3(v) => { v[0] = [10.0, 10.0, 10.0]; } _ => unreachable!(), } m.insert_attribute(Mesh::ATTRIBUTE_POSITION, p); mutate_mesh_state.0 = true; } } /// For testing the first part - assigning a new handle. fn assign_new_mesh( mut query: Query<&mut Handle<Mesh>, With<Aabb>>, time: Res<Time>, global_meshes: Res<Meshes>, ) { let s = time.seconds_since_startup() as usize; let idx = s % global_meshes.0.len(); for mut handle in query.iter_mut() { *handle = global_meshes.0[idx].clone_weak(); } } ``` </details> ## Changelog ### Fixed Entity `Aabb`s not updating when meshes are mutated or re-assigned. |
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What is Bevy?
Bevy is a refreshingly simple data-driven game engine built in Rust. It is free and open-source forever!
WARNING
Bevy is still in the very early stages of development. APIs can and will change (now is the time to make suggestions!). Important features are missing. Documentation is sparse. Please don't build any serious projects in Bevy unless you are prepared to be broken by API changes constantly.
MSRV: Bevy relies heavily on improvements in the Rust language and compiler. As a result, the Minimum Supported Rust Version (MSRV) is "the latest stable release" of Rust.
Design Goals
- Capable: Offer a complete 2D and 3D feature set
- Simple: Easy for newbies to pick up, but infinitely flexible for power users
- Data Focused: Data-oriented architecture using the Entity Component System paradigm
- Modular: Use only what you need. Replace what you don't like
- Fast: App logic should run quickly, and when possible, in parallel
- Productive: Changes should compile quickly ... waiting isn't fun
About
- Features: A quick overview of Bevy's features.
- News: A development blog that covers our progress, plans and shiny new features.
Docs
- The Bevy Book: Bevy's official documentation. The best place to start learning Bevy.
- Bevy Rust API Docs: Bevy's Rust API docs, which are automatically generated from the doc comments in this repo.
- Official Examples: Bevy's dedicated, runnable examples, which are great for digging into specific concepts.
- Community-Made Learning Resources: More tutorials, documentation, and examples made by the Bevy community.
Community
Before contributing or participating in discussions with the community, you should familiarize yourself with our Code of Conduct.
- Discord: Bevy's official discord server.
- Reddit: Bevy's official subreddit.
- GitHub Discussions: The best place for questions about Bevy, answered right here!
- Bevy Assets: A collection of awesome Bevy projects, tools, plugins and learning materials.
If you'd like to help build Bevy, check out the Contributor's Guide. For simple problems, feel free to open an issue or PR and tackle it yourself!
For more complex architecture decisions and experimental mad science, please open an RFC (Request For Comments) so we can brainstorm together effectively!
Getting Started
We recommend checking out The Bevy Book for a full tutorial.
Follow the Setup guide to ensure your development environment is set up correctly. Once set up, you can quickly try out the examples by cloning this repo and running the following commands:
# Switch to the correct version (latest release, default is main development branch)
git checkout latest
# Runs the "breakout" example
cargo run --example breakout
To draw a window with standard functionality enabled, use:
use bevy::prelude::*;
fn main(){
App::new()
.add_plugins(DefaultPlugins)
.run();
}
Fast Compiles
Bevy can be built just fine using default configuration on stable Rust. However for really fast iterative compiles, you should enable the "fast compiles" setup by following the instructions here.
Libraries Used
Bevy is only possible because of the hard work put into these foundational technologies:
- wgpu: modern / low-level / cross-platform graphics library inspired by Vulkan
- glam-rs: a simple and fast 3D math library for games and graphics
- winit: cross-platform window creation and management in Rust
Bevy Cargo Features
This list outlines the different cargo features supported by Bevy. These allow you to customize the Bevy feature set for your use-case.
Third Party Plugins
Plugins are very welcome to extend Bevy's features. Guidelines are available to help integration and usage.
Thanks and Alternatives
Additionally, we would like to thank the Amethyst, macroquad, coffee, ggez, Fyrox, and Piston projects for providing solid examples of game engine development in Rust. If you are looking for a Rust game engine, it is worth considering all of your options. Each engine has different design goals, and some will likely resonate with you more than others.
License
Bevy is free and open source! All code in this repository is dual-licensed under either:
- MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
at your option. This means you can select the license you prefer! This dual-licensing approach is the de-facto standard in the Rust ecosystem and there are very good reasons to include both.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.