015617a774
## New Features This adds the following to the new renderer: * **Shader Assets** * Shaders are assets again! Users no longer need to call `include_str!` for their shaders * Shader hot-reloading * **Shader Defs / Shader Preprocessing** * Shaders now support `# ifdef NAME`, `# ifndef NAME`, and `# endif` preprocessor directives * **Bevy RenderPipelineDescriptor and RenderPipelineCache** * Bevy now provides its own `RenderPipelineDescriptor` and the wgpu version is now exported as `RawRenderPipelineDescriptor`. This allows users to define pipelines with `Handle<Shader>` instead of needing to manually compile and reference `ShaderModules`, enables passing in shader defs to configure the shader preprocessor, makes hot reloading possible (because the descriptor can be owned and used to create new pipelines when a shader changes), and opens the doors to pipeline specialization. * The `RenderPipelineCache` now handles compiling and re-compiling Bevy RenderPipelineDescriptors. It has internal PipelineLayout and ShaderModule caches. Users receive a `CachedPipelineId`, which can be used to look up the actual `&RenderPipeline` during rendering. * **Pipeline Specialization** * This enables defining per-entity-configurable pipelines that specialize on arbitrary custom keys. In practice this will involve specializing based on things like MSAA values, Shader Defs, Bind Group existence, and Vertex Layouts. * Adds a `SpecializedPipeline` trait and `SpecializedPipelines<MyPipeline>` resource. This is a simple layer that generates Bevy RenderPipelineDescriptors based on a custom key defined for the pipeline. * Specialized pipelines are also hot-reloadable. * This was the result of experimentation with two different approaches: 1. **"generic immediate mode multi-key hash pipeline specialization"** * breaks up the pipeline into multiple "identities" (the core pipeline definition, shader defs, mesh layout, bind group layout). each of these identities has its own key. looking up / compiling a specific version of a pipeline requires composing all of these keys together * the benefit of this approach is that it works for all pipelines / the pipeline is fully identified by the keys. the multiple keys allow pre-hashing parts of the pipeline identity where possible (ex: pre compute the mesh identity for all meshes) * the downside is that any per-entity data that informs the values of these keys could require expensive re-hashes. computing each key for each sprite tanked bevymark performance (sprites don't actually need this level of specialization yet ... but things like pbr and future sprite scenarios might). * this is the approach rafx used last time i checked 2. **"custom key specialization"** * Pipelines by default are not specialized * Pipelines that need specialization implement a SpecializedPipeline trait with a custom key associated type * This allows specialization keys to encode exactly the amount of information required (instead of needing to be a combined hash of the entire pipeline). Generally this should fit in a small number of bytes. Per-entity specialization barely registers anymore on things like bevymark. It also makes things like "shader defs" way cheaper to hash because we can use context specific bitflags instead of strings. * Despite the extra trait, it actually generally makes pipeline definitions + lookups simpler: managing multiple keys (and making the appropriate calls to manage these keys) was way more complicated. * I opted for custom key specialization. It performs better generally and in my opinion is better UX. Fortunately the way this is implemented also allows for custom caches as this all builds on a common abstraction: the RenderPipelineCache. The built in custom key trait is just a simple / pre-defined way to interact with the cache ## Callouts * The SpecializedPipeline trait makes it easy to inherit pipeline configuration in custom pipelines. The changes to `custom_shader_pipelined` and the new `shader_defs_pipelined` example illustrate how much simpler it is to define custom pipelines based on the PbrPipeline. * The shader preprocessor is currently pretty naive (it just uses regexes to process each line). Ultimately we might want to build a more custom parser for more performance + better error handling, but for now I'm happy to optimize for "easy to implement and understand". ## Next Steps * Port compute pipelines to the new system * Add more preprocessor directives (else, elif, import) * More flexible vertex attribute specialization / enable cheaply specializing on specific mesh vertex layouts |
||
---|---|---|
.. | ||
2d | ||
3d | ||
android | ||
app | ||
asset | ||
async_tasks | ||
audio | ||
diagnostics | ||
ecs | ||
game | ||
input | ||
ios | ||
reflection | ||
scene | ||
shader | ||
tools | ||
ui | ||
wasm | ||
window | ||
hello_world.rs | ||
README.md |
Examples
These examples demonstrate the main features of Bevy and how to use them.
To run an example, use the command cargo run --example <Example>
, and add the option --features x11
or --features wayland
to force the example to run on a specific window compositor, e.g.
cargo run --features wayland --example hello_world
⚠️ Note: for users of releases on crates.io!
There are often large differences and incompatible API changes between the latest crates.io release and the development version of Bevy in the git main branch!
If you are using a released version of bevy, you need to make sure you are viewing the correct version of the examples!
- Latest release: https://github.com/bevyengine/bevy/tree/latest/examples
- Specific version, such as
0.4
: https://github.com/bevyengine/bevy/tree/v0.4.0/examples
When you clone the repo locally to run the examples, use git checkout
to get the correct version:
# `latest` always points to the newest release
git checkout latest
# or use a specific version
git checkout v0.4.0
Table of Contents
The Bare Minimum
Hello, World!
Example | File | Description |
---|---|---|
hello_world |
hello_world.rs |
Runs a minimal example that outputs "hello world" |
Cross-Platform Examples
2D Rendering
Example | File | Description |
---|---|---|
contributors |
2d/contributors.rs |
Displays each contributor as a bouncy bevy-ball! |
many_sprites |
2d/many_sprites.rs |
Displays many sprites in a grid arragement! Used for performance testing. |
mesh |
2d/mesh.rs |
Renders a custom mesh |
pipelined_texture_atlas |
2d/pipelined_texture_atlas.rs |
Generates a texture atlas (sprite sheet) from individual sprites |
sprite |
2d/sprite.rs |
Renders a sprite |
sprite_sheet |
2d/sprite_sheet.rs |
Renders an animated sprite |
text2d |
2d/text2d.rs |
Generates text in 2d |
sprite_flipping |
2d/sprite_flipping.rs |
Renders a sprite flipped along an axis |
texture_atlas |
2d/texture_atlas.rs |
Generates a texture atlas (sprite sheet) from individual sprites |
3D Rendering
Example | File | Description |
---|---|---|
3d_scene |
3d/3d_scene.rs |
Simple 3D scene with basic shapes and lighting |
3d_scene_pipelined |
3d/3d_scene_pipelined.rs |
Simple 3D scene with basic shapes and lighting |
cornell_box_pipelined |
3d/cornell_box_pipelined.rs |
Re-production of the cornell box |
load_gltf |
3d/load_gltf.rs |
Loads and renders a gltf file as a scene |
load_gltf_pipelined |
3d/load_gltf_pipelined.rs |
Loads and renders a gltf file as a scene |
many_cubes_pipelined |
3d/many_cubes_pipelined.rs |
Simple benchmark to test per-entity draw overhead |
msaa |
3d/msaa.rs |
Configures MSAA (Multi-Sample Anti-Aliasing) for smoother edges |
orthographic |
3d/orthographic.rs |
Shows how to create a 3D orthographic view (for isometric-look games or CAD applications) |
orthographic_pipelined |
3d/orthographic_pipelined.rs |
Shows how to create a 3D orthographic view (for isometric-look games or CAD applications) |
parenting |
3d/parenting.rs |
Demonstrates parent->child relationships and relative transformations |
pbr |
3d/pbr.rs |
Demonstrates use of Physically Based Rendering (PBR) properties |
pbr_pipelined |
3d/pbr_pipelined.rs |
Demonstrates use of Physically Based Rendering (PBR) properties |
render_to_texture |
3d/render_to_texture.rs |
Shows how to render to texture |
shadow_caster_receiver_pipelined |
3d/shadow_caster_receiver_pipelined.rs |
Demonstrates how to prevent meshes from casting/receiving shadows in a 3d scene |
shadow_biases_pipelined |
3d/shadow_biases_pipelined.rs |
Demonstrates how shadow biases affect shadows in a 3d scene |
spawner |
3d/spawner.rs |
Renders a large number of cubes with changing position and material |
texture |
3d/texture.rs |
Shows configuration of texture materials |
texture_pipelined |
3d/texture_pipelined.rs |
Shows configuration of texture materials |
update_gltf_scene |
3d/update_gltf_scene.rs |
Update a scene from a gltf file, either by spawning the scene as a child of another entity, or by accessing the entities of the scene |
wireframe |
3d/wireframe.rs |
Showcases wireframe rendering |
z_sort_debug |
3d/z_sort_debug.rs |
Visualizes camera Z-ordering |
Application
Example | File | Description |
---|---|---|
custom_loop |
app/custom_loop.rs |
Demonstrates how to create a custom runner (to update an app manually). |
drag_and_drop |
app/drag_and_drop.rs |
An example that shows how to handle drag and drop in an app. |
empty |
app/empty.rs |
An empty application (does nothing) |
empty_defaults |
app/empty_defaults.rs |
An empty application with default plugins |
headless |
app/headless.rs |
An application that runs without default plugins |
logs |
app/logs.rs |
Illustrate how to use generate log output |
plugin |
app/plugin.rs |
Demonstrates the creation and registration of a custom plugin |
plugin_group |
app/plugin_group.rs |
Demonstrates the creation and registration of a custom plugin group |
return_after_run |
app/return_after_run.rs |
Show how to return to main after the Bevy app has exited |
thread_pool_resources |
app/thread_pool_resources.rs |
Creates and customizes the internal thread pool |
Assets
Example | File | Description |
---|---|---|
asset_loading |
asset/asset_loading.rs |
Demonstrates various methods to load assets |
custom_asset |
asset/custom_asset.rs |
Implements a custom asset loader |
custom_asset_io |
asset/custom_asset_io.rs |
Implements a custom asset io loader |
hot_asset_reloading |
asset/hot_asset_reloading.rs |
Demonstrates automatic reloading of assets when modified on disk |
Async Tasks
Example | File | Description |
---|---|---|
async_compute |
async_tasks/async_compute.rs |
How to use AsyncComputeTaskPool to complete longer running tasks |
Audio
Example | File | Description |
---|---|---|
audio |
audio/audio.rs |
Shows how to load and play an audio file |
Diagnostics
Example | File | Description |
---|---|---|
custom_diagnostic |
diagnostics/custom_diagnostic.rs |
Shows how to create a custom diagnostic |
log_diagnostics |
diagnostics/log_diagnostics.rs |
Add a plugin that logs diagnostics, like frames per second (FPS), to the console |
ECS (Entity Component System)
Example | File | Description |
---|---|---|
ecs_guide |
ecs/ecs_guide.rs |
Full guide to Bevy's ECS |
component_change_detection |
ecs/component_change_detection.rs |
Change detection on components |
event |
ecs/event.rs |
Illustrates event creation, activation, and reception |
fixed_timestep |
ecs/fixed_timestep.rs |
Shows how to create systems that run every fixed timestep, rather than every tick |
hierarchy |
ecs/hierarchy.rs |
Creates a hierarchy of parents and children entities |
iter_combinations |
ecs/iter_combinations.rs |
Shows how to iterate over combinations of query results. |
parallel_query |
ecs/parallel_query.rs |
Illustrates parallel queries with ParallelIterator |
removal_detection |
ecs/removal_detection.rs |
Query for entities that had a specific component removed in a previous stage during the current frame. |
startup_system |
ecs/startup_system.rs |
Demonstrates a startup system (one that runs once when the app starts up) |
state |
ecs/state.rs |
Illustrates how to use States to control transitioning from a Menu state to an InGame state |
system_chaining |
ecs/system_chaining.rs |
Chain two systems together, specifying a return type in a system (such as Result ) |
system_param |
ecs/system_param.rs |
Illustrates creating custom system parameters with SystemParam |
system_sets |
ecs/system_sets.rs |
Shows SystemSet use along with run criterion |
timers |
ecs/timers.rs |
Illustrates ticking Timer resources inside systems and handling their state |
Games
Example | File | Description |
---|---|---|
alien_cake_addict |
game/alien_cake_addict.rs |
Eat the cakes. Eat them all. An example 3D game |
breakout |
game/breakout.rs |
An implementation of the classic game "Breakout" |
Input
Example | File | Description |
---|---|---|
char_input_events |
input/char_input_events.rs |
Prints out all chars as they are inputted. |
gamepad_input |
input/gamepad_input.rs |
Shows handling of gamepad input, connections, and disconnections |
gamepad_input_events |
input/gamepad_input_events.rs |
Iterates and prints gamepad input and connection events |
keyboard_input |
input/keyboard_input.rs |
Demonstrates handling a key press/release |
keyboard_input_events |
input/keyboard_input_events.rs |
Prints out all keyboard events |
keyboard_modifiers |
input/keyboard_modifiers.rs |
Demonstrates using key modifiers (ctrl, shift) |
mouse_input |
input/mouse_input.rs |
Demonstrates handling a mouse button press/release |
mouse_input_events |
input/mouse_input_events.rs |
Prints out all mouse events (buttons, movement, etc.) |
touch_input |
input/touch_input.rs |
Displays touch presses, releases, and cancels |
touch_input_events |
input/touch_input_events.rs |
Prints out all touch inputs |
Reflection
Example | File | Description |
---|---|---|
reflection |
reflection/reflection.rs |
Demonstrates how reflection in Bevy provides a way to dynamically interact with Rust types |
generic_reflection |
reflection/generic_reflection.rs |
Registers concrete instances of generic types that may be used with reflection |
reflection_types |
reflection/reflection_types.rs |
Illustrates the various reflection types available |
trait_reflection |
reflection/trait_reflection.rs |
Allows reflection with trait objects |
Scene
Example | File | Description |
---|---|---|
scene |
scene/scene.rs |
Demonstrates loading from and saving scenes to files |
Shaders
Example | File | Description |
---|---|---|
animate_shader |
shader/animate_shader.rs |
Shows how to animate a shader by accessing a time uniform variable |
array_texture |
shader/array_texture.rs |
Illustrates how to create a texture for use with a texture2DArray shader uniform variable |
custom_shader_pipelined |
shader/custom_shader_pipelined.rs |
Illustrates how to create custom shaders |
hot_shader_reloading |
shader/hot_shader_reloading.rs |
Illustrates how to load shaders such that they can be edited while the example is still running |
mesh_custom_attribute |
shader/mesh_custom_attribute.rs |
Illustrates how to add a custom attribute to a mesh and use it in a custom shader |
shader_custom_material |
shader/shader_custom_material.rs |
Illustrates creating a custom material and a shader that uses it |
shader_defs |
shader/shader_defs.rs |
Demonstrates creating a custom material that uses "shaders defs" (a tool to selectively toggle parts of a shader) |
shader_defs_pipelined |
shader/shader_defs_pipelined.rs |
Demonstrates creating a custom material that uses "shaders defs" (a tool to selectively toggle parts of a shader) |
Tests
Example | File | Description |
---|---|---|
how_to_test_systems |
../tests/how_to_test_systems.rs |
How to test systems with commands, queries or resources |
Tools
Example | File | Description |
---|---|---|
bevymark |
tools/bevymark.rs |
A heavy workload to benchmark your system with Bevy |
bevymark_pipelined |
tools/bevymark_pipelined.rs |
A heavy workload to benchmark your system with Bevy |
UI (User Interface)
Example | File | Description |
---|---|---|
button |
ui/button.rs |
Illustrates creating and updating a button |
font_atlas_debug |
ui/font_atlas_debug.rs |
Illustrates how FontAtlases are populated (used to optimize text rendering internally) |
text |
ui/text.rs |
Illustrates creating and updating text |
text_debug |
ui/text_debug.rs |
An example for debugging text layout |
ui |
ui/ui.rs |
Illustrates various features of Bevy UI |
Window
Example | File | Description |
---|---|---|
clear_color |
window/clear_color.rs |
Creates a solid color window |
clear_color_pipelined |
window/clear_color_pipelined.rs |
Creates a solid color window with the pipelined renderer |
multiple_windows |
window/multiple_windows.rs |
Creates two windows and cameras viewing the same mesh |
scale_factor_override |
window/scale_factor_override.rs |
Illustrates how to customize the default window settings |
window_settings |
window/window_settings.rs |
Demonstrates customizing default window settings |
Platform-Specific Examples
Android
Setup
rustup target add aarch64-linux-android armv7-linux-androideabi
cargo install cargo-apk
The Android SDK must be installed, and the environment variable ANDROID_SDK_ROOT
set to the root Android sdk
folder.
When using NDK (Side by side)
, the environment variable ANDROID_NDK_ROOT
must also be set to one of the NDKs in sdk\ndk\[NDK number]
.
Build & Run
To run on a device setup for Android development, run:
cargo apk run --example android
⚠️ At this time Bevy does not work in Android Emulator.
When using Bevy as a library, the following fields must be added to Cargo.toml
:
[package.metadata.android]
build_targets = ["aarch64-linux-android", "armv7-linux-androideabi"]
target_sdk_version = 29
min_sdk_version = 16
Please reference cargo-apk
README for other Android Manifest fields.
Old phones
Bevy by default targets Android API level 29 in its examples which is the Play Store's minimum API to upload or update apps. Users of older phones may want to use an older API when testing.
To use a different API, the following fields must be updated in Cargo.toml:
[package.metadata.android]
target_sdk_version = >>API<<
min_sdk_version = >>API or less<<
Example | File | Description |
---|---|---|
android |
android/android.rs |
The 3d/3d_scene.rs example for Android |
iOS
Setup
rustup target add aarch64-apple-ios x86_64-apple-ios
cargo install cargo-lipo
Build & Run
Using bash:
cd examples/ios
make run
In an ideal world, this will boot up, install and run the app for the first
iOS simulator in your xcrun simctl devices list
. If this fails, you can
specify the simulator device UUID via:
DEVICE_ID=${YOUR_DEVICE_ID} make run
If you'd like to see xcode do stuff, you can run
open bevy_ios_example.xcodeproj/
which will open xcode. You then must push the zoom zoom play button and wait for the magic.
The Xcode build GUI will by default build the rust library for both
x86_64-apple-ios
, and aarch64-apple-ios
which may take a while. If you'd
like speed this up, you update the IOS_TARGETS
User-Defined environment
variable in the "cargo_ios
target" to be either x86_64-apple-ios
or
aarch64-apple-ios
depending on your goal.
Note: if you update this variable in Xcode, it will also change the default
used for the Makefile
.
Example | File | Description |
---|---|---|
ios |
ios/src/lib.rs |
The 3d/3d_scene.rs example for iOS |
WASM
Setup
rustup target add wasm32-unknown-unknown
cargo install wasm-bindgen-cli
Build & Run
Following is an example for headless_wasm
. For other examples in wasm/ directory,
change the headless_wasm
in the following commands and edit examples/wasm/index.html
to point to the correct .js
file.
cargo build --example headless_wasm --target wasm32-unknown-unknown --no-default-features
wasm-bindgen --out-dir examples/wasm/target --target web target/wasm32-unknown-unknown/debug/examples/headless_wasm.wasm
Then serve examples/wasm
dir to browser. i.e.
basic-http-server examples/wasm
Example | File | Description |
---|---|---|
hello_wasm |
wasm/hello_wasm.rs |
Runs a minimal example that logs "hello world" to the browser's console |
assets_wasm |
wasm/assets_wasm.rs |
Demonstrates how to load assets from wasm |
headless_wasm |
wasm/headless_wasm.rs |
Sets up a schedule runner and continually logs a counter to the browser's console |
winit_wasm |
wasm/winit_wasm.rs |
Logs user input to the browser's console. Requires the bevy_winit features |