Remove wasm specific examples (#3705)

# 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

Cargo.toml

@@ -498,27 +498,6 @@ path = "examples/window/transparent_window.rs"
 name = "window_settings"
 path = "examples/window/window_settings.rs"
 
-# WASM
-[[example]]
-name = "hello_wasm"
-path = "examples/wasm/hello_wasm.rs"
-required-features = []
-
-[[example]]
-name = "assets_wasm"
-path = "examples/wasm/assets_wasm.rs"
-required-features = ["bevy_winit"]
-
-[[example]]
-name = "headless_wasm"
-path = "examples/wasm/headless_wasm.rs"
-required-features = []
-
-[[example]]
-name = "winit_wasm"
-path = "examples/wasm/winit_wasm.rs"
-required-features = ["bevy_winit"]
-
 # Android
 [[example]]
 crate-type = ["cdylib"]

examples/README.md

@@ -366,24 +366,34 @@ cargo install wasm-bindgen-cli
 
 ### Build & Run
 
-Following is an example for `headless_wasm`. For other examples in wasm/ directory,
+Following is an example for `lighting`. For other examples, change the `lighting` in the
-change the `headless_wasm` in the following commands **and edit** `examples/wasm/index.html`
+following commands.
-to point to the correct `.js` file.
 
 ```sh
-cargo build --example headless_wasm --target wasm32-unknown-unknown --no-default-features
+cargo build --release --example lighting --target wasm32-unknown-unknown
-wasm-bindgen --out-dir examples/wasm/target --target web target/wasm32-unknown-unknown/debug/examples/headless_wasm.wasm
+wasm-bindgen --out-name wasm_example --out-dir examples/wasm/target --target web target/wasm32-unknown-unknown/release/examples/lighting.wasm
 ```
 
-Then serve `examples/wasm` dir to browser. i.e.
+The first command will build the example for the wasm target, creating a binary. Then,
+[wasm-bindgen-cli](https://rustwasm.github.io/wasm-bindgen/reference/cli.html) is used to create
+javascript bindings to this wasm file, which can be loaded using this
+[example HTML file](./wasm/index.html).
+
+Then serve `examples/wasm` directory to browser. i.e.
 
 ```sh
+# cargo install basic-http-server
 basic-http-server examples/wasm
+
+# with python
+python3 -m http.server --directory examples/wasm
+
+# with ruby
+ruby -run -ehttpd examples/wasm
 ```
 
-Example | File | Description
+### Loading Assets
---- | --- | ---
+
-`hello_wasm` | [`wasm/hello_wasm.rs`](./wasm/hello_wasm.rs) | Runs a minimal example that logs "hello world" to the browser's console
+To load assets, they need to be available in the folder examples/wasm/assets. Cloning this
-`assets_wasm` | [`wasm/assets_wasm.rs`](./wasm/assets_wasm.rs) | Demonstrates how to load assets from wasm
+repository will set it up as a symlink on Linux and macOS, but you will need to manually move
-`headless_wasm` | [`wasm/headless_wasm.rs`](./wasm/headless_wasm.rs) | Sets up a schedule runner and continually logs a counter to the browser's console
+the assets on Windows.
-`winit_wasm` | [`wasm/winit_wasm.rs`](./wasm/winit_wasm.rs) | Logs user input to the browser's console. Requires the `bevy_winit` features

examples/wasm/assets

@@ -0,0 +1 @@
+../../assets

examples/wasm/assets_wasm.rs

@@ -1,68 +0,0 @@
-use bevy::{
-    asset::{AssetLoader, AssetServerSettings, LoadContext, LoadedAsset},
-    prelude::*,
-    reflect::TypeUuid,
-    utils::BoxedFuture,
-};
-
-fn main() {
-    App::new()
-        .insert_resource(AssetServerSettings {
-            asset_folder: "/".to_string(),
-        })
-        .add_plugins(DefaultPlugins)
-        .add_asset::<RustSourceCode>()
-        .init_asset_loader::<RustSourceCodeLoader>()
-        .add_startup_system(load_asset)
-        .add_system(print_asset)
-        .run();
-}
-
-struct State {
-    handle: Handle<RustSourceCode>,
-    printed: bool,
-}
-
-fn load_asset(mut commands: Commands, asset_server: Res<AssetServer>) {
-    commands.insert_resource(State {
-        handle: asset_server.load("assets_wasm.rs"),
-        printed: false,
-    });
-}
-
-fn print_asset(mut state: ResMut<State>, rust_sources: Res<Assets<RustSourceCode>>) {
-    if state.printed {
-        return;
-    }
-
-    if let Some(code) = rust_sources.get(&state.handle) {
-        info!("code: {}", code.0);
-        state.printed = true;
-    }
-}
-
-#[derive(Debug, TypeUuid)]
-#[uuid = "1c3445ab-97d3-449c-ab35-16ba30e4c29d"]
-pub struct RustSourceCode(pub String);
-
-#[derive(Default)]
-pub struct RustSourceCodeLoader;
-
-impl AssetLoader for RustSourceCodeLoader {
-    fn load<'a>(
-        &'a self,
-        bytes: &'a [u8],
-        load_context: &'a mut LoadContext,
-    ) -> BoxedFuture<'a, Result<(), anyhow::Error>> {
-        Box::pin(async move {
-            load_context.set_default_asset(LoadedAsset::new(RustSourceCode(String::from_utf8(
-                bytes.into(),
-            )?)));
-            Ok(())
-        })
-    }
-
-    fn extensions(&self) -> &[&str] {
-        &["rs"]
-    }
-}

examples/wasm/headless_wasm.rs

@@ -1,34 +0,0 @@
-use bevy::{
-    app::{ScheduleRunnerPlugin, ScheduleRunnerSettings},
-    log::LogPlugin,
-    prelude::*,
-    utils::Duration,
-};
-
-fn main() {
-    App::new()
-        .insert_resource(ScheduleRunnerSettings::run_loop(Duration::from_secs_f64(
-            1.0 / 60.0,
-        )))
-        .add_plugin(ScheduleRunnerPlugin::default())
-        .add_plugin(LogPlugin::default())
-        .add_startup_system(hello_world_system)
-        .add_system(counter)
-        .run();
-}
-
-fn hello_world_system() {
-    info!("hello wasm");
-}
-
-fn counter(mut state: Local<CounterState>) {
-    if state.count % 60 == 0 {
-        info!("counter system: {}", state.count);
-    }
-    state.count += 1;
-}
-
-#[derive(Default)]
-struct CounterState {
-    count: u32,
-}

examples/wasm/hello_wasm.rs

@@ -1,12 +0,0 @@
-use bevy::{log::LogPlugin, prelude::*};
-
-fn main() {
-    App::new()
-        .add_plugin(LogPlugin::default())
-        .add_system(hello_wasm_system)
-        .run();
-}
-
-fn hello_wasm_system() {
-    info!("hello wasm");
-}

examples/wasm/index.html

@@ -21,7 +21,7 @@
     </style>
   </head>
   <script type="module">
-    import init from './target/headless_wasm.js'
+    import init from './target/wasm_example.js'
     init()
   </script>
 </html>

examples/wasm/winit_wasm.rs

@@ -1,89 +0,0 @@
-use bevy::{
-    input::{
-        keyboard::KeyboardInput,
-        mouse::{MouseButtonInput, MouseMotion, MouseWheel},
-    },
-    prelude::*,
-};
-
-fn main() {
-    App::new()
-        .insert_resource(WindowDescriptor {
-            width: 300.,
-            height: 300.,
-            ..Default::default()
-        })
-        .add_plugins(DefaultPlugins)
-        // One time greet
-        .add_startup_system(hello_wasm_system)
-        // Track ticks (sanity check, whether game loop is running)
-        .add_system(counter)
-        // Track input events
-        .add_system(track_input_events)
-        .run();
-}
-
-fn hello_wasm_system() {
-    info!("hello wasm");
-}
-
-fn counter(mut state: Local<CounterState>, time: Res<Time>) {
-    if state.count % 60 == 0 {
-        info!(
-            "tick {} @ {:?} [Δ{}]",
-            state.count,
-            time.time_since_startup(),
-            time.delta_seconds()
-        );
-    }
-    state.count += 1;
-}
-
-#[derive(Default)]
-struct CounterState {
-    count: u32,
-}
-
-fn track_input_events(
-    mut ev_keys: EventReader<KeyboardInput>,
-    mut ev_cursor: EventReader<CursorMoved>,
-    mut ev_motion: EventReader<MouseMotion>,
-    mut ev_mousebtn: EventReader<MouseButtonInput>,
-    mut ev_scroll: EventReader<MouseWheel>,
-) {
-    // Keyboard input
-    for ev in ev_keys.iter() {
-        if ev.state.is_pressed() {
-            info!("Just pressed key: {:?}", ev.key_code);
-        } else {
-            info!("Just released key: {:?}", ev.key_code);
-        }
-    }
-
-    // Absolute cursor position (in window coordinates)
-    for ev in ev_cursor.iter() {
-        info!("Cursor at: {}", ev.position);
-    }
-
-    // Relative mouse motion
-    for ev in ev_motion.iter() {
-        info!("Mouse moved {} pixels", ev.delta);
-    }
-
-    // Mouse buttons
-    for ev in ev_mousebtn.iter() {
-        if ev.state.is_pressed() {
-            info!("Just pressed mouse button: {:?}", ev.button);
-        } else {
-            info!("Just released mouse button: {:?}", ev.button);
-        }
-    }
-
-    // scrolling (mouse wheel, touchpad, etc.)
-    for ev in ev_scroll.iter() {
-        info!(
-            "Scrolled vertically by {} and horizontally by {}.",
-            ev.y, ev.x
-        );
-    }
-}