Vendor dependencies for 0.3.0 release

vendor/bevy/examples/app/plugin_group.rs

@@ -0,0 +1,59 @@
+//! Demonstrates the creation and registration of a custom plugin group.
+//! [`PluginGroup`]s are a way to group sets of plugins that should be registered together.
+
+use bevy::{app::PluginGroupBuilder, prelude::*};
+
+fn main() {
+    App::new()
+        .add_plugins((
+            // Two PluginGroups that are included with bevy are DefaultPlugins and MinimalPlugins
+            DefaultPlugins,
+            // Adding a plugin group adds all plugins in the group by default
+            HelloWorldPlugins,
+        ))
+        // You can also modify a PluginGroup (such as disabling plugins) like this:
+        // .add_plugins(
+        //     HelloWorldPlugins
+        //         .build()
+        //         .disable::<PrintWorldPlugin>()
+        //         .add_before::<PrintHelloPlugin>(
+        //             bevy::diagnostic::LogDiagnosticsPlugin::default(),
+        //         ),
+        // )
+        .run();
+}
+
+/// A group of plugins that produce the "hello world" behavior
+pub struct HelloWorldPlugins;
+
+impl PluginGroup for HelloWorldPlugins {
+    fn build(self) -> PluginGroupBuilder {
+        PluginGroupBuilder::start::<Self>()
+            .add(PrintHelloPlugin)
+            .add(PrintWorldPlugin)
+    }
+}
+
+struct PrintHelloPlugin;
+
+impl Plugin for PrintHelloPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(Update, print_hello_system);
+    }
+}
+
+fn print_hello_system() {
+    info!("hello");
+}
+
+struct PrintWorldPlugin;
+
+impl Plugin for PrintWorldPlugin {
+    fn build(&self, app: &mut App) {
+        app.add_systems(Update, print_world_system);
+    }
+}
+
+fn print_world_system() {
+    info!("world");
+}