Example for 2D Frustum Culling (#1503)

This adds a new project for showing off Frustum Culling.
(Master runs this at sub 1 FPS while with the frustum culling it runs at 144 FPS on my system)

Short clip of the project running:
https://streamable.com/vvzh2u

Cargo.toml

@@ -94,6 +94,10 @@ path = "examples/hello_world.rs"
 name = "contributors"
 path = "examples/2d/contributors.rs"
 
+[[example]]
+name = "many_sprites"
+path = "examples/2d/many_sprites.rs"
+
 [[example]]
 name = "sprite"
 path = "examples/2d/sprite.rs"

examples/2d/many_sprites.rs

@@ -0,0 +1,95 @@
+use bevy::{
+    diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
+    math::Quat,
+    prelude::*,
+};
+
+use rand::Rng;
+
+const CAMERA_SPEED: f32 = 1000.0;
+
+pub struct PrintTimer(Timer);
+pub struct Position(Transform);
+
+///This example is for performance testing purposes.
+///See https://github.com/bevyengine/bevy/pull/1492
+fn main() {
+    App::build()
+        .add_plugin(LogDiagnosticsPlugin::default())
+        .add_plugin(FrameTimeDiagnosticsPlugin::default())
+        .insert_resource(bevy::log::LogSettings {
+            level: bevy::log::Level::DEBUG,
+            ..Default::default()
+        })
+        .add_plugins(DefaultPlugins)
+        .add_startup_system(setup.system())
+        .add_system(tick.system().label("Tick"))
+        .add_system(move_camera.system().after("Tick"))
+        .run()
+}
+
+fn setup(
+    mut commands: Commands,
+    assets: Res<AssetServer>,
+    mut materials: ResMut<Assets<ColorMaterial>>,
+) {
+    let mut rng = rand::thread_rng();
+
+    let tile_size = Vec2::splat(64.0);
+    let map_size = Vec2::splat(320.0);
+
+    let half_x = (map_size.x / 2.0) as i32;
+    let half_y = (map_size.y / 2.0) as i32;
+
+    let sprite_handle = materials.add(assets.load("branding/icon.png").into());
+
+    commands
+        .spawn()
+        .insert_bundle(OrthographicCameraBundle::new_2d())
+        .insert(PrintTimer(Timer::from_seconds(1.0, true)))
+        .insert(Position(Transform::from_translation(Vec3::new(
+            0.0, 0.0, 1000.0,
+        ))));
+
+    for y in -half_y..half_y {
+        for x in -half_x..half_x {
+            let position = Vec2::new(x as f32, y as f32);
+            let translation = (position * tile_size).extend(rng.gen::<f32>());
+            let rotation = Quat::from_rotation_z(rng.gen::<f32>());
+            let scale = Vec3::splat(rng.gen::<f32>() * 2.0);
+
+            commands.spawn().insert_bundle(SpriteBundle {
+                material: sprite_handle.clone(),
+                transform: Transform {
+                    translation,
+                    rotation,
+                    scale,
+                },
+                sprite: Sprite::new(tile_size),
+                ..Default::default()
+            });
+        }
+    }
+}
+
+fn move_camera(time: Res<Time>, mut query: Query<(&mut Transform, &mut Position)>) {
+    for (mut transform, mut position) in query.iter_mut() {
+        position
+            .0
+            .rotate(Quat::from_rotation_z(time.delta_seconds() * 0.5));
+        position.0 =
+            position.0 * Transform::from_translation(Vec3::X * CAMERA_SPEED * time.delta_seconds());
+        transform.translation = position.0.translation;
+        transform.rotation *= Quat::from_rotation_z(time.delta_seconds() / 2.0);
+    }
+}
+
+fn tick(time: Res<Time>, sprites: Query<&Sprite>, mut query: Query<&mut PrintTimer>) {
+    for mut timer in query.iter_mut() {
+        timer.0.tick(time.delta());
+
+        if timer.0.just_finished() {
+            println!("Sprites: {}", sprites.iter().count(),);
+        }
+    }
+}

examples/README.md

@@ -72,6 +72,7 @@ Example | Main | Description
 Example | Main | Description
 --- | --- | ---
 `contributors` | [`2d/contributors.rs`](./2d/contributors.rs) | Displays each contributor as a bouncy bevy-ball!
+`many_sprites` | [`2d/many_sprites.rs`](./2d/many_sprites.rs) | Displays many sprites in a grid arragement! Used for performance testing.
 `sprite` | [`2d/sprite.rs`](./2d/sprite.rs) | Renders a sprite
 `sprite_sheet` | [`2d/sprite_sheet.rs`](./2d/sprite_sheet.rs) | Renders an animated sprite
 `text2d` | [`2d/text2d.rs`](./2d/text2d.rs) | Generates text in 2d