Add animated_logo example

Cargo.toml

@@ -55,6 +55,14 @@ required-features = [
   "bevy/bevy_winit",
 ]
 
+[[example]]
+name = "animated_logo"
+required-features = [
+  "bevy_sprite",
+  "span_tween",
+  "bevy/bevy_winit",
+]
+
 [[example]]
 name = "demo_follow"
 required-features = [

examples/animated_logo.rs

@@ -0,0 +1,108 @@
+use std::f32::consts::TAU;
+
+use bevy::prelude::*;
+use bevy_tween::prelude::*;
+
+fn main() {
+    App::new()
+        .add_plugins((DefaultPlugins, DefaultTweenPlugins))
+        .add_systems(Startup, setup)
+        .run();
+}
+
+fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
+    commands.spawn(Camera2dBundle::default());
+
+    let bevy_text = asset_server.load("bevy.png");
+    let tween_text = asset_server.load("tween.png");
+    let square_image = asset_server.load("big_triangle.png");
+    let ease = EaseFunction::ExponentialInOut;
+
+    commands.spawn(SpriteBundle {
+        texture: bevy_text,
+        transform: Transform::from_xyz(-300., 0., 0.),
+        ..Default::default()
+    });
+
+    commands.spawn(SpriteBundle {
+        texture: tween_text,
+        transform: Transform::from_xyz(350., 0., 0.),
+        ..Default::default()
+    });
+
+    // colors by https://color-hex.org/color-palettes/189
+    let colors = vec![
+        Color::rgb_u8(0, 128, 191),
+        Color::rgb_u8(0, 172, 223),
+        Color::rgb_u8(85, 208, 255),
+        Color::rgb_u8(124, 232, 255),
+        Color::rgb_u8(204, 249, 255),
+    ];
+    let squares = colors
+        .iter()
+        .enumerate()
+        .map(|(i, color)| {
+            triangle(&mut commands, square_image.clone(), *color, i as f32)
+        })
+        .collect::<Vec<_>>();
+
+    let secs = 8.;
+
+    commands
+        .spawn(
+            SpanTweenerBundle::new(Duration::from_secs_f32(secs))
+                .with_repeat(Repeat::Infinitely),
+        )
+        .with_children(|c| {
+            snap_rotate(c, squares[4], secs, 5, 4., ease);
+            snap_rotate(c, squares[3], secs, 5, 5., ease);
+            snap_rotate(c, squares[2], secs, 5, 6., ease);
+            snap_rotate(c, squares[1], secs, 5, 7., ease);
+            snap_rotate(c, squares[0], secs, 5, 8., ease);
+        });
+}
+
+fn snap_rotate(
+    c: &mut ChildBuilder<'_>,
+    entity: Entity,
+    secs: f32,
+    max: usize,
+    rev: f32,
+    ease: EaseFunction,
+) {
+    for i in 0..max {
+        let max = max as f32;
+        let i = i as f32;
+        c.child_tweens().tween(
+            Duration::from_secs_f32(i / max * secs)
+                ..Duration::from_secs_f32((i + 1.) / max * secs),
+            ease,
+            ComponentDynTween::new_target_boxed(
+                entity,
+                interpolate::AngleZ {
+                    start: rev * TAU * (max - i) / max,
+                    end: rev * TAU * (max - i - 1.) / max,
+                },
+            ),
+        );
+    }
+}
+
+fn triangle(
+    commands: &mut Commands,
+    texture: Handle<Image>,
+    color: Color,
+    z: f32,
+) -> Entity {
+    commands
+        .spawn((SpriteBundle {
+            sprite: Sprite {
+                color,
+                ..Default::default()
+            },
+            transform: Transform::from_xyz(0., 0., z),
+            texture,
+            ..Default::default()
+        },))
+        .id()
+}