Adding a bezier curve example

Cargo.toml

@@ -713,6 +713,16 @@ description = "Create and play an animation defined by code that operates on the
 category = "Animation"
 wasm = true
 
+[[example]]
+name = "cubic_curve"
+path = "examples/animation/cubic_curve.rs"
+
+[package.metadata.example.cubic_curve]
+name = "Cubic Curve"
+description = "Bezier curve example showing a cube following a cubic curve"
+category = "Animation"
+wasm = true
+
 [[example]]
 name = "custom_skinned_mesh"
 path = "examples/animation/custom_skinned_mesh.rs"

examples/README.md

@@ -143,6 +143,7 @@ Example | Description
 --- | ---
 [Animated Fox](../examples/animation/animated_fox.rs) | Plays an animation from a skinned glTF
 [Animated Transform](../examples/animation/animated_transform.rs) | Create and play an animation defined by code that operates on the `Transform` component
+[Cubic Curve](../examples/animation/cubic_curve.rs) | Bezier curve example showing a cube following a cubic curve
 [Custom Skinned Mesh](../examples/animation/custom_skinned_mesh.rs) | Skinned mesh example with mesh and joints data defined in code
 [glTF Skinned Mesh](../examples/animation/gltf_skinned_mesh.rs) | Skinned mesh example with mesh and joints data loaded from a glTF file
 

examples/animation/cubic_curve.rs

@@ -0,0 +1,93 @@
+//! Demonstrates how to work with Cubic curves.
+//!
+
+use bevy::{math::cubic_splines::CubicCurve, prelude::*};
+
+#[derive(Component)]
+pub struct Curve(CubicCurve<Vec3>);
+
+fn main() {
+ App::new()
+ .add_plugins(DefaultPlugins)
+ .add_systems(Startup, setup)
+ .add_systems(Update, animate_cube)
+ .run();
+}
+
+fn setup(
+ mut commands: Commands,
+ mut meshes: ResMut<Assets<Mesh>>,
+ mut materials: ResMut<Assets<StandardMaterial>>,
+) {
+ // Define your control points
+ // These points will define the curve
+ // You can learn more about bezier curves here
+ // https://en.wikipedia.org/wiki/B%C3%A9zier_curve
+ let control_point1 = Vec3::new(-6., 2., 0.);
+ let control_point2 = Vec3::new(12., 8., 0.);
+
+ let control_point3 = Vec3::new(-12., 8., 0.);
+ let control_point4 = Vec3::new(6., 2., 0.);
+
+ let points = [[
+ control_point1,
+ control_point2,
+ control_point3,
+ control_point4,
+ ]];
+
+ // Make a CubicCurve
+ let bezier = Bezier::new(points).to_curve();
+
+ // Spawning a cube to experiment on
+ commands.spawn((
+ PbrBundle {
+ mesh: meshes.add(shape::Cube::default().into()),
+ material: materials.add(Color::ORANGE.into()),
+ transform: Transform::from_translation(control_point1),
+ ..default()
+ },
+ Curve(bezier),
+ ));
+
+ // Some light to see something
+ commands.spawn(PointLightBundle {
+ point_light: PointLight {
+ intensity: 9000.,
+ range: 100.,
+ shadows_enabled: true,
+ ..default()
+ },
+ transform: Transform::from_xyz(8., 16., 8.),
+ ..default()
+ });
+
+ // ground plane
+ commands.spawn(PbrBundle {
+ mesh: meshes.add(shape::Plane::from_size(50.).into()),
+ material: materials.add(Color::SILVER.into()),
+ ..default()
+ });
+
+ // The camera
+ commands.spawn(Camera3dBundle {
+ transform: Transform::from_xyz(0., 6., 12.).looking_at(Vec3::new(0., 3., 0.), Vec3::Y),
+ ..default()
+ });
+}
+
+pub fn animate_cube(
+ time: Res<Time>,
+ mut query: Query<(&mut Transform, &Curve)>,
+ mut gizmos: Gizmos,
+) {
+ let step = (time.elapsed_seconds().sin() + 1.) / 2.;
+
+ for (mut transform, cubic_curve) in &mut query {
+ // Draw the curve
+ gizmos.linestrip(cubic_curve.0.iter_positions(50), Color::WHITE);
+ // position takes a point from the curve where 0 is the initial point
+ // and 1 is the last point
+ transform.translation = cubic_curve.0.position(step);
+ }
+}