Fix examples after changes to Time

Author: nakedible

examples/2d/rotation.rs

@@ -2,13 +2,12 @@
 
 use bevy::prelude::*;
 
-const TIME_STEP: f32 = 1.0 / 60.0;
 const BOUNDS: Vec2 = Vec2::new(1200.0, 640.0);
 
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
-        .insert_resource(FixedTime::new_from_secs(TIME_STEP))
+        .insert_resource(Time::<Fixed>::from_hz(60.0))
         .add_systems(Startup, setup)
         .add_systems(
             FixedUpdate,
@@ -117,6 +116,7 @@ fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
 
 /// Demonstrates applying rotation and movement based on keyboard input.
 fn player_movement_system(
+    time: Res<Time>,
     keyboard_input: Res<Input<KeyCode>>,
     mut query: Query<(&Player, &mut Transform)>,
 ) {
@@ -138,12 +138,14 @@ fn player_movement_system(
     }
 
     // update the ship rotation around the Z axis (perpendicular to the 2D plane of the screen)
-    transform.rotate_z(rotation_factor * ship.rotation_speed * TIME_STEP);
+    transform.rotate_z(rotation_factor * ship.rotation_speed * time.delta_seconds());
 
-    // get the ship's forward vector by applying the current rotation to the ships initial facing vector
+    // get the ship's forward vector by applying the current rotation to the ships initial facing
+    // vector
     let movement_direction = transform.rotation * Vec3::Y;
-    // get the distance the ship will move based on direction, the ship's movement speed and delta time
-    let movement_distance = movement_factor * ship.movement_speed * TIME_STEP;
+    // get the distance the ship will move based on direction, the ship's movement speed and delta
+    // time
+    let movement_distance = movement_factor * ship.movement_speed * time.delta_seconds();
     // create the change in translation using the new movement direction and distance
     let translation_delta = movement_direction * movement_distance;
     // update the ship translation with our new translation delta
@@ -182,8 +184,8 @@ fn snap_to_player_system(
 /// if not, which way to rotate to face the player. The dot product on two unit length vectors
 /// will return a value between -1.0 and +1.0 which tells us the following about the two vectors:
 ///
-/// * If the result is 1.0 the vectors are pointing in the same direction, the angle between them
-///   is 0 degrees.
+/// * If the result is 1.0 the vectors are pointing in the same direction, the angle between them is
+///   0 degrees.
 /// * If the result is 0.0 the vectors are perpendicular, the angle between them is 90 degrees.
 /// * If the result is -1.0 the vectors are parallel but pointing in opposite directions, the angle
 ///   between them is 180 degrees.
@@ -198,6 +200,7 @@ fn snap_to_player_system(
 /// floating point precision loss, so it pays to clamp your dot product value before calling
 /// `acos`.
 fn rotate_to_player_system(
+    time: Res<Time>,
     mut query: Query<(&RotateToPlayer, &mut Transform), Without<Player>>,
     player_query: Query<&Transform, With<Player>>,
 ) {
@@ -242,7 +245,8 @@ fn rotate_to_player_system(
         let max_angle = forward_dot_player.clamp(-1.0, 1.0).acos(); // clamp acos for safety
 
         // calculate angle of rotation with limit
-        let rotation_angle = rotation_sign * (config.rotation_speed * TIME_STEP).min(max_angle);
+        let rotation_angle =
+            rotation_sign * (config.rotation_speed * time.delta_seconds()).min(max_angle);
 
         // rotate the enemy to face the player
         enemy_transform.rotate_z(rotation_angle);

examples/ecs/fixed_timestep.rs

@@ -2,7 +2,6 @@
 
 use bevy::prelude::*;
 
-const FIXED_TIMESTEP: f32 = 0.5;
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
@@ -11,28 +10,31 @@ fn main() {
         // add our system to the fixed timestep schedule
         .add_systems(FixedUpdate, fixed_update)
         // configure our fixed timestep schedule to run twice a second
-        .insert_resource(FixedTime::new_from_secs(FIXED_TIMESTEP))
+        .insert_resource(Time::<Fixed>::from_seconds(0.5))
         .run();
 }
 
 fn frame_update(mut last_time: Local<f32>, time: Res<Time>) {
+    // Default `Time` is `Time<Virtual>` here
     info!(
         "time since last frame_update: {}",
-        time.raw_elapsed_seconds() - *last_time
+        time.elapsed_seconds() - *last_time
     );
-    *last_time = time.raw_elapsed_seconds();
+    *last_time = time.elapsed_seconds();
 }
 
-fn fixed_update(mut last_time: Local<f32>, time: Res<Time>, fixed_time: Res<FixedTime>) {
+fn fixed_update(mut last_time: Local<f32>, time: Res<Time>, fixed_time: Res<Time<Fixed>>) {
+    // Default `Time`is `Time<Fixed>` here
     info!(
         "time since last fixed_update: {}\n",
-        time.raw_elapsed_seconds() - *last_time
+        time.elapsed_seconds() - *last_time
     );
 
-    info!("fixed timestep: {}\n", FIXED_TIMESTEP);
+    info!("fixed timestep: {}\n", time.delta_seconds());
+    // If we want to see the overstep, we need to access `Time<Fixed>` specifically
     info!(
         "time accrued toward next fixed_update: {}\n",
-        fixed_time.accumulated().as_secs_f32()
+        fixed_time.overstep().as_secs_f32()
     );
-    *last_time = time.raw_elapsed_seconds();
+    *last_time = time.elapsed_seconds();
 }

examples/ecs/iter_combinations.rs

@@ -3,8 +3,6 @@
 use bevy::{pbr::AmbientLight, prelude::*};
 use rand::{rngs::StdRng, Rng, SeedableRng};
 
-const DELTA_TIME: f32 = 0.01;
-
 fn main() {
     App::new()
         .add_plugins(DefaultPlugins)
@@ -13,7 +11,6 @@ fn main() {
             ..default()
         })
         .insert_resource(ClearColor(Color::BLACK))
-        .insert_resource(FixedTime::new_from_secs(DELTA_TIME))
         .add_systems(Startup, generate_bodies)
         .add_systems(FixedUpdate, (interact_bodies, integrate))
         .add_systems(Update, look_at_star)
@@ -41,6 +38,7 @@ struct BodyBundle {
 }
 
 fn generate_bodies(
+    time: Res<Time>,
     mut commands: Commands,
     mut meshes: ResMut<Assets<Mesh>>,
     mut materials: ResMut<Assets<StandardMaterial>>,
@@ -96,7 +94,7 @@ fn generate_bodies(
                         rng.gen_range(vel_range.clone()),
                         rng.gen_range(vel_range.clone()),
                         rng.gen_range(vel_range.clone()),
-                    ) * DELTA_TIME,
+                    ) * time.delta_seconds(),
             ),
         });
     }
@@ -160,8 +158,8 @@ fn interact_bodies(mut query: Query<(&Mass, &GlobalTransform, &mut Acceleration)
     }
 }
 
-fn integrate(mut query: Query<(&mut Acceleration, &mut Transform, &mut LastPos)>) {
-    let dt_sq = DELTA_TIME * DELTA_TIME;
+fn integrate(time: Res<Time>, mut query: Query<(&mut Acceleration, &mut Transform, &mut LastPos)>) {
+    let dt_sq = time.delta_seconds() * time.delta_seconds();
     for (mut acceleration, mut transform, mut last_pos) in &mut query {
         // verlet integration
         // x(t+dt) = 2x(t) - x(t-dt) + a(t)dt^2 + O(dt^4)

examples/games/breakout.rs

@@ -53,10 +53,9 @@ fn main() {
         .insert_resource(Scoreboard { score: 0 })
         .insert_resource(ClearColor(BACKGROUND_COLOR))
         .add_event::<CollisionEvent>()
-        // Configure how frequently our gameplay systems are run
-        .insert_resource(FixedTime::new_from_secs(1.0 / 60.0))
         .add_systems(Startup, setup)
         // Add our gameplay simulation systems to the fixed timestep schedule
+        // which runs at 64 Hz by default
         .add_systems(
             FixedUpdate,
             (
@@ -306,7 +305,7 @@ fn setup(
 fn move_paddle(
     keyboard_input: Res<Input<KeyCode>>,
     mut query: Query<&mut Transform, With<Paddle>>,
-    time_step: Res<FixedTime>,
+    time: Res<Time>,
 ) {
     let mut paddle_transform = query.single_mut();
     let mut direction = 0.0;
@@ -321,7 +320,7 @@ fn move_paddle(
 
     // Calculate the new horizontal paddle position based on player input
     let new_paddle_position =
-        paddle_transform.translation.x + direction * PADDLE_SPEED * time_step.period.as_secs_f32();
+        paddle_transform.translation.x + direction * PADDLE_SPEED * time.delta_seconds();
 
     // Update the paddle position,
     // making sure it doesn't cause the paddle to leave the arena
@@ -331,10 +330,10 @@ fn move_paddle(
     paddle_transform.translation.x = new_paddle_position.clamp(left_bound, right_bound);
 }
 
-fn apply_velocity(mut query: Query<(&mut Transform, &Velocity)>, time_step: Res<FixedTime>) {
+fn apply_velocity(mut query: Query<(&mut Transform, &Velocity)>, time: Res<Time>) {
     for (mut transform, velocity) in &mut query {
-        transform.translation.x += velocity.x * time_step.period.as_secs_f32();
-        transform.translation.y += velocity.y * time_step.period.as_secs_f32();
+        transform.translation.x += velocity.x * time.delta_seconds();
+        transform.translation.y += velocity.y * time.delta_seconds();
     }
 }
 

examples/stress_tests/bevymark.rs

@@ -10,6 +10,7 @@ use bevy::{
     prelude::*,
     render::render_resource::{Extent3d, TextureDimension, TextureFormat},
     sprite::{MaterialMesh2dBundle, Mesh2dHandle},
+    utils::Duration,
     window::{PresentMode, WindowResolution},
 };
 use rand::{rngs::StdRng, seq::SliceRandom, Rng, SeedableRng};
@@ -122,7 +123,9 @@ fn main() {
                 counter_system,
             ),
         )
-        .insert_resource(FixedTime::new_from_secs(FIXED_TIMESTEP))
+        .insert_resource(Time::<Fixed>::from_duration(Duration::from_secs_f32(
+            FIXED_TIMESTEP,
+        )))
         .run();
 }