Sailing physics sketching

src/main.rs

@@ -1,13 +1,23 @@
 use bevy::prelude::*;
 
-#[derive(Component)]
+const MAX_SAILING_SPEED: f32 = 0.9;
+const MAX_TURN_SPEED: f32 = 0.1;
+
+#[derive(Component, Default)]
 struct EntityPhysics {
     x: f32,
     y: f32,
     speed: f32,
+    turn_speed: f32,
     heading: f32,
 }
 
+#[derive(Component, Default)]
+struct InputState {
+    x: f32,
+    y: f32,
+}
+
 fn main() {
     let mut app = App::new();
 
@@ -36,42 +46,61 @@ fn sprite_setup(assets: Res<AssetServer>, mut commands: Commands) {
             image: sprite_handle,
             ..default()
         },
-        EntityPhysics {
-            x: 0.,
-            y: 0.,
-            speed: 0.,
-            heading: 0.,
-        },
+        EntityPhysics::default(),
+        InputState::default(),
     ));
 }
 
-fn handle_keys(mut q_player: Query<&mut EntityPhysics>, keys: Res<ButtonInput<KeyCode>>) {
+fn handle_keys(mut q_player: Query<&mut InputState>, keys: Res<ButtonInput<KeyCode>>) {
     if keys.just_pressed(KeyCode::KeyQ) {
         info!("Quit.");
     }
 
-    let Ok(mut player) = q_player.single_mut() else {
+    let Ok(mut input) = q_player.single_mut() else {
         return;
     };
 
-    if keys.just_pressed(KeyCode::ArrowUp) {
-        player.speed += 0.1;
+    if keys.pressed(KeyCode::ArrowUp) {
+        input.y = 1.;
+    } else if keys.pressed(KeyCode::ArrowDown) {
+        input.y = -1.;
+    } else {
+        input.y = 0.;
     }
 
-    if keys.just_pressed(KeyCode::ArrowRight) {
-        player.heading += 0.1;
-    }
-
-    if keys.just_pressed(KeyCode::ArrowLeft) {
-        player.heading -= 0.1;
+    if keys.pressed(KeyCode::ArrowRight) {
+        input.x = 1.;
+    } else if keys.pressed(KeyCode::ArrowLeft) {
+        input.x = -1.;
+    } else {
+        input.x = 0.;
     }
 }
 
-fn player_physics(mut q_player: Query<(&mut EntityPhysics, &mut Transform)>) {
-    let Ok((mut physics, mut transform)) = q_player.single_mut() else {
+fn player_physics(mut q_player: Query<(&InputState, &mut EntityPhysics, &mut Transform)>) {
+    let Ok((input, mut physics, mut transform)) = q_player.single_mut() else {
         return;
     };
 
+    if input.x < 0. {
+        physics.turn_speed -= 0.1;
+    } else if input.x > 0. {
+        physics.turn_speed += 0.1;
+    }
+
+    physics.turn_speed = physics.turn_speed.clamp(-MAX_TURN_SPEED, MAX_TURN_SPEED);
+    physics.heading += physics.turn_speed * 0.1;
+
+    if input.y > 0. {
+        physics.speed += 0.1;
+    } else if input.y < 0. {
+        physics.speed -= 0.1;
+    } else {
+        physics.speed *= 0.99;
+    }
+
+    physics.speed = physics.speed.clamp(-MAX_SAILING_SPEED, MAX_SAILING_SPEED);
+
     let x_speed = physics.heading.sin() * physics.speed;
     let y_speed = physics.heading.cos() * physics.speed;