Add Transform Helper methods

crates/bevy_transform/src/components/transform.rs

@@ -288,6 +288,43 @@ impl Transform {
         self.local_z()
     }
 
+    /// Translates the entity in the local space using a given direction, speed, and delta time.
+    ///
+    /// The translation is applied directly to the entity's local position without considering
+    /// the entity's rotation. This means the entity moves along the provided direction in its
+    /// own local space.
+    ///
+    /// # Parameters
+    /// - `direction`: A `Vec3` representing the direction of movement in the entity's local space.
+    /// - `speed`: A `f32` representing the speed at which the entity should move.
+    /// - `delta_time_seconds`: A `f32` representing the time elapsed in seconds, typically
+    ///   the time since the last frame.
+    pub fn translate(&mut self, direction: Vec3, speed: f32, delta_time_seconds: f32) {
+        self.translation += direction * speed * delta_time_seconds;
+    }
+
+    /// Translates the entity in local space, taking into account the entity's rotation, speed,
+    /// and delta time.
+    ///
+    /// The translation is relative to the entity's rotation. This means the movement will be in
+    /// the direction the entity is currently facing, which allows the entity to move "forward"
+    /// or in any rotated direction relative to its local orientation.
+    ///
+    /// # Parameters
+    /// - `direction`: A `Vec3` representing the direction of movement, relative to the entity's
+    ///   local orientation.
+    /// - `speed`: A `f32` representing the speed at which the entity should move.
+    /// - `delta_time_seconds`: A `f32` representing the time elapsed in seconds, typically
+    ///   the time since the last frame.
+    pub fn translate_with_local_rotation(
+        &mut self,
+        direction: Vec3,
+        speed: f32,
+        delta_time_seconds: f32,
+    ) {
+        self.translation += self.rotation * direction * speed * delta_time_seconds;
+    }
+
     /// Rotates this [`Transform`] by the given rotation.
     ///
     /// If this [`Transform`] has a parent, the `rotation` is relative to the rotation of the parent.

examples/transforms/translation.rs

@@ -68,7 +68,6 @@ fn move_cube(mut cubes: Query<(&mut Transform, &mut Movable)>, timer: Res<Time>)
         if (cube.spawn - transform.translation).length() > cube.max_distance {
             cube.speed *= -1.0;
         }
-        let direction = transform.local_x();
-        transform.translation += direction * cube.speed * timer.delta_seconds();
+        transform.translate(Vec3::X, cube.speed, timer.delta_seconds());
     }
 }