Exercises

It's very easy to avoid collisions with the asteroids as they don't move... Let's make this game a bit harder!

Moving the Asteroids

Make the asteroids move in random directions, at random speeds.

Tips:

• Add information about direction and speed to the Asteroid component.
• Add a system to update the position of the asteroids based on their direction and speed.

Losing the Game

Let's go back to the menu when colliding with an asteroid.

Tips:

• Use the ResMut<NextState<GameStates>> system parameter to change the current state on collision

Explosion Effect on Collision

It's nicer to see what happened before going back to the menu, let's display an explosion and wait a bit.

Tips:

• Load the asset for the explosion effect
• Spawn a sprite at the same Transform as the ship, with a Timer
  • Use the Commands system parameter to spawn the explosion sprite
• Despawn the ship
• Add a new system that will tick the timer
• After the timer is done, despawn it and change state
• Some systems will return errors now as they try to access the player transform
  • Those are the systems handling player control and collisions with asteroids
  • Those systems shouldn't do anything when there isn't a player
  • Instead of using ? with single / single_mut when querying for it, use let Ok(...) = query.single() else { return Ok(()); };