Asteroids

Objectives

• You will create a game that mimics gameplay of Asteroids
• The player will be able to move around using the keyboard
• The player's ship will be affected by momentum and physics
• The player will be able to fire at asteroids and break them apart
• Points will be given to the player for destroying asteroids

Requirements

Ship Movement

• Pressing the Right-key turns the ship to the right
• Pressing the Left-key turns the ship to the left
• Pressing the Up-key will accelerate the ship and go forwards
  1. Create a speed variable and set it to 0
  2. If the Up-key is pressed, then increase speed by a little bit (e.g. 0.5)
  3. Else, if speed is greater than 0, then decrease speed by a little bit (e.g. -0.5)
  4. Move the ship speed steps
• Pressing the Down-key will decelerate the ship and go backwards
  • Follow the same steps as the Up-key, but reverse/negate everything

Screen-wrapping

• If the ship goes beyond the top edge, it should appear at the bottom edge of the screen, and vice versa
• If the ship goes beyond the right edge, it should appear at the left edge of the screen, and vice versa

Firing Projectiles

• Pressing space bar down will fire a projectile (use clones)
  • The projectile should disappear when it hits the edge of the screen
  • If the space bar is held down, a projectiles (clones) should be fired every 0.5 second
• A laser/firing sound should be played when a projectile is fired

Asteroids

• Multiple asteroids should appear on the screen doing the following:

1. Make an asteroid appear at a random edge of the screen
   1. Pick a random number between 1-4 (each number corresponds to a side)
   2. Use if-statements to check for each number 1 through 4,
      1. Tell the asteroid to appear at a random place along that side (will be different for each side)
      2. Give it a random direction (depends on the side the asteroid is located)
2. Have the asteroid move across the screen
3. The asteroid should disappear when it hits another edge

Asteroid Collisions

• If asteroids collide with the ship:
  • Play a sound for the collision
  • Show an explosion or animation
  • Display a "Game over" message
• If projectiles hit the asteroids:
  • The asteroid should break apart
    1. Change its size by 25
    2. Randomize its direction
    3. Create a clone that moves in the opposite direction
    4. If the size is less than 25, then delete the clone and hide the asteroid
  • Play a sound for the explosion
  • Points given to the player

Aesthetics

• Use a basic star field for the background
• Find simple background music to use -- something appropriate for the theme of the game

Advanced Requirements

• Health bar for the ship
• Other flying objects on the screen give different point values
• Use a cloud variable for the high score