At the end of the functions section, the case study should resemble this example solution:
namespace SpriteKind {
export const Asteroid = SpriteKind.create();
export const PowerUp = SpriteKind.create();
export const Laser = SpriteKind.create();
}
enum PowerUpType {
Health,
Score
}
/**
* Contains the images used in the game
*/
namespace spritesheet {
export let player: Image = img`
. . . . 8 . . . .
. . . 8 8 8 . . .
. . . 8 1 8 . . .
. . 2 8 1 8 2 . .
. 2 2 8 8 8 2 2 .
2 2 2 8 8 8 2 2 2
. . . 5 . 5 . . .
`;
export let enemy: Image = img`
5 5 . . . . 5 5
7 7 7 7 7 7 7 7
. 9 9 7 7 9 9 .
. 7 7 7 7 7 7 .
. . . 9 9 . . .
`;
export let asteroid: Image = sprites.space.spaceAsteroid0;
export let powerUp: Image = img`
. . . 5 5 5 5 5 . . .
. . 5 5 5 f 5 5 5 . .
. 5 5 5 f f f 5 5 5 .
5 5 5 f 5 f 5 f 5 5 5
5 5 5 5 f 5 5 5 5 5 5
5 5 5 5 5 f 5 5 5 5 5
5 5 5 5 5 5 f 5 5 5 5
5 5 5 f 5 f 5 f 5 5 5
. 5 5 5 f f f 5 5 5 .
. . 5 5 5 f 5 5 5 . .
. . . 5 5 5 5 5 . . .
`;
export let laser: Image = img`
4
4
`;
}
/**
* Creates and controls the asteroids within the game
*/
namespace asteroids {
sprites.onCreated(SpriteKind.Asteroid, function (sprite: Sprite) {
sprite.setFlag(SpriteFlag.AutoDestroy, true);
setPosition(sprite, 10);
setMotion(sprite);
});
game.onUpdateInterval(1500, function () {
sprites.create(spritesheet.asteroid, SpriteKind.Asteroid);
});
/**
* Set the initial velocities for the given sprite
* @param asteroid the asteroid to set the initial velocities of
*/
function setMotion(asteroid: Sprite) {
asteroid.vx = randint(-8, 8);
asteroid.vy = randint(35, 20);
}
/**
* Place the given sprite at a random location at the top of the screen
* @param sprite the sprite to place at the top of the screen
* @param edge how many pixels between either edge of the screen to set
*/
function setPosition(sprite: Sprite, edge: number) {
sprite.x = randint(edge, screen.width - edge);
sprite.y = 0;
}
}
/**
* Creates and controls the player's ship
*/
namespace ship {
export let player: Sprite = initialize();
/**
* @returns a player sprite that moves with the directional buttons
*/
function initialize(): Sprite {
let sprite = sprites.create(spritesheet.player, SpriteKind.Player)
controller.moveSprite(sprite, 80, 30);
sprite.x = screen.width / 2;
sprite.y = screen.height - 20;
return sprite;
}
// When the player presses A, fire a laser from the spaceship
controller.A.onEvent(ControllerButtonEvent.Pressed, function () {
sprites.createProjectile(spritesheet.laser, 0, -40, SpriteKind.Laser, player);
});
}
/**
* Creates and controls the enemies in the game
*/
namespace enemy {
createEnemy();
/**
* @returns an enemy sprite that is positioned at the top of the screen
*/
function createEnemy(): Sprite {
let enemy = sprites.create(spritesheet.enemy, SpriteKind.Enemy);
setPosition(enemy, 10);
enemy.vy = 10;
return enemy;
}
/**
* Place the given sprite at a random location at the top of the screen
* @param sprite the sprite to place at the top of the screen
* @param edge how many pixels between either edge of the screen to set
*/
function setPosition(sprite: Sprite, edge: number) {
sprite.x = randint(edge, screen.width - edge);
sprite.y = 0;
}
}
/**
* Generates powerups for the player to collect
*/
namespace powerups {
let availablePowerUps = [
PowerUpType.Health,
PowerUpType.Score
];
sprites.onCreated(SpriteKind.PowerUp, function (sprite: Sprite) {
sprite.data = Math.pickRandom(availablePowerUps);
sprite.setFlag(SpriteFlag.AutoDestroy, true);
setPosition(sprite, 10);
setMotion(sprite);
});
/**
* Place the given sprite at a random location at the top of the screen
* @param sprite the sprite to place at the top of the screen
* @param edge how many pixels between either edge of the screen to set
*/
function setPosition(sprite: Sprite, edge: number) {
sprite.x = randint(edge, screen.width - edge);
sprite.y = 0;
}
/**
* Set the initial velocities for the given sprite
* @param powerUp the powerUp to set the initial velocities of
*/
function setMotion(powerUp: Sprite) {
powerUp.vy = 60;
}
/**
* @param powerUp sprite to get type of
* @returns the type of the given powerUp
*/
export function getType(powerUp: Sprite): PowerUpType {
return powerUp.data;
}
game.onUpdateInterval(1000, function () {
if (Math.percentChance(33)) {
sprites.create(spritesheet.powerUp, SpriteKind.PowerUp);
}
});
}
/**
* Handle overlaps between different sprites
*/
namespace overlapevents {
// When the player hits an asteroid, damage the player and destroy the asteroid
sprites.onOverlap(SpriteKind.Player, SpriteKind.Asteroid, function (sprite: Sprite, otherSprite: Sprite) {
info.changeLifeBy(-1);
otherSprite.destroy();
});
// When the player hits an enemy, damage the player and destroy the enemy
sprites.onOverlap(SpriteKind.Player, SpriteKind.Enemy, function (sprite: Sprite, otherSprite: Sprite) {
info.changeLifeBy(-1);
otherSprite.destroy();
});
// When a laser hits an asteroid, destroy both sprites
sprites.onOverlap(SpriteKind.Laser, SpriteKind.Asteroid, function (sprite: Sprite, otherSprite: Sprite) {
otherSprite.destroy();
sprite.destroy();
});
// When a laser hits an enemy, destroy both sprites
sprites.onOverlap(SpriteKind.Laser, SpriteKind.Enemy, function (sprite: Sprite, otherSprite: Sprite) {
otherSprite.destroy();
sprite.destroy();
});
// When a player hits a powerup, apply the bonus for that powerup
sprites.onOverlap(SpriteKind.Player, SpriteKind.PowerUp, function (sprite: Sprite, otherSprite: Sprite) {
let powerUp: number = powerups.getType(otherSprite);
otherSprite.destroy();
if (powerUp == PowerUpType.Health) {
sprite.say("Got health!", 500);
info.changeLifeBy(1);
} else if (powerUp == PowerUpType.Score) {
sprite.say("Score!", 500);
info.changeScoreBy(15);
}
});
}
/**
* Set up the state of the game
*/
namespace status {
initialize(4, 0);
/**
* Sets up the initial state of the game
* @param life the initial life to set
* @param score the initial score to set
*/
function initialize(life: number, score: number) {
info.setLife(life);
info.setScore(score);
}
}