/// <summary>
/// Called when an Alien is able to launch a bomb. Sets the position of the bomb according to the
/// alien's position then adds it to the list of Projectiles.
/// </summary>
/// <param name="alien">The Alien that will launch the bomb.</param>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
public override void Launch(Rectangle alien, GameTime gameTime)
{
int xCoordinate = alien.X + (alien.Width / 2);
int yCoordinate = alien.Bottom + 1;
ProjectileSprite projectile = new ProjectileSprite(game, bombImage, false, 6F);
projectile.Initialize();
projectile.SetPosition(xCoordinate, yCoordinate);
bullets.Add(projectile);
}
/// <summary>
/// Checks if there was a collision between a bomb and a player.
/// </summary>
/// <param name="bomb">Bomb that was launched by an Alien to be checked for collisions.</param>
protected override bool checkCollision(ProjectileSprite bomb)
{
bool collision = false;
if (bomb.GetBoundary().Intersects(player.GetBoundary()))
{
onPlayerCollision(player, 0);
collision = true;
playerDeathSound.Play();
}
return(collision);
}
/// <summary>
/// Called when a Player is able to launch a laser. Sets the position of the laser according to the
/// Players's position then adds it to the list of Projectiles. Controls how rapidly a player
/// can fire a laser through throttling.
/// </summary>
/// <param name="player">The border of the player object</param>
/// <param name="gameTime">Provides a snapshot of timing values</param>
public override void Launch(Rectangle player, GameTime gameTime)
{
int yCoordinate = player.Top - 1 - imageLaser.Height;
int xCoordinate = player.X + (player.Width / 2 - 1);
if (gameTime.TotalGameTime - previousLaunchTime > tolerance)
{
projectile = new ProjectileSprite(game, imageLaser, true, 8F);
projectile.Initialize();
projectile.SetPosition(xCoordinate, yCoordinate);
bullets.Add(projectile);
previousLaunchTime = gameTime.TotalGameTime;
laserSound.Play();
}
}
/// <summary>
/// Checks if there was a collision between a laser and an alien by iterating through the AlienSquad
/// array. Returns True if a collision was detected, False if there was no collision. Also checks for
/// a collision with the mothership.
/// </summary>
/// <param name="laser">Laser that was launched by a player to be checked for collisions.</param>
/// <returns>A boolean representing if a collision was detected</returns>
protected override bool checkCollision(ProjectileSprite laser)
{
bool collision = false;
int pts = 0;
for (int row = 0; row < alienSquad.getAlienRowCount(); row++)
{
for (int col = 0; col < alienSquad.getAlienColumnCount(); col++)
{
if (laser.GetBoundary().Intersects(alienSquad[row, col].GetBoundary()))
{
if (alienSquad[row, col].GetAlienState() == AlienState.ACTIVE)
{
// Only gives points if Alien dies, on higher difficulties multiple hits will not award points
if (alienSquad[row, col].GetHitPoints() == 1)
{
pts = 10 + (alienSquad.getAlienRowCount() - 1 - row) * 10;
}
onAlienCollision(alienSquad[row, col], pts);
collision = true;
//remove laser after it hits alien
laser.Dispose();
bullets.Remove(laser);
return(collision);
}
}
}
}
if (laser.GetBoundary().Intersects(mothership.GetBoundary()))
{
if (mothership.GetAlienState() == AlienState.ACTIVE)
{
onMothershipCollision(mothership, 100);
collision = true;
// remove laser after it hits alien
laser.Dispose();
bullets.Remove(laser);
return(collision);
}
}
return(collision);
}
/// <summary>
/// Allows the game component to update itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
public override void Update(GameTime gameTime)
{
if (game.GetGameState() == Game1.GameState.Playing)
{
for (int ctr = 0; ctr < bullets.Count; ctr++)
{
bullets[ctr].Update(gameTime);
ProjectileSprite bullet = bullets[ctr];
// if bullets encounter a collision with a sprite
if (checkCollision(bullets[ctr]))
{
}
// if bullets go past screen
else if (bullets[ctr].GetPosition().Y > screenHeight || bullets[ctr].GetPosition().Y < 0)
{
bullets[ctr].Dispose();
bullets.Remove(bullets[ctr]);
}
}
}
base.Update(gameTime);
}
/// <summary> /// Abstract checkCollision method that each derived class must override /// </summary> /// <param name="projectile">The projectile object</param> /// <returns>Whether a collision occured or not</returns> protected abstract bool checkCollision(ProjectileSprite projectile);
