public static void MoveAliens(AlienListModel alienList)
{
foreach (var alien in alienList.Aliens)
{
alien.ShuntPosition();
}
}
public static void CheckIfAlienShot(double gameTimeSeconds, AlienListModel alienList, ShipBulletListModel shipBulletsList, ExplosionListModel explosionsList, ScoreModel Scoring, GameSounds gameSounds)
{
CheckIfAlienShotAndThen(
gameTimeSeconds, alienList, shipBulletsList, alien =>
{
AddExplosion(gameTimeSeconds, alien.CentrePoint, explosionsList, gameSounds);
Scoring.SetScore(Scoring.Score + 1);
});
}
public static void RemoveOffScreenObjects(AlienListModel aliensList, ShipBulletListModel shipBulletList, AlienBulletListModel alienBulletList, StarscapeModel starList, ScoreModel scoring)
{
shipBulletList.ShipBullets.RemoveAll(b => b.CentrePoint.x > RetroScreen.WidthInPixels);
alienBulletList.AlienBullets.RemoveAll(b => b.CentrePoint.x < 0);
starList.Stars.RemoveAll(s => s.CentrePoint.x < 0);
int numberOfAliensRemoved = aliensList.Aliens.RemoveAll(a => a.CentrePoint.x < 0);
scoring.SetScore(Math.Max(0, scoring.Score - numberOfAliensRemoved));
}
public static void CheckIfShipShot(double gameTimeSeconds, ShipModel ship, AlienListModel aliensList, AlienBulletListModel alienBulletList, ExplosionListModel explosions, GameSounds gameSounds)
{
if (!ship.IsDestroyed)
{
bool shipDestroyed =
alienBulletList.AlienBullets.Exists(b => CollisionDetection.Hits(b.CentrePoint, ship.CentrePoint, CollisionDetectRange)) ||
aliensList.Aliens.Exists(a => CollisionDetection.Hits(a.CentrePoint, ship.CentrePoint, CollisionDetectRange));
if (shipDestroyed)
{
DestroyShip(gameTimeSeconds, ship, explosions, gameSounds);
}
}
}
public static void ConsiderAddingAlienAndThen(double gameTimeSeconds, AlienListModel alienList, Random randomGenerator, Action <AlienModel> andThen)
{
var elapsedTime = gameTimeSeconds - alienList.LastTimeWeConsideredAddingAnAlien; // Quiz: Why work things out in seconds (as given by gameTimeSeconds), compared to the Alien.Speed and Star.Speed technique? What's the difference, and is one technique best?
if (elapsedTime > AlienListModel.TimeBetweenAddingAliens)
{
if (alienList.Aliens.Count < AlienListModel.MaxAliensOnScreenAtOnce) // Quiz: Why limit this?
{
var alienY = randomGenerator.Next(AlienModel.HighestY, AlienModel.LowestY); // NB: Y axis runs the other way up from normal mathematics!
var speed = randomGenerator.Next(1, 5);
var newAlien = new AlienModel(new Point(AlienModel.IntroductionX, alienY), speed);
alienList.Aliens.Add(newAlien);
andThen(newAlien);
}
alienList.LastTimeWeConsideredAddingAnAlien = gameTimeSeconds; // Quiz: Why are we doing this here?
}
}
public static void CheckIfAlienShotAndThen(double gameTimeSeconds, AlienListModel alienList, ShipBulletListModel shipBulletsList, Action <AlienModel> andThen)
{
var bulletsToRemove = new List <ShipBulletModel>();
var aliensToRemove = new List <AlienModel>();
foreach (var bullet in shipBulletsList.ShipBullets)
{
foreach (var alien in alienList.Aliens)
{
if (CollisionDetection.Hits(bullet.CentrePoint, alien.CentrePoint, CollisionDetectRange)) // Quiz: This design means hitting NEAR the centre of the alien!
{
bulletsToRemove.Add(bullet);
aliensToRemove.Add(alien);
andThen(alien);
}
}
}
alienList.Aliens.RemoveAll(a => aliensToRemove.Contains(a));
shipBulletsList.ShipBullets.RemoveAll(b => bulletsToRemove.Contains(b));
}
public static void ConsiderAddingAlien(double gameTimeSeconds, ShipModel ship, AlienListModel alienList, Random randomGenerator, AlienBulletListModel alienBulletList, GameSounds gameSounds)
{
if (!ship.IsDestroyed) // Quiz: Why not add aliens in the period while the ship is "destroyed"?
{
ConsiderAddingAlienAndThen(gameTimeSeconds, alienList, randomGenerator, alien =>
{
if (randomGenerator.Next(0, 100) > AlienModel.PercentChangeAlienFiresWhenCreated) // Quiz: Does my hard-coded constant really 100 matter here? Is this bad practice?
{
CauseAlienToFire(alien, alienBulletList, gameSounds);
}
});
}
}
