/// <summary>
/// Main game-play routine to determine object state and screen refresh.
/// </summary>
public void DrawScreen()
{
if (_paused)
{
// Pause flashes on and off
if (_pauseTimer > PAUSE_INTERVAL / 2)
{
_textDraw.DrawText(
"PAUSE"
, TextDraw.Justify.CENTER
, ScreenCanvas.CANVAS_HEIGHT / 3
, 200, 400
);
}
if (--_pauseTimer < 0)
{
_pauseTimer = PAUSE_INTERVAL;
}
}
else // Do all game processing if game is not paused
{
var origScore = _score.CurrentScore;
// If no ship displaying, after explosions are done
// get a new one - or end the game
var noExplosions = _cache.ExplosionCount() == 0;
if (!_cache.Ship.IsAlive && noExplosions)
{
if (!_score.HasReserveShips())
{
// Game over
_inProcess = false;
}
else if (_collisionManager.IsCenterSafe())
{
_score.DecrementReserveShips();
_cache.UpdatedShip(new Ship());
}
}
// Create a new asteroid belt if no explosions and no asteroids
if (noExplosions && _cache.Belt.Count() == 0)
{
_cache.UpdateBelt(new AsteroidBelt(++_currentLevel));
}
// Move all objects starting with the ship
_cache.Ship.Move();
//Move the saucer and its missile
if (_cache.Saucer != null)
{
if (_cache.Saucer.Move())
{
//Aim for the ship oe nothing
var target = _cache.Ship.IsAlive
? _cache.Ship.GetCurrLoc()
: default(Point?);
_cache.Saucer.Target(target);
}
else
{
//Saucer has completed its passes
_cache.UpdateSaucer(null);
_neededSaucerPoints = SAUCER_SCORE;
}
}
//Move the bullets, asteroids, and explosions
_collisionManager.MoveBullets();
_collisionManager.MoveAsteroids();
_collisionManager.MoveExplosions();
// Check bullets for collisions
foreach (var bullet in _cache.GetBulletsInFlight())
{
var points = new List <Point> {
bullet.Location
};
if (_collisionManager.AsteroidBeltCollision(points) ||
_collisionManager.SaucerCollision(points) ||
_collisionManager.MissileCollision(bullet.ScreenObject.GetPoints()))
{
_cache.AddExplosion(bullet.Location);
bullet.ScreenObject.Disable();
}
}
// Check ship for collisions
if (_cache.Ship.IsAlive)
{
var shipPoints = _cache.ShipPoints;
if (_collisionManager.SaucerCollision(shipPoints) ||
_collisionManager.MissileCollision(shipPoints) ||
_collisionManager.AsteroidBeltCollision(shipPoints)
)
{
foreach (var explosion in _cache.Ship.Explode())
{
_cache.AddExplosion(explosion);
}
}
}
//See if a bullet or the ship hit the saucer
if (_cache.Saucer != null && !_cache.Saucer.IsAlive)
{
_cache.UpdateSaucer(null);
_neededSaucerPoints = SAUCER_SCORE;
}
//See if the score is enough to show a suacer
else if (_cache.Saucer == null)
{
_neededSaucerPoints -= _score.CurrentScore - origScore;
if (_neededSaucerPoints <= 0)
{
var pt = new Point(
Random.Next(2) == 0 ? 0 : ScreenCanvas.CANVAS_WIDTH
, (Random.Next(10, 90) * ScreenCanvas.CANVAS_HEIGHT) / 100
);
_cache.UpdateSaucer(new Saucer(pt));
}
}
}
//Commit the changes
_cache.Repopulate();
// Draw all objects
_drawingManager.DrawObjects();
_score.Draw();
}
