private void nextWave()
{
// Increment the Wave property, clear the private _invaders collection, and then
// create all of the Invader objects, giving each of them a Location field with
// the correct coordinates. Try spacing them out so that they’re spaced 1.4 invader
// lengths apart horizontally, and 1.4 invader heights vertically.
Wave++;
_invaders.Clear();
if (_mothership != null)
{
_mothership.Escape();
OnShipChanged(_mothership, false);
_mothership = null;
}
RemoveAllShots();
_invaderDirection = Direction.Left;
InvaderType invaderType;
for (int row = 0; row < 6; row++)
{
switch (row)
{
case 0:
invaderType = InvaderType.Spaceship;
break;
case 1:
invaderType = InvaderType.Bug;
break;
case 2:
invaderType = InvaderType.Saucer;
break;
case 3:
invaderType = InvaderType.Satellite;
break;
default:
invaderType = InvaderType.Star;
break;
}
for (int column = 0; column < 11; column++)
{
Point location = new Point(column * Invader.InvaderSize.Width * 1.4,
row * Invader.InvaderSize.Height * 1.4);
_invaders.Add(new Invader(invaderType, location, _invaderScores[invaderType]));
OnShipChanged(_invaders[_invaders.Count - 1], false);
}
}
}
private void CheckForMothershipCollisions()
{
// We check to see if the mothership is null because it could have escaped off the edge
// of the screen
if (_mothership == null)
return;
List<Shot> playerShots = _playerShots.ToList();
foreach (Shot shot in playerShots)
{
Rect shotRect = new Rect(shot.Location.X, shot.Location.Y, Shot.ShotSize.Width,
Shot.ShotSize.Height);
if (RectsOverlap(_mothership.Area, shotRect))
{
Mothership deadMothership = _mothership;
_mothership = null;
_playerShots.Remove(shot);
OnShotMoved(shot, true);
OnShipChanged(deadMothership, true);
Score += deadMothership.Score;
// An extra life is awarded for destroying a mothership
if (Lives + 1 <= MaximumLives)
Lives++;
break;
}
}
}
private void MoveInvaders()
{
TimeSpan timeSinceLastMove = DateTime.Now - _lastUpdated;
double msBetweenMoves = Math.Max(7 - Wave, 1) * (2 * _invaders.Count());
if (timeSinceLastMove >= TimeSpan.FromMilliseconds(msBetweenMoves))
{
_lastUpdated = DateTime.Now;
if (_invaderDirection == Direction.Right)
{
var invadersTouchingRightBoundary =
from invader in _invaders
where invader.Area.Right > PlayAreaSize.Width - Invader.HorizontalPixelsPerMove * 2
select invader;
if (invadersTouchingRightBoundary.Count() > 0)
{
_invaderDirection = Direction.Down;
foreach (Invader invader in _invaders)
{
invader.Move(_invaderDirection);
OnShipChanged(invader, false);
}
_justMovedDown = true;
_invaderDirection = Direction.Left;
}
else
{
_justMovedDown = false;
foreach (Invader invader in _invaders)
{
invader.Move(_invaderDirection);
OnShipChanged(invader, false);
}
}
}
else if (_invaderDirection == Direction.Left)
{
var invadersTouchingLeftBoundary =
from invader in _invaders
where invader.Area.Left < Invader.HorizontalPixelsPerMove * 2
select invader;
if (invadersTouchingLeftBoundary.Count() > 0)
{
_invaderDirection = Direction.Down;
foreach (Invader invader in _invaders)
{
invader.Move(_invaderDirection);
OnShipChanged(invader, false);
}
_justMovedDown = true;
_invaderDirection = Direction.Right;
}
else
{
_justMovedDown = false;
foreach (Invader invader in _invaders)
{
invader.Move(_invaderDirection);
OnShipChanged(invader, false);
}
}
}
}
TimeSpan timeSinceLastMothershipMove = DateTime.Now - _lastMothershipUpdate;
double msBetweenMothershipMoves = Math.Max(7 - Wave, 1) * (_invaders.Count() / 2);
if (_mothership != null && timeSinceLastMothershipMove >
TimeSpan.FromMilliseconds(msBetweenMothershipMoves))
{
_lastMothershipUpdate = DateTime.Now;
if (_mothership.Area.Right > PlayAreaSize.Width - Mothership.HorizontalPixelsPerMove * 2)
{
_mothership.Escape();
OnShipChanged(_mothership, false);
_mothership = null;
}
else
{
_mothership.Move(Direction.Right);
OnShipChanged(_mothership, false);
}
}
}
private void AddMothership()
{
_mothership = new Mothership(new Point(0, 0), _invaderScores[InvaderType.Mothership]);
OnShipChanged(_mothership, false);
}