/// <summary>
/// When a ship is hit by a projectile then remove the a health point remove
/// the projectile form the world
/// </summary>
private void HitAProjectile(Ship ship, Projectile projectile)
{
if (kingIsOn)
{
// find the owner of the projectile
int shipID = projectile.GetOwner();
if (allShips.TryGetValue(shipID, out Ship projectileShip))
{
// if the projectile is from the king or the ship is the king then...
if (ship.IsKing() || projectileShip.IsKing())
{
// subtract a health point from the ship
ship.SetHP(ship.GetHP() - 1);
if (!ship.IsAlive())
{
// increase the ship's score who shot the projectile by 1
projectileShip.SetScore(projectileShip.GetScore() + 1);
}
// register that the projectile hit a non-team member
ship.ShotsHit++;
}
if (ship.IsKing() && !ship.IsAlive())
{
// make sure that the ship that died is no longer king
ship.SetKing(false);
ship.SetName(ship.GetName().Substring(5));
// select a new king
Ship newKingShip = RandomShip();
newKingShip.SetKing(true);
newKingShip.SetName("King " + newKingShip.GetName());
}
}
// set the projectile to dead
projectile.Alive(false);
}
else
{
// subtract a health point
ship.SetHP(ship.GetHP() - 1);
if (!ship.IsAlive())
{
// find the owner of the projectile
int shipID = projectile.GetOwner();
allShips.TryGetValue(shipID, out Ship projectileShip);
// increase the ship's score who shot the projectile by 1
projectileShip.SetScore(projectileShip.GetScore() + 1);
}
// set the projectile to dead
projectile.Alive(false);
// register that the projectile hit a ship
ship.ShotsHit++;
}
}
/// <summary>
/// If Ship s does not exist in ships adds it. If the id already exists
/// in ships, updates reference in ships to s.
/// </summary>
public void AddShip(Ship ship)
{
// if the ship is null then do nothing
if (ship == null)
{
return;
}
// if the ship is dead then remove it from the world
if (!ship.IsAlive())
{
aliveShips.Remove(ship.GetID());
}
// if the ship is in the world then replace the old ship with the passed in ship
else if (aliveShips.ContainsKey(ship.GetID()))
{
aliveShips[ship.GetID()] = ship;
}
// if the ship is not in the world then add it
else
{
aliveShips.Add(ship.GetID(), ship);
}
// we have taken care of the alive ships, now lets keep track of all ships
AddAllShips(ship);
}
/// <summary>
/// Detects whether or not a ship is hit by a projectile
/// </summary>
private void CollisionWithAProjectile(Ship ship, Projectile projectile)
{
if (ship.GetID() != projectile.GetOwner() && ship.IsAlive())
{
if (WithinARadius(ship.GetLocation(), projectile.GetLocation(), shipSize))
{
// the passed in ship was hit by a projectile so we update health and remove
// the projectile from the world
HitAProjectile(ship, projectile);
}
}
}
/// <summary>
/// Computes the acceleration, velocity, and position of the passed in ship
/// </summary>
public void MotionForShips(Ship ship)
{
// if the ship isn't alive, just skip it
if (!ship.IsAlive())
{
return;
}
// handle left turn command
if (ship.TurnLeft)
{
ship.GetDirection().Rotate(-turningRate);
ship.TurnLeft = false;
}
// handle right turn command
else if (ship.TurnRight)
{
ship.GetDirection().Rotate(turningRate);
ship.TurnRight = false;
}
// spawn a projectile if projectile command has been given
if (ship.FireProjectile)
{
Projectile p = new Projectile(ship.GetID(), projectileID++, ship.GetLocation(), ship.GetDirection());
AddProjectile(p);
ship.FireProjectile = false;
ship.ResetFireTimer();
// we just fired a projectile, increment total number of fired projectiles
ship.ShotsFired++;
}
//get a zero vector
Vector2D acceleration = new Vector2D(0.0, 0.0);
//compute the acceleration caused by the star
foreach (Star star in stars.Values)
{
Vector2D g = star.GetLocation() - ship.GetLocation();
g.Normalize();
acceleration = acceleration + g * star.GetMass();
}
if (ship.HasThrust())
{
//compute the acceleration due to thrust
Vector2D t = new Vector2D(ship.GetDirection());
t = t * engineStrength;
acceleration = acceleration + t;
}
// recalculate velocity and location
ship.SetVelocity(ship.GetVelocity() + acceleration);
ship.SetLocation(ship.GetVelocity() + ship.GetLocation());
// check to see if ship is off screen
Wraparound(ship);
// check for collisions with any star
foreach (Star star in stars.Values)
{
CollisionWithAStar(ship, star);
}
// check for collisions with any projectiles
foreach (Projectile proj in projectiles.Values)
{
CollisionWithAProjectile(ship, proj);
}
ship.IncrementFireTimer();
}
