/**
* update called to make this enemy move in the parabola like pattern aswell as make it fire at a
* set interval
*/
@Override
public void update(float timePassed) {
Position newPosition = this.getShip().getPositionClone();
double newX = newPosition.getX() + speed * timePassed;
newPosition.setX(newX);
newPosition.setY(calcY(newX));
this.getShip().setPosition(newPosition);
this.getWeapon()
.fire(this.getShip().getPositionClone(), PlayerID.ENEMY, new Rotation(0), timePassed);
}
/**
* Creates a new ParabolaEnemy
*
* @param startPoint where the ParabolaEnemy will appear
* @param midPoint a point between the startPoint and the endPoint (in x coordinate), specifying
* the look of the movement curve
* @param endPosition where the ParabolaEnemy will move towards
* @param weaponName what kind of weapon this enemy will wield
*/
public ParabolaEnemy(
Position startPoint, Position midPoint, Position endPoint, ObjectName weaponName) {
super(
new EnemyShip(startPoint, SHIP_SIZE, SHIP_SIZE, HITPOINTS, ObjectName.PARABOLA_ENEMYSHIP),
WeaponFactory.getNewWeapon(weaponName));
if (!midPointIsInMiddle(startPoint.getX(), midPoint.getX(), endPoint.getX())) {
throw new IllegalArgumentException(
"MidPoints x-coordinate must lie between startPoints"
+ " x-coordinate and endPoints x-coordinate");
}
this.startPoint = startPoint;
this.midPoint = midPoint;
this.endPoint = endPoint;
// negate speed if the curve goes from right to left
if (endPoint.getX() - startPoint.getX() < 0) {
speed *= -1;
}
}
@Override
public void fire(
final Position shipPosition,
final PlayerID playerId,
final Rotation rotation,
final float timeElapsed) {
cooldown = cooldown - timeElapsed;
if (cooldown < 0) {
cooldown = cooldown + INIT_COOLDOWN;
this.getBulletManager()
.addBullet(
new BasicBullet(
shipPosition.getX(),
shipPosition.getY(),
BULLET_WIDTH,
BULLET_HEIGHT,
playerId,
new Rotation(rotation.getAngle() + currentAngle),
BULLET_DAMAGE));
currentAngle = currentAngle + ANGLE_STEP;
}
}
/**
* Calculates a vertical value for a quadratic function using Lagrange's from of the interpolation
* polynomial The formula takes a flipped Y axis in consideration
*
* @param x the horizontal coordinate
* @return a new value for Y
*/
private double calcY(double x) {
double x0 = startPoint.getX();
double x1 = midPoint.getX();
double x2 = endPoint.getX();
double l0 = ((x - x1) * (x - x2)) / ((x0 - x1) * (x0 - x2));
double l1 = ((x - x0) * (x - x2)) / ((x1 - x0) * (x1 - x2));
double l2 = ((x - x0) * (x - x1)) / ((x2 - x0) * (x2 - x1));
return startPoint.getY() * l0 + midPoint.getY() * l1 + endPoint.getY() * l2;
}
