/* -------------------------------------------------------------*/
private void gravityEffect(ArrayList movingObjects) {
// find effect of gravity on this objects from all other objects
for (int i = 0; i < movingObjects.size(); i++) {
// reset variables
double add_vx = 0.0;
double add_vy = 0.0;
SpaceObject object = (SpaceObject) movingObjects.get(i);
if (object.getObjCount() != objectNum
&& // ignore yourself (distance = 0!)
!object.isBullet()
&& // ignore bullets
!object.isSpaceShip()) // ignore spaceships
{
// find distance vector between planet and ball
int x = pos_x - object.getXPos();
int y = pos_y - object.getYPos();
double distance = Math.sqrt(x * x + y * y);
// find effect of planet on velocity
double add_vec = (SpaceObject.G * k * object.getMass() * ballMass) / (distance * distance);
add_vx = -(x / distance) * add_vec;
add_vy = -(y / distance) * add_vec;
// add objects speeds onto spaceship speed (clip speed if too large)
x_speed += add_vx;
y_speed += add_vy;
}
}
}
/* -------------------------------------------------------------*/
private void objectCollision(ArrayList movingObjects) {
for (int i = 0; i < movingObjects.size(); i++) {
// make sure not testing if collided with yourself :P
if (((SpaceObject) movingObjects.get(i)).getObjCount() != objectNum) {
SpaceObject object = (SpaceObject) movingObjects.get(i);
// find distance vector between two objects
int x = pos_x - object.getXPos();
int y = pos_y - object.getYPos();
double distance = Math.sqrt(x * x + y * y);
// has it collided with the object?
if (distance < (radius + object.getRadius())) {
// has it collided with a BULLET (or MISSILE)?
if (object.isBullet()) {
// do nothing
}
// is it another SPACESHIP? (INSTANT DEATH)
else if (object.isSpaceShip()) {
// do nothing
}
// collided with anything else (e.g PLANET): (INSTANT DEATH)
else {
collision.play();
kill(movingObjects); // object has died
}
}
}
} // end for loop
}