/**
* Detect if two bodies are crashing into each other If they are, then create and return the
* resultant body, if they aren't, then return a null value. *
*/
private static Body crash(Body m1, Body m2) {
// Distance formula to determine if two bodies are touching
if (StrictMath.sqrt(
StrictMath.pow((m2.getposx() - m1.getposx()), 2)
+ StrictMath.pow((m2.getposy() - m1.getposy()), 2))
< (m1.getSize() + m2.getSize())) {
int mass, size;
double vX, vY, pX, pY;
Color color;
mass = (m1.getMass() + m2.getMass());
size = ((m1.getSize() + m2.getSize()));
color = combineColor(m1, m2);
// Get the resultant velocities with the inelastic collisions equation:
// V = (M1*V1 + M2*V2)/(M1+M2)
vX =
((m1.getvelx() * m1.getMass() + m2.getvelx() * m2.getMass())
/ (m1.getMass() + m2.getMass()));
vY =
((m1.getvely() * m1.getMass() + m2.getvely() * m2.getMass())
/ (m1.getMass() + m2.getMass()));
// Whichever body is bigger absorbs the other body
if (m1.getMass() > m2.getMass()) {
pX = m1.getposx();
pY = m1.getposy();
} else {
pX = m2.getposx();
pY = m2.getposy();
}
return (new Body(mass, size, color, vX, vY, pX, pY));
} else return null;
}
/** Change the velocity with the force calculations * */
private static void velChanges(Body b, ArrayList<Body> system) {
double xAccel = 0;
double yAccel = 0;
for (Body body : system) {
if (body.getSize() > 500) deletions.add(body);
if (b != body) {
/**
* Check the entire system for collisions and make the necessary changes. This way will
* prevent the ConcurrentModificationExceptions I've been fighting *
*/
Body test = crash(b, body);
if (test != null) {
if (!body.getLocked())
// Bodies get added to the list twice because a crashes
// into b and b also crashes into a.
// Added if statements to make sure that things aren't being
// double counted.
if (!deletions.contains(body)) deletions.add(body);
if (!b.getLocked()) if (!deletions.contains(b)) deletions.add(b);
if (!b.getLocked() || !body.getLocked()) {
boolean add = true;
for (int i = 0; i < additions.size(); i++) {
if (test.equals(additions.get(i))) add = false;
}
if (add) additions.add(test);
}
}
// If there's no collision, then just do the calculations.
else {
xAccel += calculateAcceleration(calculateGravity(b, body, true), b);
yAccel += calculateAcceleration(calculateGravity(b, body, false), b);
}
}
}
xAccel = Multiplier * xAccel; // Static Multipliers to
yAccel = Multiplier * yAccel; // make things play nicer
b.setvelx(b.getvelx() + xAccel);
b.setvely(b.getvely() + yAccel);
}
/** Change the position to the new position * */
private static void posChanges(Body b) {
b.setposx(b.getposx() + b.getvelx());
b.setposy(b.getposy() + b.getvely());
}
