public void calculateForces(ArrayList objects) { for (int i = 0; i < objects.size(); i++) { CelestialObject obj = (CelestialObject) objects.get(i); ArrayList forces = obj.getForces(); float totalForceX = 0; float totalForceY = 0; for (int j = 0; j < forces.size(); j++) { totalForceX += ((PVector) forces.get(j)).x; totalForceY += ((PVector) forces.get(j)).y; } PVector newAccel = new PVector(totalForceX / obj.getMass(), totalForceY / obj.getMass()); obj.setAcceleration(newAccel); } for (int i = 0; i < objects.size(); i++) { CelestialObject obj1 = (CelestialObject) objects.get(i); float forceX = 0; float forceY = 0; obj1.clearForces(); if (obj1.getClass() == Star.class) { println(obj1.getVelocity()); continue; } for (int j = 0; j < objects.size(); j++) { CelestialObject obj2 = (CelestialObject) objects.get(j); if (i == j) continue; PVector pvDistance = PVector.sub(obj2.getPosition(), obj1.getPosition()); // println("distance: x:" + pvDistance.x + " y:" + pvDistance.y); float distance = sqrt(sq(pvDistance.y) + sq(pvDistance.x)); float angle = degrees(atan2(pvDistance.y, pvDistance.x)); float force = (G * obj1.getMass() * obj2.getMass()) / sq(distance); forceX = force * cos(radians(angle)); forceY = force * sin(radians(angle)); // println("FORCES on " + obj1.getName() + ":" + forceX + "," + forceY); obj1.addForce(new PVector(forceX, forceY)); println(); } } }