public void update() {
// See Compute Area for reason of the absolute value and signum of area...
double pressureForce =
Constants.get().getPressure() * (Math.abs(area) - Math.abs(desiredArea));
pressureForce =
Math.signum(area) * Math.signum(pressureForce) * Math.sqrt(Math.abs(pressureForce));
// The pressure is applied on every segment proportionally to its area.
for (int i = 0, n = nodeList.size(); i < n; i++) {
Node prevNode = nodeList.get(i);
Node curNode = nodeList.get((i + 1) % n);
Node nextNode = nodeList.get((i + 2) % n);
Vector2D prevVector = curNode.getPosition().subtract(prevNode.getPosition()).rotate270();
Vector2D nextVector = nextNode.getPosition().subtract(curNode.getPosition()).rotate270();
forces.put(curNode, prevVector.scale(pressureForce).add(nextVector.scale(pressureForce)));
}
}
