// ----------------------------- Update -----------------------------------
//
// updates the ball physics, tests for any collisions and adjusts
// the ball's velocity accordingly
// ------------------------------------------------------------------------
public void update(float tpf) {
// keep a record of the old position so the goal::scored method
// can utilize it for goal testing
if (position != null) {
oldPos.cloneVec(position);
}
// Test for collisions
testCollisionWithWalls(pitchBoundary);
// Simulate Params.Instance().Friction. Make sure the speed is positive
// first though
double friction = Params.Instance().Friction;
// println (velocity)
// println("LengthSq" + velocity.LengthSq() +" friction " + friction)
if (velocity.LengthSq() > friction * friction) {
velocity = velocity.plus(Vec2DNormalize(velocity).multiply(friction));
// println (velocity)
position = position.plus(velocity.multiply(tpf));
// println (position)
// update heading
heading = Vec2DNormalize(velocity);
}
super.update(tpf);
}
// ----------------------- PlaceAtLocation -------------------------------------
//
// positions the ball at the desired location and sets the ball's velocity to
// zero
// -----------------------------------------------------------------------------
public void placeAtPosition(Vector2D NewPos) {
position = NewPos;
oldPos.cloneVec(position);
velocity.setZero();
}
// -------------------------- Kick ----------------------------------------
//
// applys a force to the ball in the direction of heading. Truncates
// the new velocity to make sure it doesn't exceed the max allowable.
// ------------------------------------------------------------------------
public void kick(Vector2D direction, double force) {
// ensure direction is normalized
Vector2D d = direction.cloneVec();
d.Normalize();
// calculate the acceleration
Vector2D acceleration = d.multiply(force).divide(mass);
// update the velocity
velocity.cloneVec(acceleration);
}