void wander() {
float wanderR = 10.0f; // radius for our "wander circle"
float wanderD = 20.0f; // distance for our "wander circle"
wandertheta += random(-1, 1); // randomly changet wander theta
// now we have to calculate the new location to steer towards on the wander circle
Vector3D v = vel.copy();
v.normalize(); // our heading
float xoff =
wanderD * v.x() + wanderR * cos(wandertheta); // x spot on circle based on heading
float yoff =
wanderD * v.y() + wanderR * sin(wandertheta); // y spot on circle based on heading
Vector3D target = Vector3D.add(loc, new Vector3D(xoff, yoff)); // add the location
acc.add(steer(target, false)); // steer towards it
}
// a method that calculates a steering vector towards a target
// takes a second argument, if true, it slows down as it approaches the target
Vector3D steer(Vector3D target, boolean slowdown) {
Vector3D steer; // the steering vector
Vector3D desired =
Vector3D.sub(target, loc); // a vector pointing from the location to the target
float d = desired.magnitude(); // distance from the target is the magnitude of the vector
// if the distance is greater than 0, calc steering (otherwise return zero vector)
if (d > 0) {
// normalize desired
desired.normalize();
// two options for magnitude (1 -- based on distance, 2 -- maxspeed)
if ((slowdown) && (d < 100.0f)) desired.mult(maxspeed * (d / 100.0f));
else desired.mult(maxspeed);
// STEERING VECTOR IS DESIREDVECTOR MINUS VELOCITY
steer = Vector3D.sub(desired, vel);
steer.limit(maxforce); // limit to maximum steering force
} else {
steer = new Vector3D(0, 0);
}
return steer;
}