com.badlogic.gdx.ai.steer.behaviors.Cohesion Maven / Gradle / Ivy
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package com.badlogic.gdx.ai.steer.behaviors;
import com.badlogic.gdx.ai.steer.GroupBehavior;
import com.badlogic.gdx.ai.steer.Limiter;
import com.badlogic.gdx.ai.steer.Proximity;
import com.badlogic.gdx.ai.steer.Proximity.ProximityCallback;
import com.badlogic.gdx.ai.steer.Steerable;
import com.badlogic.gdx.ai.steer.SteeringAcceleration;
import com.badlogic.gdx.math.Vector;
/** {@code Cohesion} is a group behavior producing a linear acceleration that attempts to move the agent towards the center of mass
* of the agents in its immediate area defined by the given {@link Proximity}. The acceleration is calculated by first iterating
* through all the neighbors and averaging their position vectors. This gives us the center of mass of the neighbors, the place
* the agents wants to get to, so it seeks to that position.
*
* A sheep running after its flock is demonstrating cohesive behavior. Use this behavior to keep a group of agents together.
*
* @param Type of vector, either 2D or 3D, implementing the {@link Vector} interface
*
* @author davebaol */
public class Cohesion> extends GroupBehavior implements ProximityCallback {
private T centerOfMass;
/** Creates a {@code Cohesion} for the specified owner and proximity.
* @param owner the owner of this behavior.
* @param proximity the proximity to detect the owner's neighbors */
public Cohesion (Steerable owner, Proximity proximity) {
super(owner, proximity);
}
@Override
protected SteeringAcceleration calculateRealSteering (SteeringAcceleration steering) {
steering.setZero();
centerOfMass = steering.linear;
int neighborCount = proximity.findNeighbors(this);
if (neighborCount > 0) {
// The center of mass is the average of the sum of positions
centerOfMass.scl(1f / neighborCount);
// Now seek towards that position.
centerOfMass.sub(owner.getPosition()).nor().scl(getActualLimiter().getMaxLinearAcceleration());
}
return steering;
}
@Override
public boolean reportNeighbor (Steerable neighbor) {
// Accumulate neighbor position
centerOfMass.add(neighbor.getPosition());
return true;
}
//
// Setters overridden in order to fix the correct return type for chaining
//
@Override
public Cohesion setOwner (Steerable owner) {
this.owner = owner;
return this;
}
@Override
public Cohesion setEnabled (boolean enabled) {
this.enabled = enabled;
return this;
}
/** Sets the limiter of this steering behavior. The given limiter must at least take care of the maximum linear acceleration.
* @return this behavior for chaining. */
@Override
public Cohesion setLimiter (Limiter limiter) {
this.limiter = limiter;
return this;
}
}