src/appletbots/swarm/SwarmAgent.java

   1 /*
   2  * Copyright (c) 2002 Erik Rasmussen - All Rights Reserverd
   3  */
   4 package appletbots.swarm;
   5
   6 import appletbots.Agent;
   7 import appletbots.geometry.Vector;
   8
   9 import java.awt.*;
  10 import java.util.ArrayList;
  11 import java.util.Collections;
  12 import java.util.List;
  13
  14
  15 /**
  16  * A swarm agent looks at its neighbors, chooses a certain number
  17  * of them, and accelerates in the direction of their average velocity,
  18  * with a part of its acceleration being randomized.
  19  *
  20  * @author Erik Rasmussen
  21  */
  22 public class SwarmAgent extends Agent
  23 {
  24         /**
  25          * The number of neighbors to follow
  26          */
  27         private int numNeighborsToFollow;
  28
  29         /**
  30          * Choose neighbors by proximity when true, randomly when false
  31          */
  32         private boolean chooseNeighborsByProximity;
  33
  34         /**
  35          * Percentage of acceleration to be random
  36          */
  37         private double randomizationFactor;
  38
  39         /**
  40          * Constructs a swarm agent with the given parameters
  41          *
  42          * @param size                       The agent's radius
  43          * @param sight                      The distance the agent can see
  44          * @param maxSpeed                   The maximum speed the agent can travel
  45          * @param maxAcceleration            The maximum acceleration for this agent
  46          * @param numNeighborsToFollow       The number of neightbors to follow
  47          * @param chooseNeighborsByProximity How to choose neighbors to follow
  48          * @param randomizationFactor        The percentage of acceleration to be random
  49          */
  50         public SwarmAgent(final int size, final int sight, final double maxSpeed, final double maxAcceleration, final int numNeighborsToFollow, final boolean chooseNeighborsByProximity, final double randomizationFactor)
  51         {
  52                 super(size, sight, maxSpeed, maxAcceleration);
  53                 this.numNeighborsToFollow = numNeighborsToFollow;
  54                 this.chooseNeighborsByProximity = chooseNeighborsByProximity;
  55                 this.randomizationFactor = randomizationFactor;
  56                 this.color = Color.cyan;
  57         }
  58
  59         /**
  60          * Observes the world, and follows the Swarm Agent Algorithm.
  61          */
  62         public void observeWorld()
  63         {
  64                 final List neighbors = world.getNeighbors(this);
  65                 if (chooseNeighborsByProximity)
  66                         Collections.sort(neighbors, world.objectDistanceComparator(this));
  67                 else
  68                         Collections.shuffle(neighbors);
  69
  70                 final List velocitiesOfNeighborsToFollow = new ArrayList();
  71                 for (int i = 0; i < neighbors.size() && i < numNeighborsToFollow; i++)
  72                 {
  73                         final Agent neighbor = (Agent) neighbors.get(i);
  74                         velocitiesOfNeighborsToFollow.add(world.getVelocity(neighbor));
  75                 }
  76
  77                 final Vector randomization = Vector.getRandom(getMaxAcceleration() * randomizationFactor);
  78                 final Vector averageNeighborVelocity = Vector.average(velocitiesOfNeighborsToFollow).multiply(1 - randomizationFactor);
  79
  80                 setAcceleration(averageNeighborVelocity.add(randomization));
  81         }
  82 }