src/appletbots/tag/TagAgent.java

   1 /*
   2  * Copyright (c) 2002 Erik Rasmussen - All Rights Reserverd
   3  */
   4 package appletbots.tag;
   5
   6 import appletbots.Agent;
   7 import appletbots.WorldObject;
   8 import appletbots.geometry.Vector;
   9
  10 import java.awt.*;
  11 import java.util.List;
  12
  13 /**
  14  * If a tag agent is "it", he will try to touch whichever non-"it" agent is
  15  * closest to him.  When that contact is made, the agent he touched is "it".
  16  * If a tag agent is not "it", he will not accelerate unless he sees an agent
  17  * that is "it", in which case the non-"it" agent will accelerate away from
  18  * the agent that is "it".  Additionally, when an agent is tagged "it", its
  19  * maximum speed decreases by 20% and it must wait 10 time cycles before
  20  * accelerating; this is to prevent two agents getting locked together
  21  * repeatedly tagging one another.
  22  *
  23  * @author Erik Rasmussen
  24  */
  25 public class TagAgent extends Agent
  26 {
  27         /**
  28          * The "it" flag
  29          */
  30         private boolean it;
  31         /**
  32          * The number of time cycles to wait after being tagged "it"
  33          */
  34         private int timeToWait;
  35
  36         /**
  37          * Constructs a new TagAgent with the given parameters
  38          *
  39          * @param size            The agent's radius
  40          * @param sight           The distance the agent can see
  41          * @param maxSpeed        The maximum speed the agent can travel
  42          * @param maxAcceleration The maximum acceleration for this agent
  43          */
  44         public TagAgent(final int size, final int sight, final double maxSpeed, final double maxAcceleration)
  45         {
  46                 super(size, sight, maxSpeed, maxAcceleration);
  47                 this.color = Color.cyan;
  48         }
  49
  50         /**
  51          * Observes the world, and follows the Tag Agent Algorithm.
  52          */
  53         public void observeWorld()
  54         {
  55                 if (timeToWait > 0)
  56                 {
  57                         setAcceleration(new Vector(0, 0));
  58                         timeToWait--;
  59                         return;
  60                 }
  61                 final List neighbors = world.getNeighbors(this);
  62                 double distanceToClosestOppNeighbor = Double.MAX_VALUE;
  63                 TagAgent closestNeighborWithOppositeItFlag = null;
  64                 for (int i = 0; i < neighbors.size(); i++)
  65                 {
  66                         final Agent neighbor = (Agent) neighbors.get(i);
  67                         if (neighbor instanceof TagAgent)
  68                         {
  69                                 final TagAgent tagNeighbor = (TagAgent) neighbor;
  70                                 if (tagNeighbor.isIt() == !it)
  71                                 {
  72                                         final double distance = world.getVectorToObject(this, tagNeighbor).getLength();
  73                                         if (distance < distanceToClosestOppNeighbor)
  74                                         {
  75                                                 distanceToClosestOppNeighbor = distance;
  76                                                 closestNeighborWithOppositeItFlag = tagNeighbor;
  77                                         }
  78                                 }
  79                         }
  80                 }
  81                 if (closestNeighborWithOppositeItFlag == null)
  82                         setAcceleration(new Vector(0, 0));
  83                 else
  84                 {
  85                         Vector toClosestOppNeighbor = world.getVectorToObject(this, closestNeighborWithOppositeItFlag);
  86                         toClosestOppNeighbor = toClosestOppNeighbor.setLength(maxAcceleration);
  87                         setAcceleration(it ? toClosestOppNeighbor : toClosestOppNeighbor.multiply(-1));
  88                 }
  89         }
  90
  91         /**
  92          * Sets whether or not this agent is "it"
  93          *
  94          * @param it Whether or not this agent is "it"
  95          */
  96         public void setIt(final boolean it)
  97         {
  98                 if (this.it == !it)
  99                 {
 100                         this.it = it;
 101                         if (it)
 102                         {
 103                                 color = Color.pink;
 104                                 maxSpeed *= 0.8;
 105                                 timeToWait = 10;
 106                         }
 107                         else
 108                         {
 109                                 color = Color.cyan;
 110                                 maxSpeed *= 1.25;
 111                                 timeToWait = 0;
 112                         }
 113                 }
 114         }
 115
 116         /**
 117          * Returns whether or not this agent is "it"
 118          *
 119          * @return Whether or not this agent is "it"
 120          */
 121         public boolean isIt()
 122         {
 123                 return it;
 124         }
 125
 126         /**
 127          * Informs the object that it has been in a collision
 128          *
 129          * @param object The object collided with
 130          */
 131         public void collidedWith(final WorldObject object)
 132         {
 133                 if (object instanceof TagAgent)
 134                 {
 135                         final TagAgent tagAgent = (TagAgent) object;
 136                         if (tagAgent.isIt() == !it)
 137                         {
 138                                 tagAgent.setIt(it);
 139                                 setIt(!it);
 140                         }
 141                 }
 142         }
 143 }