src/appletbots/gatherers/Gatherer.java

   1 /*
   2  * Copyright (c) 2002 Erik Rasmussen - All Rights Reserverd
   3  */
   4 package appletbots.gatherers;
   5
   6 import appletbots.CarriableObject;
   7 import appletbots.CarrierAgent;
   8 import appletbots.CollisionException;
   9 import appletbots.WorldObject;
  10 import appletbots.geometry.Vector;
  11
  12 import java.awt.*;
  13 import java.util.ArrayList;
  14 import java.util.List;
  15
  16 /**
  17  * A gatherer agent chooses the closest visible piece of food
  18  * that is currently not being carried by anyone (and is not
  19  * already in the agent's home base) and accelerates towards it.
  20  * If no "uncarried" food can be found, the agent tries to find
  21  * food carried by a member of the opposing team to accelerate
  22  * towards.  If no food is visible the agent sets his acceleration
  23  * to a random vector to search for food.  When it gets close
  24  * enough to pick up a piece of food, it picks it up and carries
  25  * it towards its home base corner for 20 time cycles, and drops
  26  * it again.  The gatherer must then rest for 10 time cycles
  27  * before picking up another piece of food.  During these 10
  28  * time cycles, the "exhausted" agent does not accelerate.
  29  *
  30  * @author Erik Rasmussen
  31  */
  32 public class Gatherer extends CarrierAgent
  33 {
  34         /**
  35          * Whether or not the agent is on the team with the home base in the
  36          * bottom right-hand corner of the world
  37          */
  38         protected boolean bottomRightTeam;
  39         /**
  40          * The amount of time the gatherer has been carrying a piece of food
  41          */
  42         protected int timeCarried;
  43         /**
  44          * The the amount of time needed to rest
  45          */
  46         protected int timeToRest;
  47         /**
  48          * The vector pointing in the direction of the agent's home base
  49          */
  50         protected Vector towardsHome;
  51
  52         /**
  53          * Constructs a new Gatherer with the given parameters
  54          *
  55          * @param pickupDistance  The distance from an object the agent must be to
  56          *                        pick up the object
  57          * @param bottomRightTeam Whether or not this agent is on the team moving
  58          *                        food to the bottom right corner of the world
  59          * @param size            The agent's radius
  60          * @param sight           The distance the agent can see
  61          * @param maxSpeed        The maximum speed the agent can travel
  62          * @param maxAcceleration The maximum acceleration for this agent
  63          */
  64         public Gatherer(final int pickupDistance, final boolean bottomRightTeam, final int size, final int sight, final double maxSpeed, final double maxAcceleration)
  65         {
  66                 super(pickupDistance, size, sight, maxSpeed, maxAcceleration);
  67                 this.bottomRightTeam = bottomRightTeam;
  68                 if (bottomRightTeam)
  69                 {
  70                         this.color = Color.cyan;
  71                         towardsHome = new Vector(1, 1);
  72                         towardsHome = towardsHome.setLength(maxAcceleration);
  73                 }
  74                 else
  75                 {
  76                         this.color = Color.pink;
  77                         towardsHome = new Vector(-1, -1);
  78                         towardsHome = towardsHome.setLength(maxAcceleration);
  79                 }
  80         }
  81
  82         /**
  83          * Observes the world, and follows the Gatherer Algorithm.
  84          */
  85         public void observeWorld()
  86         {
  87                 timeToRest--;
  88                 if (hasItems())
  89                 {
  90                         timeCarried--;
  91                         setAcceleration(towardsHome);
  92                         if (timeCarried < 0)
  93                                 dropFood();
  94                 }
  95                 else if (timeToRest <= 0)
  96                 {
  97                         Food food = chooseFood(false);
  98                         // if no uncarried food found, search for carried food
  99                         if (food == null)
 100                                 food = chooseFood(true);
 101                         if (food == null)
 102                                 setAcceleration(Vector.getRandom(maxAcceleration));
 103                         else if (world.getVectorToObject(this, food).getLength() <= getPickUpDistance() &&
 104                                  food.getCarriedBy() == null)
 105                         {
 106                                 pickUp(food);
 107                                 setAcceleration(towardsHome);
 108                         }
 109                         else
 110                                 setAcceleration(world.getVectorToObject(this, food));
 111                 }
 112                 else
 113                         setAcceleration(new Vector(0, 0));
 114         }
 115
 116         /**
 117          * Selects closest visible food not already in home base
 118          *
 119          * @param carried Whether or not the food we are looking for is being
 120          *                carried
 121          * @return The closest visible food not already in home base
 122          */
 123         protected Food chooseFood(final boolean carried)
 124         {
 125                 final List seenObjects = world.getSeenObjects(this);
 126                 final List foods = new ArrayList();
 127                 for (int i = 0; i < seenObjects.size(); i++)
 128                 {
 129                         final WorldObject object = (WorldObject) seenObjects.get(i);
 130                         if (object instanceof Food)
 131                         {
 132                                 final Food food = (Food) object;
 133                                 if ((carried && food.getCarriedBy() != null && ((Gatherer) food.getCarriedBy()).isBottomRightTeam() != bottomRightTeam) ||
 134                                     (!carried && food.getCarriedBy() == null && !((GatherersWorld) world).isInHome(object, bottomRightTeam)))
 135                                         foods.add(object);
 136                         }
 137                 }
 138                 if (!foods.isEmpty())
 139                 {
 140                         // choose closest piece of food
 141                         double minDistance = Double.MAX_VALUE;
 142                         Food closestFood = null;
 143                         for (int i = 0; i < foods.size(); i++)
 144                         {
 145                                 final Food food = (Food) foods.get(i);
 146                                 final double distance = world.getVectorToObject(this, food).getLength();
 147                                 if (distance < minDistance)
 148                                 {
 149                                         minDistance = distance;
 150                                         closestFood = food;
 151                                 }
 152                         }
 153                         return closestFood;
 154                 }
 155                 else
 156                         return null;
 157         }
 158
 159         /**
 160          * Returns the nearest visible gatherer
 161          *
 162          * @param opponent If true will return nearest visible opponent, otherwise nearest teammate
 163          * @return The nearest visible gatherer
 164          */
 165         protected Gatherer getNearestGatherer(final boolean opponent)
 166         {
 167                 final List seenObjects = world.getSeenObjects(this);
 168                 final List gatherers = new ArrayList();
 169                 for (int i = 0; i < seenObjects.size(); i++)
 170                 {
 171                         final WorldObject object = (WorldObject) seenObjects.get(i);
 172                         if (object instanceof Gatherer &&
 173                             ((opponent && ((Gatherer) object).bottomRightTeam != bottomRightTeam) ||
 174                              (!opponent && ((Gatherer) object).bottomRightTeam == bottomRightTeam)))
 175                                 gatherers.add(object);
 176                 }
 177                 if (!gatherers.isEmpty())
 178                 {
 179                         // choose nearest opponent
 180                         double minDistance = Double.MAX_VALUE;
 181                         Gatherer nearestGatherer = null;
 182                         for (int i = 0; i < gatherers.size(); i++)
 183                         {
 184                                 final Gatherer gatherer = (Gatherer) gatherers.get(i);
 185                                 final double distance = world.getVectorToObject(this, gatherer).getLength();
 186                                 if (distance < minDistance)
 187                                 {
 188                                         minDistance = distance;
 189                                         nearestGatherer = gatherer;
 190                                 }
 191                         }
 192                         return nearestGatherer;
 193                 }
 194                 else
 195                         return null;
 196         }
 197
 198         /**
 199          * Returns whether or not the agent is on the team with the home base in
 200          * the bottom right-hand corner of the world
 201          *
 202          * @return Whether or not the agent is on the team with the home base in the
 203          *         bottom right-hand corner of the world
 204          */
 205         public boolean isBottomRightTeam()
 206         {
 207                 return bottomRightTeam;
 208         }
 209
 210         /**
 211          * Attempts to drop any carried food
 212          */
 213         protected void dropFood()
 214         {
 215                 if (hasItems())
 216                 {
 217                         try
 218                         {
 219                                 drop(getInventory()[0]);
 220                                 timeToRest = 10;
 221                         }
 222                         catch (CollisionException e)
 223                         {
 224                         }
 225                 }
 226         }
 227
 228         /**
 229          * Picks up an object
 230          *
 231          * @param item The object to pick up
 232          */
 233         protected void pickUp(final CarriableObject item)
 234         {
 235                 super.pickUp(item);
 236                 timeCarried = 20;
 237         }
 238 }