Class CarGame

java.lang.Object
  CarGame

public class CarGame
extends java.lang.Object

This class represents the car game. The car game maintains information about the highway where the game is happening as well as about the player, the player's score, and how much time is left in the game. It also defines a random number generator that is used throughout the game and keeps track of the current tick number.

Author:

Dalibor Zeleny (dalibor@cs.wisc.edu)

static double	DROP_CARS_DISTANCE If the distance of any car is more than this constant's value from the player's car, it will get removed from the highway.
static long	TICKS_PER_SECOND The number of ticks in each second.

Constructor Summary

CarGame(int numLanes, double tickLength, java.lang.String playerName, int ticksBeforeStart)
Creates a new CarGame object with the specified properties

Method Summary

private void	addRandomCar() Add one random car to the highway.
private void	addRandomCoin() Add one random coin to the highway.
private void	checkForCrashes() If there are any cars that crashed into each other (that is, they overlap), this method should remove them from the highway.
Highway	getHighway() Returns a reference to the highway where the game is happening.
Driver	getPlayer() Returns a reference to an object that represents the player.
java.util.Random	getRNG() Returns a reference to the random number generator used by this game.
long	getScore() Returns the player's score.
long	getTickNumber() Returns the current tick number.
double	getTimeLeft() Returns how many seconds are remaining in the game.
boolean	isGameOver() Indicates whether the game is over.
private void	moveEverything() Every car and every coin should now move (tick) for the amount of time specified by the game's tick length.
private void	notifyDrivers() For each car on the highway, tell its driver about nearby cars by calling the makeDecision() method.
private void	pickUpCoins() For each coin on the highway, check if it overlaps with the player's car.
private void	processKeysPressed() This method processes key presses made before this tick.
private void	removeDistantCars() To speed up the game, all cars whose distance from the player's car is more than DROP_CARS_DISTANCE should be removed from the highway.
private void	removeExpiredCoins() Remove all expired coins from the highway so that the player cannot pick the up and get points/time for them.
void	reset() Restarts the game.
void	setAddCarProbability(double addCarProbability) Updates the probability with which another car should be added in each tick using the parameter as the new value.
void	setAddCoinProbability(double addObjectProbability) Updates the probability with which another object should be added in each tick using the parameter as the new value.
void	tick() Runs one tick of the game.
java.lang.String	toString() Returns a string description of the game's state.
void	updateKeystrokes(boolean[] keystrokes) Updates which keys were pressed before this tick.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

r

private java.util.Random r

keysPressed

private boolean[] keysPressed

TICKS_PER_SECOND

public static long TICKS_PER_SECOND

The number of ticks in each second.

DROP_CARS_DISTANCE

public static double DROP_CARS_DISTANCE

If the distance of any car is more than this constant's value from the player's car, it will get removed from the highway.

addCarProbability

private double addCarProbability

addCoinProbability

private double addCoinProbability

tickLength

private double tickLength

highway

private Highway highway

tickNumber

private long tickNumber

ticksBeforeStart

private long ticksBeforeStart

player

private Driver player

playerLaneNumber

private int playerLaneNumber

timeLeft

private double timeLeft

score

private long score

Constructor Detail

CarGame

public CarGame(int numLanes,
               double tickLength,
               java.lang.String playerName,
               int ticksBeforeStart)

Creates a new CarGame object with the specified properties

Parameters:

numLanes - Number of lanes in the highway

tickLength - Length of a tick. Recommended: 0.01

playerName - Name of the player

ticksBeforeStart - Number of ticks before the start of the game. This allows other parts of the program to do some setup before the game actually starts and also to display a nice countdown.

Method Detail

getRNG

public java.util.Random getRNG()

Returns a reference to the random number generator used by this game.

Returns:

a reference to the random number generator used by this game.

updateKeystrokes

public void updateKeystrokes(boolean[] keystrokes)

Updates which keys were pressed before this tick. The keystrokes will be acknowledged by the game in its next tick. The array indices correspond to the constants KEY_UP, KEY_RIGHT, KEY_DOWN and KEY_LEFT in CarGameController. You should not call this method from anywhere in your code.

Parameters:

keystrokes - An array indicating which keys were pressed. An array element is true if and only if its corresponding key was pressed.

getPlayer

public Driver getPlayer()

Returns a reference to an object that represents the player.

Returns:

a reference to an object that represents the player.

getScore

public long getScore()

Returns the player's score.

Returns:

the player's score.

getTimeLeft

public double getTimeLeft()

Returns how many seconds are remaining in the game.

Returns:

how many seconds are remaining in the game.

getTickNumber

public long getTickNumber()

Returns the current tick number.

Returns:

the current tick number.

setAddCarProbability

public void setAddCarProbability(double addCarProbability)

Updates the probability with which another car should be added in each tick using the parameter as the new value.

Parameters:

addCarProbability - A positive double value that is less than 1.

setAddCoinProbability

public void setAddCoinProbability(double addObjectProbability)

Updates the probability with which another object should be added in each tick using the parameter as the new value.

Parameters:

addObjectProbability - A positive double value that is less than 1.

tick

public void tick()

Runs one tick of the game. You should not modify this method's code.

getHighway

public Highway getHighway()

Returns a reference to the highway where the game is happening.

Returns:

a reference to the highway where the game is happening.

isGameOver

public boolean isGameOver()

Indicates whether the game is over. The game is over when the player crashed his car or when time runs out.

Returns:

whether the game is over.

reset

public void reset()

Restarts the game. This should restore the highway to the state it was in right after the constructor finished.

toString

public java.lang.String toString()

Returns a string description of the game's state. Here is an example of what the output could look like: Tick 962, score: 2172, time left: 53 Lane 0: 5 car(s), 1 coin(s) CAR 0: ID: 41, distance: 1098.5299999999847, velocity: 33.0, length: 4.0; driven by Bob who prefers 33.0 CAR 1: ID: 35, distance: 1042.9299999999862, velocity: 43.0, length: 3.75; driven by Bob who prefers 43.0 CAR 2: ID: 31, distance: 1008.4099999999748, velocity: 56.0, length: 3.75; driven by Bob who prefers 56.0 CAR 3: ID: 4, distance: 845.9199999999934, velocity: 66.0, length: 3.5; driven by Bob who prefers 66.0 CAR 4: ID: 2, distance: 563.2399999999914, velocity: 52.0, length: 5.75; driven by Bob who prefers 52.0 COIN 0: ID: 3, at distance: 955.850000000004 with score bonus 796(-12 decrease), time bonus 6.300000000000006(-0.1 decrease) and decrease period 5. It has lived 88 out of 400 ticks Lane 1: 9 car(s), 0 coin(s) CAR 0: ID: 40, distance: 1277.4299999999923, velocity: 78.0, length: 4.5; driven by Bob who prefers 78.0 CAR 1: ID: 42, distance: 1184.5500000000104, velocity: 70.0, length: 4.0; driven by Bob who prefers 70.0 CAR 2: ID: 36, distance: 1126.8599999999908, velocity: 53.0, length: 4.5; driven by Bob who prefers 53.0 CAR 3: ID: 34, distance: 1119.609999999992, velocity: 52.0, length: 3.25; driven by Bob who prefers 52.0 CAR 4: ID: 39, distance: 993.3899999999787, velocity: 24.0, length: 4.5; driven by Bob who prefers 24.0 CAR 5: ID: 1, distance: 926.25, velocity: 100.0, length: 5.0; driven by Dalibor who prefers 10.0 CAR 6: ID: 15, distance: 906.5300000000148, velocity: 48.0, length: 4.75; driven by Bob who prefers 48.0 CAR 7: ID: 11, distance: 787.7300000000116, velocity: 36.0, length: 4.75; driven by Bob who prefers 36.0 CAR 8: ID: 3, distance: 768.1599999999852, velocity: 68.0, length: 3.0; driven by Bob who prefers 68.0 Lane 2: 9 car(s), 0 coin(s) CAR 0: ID: 49, distance: 1351.3499999999992, velocity: 30.0, length: 4.25; driven by Bob who prefers 30.0 CAR 1: ID: 46, distance: 1246.3000000000086, velocity: 43.0, length: 4.5; driven by Bob who prefers 43.0 CAR 2: ID: 32, distance: 1102.5899999999992, velocity: 66.0, length: 5.25; driven by Bob who prefers 66.0 CAR 3: ID: 12, distance: 1082.0099999999923, velocity: 76.0, length: 3.75; driven by Bob who prefers 76.0 CAR 4: ID: 24, distance: 1017.5600000000327, velocity: 69.0, length: 5.5; driven by Bob who prefers 69.0 CAR 5: ID: 8, distance: 999.5899999999751, velocity: 78.0, length: 5.0; driven by Bob who prefers 78.0 CAR 6: ID: 7, distance: 720.7999999999781, velocity: 40.0, length: 5.0; driven by Bob who prefers 40.0 CAR 7: ID: 13, distance: 683.0499999999809, velocity: 40.0, length: 5.5; driven by Bob who prefers 40.0 CAR 8: ID: 5, distance: 618.3800000000087, velocity: 49.0, length: 4.25; driven by Bob who prefers 49.0 Lane 3: 10 car(s), 0 coin(s) CAR 0: ID: 47, distance: 1275.75, velocity: 75.0, length: 3.25; driven by Bob who prefers 75.0 CAR 1: ID: 28, distance: 1205.6399999999908, velocity: 77.0, length: 3.5; driven by Bob who prefers 77.0 CAR 2: ID: 26, distance: 1139.090000000015, velocity: 72.0, length: 5.0; driven by Bob who prefers 72.0 CAR 3: ID: 9, distance: 1050.9299999999841, velocity: 65.0, length: 3.5; driven by Bob who prefers 65.0 CAR 4: ID: 25, distance: 1037.4000000000206, velocity: 71.0, length: 4.75; driven by Bob who prefers 71.0 CAR 5: ID: 23, distance: 977.1699999999805, velocity: 66.0, length: 4.0; driven by Bob who prefers 66.0 CAR 6: ID: 21, distance: 954.5500000000054, velocity: 59.0, length: 4.75; driven by Bob who prefers 59.0 CAR 7: ID: 14, distance: 930.2699999999837, velocity: 78.0, length: 3.75; driven by Bob who prefers 78.0 CAR 8: ID: 20, distance: 890.2200000000081, velocity: 47.0, length: 4.25; driven by Bob who prefers 47.0 CAR 9: ID: 17, distance: 800.0099999999715, velocity: 56.0, length: 5.0; driven by Bob who prefers 56.0 Lane 4: 17 car(s), 0 coin(s) CAR 0: ID: 50, distance: 1344.25, velocity: 25.0, length: 4.0; driven by Bob who prefers 25.0 CAR 1: ID: 48, distance: 1270.1099999999974, velocity: 36.0, length: 4.5; driven by Bob who prefers 36.0 CAR 2: ID: 44, distance: 1221.8199999999824, velocity: 37.0, length: 5.75; driven by Bob who prefers 37.0 CAR 3: ID: 45, distance: 1188.4500000000062, velocity: 20.0, length: 4.0; driven by Bob who prefers 20.0 CAR 4: ID: 43, distance: 1178.0500000000147, velocity: 41.0, length: 3.75; driven by Bob who prefers 41.0 CAR 5: ID: 37, distance: 1090.7500000000048, velocity: 42.0, length: 3.25; driven by Bob who prefers 42.0 CAR 6: ID: 38, distance: 1000.0899999999892, velocity: 29.0, length: 4.5; driven by Bob who prefers 29.0 CAR 7: ID: 30, distance: 980.469999999988, velocity: 22.0, length: 3.5; driven by Bob who prefers 22.0 CAR 8: ID: 22, distance: 974.7300000000337, velocity: 44.0, length: 4.5; driven by Bob who prefers 44.0 CAR 9: ID: 27, distance: 941.9799999999896, velocity: 27.0, length: 5.5; driven by Bob who prefers 27.0 CAR 10: ID: 18, distance: 929.839999999977, velocity: 67.0, length: 3.0; driven by Bob who prefers 67.0 CAR 11: ID: 33, distance: 894.4700000000081, velocity: 22.0, length: 4.5; driven by Bob who prefers 22.0 CAR 12: ID: 29, distance: 847.9400000000202, velocity: 33.0, length: 4.0; driven by Bob who prefers 33.0 CAR 13: ID: 19, distance: 824.6199999999726, velocity: 31.0, length: 4.0; driven by Bob who prefers 31.0 CAR 14: ID: 16, distance: 682.4900000000073, velocity: 24.0, length: 3.75; driven by Bob who prefers 24.0 CAR 15: ID: 10, distance: 611.5900000000147, velocity: 22.0, length: 3.0; driven by Bob who prefers 22.0 CAR 16: ID: 6, distance: 562.6199999999928, velocity: 51.0, length: 5.75; driven by Bob who prefers 51.0

Overrides:

toString in class java.lang.Object

init

private void init()

Sets up the initial state of the game (empties the highway, resets the number of ticks to ticksBeforeStart, puts a new player in there, and so on)

notifyDrivers

private void notifyDrivers()

For each car on the highway, tell its driver about nearby cars by calling the makeDecision() method. Once the makeDecision() method returns, put the car in the correct lane if the driver chose to switch lanes. The makeDecision() method should not get called twice for any driver, which you can guarantee by properly using the canAct() and setCanAct() methods.

pickUpCoins

private void pickUpCoins()

For each coin on the highway, check if it overlaps with the player's car. If it does, update the player's score and time left and remove that coin from the highway.

processKeysPressed

private void processKeysPressed()

This method processes key presses made before this tick. They key presses are located in the instance variable keysPressed which we provided in the code skeleton. Make use of that array to change the velocity of the player's car and the lane that car is in. Refer to constants defined in CarGameController to find out what the individual array elements mean. For example, this.keysPressed[CarGameController.KEY_UP] tells us whether the up key was pressed.
The following should happen:

• If the up key is pressed, the player's car should move one lane to the left, even if this causes an accident. Nothing should happen if the player's car is in the leftmost lane already.
• If the right key is pressed, the player's car velocity should increase by 1.
• If the down key is pressed, the player's car should move one lane to the right, even if this causes an accident. Nothing should happen if the player's car is in the rightmost lane already.
• If the left key is pressed, the player's car velocity should decrease by 1.

Once this method returns, the keysPressed array should indicate that no keys were pressed.

moveEverything

private void moveEverything()

Every car and every coin should now move (tick) for the amount of time specified by the game's tick length.

removeExpiredCoins

private void removeExpiredCoins()

Remove all expired coins from the highway so that the player cannot pick the up and get points/time for them.

removeDistantCars

private void removeDistantCars()

To speed up the game, all cars whose distance from the player's car is more than DROP_CARS_DISTANCE should be removed from the highway.

addRandomCar

private void addRandomCar()

Add one random car to the highway. Place it in a random lane at a random distance away from the player's car and give it a new driver who should have a random preferred velocity. Placing this car on the highway should not cause an accident, so make sure to check your random location and change it if necessary.

addRandomCoin

private void addRandomCoin()

Add one random coin to the highway. Place it in a random lane and pick some interesting properties for it. Again, we leave the details up to your creativity.

checkForCrashes

private void checkForCrashes()

If there are any cars that crashed into each other (that is, they overlap), this method should remove them from the highway.