Mega Code Archive
Dungeon game
<![CDATA[
/*
Title: J2ME Games With MIDP2
Authors: Carol Hamer
Publisher: Apress
ISBN: 1590593820
*/
import java.io.*;
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.*;
import javax.microedition.midlet.*;
import javax.microedition.rms.*;
/**
* This is the main class of the dungeon game.
*
* @author Carol Hamer
*/
public class Dungeon extends MIDlet implements CommandListener {
//-----------------------------------------------------
// game object fields
/**
* The canvas that the dungeon is drawn on.
*/
private DungeonCanvas myCanvas;
/**
* the thread that advances the game clock.
*/
private GameThread myGameThread;
//-----------------------------------------------------
// command fields
/**
* The button to exit the game.
*/
private Command myExitCommand = new Command("Exit", Command.EXIT, 99);
/**
* The command to save the game in progress.
*/
private Command mySaveCommand = new Command("Save Game", Command.SCREEN, 2);
/**
* The command to restore a previously saved game.
*/
private Command myRestoreCommand = new Command("Restore Game",
Command.SCREEN, 2);
/**
* the command to start moving when the game is paused.
*/
private Command myGoCommand = new Command("Go", Command.SCREEN, 1);
/**
* the command to pause the game.
*/
private Command myPauseCommand = new Command("Pause", Command.SCREEN, 1);
/**
* the command to start a new game.
*/
private Command myNewCommand = new Command("Next Board", Command.SCREEN, 1);
//-----------------------------------------------------
// initialization and game state changes
/**
* Initialize the canvas and the commands.
*/
public Dungeon() {
try {
// create the canvas and set up the commands:
myCanvas = new DungeonCanvas(this);
myCanvas.addCommand(myExitCommand);
myCanvas.addCommand(mySaveCommand);
myCanvas.addCommand(myRestoreCommand);
myCanvas.addCommand(myPauseCommand);
myCanvas.setCommandListener(this);
} catch (Exception e) {
// if there's an error during creation, display it as an alert.
errorMsg(e);
}
}
/**
* Switch the command to the play again command. (removing other commands
* that are no longer relevant)
*/
void setNewCommand() {
myCanvas.removeCommand(myPauseCommand);
myCanvas.removeCommand(myGoCommand);
myCanvas.addCommand(myNewCommand);
}
/**
* Switch the command to the go command. (removing other commands that are
* no longer relevant)
*/
void setGoCommand() {
myCanvas.removeCommand(myPauseCommand);
myCanvas.removeCommand(myNewCommand);
myCanvas.addCommand(myGoCommand);
}
/**
* Switch the command to the pause command. (removing other commands that
* are no longer relevant)
*/
void setPauseCommand() {
myCanvas.removeCommand(myNewCommand);
myCanvas.removeCommand(myGoCommand);
myCanvas.addCommand(myPauseCommand);
}
//----------------------------------------------------------------
// implementation of MIDlet
// these methods may be called by the application management
// software at any time, so we always check fields for null
// before calling methods on them.
/**
* Start the application.
*/
public void startApp() throws MIDletStateChangeException {
if (myCanvas != null) {
if (myGameThread == null) {
// create the thread and start the game:
myGameThread = new GameThread(myCanvas);
myCanvas.start();
myGameThread.start();
} else {
// in case this gets called again after
// the application has been started once:
myCanvas.removeCommand(myGoCommand);
myCanvas.addCommand(myPauseCommand);
myCanvas.flushKeys();
myGameThread.resumeGame();
}
}
}
/**
* Stop the threads and throw out the garbage.
*/
public void destroyApp(boolean unconditional)
throws MIDletStateChangeException {
myCanvas = null;
if (myGameThread != null) {
myGameThread.requestStop();
}
myGameThread = null;
System.gc();
}
/**
* Pause the game.
*/
public void pauseApp() {
if (myCanvas != null) {
setGoCommand();
}
if (myGameThread != null) {
myGameThread.pause();
}
}
//----------------------------------------------------------------
// implementation of CommandListener
/*
* Respond to a command issued on the Canvas. (reset, exit, or change size
* prefs).
*/
public void commandAction(Command c, Displayable s) {
try {
if (c == myGoCommand) {
myCanvas.setNeedsRepaint();
myCanvas.removeCommand(myGoCommand);
myCanvas.addCommand(myPauseCommand);
myCanvas.flushKeys();
myGameThread.resumeGame();
} else if (c == myPauseCommand) {
myCanvas.setNeedsRepaint();
myCanvas.removeCommand(myPauseCommand);
myCanvas.addCommand(myGoCommand);
myGameThread.pause();
} else if (c == myNewCommand) {
myCanvas.setNeedsRepaint();
// go to the next board and restart the game
myCanvas.removeCommand(myNewCommand);
myCanvas.addCommand(myPauseCommand);
myCanvas.reset();
myGameThread.resumeGame();
/*} else if (c == Alert.DISMISS_COMMAND) {
// if there was a serious enough error to
// cause an alert, then we end the game
// when the user is done reading the alert:
// (Alert.DISMISS_COMMAND is the default
// command that is placed on an Alert
// whose timeout is FOREVER)
destroyApp(false);
notifyDestroyed();*/
} else if (c == mySaveCommand) {
myCanvas.setNeedsRepaint();
myCanvas.saveGame();
} else if (c == myRestoreCommand) {
myCanvas.setNeedsRepaint();
myCanvas.removeCommand(myNewCommand);
myCanvas.removeCommand(myGoCommand);
myCanvas.addCommand(myPauseCommand);
myCanvas.revertToSaved();
} else if (c == myExitCommand) {
destroyApp(false);
notifyDestroyed();
}
} catch (Exception e) {
errorMsg(e);
}
}
//-------------------------------------------------------
// error methods
/**
* Converts an exception to a message and displays the message..
*/
void errorMsg(Exception e) {
if (e.getMessage() == null) {
errorMsg(e.getClass().getName());
} else {
errorMsg(e.getClass().getName() + ":" + e.getMessage());
}
}
/**
* Displays an error message alert if something goes wrong.
*/
void errorMsg(String msg) {
Alert errorAlert = new Alert("error", msg, null, AlertType.ERROR);
errorAlert.setCommandListener(this);
errorAlert.setTimeout(Alert.FOREVER);
Display.getDisplay(this).setCurrent(errorAlert);
}
}
/**
* This class represents doors and keys.
*
* @author Carol Hamer
*/
class DoorKey extends Sprite {
//---------------------------------------------------------
// fields
/**
* The image file shared by all doors and keys.
*/
public static Image myImage;
/**
* A code int that indicates the door or key's color.
*/
private int myColor;
//---------------------------------------------------------
// get/set data
/**
* @return the door or key's color.
*/
public int getColor() {
return (myColor);
}
//---------------------------------------------------------
// constructor and initializer
static {
try {
myImage = Image.createImage("/images/keys.png");
} catch (Exception e) {
throw (new RuntimeException(
"DoorKey.<init>-->failed to load image, caught "
+ e.getClass() + ": " + e.getMessage()));
}
}
/**
* Standard constructor sets the image to the correct frame (according to
* whether this is a door or a key and what color it should be) and then
* puts it in the correct location.
*/
public DoorKey(int color, boolean isKey, int[] gridCoordinates) {
super(myImage, DungeonManager.SQUARE_WIDTH, DungeonManager.SQUARE_WIDTH);
myColor = color;
int imageIndex = color * 2;
if (isKey) {
imageIndex++;
}
setFrame(imageIndex);
setPosition(gridCoordinates[0] * DungeonManager.SQUARE_WIDTH,
gridCoordinates[1] * DungeonManager.SQUARE_WIDTH);
}
}
/**
* This class is a set of simple utility functions that can be used to convert
* standard data types to bytes and back again. It is used especially for data
* storage, but also for sending and receiving data.
*
* @author Carol Hamer
*/
class DataConverter {
//--------------------------------------------------------
// utilities to encode small, compactly-stored small ints.
/**
* Encodes a coordinate pair into a byte.
*
* @param coordPair
* a pair of integers to be compacted into a single byte for
* storage. WARNING: each of the two values MUST BE between 0 and
* 15 (inclusive). This method does not verify the length of the
* array (which must be 2!) nor does it verify that the ints are
* of the right size.
*/
public static byte encodeCoords(int[] coordPair) {
// get the byte value of the first coordinate:
byte retVal = (new Integer(coordPair[0])).byteValue();
// move the first coordinate's value up to the top
// half of the storage byte:
retVal = (new Integer(retVal << 4)).byteValue();
// store the second coordinate in the lower half
// of the byte:
retVal += (new Integer(coordPair[1])).byteValue();
return (retVal);
}
/**
* Encodes eight ints into a byte. This could be easily modified to encode
* eight booleans.
*
* @param eight
* an array of at least eight ints. WARNING: all values must be 0
* or 1! This method does not verify that the values are in the
* correct range nor does it verify that the array is long
* enough.
* @param offset
* the index in the array eight to start reading data from.
* (should usually be 0)
*/
public static byte encode8(int[] eight, int offset) {
// get the byte value of the first int:
byte retVal = (new Integer(eight[offset])).byteValue();
// progressively move the data up one bit in the
// storage byte and then record the next int in
// the lowest spot in the storage byte:
for (int i = offset + 1; i < 8 + offset; i++) {
retVal = (new Integer(retVal << 1)).byteValue();
retVal += (new Integer(eight[i])).byteValue();
}
return (retVal);
}
//--------------------------------------------------------
// utilities to decode small, compactly-stored small ints.
/**
* Turns a byte into a pair of coordinates.
*/
public static int[] decodeCoords(byte coordByte) {
int[] retArray = new int[2];
// we perform a bitwise and with the value 15
// in order to just get the bits of the lower
// half of the byte:
retArray[1] = coordByte & 15;
// To get the bits of the upper half of the
// byte, we perform a shift to move them down:
retArray[0] = coordByte >> 4;
// bytes in Java are generally assumed to be
// signed, but in this coding algorithm we
// would like to treat them as unsigned:
if (retArray[0] < 0) {
retArray[0] += 16;
}
return (retArray);
}
/**
* Turns a byte into eight ints.
*/
public static int[] decode8(byte data) {
int[] retArray = new int[8];
// The flag allows us to look at each bit individually
// to determine if it is 1 or 0. The number 128
// corresponds to the highest bit of a byte, so we
// start with that one.
int flag = 128;
// We use a loop that checks
// the data bit by bit by performing a bitwise
// and (&) between the data byte and a flag:
for (int i = 0; i < 8; i++) {
if ((flag & data) != 0) {
retArray[i] = 1;
} else {
retArray[i] = 0;
}
// move the flag down one bit so that we can
// check the next bit of data on the next pass
// through the loop:
flag = flag >> 1;
}
return (retArray);
}
//--------------------------------------------------------
// standard integer interpretation
/**
* Uses an input stream to convert an array of bytes to an int.
*/
public static int parseInt(byte[] data) throws IOException {
DataInputStream stream = new DataInputStream(new ByteArrayInputStream(
data));
int retVal = stream.readInt();
stream.close();
return (retVal);
}
/**
* Uses an output stream to convert an int to four bytes.
*/
public static byte[] intToFourBytes(int i) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream(4);
DataOutputStream dos = new DataOutputStream(baos);
dos.writeInt(i);
baos.close();
dos.close();
byte[] retArray = baos.toByteArray();
return (retArray);
}
//--------------------------------------------------------
// integer interpretation illustrated
/**
* Java appears to treat a byte as being signed when returning it as an
* int--this function converts from the signed value to the corresponding
* unsigned value. This method is used by nostreamParseInt.
*/
public static int unsign(int signed) {
int retVal = signed;
if (retVal < 0) {
retVal += 256;
}
return (retVal);
}
/**
* Takes an array of bytes and returns an int. This version will return the
* same value as the method parseInt above. This version is included in
* order to illustrate how Java encodes int values in terms of bytes.
*
* @param data
* an array of 1, 2, or 4 bytes.
*/
public static int nostreamParseInt(byte[] data) {
// byte 0 is the high byte which is assumed
// to be signed. As we add the lower bytes
// one by one, we unsign them because because
// a single byte alone is interpreted as signed,
// but in an int only the top byte should be signed.
// (note that the high byte is the first one in the array)
int retVal = data[0];
for (int i = 1; i < data.length; i++) {
retVal = retVal << 8;
retVal += unsign(data[i]);
}
return (retVal);
}
/**
* Takes an arbitrary int and returns an array of four bytes. This version
* will return the same byte array as the method intToFourBytes above. This
* version is included in order to illustrate how Java encodes int values in
* terms of bytes.
*/
public static byte[] nostreamIntToFourBytes(int i) {
byte[] fourBytes = new byte[4];
// when you take the byte value of an int, it
// only gives you the lowest byte. So we
// get all four bytes by taking the lowest
// byte four times and moving the whole int
// down by one byte between each one.
// (note that the high byte is the first one in the array)
fourBytes[3] = (new Integer(i)).byteValue();
i = i >> 8;
fourBytes[2] = (new Integer(i)).byteValue();
i = i >> 8;
fourBytes[1] = (new Integer(i)).byteValue();
i = i >> 8;
fourBytes[0] = (new Integer(i)).byteValue();
return (fourBytes);
}
/**
* Takes an int between -32768 and 32767 and returns an array of two bytes.
* This does not verify that the argument is of the right size. If the
* absolute value of i is too high, it will not be encoded correctly.
*/
public static byte[] nostreamIntToTwoBytes(int i) {
byte[] twoBytes = new byte[2];
// when you take the byte value of an int, it
// only gives you the lowest byte. So we
// get the lower two bytes by taking the lowest
// byte twice and moving the whole int
// down by one byte between each one.
twoBytes[1] = (new Integer(i)).byteValue();
i = i >> 8;
twoBytes[0] = (new Integer(i)).byteValue();
return (twoBytes);
}
}
/**
* This class contains the data for the map of the dungeon..
*
* @author Carol Hamer
*/
class BoardDecoder {
//--------------------------------------------------------
// fields
/**
* The coordinates of where the player starts on the map in terms of the
* array indices.
*/
private int[] myPlayerSquare;
/**
* The coordinates of the goal (crown).
*/
private int[] myGoalSquare;
/**
* The coordinates of the doors. the there should be two in a row of each
* color, following the same sequence as the keys.
*/
private int[][] myDoors;
/**
* The coordinates of the Keys. the there should be of each color, following
* the same sequence as the doors.
*/
private int[][] myKeys;
/**
* The coordinates of the stone walls of the maze, encoded bit by bit.
*/
private TiledLayer myLayer;
/**
* The data in bytes that gives the various boards. This was created using
* EncodingUtils... This is a two-dimensional array: Each of the four main
* sections corresponds to one of the four possible boards.
*/
private static byte[][] myData = {
{ 0, 0, -108, -100, -24, 65, 21, 58, 53, -54, -116, -58, -56, -84,
115, -118, -1, -1, -128, 1, -103, -15, -128, 25, -97, -127,
-128, 79, -14, 1, -126, 121, -122, 1, -113, -49, -116, 1,
-100, -3, -124, 5, -25, -27, -128, 1, -1, -1 },
{ 0, 1, 122, 90, -62, 34, -43, 72, -59, -29, 56, -55, 98, 126, -79,
61, -1, -1, -125, 1, -128, 17, -26, 29, -31, 57, -72, 1,
-128, -51, -100, 65, -124, 57, -2, 1, -126, 13, -113, 1,
-97, 25, -127, -99, -8, 1, -1, -1 },
{ 0, 2, 108, -24, 18, -26, 102, 30, -58, 46, -28, -88, 34, -98, 97,
-41, -1, -1, -96, 1, -126, 57, -9, 97, -127, 69, -119, 73,
-127, 1, -109, 59, -126, 1, -26, 103, -127, 65, -103, 115,
-127, 65, -25, 73, -128, 1, -1, -1 },
{ 0, 3, -114, 18, -34, 27, -39, -60, -76, -50, 118, 90, 82, -88,
34, -74, -1, -1, -66, 1, -128, 121, -26, 125, -128, -123,
-103, 29, -112, 1, -109, 49, -112, 1, -116, -31, -128, 5,
-122, 5, -32, 13, -127, -51, -125, 1, -1, -1 }, };
//--------------------------------------------------------
// initialization
/**
* Constructor fills data fields by interpreting the data bytes.
*/
public BoardDecoder(int boardNum) throws Exception {
// we start by selecting the two dimensional
// array corresponding to the desired board:
byte[] data = myData[boardNum];
// The first two bytes give the version number and
// the board number, but we ignore them because
// they are assumed to be correct.
// The third byte of the first array is the first one
// we read: it gives the player's starting coordinates:
myPlayerSquare = DataConverter.decodeCoords(data[2]);
// the next byte gives the coordinates of the crown:
myGoalSquare = DataConverter.decodeCoords(data[3]);
// the next four bytes give the coordinates of the keys:
myKeys = new int[4][];
for (int i = 0; i < myKeys.length; i++) {
myKeys[i] = DataConverter.decodeCoords(data[i + 4]);
}
// the next eight bytes give the coordinates of the doors:
myDoors = new int[8][];
for (int i = 0; i < myDoors.length; i++) {
myDoors[i] = DataConverter.decodeCoords(data[i + 8]);
}
// now we create the TiledLayer object that is the
// background dungeon map:
myLayer = new TiledLayer(16, 16,
Image.createImage("/images/stone.png"),
DungeonManager.SQUARE_WIDTH, DungeonManager.SQUARE_WIDTH);
// now we call an internal utility that reads the array
// of data that gives the positions of the blocks in the
// walls of this dungeon:
decodeDungeon(data, myLayer, 16);
}
//--------------------------------------------------------
// get/set data
/**
* @return the number of boards currently stored in this class.
*/
public static int getNumBoards() {
return (myData.length);
}
/**
* get the coordinates of where the player starts on the map in terms of the
* array indices.
*/
public int[] getPlayerSquare() {
return (myPlayerSquare);
}
/**
* get the coordinates of the goal crown in terms of the array indices.
*/
public int[] getGoalSquare() {
return (myGoalSquare);
}
/**
* get the tiled layer that gives the map of the dungeon.
*/
public TiledLayer getLayer() {
return (myLayer);
}
/**
* Creates the array of door sprites. (call this only once to avoid creating
* redundant sprites).
*/
DoorKey[] createDoors() {
DoorKey[] retArray = new DoorKey[8];
for (int i = 0; i < 4; i++) {
retArray[2 * i] = new DoorKey(i, false, myDoors[2 * i]);
retArray[2 * i + 1] = new DoorKey(i, false, myDoors[2 * i + 1]);
}
return (retArray);
}
/**
* Creates the array of key sprites. (call this only once to avoid creating
* redundant sprites.)
*/
DoorKey[] createKeys() {
DoorKey[] retArray = new DoorKey[4];
for (int i = 0; i < 4; i++) {
retArray[i] = new DoorKey(i, true, myKeys[i]);
}
return (retArray);
}
//--------------------------------------------------------
// decoding utilities
/**
* Takes a dungeon given as a byte array and uses it to set the tiles of a
* tiled layer.
*
* The TiledLayer in this case is a 16 x 16 grid in which each square can be
* either blank (value of 0) or can be filled with a stone block (value of
* 1). Therefore each square requires only one bit of information. Each byte
* of data in the array called "data" records the frame indices of eight
* squares in the grid.
*/
private static void decodeDungeon(byte[] data, TiledLayer dungeon,
int offset) throws Exception {
if (data.length + offset < 32) {
throw (new Exception(
"BoardDecoder.decodeDungeon-->not enough data!!!"));
}
// a frame index of zero indicates a blank square
// (this is always true in a TiledLayer).
// This TiledLayer has only one possible (non-blank)
// frame, so a frame index of 1 indicates a stone block
int frame = 0;
// Each of the 32 bytes in the data array records
// the frame indices of eight block in the 16 x 16
// grid. Two bytes give one row of the dungeon,
// so we have the array index go from zero to 16
// to set the frame indices fro each of the 16 rows.
for (int i = 0; i < 16; i++) {
// The flag allows us to look at each bit individually
// to determine if it is 1 or 0. The number 128
// corresponds to the highest bit of a byte, so we
// start with that one.
int flag = 128;
// Here we check two bytes at the same time
// (the two bytes together correspond to one row
// of the dungeon). We use a loop that checks
// the bytes bit by bit by performing a bitwise
// and (&) between the data byte and a flag:
for (int j = 0; j < 8; j++) {
if ((data[offset + 2 * i] & flag) != 0) {
frame = 1;
} else {
frame = 0;
}
dungeon.setCell(j, i, frame);
if ((data[offset + 2 * i + 1] & flag) != 0) {
frame = 1;
} else {
frame = 0;
}
dungeon.setCell(j + 8, i, frame);
// move the flag down one bit so that we can
// check the next bit of data on the next pass
// through the loop:
flag = flag >> 1;
}
}
}
}
/**
* This class contains the loop that keeps the game running.
*
* @author Carol Hamer
*/
class GameThread extends Thread {
//---------------------------------------------------------
// fields
/**
* Whether or not the main thread would like this thread to pause.
*/
private boolean myShouldPause;
/**
* Whether or not the main thread would like this thread to stop.
*/
private static boolean myShouldStop;
/**
* A handle back to the graphical components.
*/
private DungeonCanvas myDungeonCanvas;
/**
* The System.time of the last screen refresh, used to regulate refresh
* speed.
*/
private long myLastRefreshTime;
//----------------------------------------------------------
// initialization
/**
* standard constructor.
*/
GameThread(DungeonCanvas canvas) {
myDungeonCanvas = canvas;
}
//----------------------------------------------------------
// utilities
/**
* Get the amount of time to wait between screen refreshes. Normally we wait
* only a single millisecond just to give the main thread a chance to update
* the keystroke info, but this method ensures that the game will not
* attempt to show too many frames per second.
*/
private long getWaitTime() {
long retVal = 1;
long difference = System.currentTimeMillis() - myLastRefreshTime;
if (difference < 75) {
retVal = 75 - difference;
}
return (retVal);
}
//----------------------------------------------------------
// actions
/**
* pause the game.
*/
void pause() {
myShouldPause = true;
}
/**
* restart the game after a pause.
*/
synchronized void resumeGame() {
myShouldPause = false;
notify();
}
/**
* stops the game.
*/
synchronized void requestStop() {
myShouldStop = true;
this.notify();
}
/**
* start the game..
*/
public void run() {
// flush any keystrokes that occurred before the
// game started:
myDungeonCanvas.flushKeys();
myShouldStop = false;
myShouldPause = false;
while (true) {
myLastRefreshTime = System.currentTimeMillis();
if (myShouldStop) {
break;
}
myDungeonCanvas.checkKeys();
myDungeonCanvas.updateScreen();
// we do a very short pause to allow the other thread
// to update the information about which keys are pressed:
synchronized (this) {
try {
wait(getWaitTime());
} catch (Exception e) {
}
}
if (myShouldPause) {
synchronized (this) {
try {
wait();
} catch (Exception e) {
}
}
}
}
}
}
/**
* This class contains the data for a game currently in progress. used to store
* a game and to resume a stored game.
*
* @author Carol Hamer
*/
class GameInfo {
//--------------------------------------------------------
// fields
/**
* The name of the datastore.
*/
public static final String STORE = "GameInfo";
/**
* This is set to true if an attempt is made to read a game when no game has
* been saved.
*/
private boolean myNoDataSaved;
/**
* The number that indicates which board the player is currently on.
*/
private int myBoardNum;
/**
* The amount of time that has passed.
*/
private int myTime;
/**
* The coordinates of where the player is on the board. coordinate values
* must be between 0 and 15.
*/
private int[] myPlayerSquare;
/**
* The coordinates of where the keys are currently found. MUST BE four sets
* of two integer coordinates. coordinate values must be between 0 and 15.
*/
private int[][] myKeyCoords;
/**
* The list of which doors are currently open. 0 = open 1 = closed WARNING:
* this array MUST have length 8.
*/
private int[] myDoorsOpen;
/**
* The number of the key that is currently being held by the player. if no
* key is held, then the value is -1.
*/
private int myHeldKey;
//--------------------------------------------------------
// data gets/sets
/**
* @return true if no saved game records were found.
*/
boolean getIsEmpty() {
return (myNoDataSaved);
}
/**
* @return The number that indicates which board the player is currently on.
*/
int getBoardNum() {
return (myBoardNum);
}
/**
* @return The number of the key that is currently being held by the player.
* if no key is held, then the value is -1.
*/
int getHeldKey() {
return (myHeldKey);
}
/**
* @return The amount of time that has passed.
*/
int getTime() {
return (myTime);
}
/**
* @return The coordinates of where the player is on the board. coordinate
* values must be between 0 and 15.
*/
int[] getPlayerSquare() {
return (myPlayerSquare);
}
/**
* @return The coordinates of where the keys are currently found. MUST BE
* four sets of two integer coordinates. coordinate values must be
* between 0 and 15.
*/
int[][] getKeyCoords() {
return (myKeyCoords);
}
/**
* @return The list of which doors are currently open. 0 = open 1 = closed
* WARNING: this array MUST have length 8.
*/
int[] getDoorsOpen() {
return (myDoorsOpen);
}
//--------------------------------------------------------
// constructors
/**
* This constructor records the game info of a game currently in progress.
*/
GameInfo(int boardNum, int time, int[] playerSquare, int[][] keyCoords,
int[] doorsOpen, int heldKey) throws Exception {
myBoardNum = boardNum;
myTime = time;
myPlayerSquare = playerSquare;
myKeyCoords = keyCoords;
myDoorsOpen = doorsOpen;
myHeldKey = heldKey;
encodeInfo();
}
/**
* This constructor reads the game configuration from memory. This is used
* to reconstruct a saved game.
*/
GameInfo() {
RecordStore store = null;
try {
// if the record store does not yet exist, don't
// create it
store = RecordStore.openRecordStore(STORE, false);
if ((store != null) && (store.getNumRecords() > 0)) {
// the first record has id number 1
// it should also be the only record since this
// particular game stores only one game.
byte[] data = store.getRecord(1);
myBoardNum = data[0];
myPlayerSquare = DataConverter.decodeCoords(data[1]);
myKeyCoords = new int[4][];
myKeyCoords[0] = DataConverter.decodeCoords(data[2]);
myKeyCoords[1] = DataConverter.decodeCoords(data[3]);
myKeyCoords[2] = DataConverter.decodeCoords(data[4]);
myKeyCoords[3] = DataConverter.decodeCoords(data[5]);
myDoorsOpen = DataConverter.decode8(data[6]);
myHeldKey = data[7];
byte[] fourBytes = new byte[4];
System.arraycopy(data, 8, fourBytes, 0, 4);
myTime = DataConverter.parseInt(fourBytes);
} else {
myNoDataSaved = true;
}
} catch (Exception e) {
// this throws when the record store doesn't exist.
// for that or any error, we assume no data is saved:
myNoDataSaved = true;
} finally {
try {
if (store != null) {
store.closeRecordStore();
}
} catch (Exception e) {
// if the record store is open this shouldn't throw.
}
}
}
//--------------------------------------------------------
// encoding method
/**
* Turn the data into a byte array and save it.
*/
private void encodeInfo() throws Exception {
RecordStore store = null;
try {
byte[] data = new byte[12];
data[0] = (new Integer(myBoardNum)).byteValue();
data[1] = DataConverter.encodeCoords(myPlayerSquare);
data[2] = DataConverter.encodeCoords(myKeyCoords[0]);
data[3] = DataConverter.encodeCoords(myKeyCoords[1]);
data[4] = DataConverter.encodeCoords(myKeyCoords[2]);
data[5] = DataConverter.encodeCoords(myKeyCoords[3]);
data[6] = DataConverter.encode8(myDoorsOpen, 0);
data[7] = (new Integer(myHeldKey)).byteValue();
byte[] timeBytes = DataConverter.intToFourBytes(myTime);
System.arraycopy(timeBytes, 0, data, 8, 4);
// if the record store does not yet exist, the second
// arg "true" tells it to create.
store = RecordStore.openRecordStore(STORE, true);
int numRecords = store.getNumRecords();
if (numRecords > 0) {
store.setRecord(1, data, 0, data.length);
} else {
store.addRecord(data, 0, data.length);
}
} catch (Exception e) {
throw (e);
} finally {
try {
if (store != null) {
store.closeRecordStore();
}
} catch (Exception e) {
// if the record store is open this shouldn't throw.
}
}
}
}
/**
* This class contains the data for the map of the dungeon. This is a utility
* class that allows a developer to write the data for a board in a simple
* format, then this class encodes the data in a format that the game can use.
*
* note that the data that this class encodes is hard-coded. that is because
* this class is intended to be used only a few times to encode the data. Once
* the board data has been encoded, it never needs to be encoded again. The
* encoding methods used in this class could be generalized to be used to create
* a board editor which would allow a user to easily create new boards, but that
* is an exercise for another day...
*
* @author Carol Hamer
*/
class EncodingUtils {
//--------------------------------------------------------
// fields
/**
* data for which squares are filled and which are blank. 0 = empty 1 =
* filled
*/
private int[][] mySquares = {
{ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
{ 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1 },
{ 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 1 },
{ 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1 },
{ 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1 },
{ 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1 },
{ 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1 },
{ 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1 },
{ 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1 },
{ 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 },
{ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }, };
/**
* The coordinates of where the player starts on the map in terms of the
* array indices.
*/
private int[] myPlayerSquare = { 7, 10 };
/**
* The coordinates of the goal (crown).
*/
private int[] myGoalSquare = { 5, 10 };
//--------------------------------------------------------
// get/set data
/**
* Creates the array of door sprites. (call this only once to avoid creating
* redundant sprites).
*/
int[][] getDoorCoords() {
int[][] retArray = new int[8][];
for (int i = 0; i < retArray.length; i++) {
retArray[i] = new int[2];
}
// red
retArray[0][0] = 12;
retArray[0][1] = 5;
retArray[1][0] = 14;
retArray[1][1] = 3;
// green
retArray[2][0] = 3;
retArray[2][1] = 8;
retArray[3][0] = 12;
retArray[3][1] = 9;
// blue
retArray[4][0] = 6;
retArray[4][1] = 2;
retArray[5][0] = 7;
retArray[5][1] = 14;
// yellow
retArray[6][0] = 11;
retArray[6][1] = 1;
retArray[7][0] = 3;
retArray[7][1] = 13;
return (retArray);
}
/**
* Creates the array of key sprites. (call this only once to avoid creating
* redundant sprites.)
*/
int[][] getKeyCoords() {
int[][] retArray = new int[4][];
for (int i = 0; i < retArray.length; i++) {
retArray[i] = new int[2];
}
// red
retArray[0][0] = 12;
retArray[0][1] = 2;
// green
retArray[1][0] = 2;
retArray[1][1] = 2;
// blue
retArray[2][0] = 13;
retArray[2][1] = 5;
// yellow
retArray[3][0] = 4;
retArray[3][1] = 8;
return (retArray);
}
//--------------------------------------------------------
// encoding / decoding utilities
/**
* Encodes the entire dungeon.
*/
byte[][] encodeDungeon() {
byte[][] retArray = new byte[2][];
retArray[0] = new byte[16];
// the first byte is the version number:
retArray[0][0] = 0;
// the second byte is the board number:
retArray[0][1] = 0;
// the player's start square:
retArray[0][2] = DataConverter.encodeCoords(myPlayerSquare);
// the goal (crown) square:
retArray[0][3] = DataConverter.encodeCoords(myGoalSquare);
//encode the keys:
int[][] keyCoords = getKeyCoords();
for (int i = 0; i < keyCoords.length; i++) {
retArray[0][i + 4] = DataConverter.encodeCoords(keyCoords[i]);
}
//encode the doors:
int[][] doorCoords = getDoorCoords();
for (int i = 0; i < doorCoords.length; i++) {
retArray[0][i + 8] = DataConverter.encodeCoords(doorCoords[i]);
}
//encode the maze:
try {
retArray[1] = encodeDungeon(mySquares);
} catch (Exception e) {
e.printStackTrace();
}
return (retArray);
}
/**
* Takes a dungeon given in terms of an array of 1s and 0s and turns it into
* an array of bytes. WARNING: the array MUST BE 16 X 16.
*/
static byte[] encodeDungeon(int[][] dungeonMap) throws Exception {
if ((dungeonMap.length != 16) || (dungeonMap[0].length != 16)) {
throw (new Exception(
"EncodingUtils.encodeDungeon-->must be 16x16!!!"));
}
byte[] retArray = new byte[32];
for (int i = 0; i < 16; i++) {
retArray[2 * i] = DataConverter.encode8(dungeonMap[i], 0);
retArray[2 * i + 1] = DataConverter.encode8(dungeonMap[i], 8);
}
return (retArray);
}
//--------------------------------------------------------
// main prints the bytes to standard out.
// (note that this class is not intended to be run as a MIDlet)
/**
* Prints the byte version of the board to standard out.
*/
public static void main(String[] args) {
try {
EncodingUtils map = new EncodingUtils();
byte[][] data = map.encodeDungeon();
System.out.println("EncodingUtils.main-->dungeon encoded");
System.out.print("{\n " + data[0][0]);
for (int i = 1; i < data[0].length; i++) {
System.out.print(", " + data[0][i]);
}
for (int i = 1; i < data[1].length; i++) {
System.out.print(", " + data[1][i]);
}
System.out.println("\n};");
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* This class handles the graphics objects.
*
* @author Carol Hamer
*/
class DungeonManager extends LayerManager {
//---------------------------------------------------------
// dimension fields
// (constant after initialization)
/**
* The x-coordinate of the place on the game canvas where the LayerManager
* window should appear, in terms of the coordiantes of the game canvas.
*/
static int CANVAS_X;
/**
* The y-coordinate of the place on the game canvas where the LayerManager
* window should appear, in terms of the coordiantes of the game canvas.
*/
static int CANVAS_Y;
/**
* The width of the display window.
*/
static int DISP_WIDTH;
/**
* The height of this object's visible region.
*/
static int DISP_HEIGHT;
/**
* the (right or left) distance the player goes in a single keystroke.
*/
static final int MOVE_LENGTH = 8;
/**
* The width of the square tiles that this game is divided into. This is the
* width of the stone walls as well as the princess and the ghost.
*/
static final int SQUARE_WIDTH = 24;
/**
* The jump index that indicates that no jump is currently in progress..
*/
static final int NO_JUMP = -6;
/**
* The maximum speed for the player's fall..
*/
static final int MAX_FREE_FALL = 3;
//---------------------------------------------------------
// game object fields
/**
* the handle back to the canvas.
*/
private DungeonCanvas myCanvas;
/**
* the background dungeon.
*/
private TiledLayer myBackground;
/**
* the player.
*/
private Sprite myPrincess;
/**
* the goal.
*/
private Sprite myCrown;
/**
* the doors.
*/
private DoorKey[] myDoors;
/**
* the keys.
*/
private DoorKey[] myKeys;
/**
* the key currently held by the player.
*/
private DoorKey myHeldKey;
/**
* The leftmost x-coordinate that should be visible on the screen in terms
* of this objects internal coordinates.
*/
private int myViewWindowX;
/**
* The top y-coordinate that should be visible on the screen in terms of
* this objects internal coordinates.
*/
private int myViewWindowY;
/**
* Where the princess is in the jump sequence.
*/
private int myIsJumping = NO_JUMP;
/**
* Whether or not the screen needs to be repainted.
*/
private boolean myModifiedSinceLastPaint = true;
/**
* Which board we're playing on.
*/
private int myCurrentBoardNum = 0;
//-----------------------------------------------------
// gets/sets
/**
* Tell the layer manager that it needs to repaint.
*/
public void setNeedsRepaint() {
myModifiedSinceLastPaint = true;
}
//-----------------------------------------------------
// initialization
// set up or save game data.
/**
* Constructor merely sets the data.
*
* @param x
* The x-coordinate of the place on the game canvas where the
* LayerManager window should appear, in terms of the coordiantes
* of the game canvas.
* @param y
* The y-coordinate of the place on the game canvas where the
* LayerManager window should appear, in terms of the coordiantes
* of the game canvas.
* @param width
* the width of the region that is to be occupied by the
* LayoutManager.
* @param height
* the height of the region that is to be occupied by the
* LayoutManager.
* @param canvas
* the DungeonCanvas that this LayerManager should appear on.
*/
public DungeonManager(int x, int y, int width, int height,
DungeonCanvas canvas) throws Exception {
myCanvas = canvas;
CANVAS_X = x;
CANVAS_Y = y;
DISP_WIDTH = width;
DISP_HEIGHT = height;
// create a decoder object that creates the dungeon and
// its associated Sprites from data.
BoardDecoder decoder = new BoardDecoder(myCurrentBoardNum);
// get the background TiledLayer
myBackground = decoder.getLayer();
// get the coordinates of the square that the princess
// starts on.
int[] playerCoords = decoder.getPlayerSquare();
// create the player sprite
myPrincess = new Sprite(Image.createImage("/images/princess.png"),
SQUARE_WIDTH, SQUARE_WIDTH);
myPrincess.setFrame(1);
// we define the reference pixel to be in the middle
// of the princess image so that when the princess turns
// from right to left (and vice versa) she does not
// appear to move to a different location.
myPrincess.defineReferencePixel(SQUARE_WIDTH / 2, 0);
// the dungeon is a 16x16 grid, so the array playerCoords
// gives the player's location in terms of the grid, and
// then we multiply those coordinates by the SQUARE_WIDTH
// to get the precise pixel where the player should be
// placed (in terms of the LayerManager's coordinate system)
myPrincess.setPosition(SQUARE_WIDTH * playerCoords[0], SQUARE_WIDTH
* playerCoords[1]);
// we append all of the Layers (TiledLayer and Sprite)
// so that this LayerManager will paint them when
// flushGraphics is called.
append(myPrincess);
// get the coordinates of the square where the crown
// should be placed.
int[] goalCoords = decoder.getGoalSquare();
myCrown = new Sprite(Image.createImage("/images/crown.png"));
myCrown.setPosition(
(SQUARE_WIDTH * goalCoords[0]) + (SQUARE_WIDTH / 4),
(SQUARE_WIDTH * goalCoords[1]) + (SQUARE_WIDTH / 2));
append(myCrown);
// The decoder creates the door and key sprites and places
// them in the correct locations in terms of the LayerManager's
// coordinate system.
myDoors = decoder.createDoors();
myKeys = decoder.createKeys();
for (int i = 0; i < myDoors.length; i++) {
append(myDoors[i]);
}
for (int i = 0; i < myKeys.length; i++) {
append(myKeys[i]);
}
// append the background last so it will be painted first.
append(myBackground);
// this sets the view screen so that the player is
// in the center.
myViewWindowX = SQUARE_WIDTH * playerCoords[0]
- ((DISP_WIDTH - SQUARE_WIDTH) / 2);
myViewWindowY = SQUARE_WIDTH * playerCoords[1]
- ((DISP_HEIGHT - SQUARE_WIDTH) / 2);
// a number of objects are created in order to set up the game,
// but they should be eliminated to free up memory:
decoder = null;
System.gc();
}
/**
* sets all variables back to their initial positions.
*/
void reset() throws Exception {
// first get rid of the old board:
for (int i = 0; i < myDoors.length; i++) {
remove(myDoors[i]);
}
myHeldKey = null;
for (int i = 0; i < myKeys.length; i++) {
remove(myKeys[i]);
}
remove(myBackground);
// now create the new board:
myCurrentBoardNum++;
// in this version we go back to the beginning if
// all boards have been completed.
if (myCurrentBoardNum == BoardDecoder.getNumBoards()) {
myCurrentBoardNum = 0;
}
// we create a new decoder object to read and interpret
// all of the data for the current board.
BoardDecoder decoder = new BoardDecoder(myCurrentBoardNum);
// get the background TiledLayer
myBackground = decoder.getLayer();
// get the coordinates of the square that the princess
// starts on.
int[] playerCoords = decoder.getPlayerSquare();
// the dungeon is a 16x16 grid, so the array playerCoords
// gives the player's location in terms of the grid, and
// then we multiply those coordinates by the SQUARE_WIDTH
// to get the precise pixel where the player should be
// placed (in terms of the LayerManager's coordinate system)
myPrincess.setPosition(SQUARE_WIDTH * playerCoords[0], SQUARE_WIDTH
* playerCoords[1]);
myPrincess.setFrame(1);
// get the coordinates of the square where the crown
// should be placed.
int[] goalCoords = decoder.getGoalSquare();
myCrown.setPosition(
(SQUARE_WIDTH * goalCoords[0]) + (SQUARE_WIDTH / 4),
(SQUARE_WIDTH * goalCoords[1]) + (SQUARE_WIDTH / 2));
// The decoder creates the door and key sprites and places
// them in the correct locations in terms of the LayerManager's
// coordinate system.
myDoors = decoder.createDoors();
myKeys = decoder.createKeys();
for (int i = 0; i < myDoors.length; i++) {
append(myDoors[i]);
}
for (int i = 0; i < myKeys.length; i++) {
append(myKeys[i]);
}
// append the background last so it will be painted first.
append(myBackground);
// this sets the view screen so that the player is
// in the center.
myViewWindowX = SQUARE_WIDTH * playerCoords[0]
- ((DISP_WIDTH - SQUARE_WIDTH) / 2);
myViewWindowY = SQUARE_WIDTH * playerCoords[1]
- ((DISP_HEIGHT - SQUARE_WIDTH) / 2);
// a number of objects are created in order to set up the game,
// but they should be eliminated to free up memory:
decoder = null;
System.gc();
}
/**
* sets all variables back to the position in the saved game.
*
* @return the time on the clock of the saved game.
*/
int revertToSaved() throws Exception {
int retVal = 0;
// first get rid of the old board:
for (int i = 0; i < myDoors.length; i++) {
remove(myDoors[i]);
}
myHeldKey = null;
for (int i = 0; i < myKeys.length; i++) {
remove(myKeys[i]);
}
remove(myBackground);
// now get the info of the saved game
// only one game is saved at a time, and the GameInfo object
// will read the saved game's data from memory.
GameInfo info = new GameInfo();
if (info.getIsEmpty()) {
// if no game has been saved, we start from the beginning.
myCurrentBoardNum = 0;
reset();
} else {
// get the time on the clock of the saved game.
retVal = info.getTime();
// get the number of the board the saved game was on.
myCurrentBoardNum = info.getBoardNum();
// create the BoradDecoder that gives the data for the
// desired board.
BoardDecoder decoder = new BoardDecoder(myCurrentBoardNum);
// get the background TiledLayer
myBackground = decoder.getLayer();
// get the coordinates of the square that the princess
// was on in the saved game.
int[] playerCoords = info.getPlayerSquare();
myPrincess.setPosition(SQUARE_WIDTH * playerCoords[0], SQUARE_WIDTH
* playerCoords[1]);
myPrincess.setFrame(1);
// get the coordinates of the square where the crown
// should be placed (this is given by the BoardDecoder
// and not from the data of the saved game because the
// crown does not move during the game.
int[] goalCoords = decoder.getGoalSquare();
myCrown.setPosition((SQUARE_WIDTH * goalCoords[0])
+ (SQUARE_WIDTH / 4), (SQUARE_WIDTH * goalCoords[1])
+ (SQUARE_WIDTH / 2));
// The decoder creates the door and key sprites and places
// them in the correct locations in terms of the LayerManager's
// coordinate system.
myDoors = decoder.createDoors();
myKeys = decoder.createKeys();
// get an array of ints that lists whether each door is
// open or closed in the saved game
int[] openDoors = info.getDoorsOpen();
for (int i = 0; i < myDoors.length; i++) {
append(myDoors[i]);
if (openDoors[i] == 0) {
// if the door was open, make it invisible
myDoors[i].setVisible(false);
}
}
// the keys can be moved by the player, so we get their
// coordinates from the GameInfo saved data.
int[][] keyCoords = info.getKeyCoords();
for (int i = 0; i < myKeys.length; i++) {
append(myKeys[i]);
myKeys[i].setPosition(SQUARE_WIDTH * keyCoords[i][0],
SQUARE_WIDTH * keyCoords[i][1]);
}
// if the player was holding a key in the saved game,
// we have the player hold that key and set it to invisible.
int heldKey = info.getHeldKey();
if (heldKey != -1) {
myHeldKey = myKeys[heldKey];
myHeldKey.setVisible(false);
}
// append the background last so it will be painted first.
append(myBackground);
// this sets the view screen so that the player is
// in the center.
myViewWindowX = SQUARE_WIDTH * playerCoords[0]
- ((DISP_WIDTH - SQUARE_WIDTH) / 2);
myViewWindowY = SQUARE_WIDTH * playerCoords[1]
- ((DISP_HEIGHT - SQUARE_WIDTH) / 2);
// a number of objects are created in order to set up the game,
// but they should be eliminated to free up memory:
decoder = null;
System.gc();
}
return (retVal);
}
/**
* save the current game in progress.
*/
void saveGame(int gameTicks) throws Exception {
int[] playerSquare = new int[2];
// the coordinates of the player are given in terms of
// the 16 x 16 dungeon grid. We divide the player's
// pixel coordinates to ge the right grid square.
// If the player was not precisely alligned with a
// grid square when the game was saved, the difference
// will be shaved off.
playerSquare[0] = myPrincess.getX() / SQUARE_WIDTH;
playerSquare[1] = myPrincess.getY() / SQUARE_WIDTH;
// save the coordinates of the current locations of
// the keys, and if a key is currently held by the
// player, we save the info of which one it was.
int[][] keyCoords = new int[4][];
int heldKey = -1;
for (int i = 0; i < myKeys.length; i++) {
keyCoords[i] = new int[2];
keyCoords[i][0] = myKeys[i].getX() / SQUARE_WIDTH;
keyCoords[i][1] = myKeys[i].getY() / SQUARE_WIDTH;
if ((myHeldKey != null) && (myKeys[i] == myHeldKey)) {
heldKey = i;
}
}
// save the information of which doors were open.
int[] doorsOpen = new int[8];
for (int i = 0; i < myDoors.length; i++) {
if (myDoors[i].isVisible()) {
doorsOpen[i] = 1;
}
}
// take all of the information we've gathered and
// create a GameInfo object that will save the info
// in the device's memory.
GameInfo info = new GameInfo(myCurrentBoardNum, gameTicks,
playerSquare, keyCoords, doorsOpen, heldKey);
}
//-------------------------------------------------------
// graphics methods
/**
* paint the game graphic on the screen.
*/
public void paint(Graphics g) throws Exception {
// only repaint if something has changed:
if (myModifiedSinceLastPaint) {
g.setColor(DungeonCanvas.WHITE);
// paint the background white to cover old game objects
// that have changed position since last paint.
// here coordinates are given
// with respect to the graphics (canvas) origin:
g.fillRect(0, 0, DISP_WIDTH, DISP_HEIGHT);
// here coordinates are given
// with respect to the LayerManager origin:
setViewWindow(myViewWindowX, myViewWindowY, DISP_WIDTH, DISP_HEIGHT);
// call the paint funstion of the superclass LayerManager
// to paint all of the Layers
paint(g, CANVAS_X, CANVAS_Y);
// don't paint again until something changes:
myModifiedSinceLastPaint = false;
}
}
//-------------------------------------------------------
// game movements
/**
* respond to keystrokes by deciding where to move and then moving the
* pieces and the view window correspondingly.
*/
void requestMove(int horizontal, int vertical) {
if (horizontal != 0) {
// see how far the princess can move in the desired
// horizontal direction (if not blocked by a wall
// or closed door)
horizontal = requestHorizontal(horizontal);
}
// vertical < 0 indicates that the user has
// pressed the UP button and would like to jump.
// therefore, if we're not currently jumping,
// we begin the jump.
if ((myIsJumping == NO_JUMP) && (vertical < 0)) {
myIsJumping++;
} else if (myIsJumping == NO_JUMP) {
// if we're not jumping at all, we need to check
// if the princess should be falling:
// we (temporarily) move the princess down and see if that
// causes a collision with the floor:
myPrincess.move(0, MOVE_LENGTH);
// if the princess can move down without colliding
// with the floor, then we set the princess to
// be falling. The variable myIsJumping starts
// negative while the princess is jumping up and
// is zero or positive when the princess is coming
// back down. We therefore set myIsJumping to
// zero to indicate that the princess should start
// falling.
if (!checkCollision()) {
myIsJumping = 0;
}
// we move the princess Sprite back to the correct
// position she was at before we (temporarily) moved
// her down to see if she would fall.
myPrincess.move(0, -MOVE_LENGTH);
}
// if the princess is currently jumping or falling,
// we calculate the vertical distance she should move
// (taking into account the horizontal distance that
// she is also moving).
if (myIsJumping != NO_JUMP) {
vertical = jumpOrFall(horizontal);
}
// now that we've calculated how far the princess
// should move, we move her. (this is a call to
// another internal method of this method
// suite, it is not a built-in LayerManager method):
move(horizontal, vertical);
}
/**
* Internal to requestMove. Calculates what the real horizontal distance
* moved should be after taking obstacles into account.
*
* @return the horizontal distance that the player can move.
*/
private int requestHorizontal(int horizontal) {
// we (temporarily) move her to the right or left
// and see if she hits a wall or a door:
myPrincess.move(horizontal * MOVE_LENGTH, 0);
if (checkCollision()) {
// if she hits something, then she's not allowed
// to go in that direction, so we set the horizontal
// move distance to zero and then move the princess
// back to where she was.
myPrincess.move(-horizontal * MOVE_LENGTH, 0);
horizontal = 0;
} else {
// if she doesn't hit anything then the move request
// succeeds, but we still move her back to the
// earlier position because this was just the checking
// phase.
myPrincess.move(-horizontal * MOVE_LENGTH, 0);
horizontal *= MOVE_LENGTH;
}
return (horizontal);
}
/**
* Internal to requestMove. Calculates the vertical change in the player's
* position if jumping or falling. this method should only be called if the
* player is currently jumping or falling.
*
* @return the vertical distance that the player should move this turn.
* (negative moves up, positive moves down)
*/
private int jumpOrFall(int horizontal) {
// by default we do not move vertically
int vertical = 0;
// The speed of rise or descent is computed using
// the int myIsJumping. Since we are in a jump or
// fall, we advance the jump by one (which simulates
// the downward pull of gravity by slowing the rise
// or accellerating the fall) unless the player is
// already falling at maximum speed. (a maximum
// free fall speed is necessary because otherwise
// it is possible for the player to fall right through
// the bottom of the maze...)
if (myIsJumping <= MAX_FREE_FALL) {
myIsJumping++;
}
if (myIsJumping < 0) {
// if myIsJumping is negative, that means that
// the princess is rising. We calculate the
// number of pixels to go up by raising 2 to
// the power myIsJumping (absolute value).
// note that we make the result negative because
// the up and down coordinates in Java are the
// reverse of the vertical coordinates we learned
// in math class: as you go up, the coordinate
// values go down, and as you go down the screen,
// the coordinate numbers go up.
vertical = -(2 << (-myIsJumping));
} else {
// if myIsJumping is positive, the princess is falling.
// we calculate the distance to fall by raising two
// to the power of the absolute value of myIsJumping.
vertical = (2 << (myIsJumping));
}
// now we temporarily move the princess the desired
// vertical distance (with the corresponding horizontal
// distance also thrown in), and see if she hits anything:
myPrincess.move(horizontal, vertical);
if (checkCollision()) {
// here we're in the case where she did hit something.
// we move her back into position and then see what
// to do about it.
myPrincess.move(-horizontal, -vertical);
if (vertical > 0) {
// in this case the player is falling.
// so we need to determine precisely how
// far she can fall before she hit the bottom
vertical = 0;
// we temporarily move her the desired horizontal
// distance while calculating the corresponding
// vertical distance.
myPrincess.move(horizontal, 0);
while (!checkCollision()) {
vertical++;
myPrincess.move(0, 1);
}
// now that we've calculated how far she can fall,
// we move her back to her earlier position
myPrincess.move(-horizontal, -vertical);
// we subtract 1 pixel from the distance calculated
// because once she has actually collided with the
// floor, she's gone one pixel too far...
vertical--;
// now that she's hit the floor, she's not jumping
// anymore.
myIsJumping = NO_JUMP;
} else {
// in this case we're going up, so she
// must have hit her head.
// This next if is checking for a special
// case where there's room to jump up exactly
// one square. In that case we increase the
// value of myIsJumping in order to make the
// princess not rise as high. The details
// of the calculation in this case were found
// through trial and error:
if (myIsJumping == NO_JUMP + 2) {
myIsJumping++;
vertical = -(2 << (-myIsJumping));
// now we see if the special shortened jump
// still makes her hit her head:
// (as usual, temporarily move her to test
// for collisions)
myPrincess.move(horizontal, vertical);
if (checkCollision()) {
// if she still hits her head even
// with this special shortened jump,
// then she was not meant to jump...
myPrincess.move(-horizontal, -vertical);
vertical = 0;
myIsJumping = NO_JUMP;
} else {
// now that we've chhecked for collisions,
// we move the player back to her earlier
// position:
myPrincess.move(-horizontal, -vertical);
}
} else {
// if she hit her head, then she should not
// jump up.
vertical = 0;
myIsJumping = NO_JUMP;
}
}
} else {
// since she didn't hit anything when we moved
// her, then all we have to do is move her back.
myPrincess.move(-horizontal, -vertical);
}
return (vertical);
}
/**
* Internal to requestMove. Once the moves have been determined, actually
* perform the move.
*/
private void move(int horizontal, int vertical) {
// repaint only if we actually change something:
if ((horizontal != 0) || (vertical != 0)) {
myModifiedSinceLastPaint = true;
}
// if the princess is moving left or right, we set
// her image to be facing the right direction:
if (horizontal > 0) {
myPrincess.setTransform(Sprite.TRANS_NONE);
} else if (horizontal < 0) {
myPrincess.setTransform(Sprite.TRANS_MIRROR);
}
// if she's jumping or falling, we set the image to
// the frame where the skirt is inflated:
if (vertical != 0) {
myPrincess.setFrame(0);
// if she's just running, we alternate between the
// two frames:
} else if (horizontal != 0) {
if (myPrincess.getFrame() == 1) {
myPrincess.setFrame(0);
} else {
myPrincess.setFrame(1);
}
}
// move the position of the view window so that
// the player stays in the center:
myViewWindowX += horizontal;
myViewWindowY += vertical;
// after all that work, we finally move the
// princess for real!!!
myPrincess.move(horizontal, vertical);
}
//-------------------------------------------------------
// sprite interactions
/**
* Drops the currently held key and picks up another.
*/
void putDownPickUp() {
// we do not want to allow the player to put
// down the key in the air, so we verify that
// we're not jumping or falling first:
if ((myIsJumping == NO_JUMP) && (myPrincess.getY() % SQUARE_WIDTH == 0)) {
// since we're picking something up or putting
// something down, the display changes and needs
// to be repainted:
setNeedsRepaint();
// if the thing we're picking up is the crown,
// we're done, the player has won:
if (myPrincess.collidesWith(myCrown, true)) {
myCanvas.setGameOver();
return;
}
// keep track of the key we're putting down in
// order to place it correctly:
DoorKey oldHeld = myHeldKey;
myHeldKey = null;
// if the princess is on top of another key,
// that one becomes the held key and is hence
// made invisible:
for (int i = 0; i < myKeys.length; i++) {
// we check myHeldKey for null because we don't
// want to accidentally pick up two keys.
if ((myPrincess.collidesWith(myKeys[i], true))
&& (myHeldKey == null)) {
myHeldKey = myKeys[i];
myHeldKey.setVisible(false);
}
}
if (oldHeld != null) {
// place the key we're putting down in the Princess's
// current position and make it visible:
oldHeld.setPosition(myPrincess.getX(), myPrincess.getY());
oldHeld.setVisible(true);
}
}
}
/**
* Checks of the player hits a stone wall or a door.
*/
boolean checkCollision() {
boolean retVal = false;
// the "true" arg meand to check for a pixel-level
// collision (so merely an overlap in image
// squares does not register as a collision)
if (myPrincess.collidesWith(myBackground, true)) {
retVal = true;
} else {
// Note: it is not necessary to synchronize
// this block because the thread that calls this
// method is the same as the one that puts down the
// keys, so there's no danger of the key being put down
// between the moment we check for the key and
// the moment we open the door:
for (int i = 0; i < myDoors.length; i++) {
// if she's holding the right key, then open the door
// otherwise bounce off
if (myPrincess.collidesWith(myDoors[i], true)) {
if ((myHeldKey != null)
&& (myDoors[i].getColor() == myHeldKey.getColor())) {
setNeedsRepaint();
myDoors[i].setVisible(false);
} else {
// if she's not holding the right key, then
// she has collided with the door just the same
// as if she had collided with a wall:
retVal = true;
}
}
}
}
return (retVal);
}
}
/**
* This class is the display of the game.
*
* @author Carol Hamer
*/
class DungeonCanvas extends GameCanvas {
//---------------------------------------------------------
// dimension fields
// (constant after initialization)
/**
* the height of the black region below the play area.
*/
static int TIMER_HEIGHT = 32;
/**
* the top corner x coordinate according to this object's coordinate
* system:.
*/
static final int CORNER_X = 0;
/**
* the top corner y coordinate according to this object's coordinate
* system:.
*/
static final int CORNER_Y = 0;
/**
* the width of the portion of the screen that this canvas can use.
*/
static int DISP_WIDTH;
/**
* the height of the portion of the screen that this canvas can use.
*/
static int DISP_HEIGHT;
/**
* the height of the font used for this game.
*/
static int FONT_HEIGHT;
/**
* the font used for this game.
*/
static Font FONT;
/**
* color constant
*/
public static final int BLACK = 0;
/**
* color constant
*/
public static final int WHITE = 0xffffff;
//---------------------------------------------------------
// game object fields
/**
* a handle to the display.
*/
private Display myDisplay;
/**
* a handle to the MIDlet object (to keep track of buttons).
*/
private Dungeon myDungeon;
/**
* the LayerManager that handles the game graphics.
*/
private DungeonManager myManager;
/**
* whether or not the game has ended.
*/
private static boolean myGameOver;
/**
* The number of ticks on the clock the last time the time display was
* updated. This is saved to determine if the time string needs to be
* recomputed.
*/
private int myOldGameTicks = 0;
/**
* the number of game ticks that have passed since the beginning of the
* game.
*/
private int myGameTicks = myOldGameTicks;
/**
* we save the time string to avoid recreating it unnecessarily.
*/
private static String myInitialString = "0:00";
/**
* we save the time string to avoid recreating it unnecessarily.
*/
private String myTimeString = myInitialString;
//-----------------------------------------------------
// gets/sets
/**
* This is called when the game ends.
*/
void setGameOver() {
myGameOver = true;
myDungeon.pauseApp();
}
/**
* Find out if the game has ended.
*/
static boolean getGameOver() {
return (myGameOver);
}
/**
* Tell the layer manager that it needs to repaint.
*/
public void setNeedsRepaint() {
myManager.setNeedsRepaint();
}
//-----------------------------------------------------
// initialization and game state changes
/**
* Constructor sets the data, performs dimension calculations, and creates
* the graphical objects.
*/
public DungeonCanvas(Dungeon midlet) throws Exception {
super(false);
myDisplay = Display.getDisplay(midlet);
myDungeon = midlet;
// calculate the dimensions
DISP_WIDTH = getWidth();
DISP_HEIGHT = getHeight();
if ((!myDisplay.isColor()) || (myDisplay.numColors() < 256)) {
throw (new Exception("game requires full-color screen"));
}
if ((DISP_WIDTH < 150) || (DISP_HEIGHT < 170)) {
throw (new Exception("Screen too small"));
}
if ((DISP_WIDTH > 250) || (DISP_HEIGHT > 250)) {
throw (new Exception("Screen too large"));
}
// since the time is painted in white on black,
// it shows up better if the font is bold:
FONT = Font
.getFont(Font.FACE_SYSTEM, Font.STYLE_BOLD, Font.SIZE_MEDIUM);
// calculate the height of the black region that the
// timer is painted on:
FONT_HEIGHT = FONT.getHeight();
TIMER_HEIGHT = FONT_HEIGHT + 8;
// create the LayerManager (where all of the interesting
// graphics go!) and give it the dimensions of the
// region it is supposed to paint:
if (myManager == null) {
myManager = new DungeonManager(CORNER_X, CORNER_Y, DISP_WIDTH,
DISP_HEIGHT - TIMER_HEIGHT, this);
}
}
/**
* This is called as soon as the application begins.
*/
void start() {
myGameOver = false;
myDisplay.setCurrent(this);
setNeedsRepaint();
}
/**
* sets all variables back to their initial positions.
*/
void reset() throws Exception {
// most of the variables that need to be reset
// are held by the LayerManager:
myManager.reset();
myGameOver = false;
setNeedsRepaint();
}
/**
* sets all variables back to the positions from a previously saved game.
*/
void revertToSaved() throws Exception {
// most of the variables that need to be reset
// are held by the LayerManager, so we
// prompt the LayerManager to get the
// saved data:
myGameTicks = myManager.revertToSaved();
myGameOver = false;
myOldGameTicks = myGameTicks;
myTimeString = formatTime();
setNeedsRepaint();
}
/**
* save the current game in progress.
*/
void saveGame() throws Exception {
myManager.saveGame(myGameTicks);
}
/**
* clears the key states.
*/
void flushKeys() {
getKeyStates();
}
/**
* If the game is hidden by another app (or a menu) ignore it since not much
* happens in this game when the user is not actively interacting with it.
* (we could pause the timer, but it's not important enough to bother with
* when the user is just pulling up a menu for a few seconds)
*/
protected void hideNotify() {
}
/**
* When it comes back into view, just make sure the manager knows that it
* needs to repaint.
*/
protected void showNotify() {
setNeedsRepaint();
}
//-------------------------------------------------------
// graphics methods
/**
* paint the game graphics on the screen.
*/
public void paint(Graphics g) {
// color the bottom segment of the screen black
g.setColor(BLACK);
g.fillRect(CORNER_X, CORNER_Y + DISP_HEIGHT - TIMER_HEIGHT, DISP_WIDTH,
TIMER_HEIGHT);
// paint the LayerManager (which paints
// all of the interesting graphics):
try {
myManager.paint(g);
} catch (Exception e) {
myDungeon.errorMsg(e);
}
// draw the time
g.setColor(WHITE);
g.setFont(FONT);
g.drawString("Time: " + formatTime(), DISP_WIDTH / 2, CORNER_Y
+ DISP_HEIGHT - 4, g.BOTTOM | g.HCENTER);
// write "Dungeon Completed" when the user finishes a board:
if (myGameOver) {
myDungeon.setNewCommand();
// clear the top region:
g.setColor(WHITE);
g.fillRect(CORNER_X, CORNER_Y, DISP_WIDTH, FONT_HEIGHT * 2 + 1);
int goWidth = FONT.stringWidth("Dungeon Completed");
g.setColor(BLACK);
g.setFont(FONT);
g.drawString("Dungeon Completed", (DISP_WIDTH - goWidth) / 2,
CORNER_Y + FONT_HEIGHT, g.TOP | g.LEFT);
}
}
/**
* a simple utility to make the number of ticks look like a time...
*/
public String formatTime() {
if ((myGameTicks / 16) != myOldGameTicks) {
myTimeString = "";
myOldGameTicks = (myGameTicks / 16) + 1;
int smallPart = myOldGameTicks % 60;
int bigPart = myOldGameTicks / 60;
myTimeString += bigPart + ":";
if (smallPart / 10 < 1) {
myTimeString += "0";
}
myTimeString += smallPart;
}
return (myTimeString);
}
//-------------------------------------------------------
// game movements
/**
* update the display.
*/
void updateScreen() {
myGameTicks++;
// paint the display
try {
paint(getGraphics());
flushGraphics(CORNER_X, CORNER_Y, DISP_WIDTH, DISP_HEIGHT);
} catch (Exception e) {
myDungeon.errorMsg(e);
}
}
/**
* Respond to keystrokes.
*/
public void checkKeys() {
if (!myGameOver) {
int vertical = 0;
int horizontal = 0;
// determine which moves the user would like to make:
int keyState = getKeyStates();
if ((keyState & LEFT_PRESSED) != 0) {
horizontal = -1;
}
if ((keyState & RIGHT_PRESSED) != 0) {
horizontal = 1;
}
if ((keyState & UP_PRESSED) != 0) {
vertical = -1;
}
if ((keyState & DOWN_PRESSED) != 0) {
// if the user presses the down key,
// we put down or pick up a key object
// or pick up the crown:
myManager.putDownPickUp();
}
// tell the manager to move the player
// accordingly if possible:
myManager.requestMove(horizontal, vertical);
}
}
}
]]>