(Re)Implementing Tetris

Try: http://tetris.muehe.org

Update There's a global high score. Enjoy beating it or - alternatively - hacking it :-)

Screenshot: Tetris in action

CoffeeScript and HTML version, should fulfill the requirements to the best of my knowledge (and I have never really played Tetris).

$ make stats
4095

Github https://github.com/henrik-muehe/tetris

Features

  • Exponential scoring
  • Next piece indicator
  • Fair randomness
  • Rotation, move and drop down
  • Game over indication
  • Highscore with server backend that should not be that easily fakeable.

Pascal

Developed in FreePascal 2.6.2, should compile with Turbo Pascal 6.0 too. Only the Crt unit is used, no external resources.

program tetris;

  uses
    Crt;

  const
    width = 10;                                  { playing field width }
    height = 20;                                 { playing field height }

  const
    piece: array [1..7, 1..3, 0..1] of ShortInt = ( { piece shapes : piece, element, coordinate }
      (( 1, 0), ( 1, 1), ( 0, 1)),               { O }
      ((-1, 0), ( 1, 0), ( 2, 0)),               { I }
      (( 0, 1), ( 1, 0), ( 2, 0)),               { L }
      (( 0, 1), (-1, 0), (-2, 0)),               { J }
      ((-1, 0), ( 1, 0), ( 0, 1)),               { T }
      (( 1, 0), ( 0, 1), (-1, 1)),               { S }
      ((-1, 0), ( 0, 1), ( 1, 1))                { Z }
    );
    color: array [1..7, 0..1] of Byte = (        { piece colors : foreground, background }
      (Yellow,       Brown),                     { O }
      (LightCyan,    Cyan),                      { I }
      (LightBlue,    Blue),                      { L }
      (White,        LightGray),                 { J }
      (LightMagenta, Magenta),                   { T }
      (LightGreen,   Green),                     { S }
      (LightRed,     Red)                        { Z }
    );

  var
    area: array [1..width + 2, 1..height + 1] of Byte; { playing field }
    coord: array [0..3, 0..1] of Byte;           { precalculated element coordinates }
    played,                                      { played pieces count }
    removed,                                     { completed lines count }
    level,                                       { current level }
    score: LongInt;                              { accumulated score }
    time,                                        { current level delay }
    wait,                                        { current piece delay }
    made,                                        { completed lines in current level }
    multi,                                       { multiline count }
    screen,                                      { original screen size }
    i, j, j2: Word;                              { counters }
    current,                                     { current piece }
    next,                                        { next piece }
    x,                                           { horizontal coordinate }
    y,                                           { vertical coordinate }
    position,                                    { rotation position }
    k: Byte;                                     { pressed key }
    ok: Boolean;                                 { aggregated condition }

{ precalculates the give piece's elements coordinates }
  procedure coordinate(current, x, y, position: Byte);
  begin
    coord[0, 0] := x;
    coord[0, 1] := y;
    for i := 1 to 3 do begin
      coord[i, 0] := x + piece[current, i, position mod 2] * (Ord(position in [0, 1]) * 2 - 1);
      coord[i, 1] := y + piece[current, i, 1 - position mod 2] * (Ord(position in [0, 3]) * 2 - 1);
    end;
  end;

{ draws a piece }
  procedure draw(current, x, y, position: Byte; visible: Boolean);
  begin
    coordinate(current, x, y, position);

    for i := 0 to 3 do begin
      GotoXY(coord[i, 0] * 2 + 1, coord[i, 1]);
      if visible then begin
        TextColor(color[current, 0]);
        TextBackground(color[current, 1]);
        Write('[]');
      end else begin
        TextBackground(Black);
        Write('  ');
      end;
    end;
  end;

{ check whether a piece can be placed in given position }
  function check(x2, y2, position2: Byte): Boolean;
  begin
    coordinate(current, x2, y2, position2);

    ok := True;
    for i := 0 to 3 do if area[coord[i, 0], coord[i, 1]] <> 0 then ok := False;

    if ok then begin
      x := x2;
      y := y2;
      position := position2;
    end;

    check := ok;
  end;

begin

  Randomize;
  TextColor(LightGray);
  TextBackground(Black);
  ClrScr;
  screen := WindMax;

  for i := 0 to width + 1 do for j := 1 to height + 1 do area[i, j] := 9 * Ord(not ((i in [1..width]) and (j in [1..height])));

  Window(1, 1, width * 2 + 4, height + 2);
  for i := 1 to (width + 2) * (height + 1) do Write('##');
  Window(3, 1, width * 2 + 2, height);
  ClrScr;
  Window(1, 1, Lo(screen), Hi(screen));

  Window(width * 2 + 7, 1, width * 2 + 25, 10);
  Writeln('Next');
  Writeln;
  Writeln;
  Writeln('Piece');
  Writeln('Line');
  Writeln('Level');
  Writeln('Score');
  Window(1, 1, Lo(screen), Hi(screen));

  played := 0;
  removed := 0;
  level := 1;
  score := 0;

  current := 9;
  next := 9;
  made := 0;

  repeat

    if current = 9 then begin
      if next = 9 then next := Random(7) + 1 else draw(next, width + 9, 1, 0, False);

      current := next;
      next := Random(7) + 1;
      x := width div 2;
      y := 1;
      position := 0;
      time := 1100 - level * 100;
      wait := time;

      Inc(played);
      Inc(score);
      if made = 25 then begin
        Inc(level);
        made := 0;
      end;

      draw(next, width + 9, 1, 0, True);

      Window(width * 2 + 15, 4, width * 2 + 25, 10);
      TextColor(LightGray);
      TextBackground(Black);
      Writeln(played:5);
      Writeln(removed:5);
      Writeln(level:5);
      Writeln(score:5);
      Window(1, 1, Lo(screen), Hi(screen));

      if not check(x, y, position) then begin
        GotoXY(width * 2 + 7, 10);
        Write('Game Over');
        Break;
      end;
    end;

    draw(current, x, y, position, True);
    GotoXY(1, 1);
    repeat Delay(1);
      Dec(wait);
    until KeyPressed or (wait = 0);
    draw(current, x, y, position, False);

    if KeyPressed then begin
      k := Ord(ReadKey);
      case k of
        75, 77: check(x + Ord(k = 77) * 2 - 1, y, position);
        72, 80: check(x, y, (position + Ord(k = 80) * 2 + 1) mod 4);
        32: begin
          time := 1;
          Inc(score);
        end;
      end;
    end;

    if wait = 0 then begin
      if not check(x, y + 1, position) then begin
        draw(current, x, y, position, True);
        for i := 0 to 3 do area[coord[i, 0], coord[i, 1]] := current;

        multi := 0;
        for j := 1 to height do begin
          ok := True;
          for i := 1 to width do if area[i, j] = 0 then ok := False;

          if ok then begin
            for j2 := j downto 2 do for i := 1 to width do area[i, j2] := area[i, j2 - 1];
            for i := 1 to width do area[i, 1] := 0;

            Inc(score, 10 + multi * 2);
            Inc(removed);
            Inc(multi);

            Window(3, 1, width * 2 + 2, height);
            TextBackground(Black);
            GotoXY(1, j);
            DelLine;
            GotoXY(1, 1);
            InsLine;
            Window(1, 1, Lo(screen), Hi(screen));
          end;

        end;
        if multi <> 0 then Inc(made);

        current := 9;
      end;
      wait := time;
    end;

  until k = 27;

  ReadKey;
  TextColor(LightGray);
  TextBackground(Black);
  ClrScr;

end.

Screenshot

Tetris in Pascal

(On Linux, in XTerm window.)

Control

  • Left – move left
  • Right – move right
  • Up – rotate counterclockwise
  • Down – rotate clockwise
  • Space – drop down
  • Esc – exit

Scoring

  • played piece – 1 point
  • dropped piece – 1 point
  • completed line – 10 point
  • multiple lines – multiplier * 2 point

Level starts at 1 and increases after each 25 line completing. (Multiple lines completed at once count as 1.)

Measurement

bash-4.2$ sed '
s/{[^{}]*}//g                  # remove comments
s/^ *\| *$//g                  # trim leading and trailing spaces
/^$/d                          # remove empty lines
s/ *\([:=<>,;+*-]\+\) */\1/g   # no space around operators
' tetris.pas | wc -c
3697

Java (Swing)

This is an implementation of the first historical Game Boy edition from Nintendo(c) from 1989.

Game Boy Tetris Nintendo

How to play:

Z = rotate left
X = rotate right
Left = move left
Right = move right
Down = move down (slowly)
Up = rotate left (just for easier use)
R = reset game

I avoided to use more than one class (because the golf aspect comes to my mind). But now it's not golfable anymore in any case... However, I zipped and Base64-encoded one Font-File and one Image-File, so I can use it in the one and only class file.

To run it, copy the Java code into your IDE and start. You don't need any additional libraries or resources.

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.ByteArrayInputStream;
import java.util.ArrayList;
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;
import java.util.zip.ZipInputStream;

import javax.imageio.ImageIO;
import javax.swing.JOptionPane;
import javax.xml.bind.DatatypeConverter;

public class JTetris extends javax.swing.JFrame {
    static Image IMAGE;
    static Font FONT;

    static {
        ZipInputStream zipImage = new ZipInputStream(new ByteArrayInputStream(DatatypeConverter.parseBase64Binary(
            "UEsDBBQAAAAIABmiWkRZ0oOouwAAAJYKAAAFAAAAYy5ibXBz8p3GxQAGZUCsAcQ3gFgCiBkZWMDiCkB5GBCA0iJyLAwl+3oYYpJsGK58u8NAKjBGAgyUgVG7QHYxKUGBAjDiBJUUQUhQAMQGA3xsFL3MMBMNRrpdEABhQxQLCiDYmHZBxCF2QdhAu8CyEHLk2cWkBJSH" +
            "xxcoCgyg5hsbAgWhbBgJUg9Wg24XWDGQHJF2QeOCUruQwEi0S0kRe5qHKCY2zQsgkv0ItAsIKC97EQnecGTYRQUwKNsbNAYAUEsBAj8AFAAAAAgAGaJaRFnSg6i7AAAAlgoAAAUAJAAAAAAAAAAgAAAAAAAAAGMuYm1wCgAgAAAAAAABABgAkJCiSyczzwGQkKJLJzPP" +
            "AZCQoksnM88BUEsFBgAAAAABAAEAVwAAAN4AAAAAAA=="
        )));

        ZipInputStream zipFont = new ZipInputStream(new ByteArrayInputStream(DatatypeConverter.parseBase64Binary(
            "UEsDBBQAAAAIAEq5UEN0MGyWoggAAHgrAAAFAAAAYS50dGbklsvvC1EUx78zU+/3OxHiEuLd1jMlxKNR70cQCxumY9oOnU5Np6osdIGEDYmwZGElkYh/gI2FBUIsvFdILNgh8Rxft4d6RyxEYvq7PZ97es73nHNv8mthAOiJFiyotRtS0xMnum4Gej0HsNXx7erbI6+7" +
            "ks8CxqNiuVk48qTbVKB3BIy8XXLtbVv6x0cBkwuzS3SYrffvuL8MYGzJj3av3BfP4P4p8yeUA8cGxqWBSau4n+Lbu6tYET8AEoMBqIrtuzuPz33D/Uyg28VqUItgxtTrvRGAAoW4LK7BsHTnb5HAE9qB6E+PidGYhCTmYjP24AxuxTGYR98UpLEIdtsXP4zvxXfjO/HN" +
            "+Gp8Kg6p9O8//8ucRns93ZK6vqXfvBccXLuv7b/QH2LjVtyyYLUAdIfJaMmz6Gc83w3yd9OuSLS0WmcxRLj1xYJY/Gz9Wcyfr79XJ6aO3MEKTEAPWsDE988Y4yQM4RGAsEEeIWyiGzLCFsZjgXACY1EQ7oJeOCzclZnHhbthHs4Ld8cQPBPugT6GKdwT841+wr0wzFgl" +
            "3BtpwxHugxHGMeG+mGycEx6EicbdNhusYFqwYCQ4LTJmL2GDnBU20dfcK2xhjXlIOIFl5i3hLhhqjRLuiow1S7gbdlu+cHdMsh4L98DwRD/hntiTmCjcC8nEaeHe2Jq4IdwHmS7ThPtiUxdPeBDWd7nYZgPo33VANqg2Q69YitQ6Owo9Z4daZdd3uGp6etqMDfWqG6rV" +
            "dugF9Fa2qQlL+T9XLQ6aE9V6t1gv22EuqEQborDuROoX0b/87JPUJjeseUFFTUumdfhUHT71Y/hUHT71Y/jULyp6NWWrKLS3ub4d7lBBQeU2LFc6oBRU1fJK5IYVO6KoXVZL/fyyUhRV56ZSBUbUtETSCfyv5h5+6fWveh1+6ZVq2DWVr3vlSDW8qKQ6/fQU+UajkdQl" +
            "2MTHAj+s+sWW/dVSDG6kMpnMjGlzsqHLpne5Khv4Pj9TiyJ2mK9/DBQtR0KcdkQyCIupsue4lZpbS+WbqRnJdCr3USLvFdXOuu3s8CpFtcetlpphTW0P2Lzf5CS7Vd7dli0uWbStXIqQRYAqmgjhoYgSIiisg41Iexzs4H4V93WSS56ONKZhBjbQU6UnpG81bB0dSGwF" +
            "20gTsJTs66zFCFhjImk990XmlnVODgGjI6qxHr0Orfoz7T/P+66rTVqjprMrUJw3ifQX6lM76mRRJ31WJ4s66cczetRXjFbaazPfha9VeeLMKPA9x5zltB2FEqlKz3K9Zy+0NomdaCpDsQcfeSzTdxkxei5SfBVEo9bpglM59Po/v281HJfw+k/PVWe/oqcBW0+bp47H" +
            "HiPt82hLpB+dT89vum/oV7IzhZyETPD7s/7wUzk/elKi3CBl9GsGb38Osox05aR36SmzWs2XPIVFiOQMOSVE8Zu+nG9UnK80krQhiowr65twtdfVXeXR5PsMxqRpc5+7yJOKtDtZ09a356GiPXvgsm6JeaHubzsCOXkfTbmT3VrB5Q1mmbMEi0hl3TNM86VxFF2QMOXL" +
            "XVsuNnEF8mtAHquDQG7DxvVYSOFbbbfVQovG0NwOVV/kFKj3g4eVJZ5/3dALAzGUIl8/MMTDAvEBAC9oe9Hu/WJ/kD9s78f3gfdvpKrPs6H/A+1VkJtADAMnWXFAqEIVqjhw6KEfzQvan/Ud/cQmJdnRjoyzBLUCFAxeZ8aOHSfgk3aU+Kp6oFqX7/mn2s5L6KF+JPoC" +
            "8QOVOqdFAqiOpICIqxbYo82LiTEcccIZF7zjgyiD14JJ9MrUfmsUWAlrx3nybJXJ/b6v1/yIene+vjHV+OQrxNUsQ5XCpSYvtZBCXZeWD85FbA8CGE3TXXlkQwTIJkI1cvQrGmlXFAOiWYslTyXZJ1XX5JWTeT8IXbEKNaBKky2OmVbG17et7AMet8D6Vlh1kZq8sgdj" +
            "RckB7b9Tnx3ELVCmouKUtBHriQZczDu8dlk1i5w+SwGrFYp5mvtc03aE9NdGqP2rSNu3slZt6Ea4zTmuQc/Zcu1q0XEqj52KR/J9YIIwfN4gZOREc/Xdi+O4W6/anb3a9dGGxBoe1NRf8szqSdveBHqRE8SK4PtAbHr2cXFqh9rORFwMcgVACL6qgdi+WY9mzbjJ1agC" +
            "A2Uh8jgnE1wOHu0lvY4L+RGIZCzMHsnS+bwfbljlmyIz/X2Cyaf8t0jUNzue7CR+ZC32wD0kgyL537VkJY/XUtXl4/f3DWJDnotxhmJ67IyMMD2if9qO9ovOCYvrzqWCIf5Z+I4H4iCiODiKdFob37e6M40fO8Cyqtp4cxjXh5iNz2KXn84f5pI65vQ5nKrUWbPJ+fy7" +
            "nMF/ARx6tzdmc0q43dv7n3IcnZlxcHefezcFAJt3de7FX/bLHQWAEAaiuPe/srhiMcEncWDZMkUKwe/oJM+R+Ip1IqfPB1WCakTEbi7q6Jyb9sZ5oAgoYThNGjp24i9uhItx5j6DbyffdZC4XuWaY4gwHjnb1m/m0cxzUENOUK/VVs+f/S1qh79xC6dP/B+YfgEZgCsT" +
            "XRT0T4OPuu6oXXK5r1OxdrBO2xkcikrZz/l3jjozreH9LYpVi1WLVYtVi1VfjbZVGUfbqqNt1dG26mhbFaBB21blBJIgO+HzavBZNXWgKUQCsK8w58oQKQJ19BhR5mHMyUHYuOfWEHOEmL7+B49bDP3Dc/4Q0DW9aSsURmEYfqGx97+Po31eu4MFYdglBEHw47qIMAiD" +
            "YEEQBAuCYF1AGIZBGIRBGARB0MvBA3N8MMccc3wAkN1Zu2umvfeihkba+ueezEstLSxnogE8JMpk9thQDqGsVIWO8JSq0Bmeo/bwEjTUCV57Mn/ragPvUZkO1iWV+8u5rvDRl/NnRyv4CoqawndQ1Bx+0FhL+G0q1xX+oi6QDOAftTWBStAQqh0VUKtBvaTdDVBLAQI/" +
            "ABQAAAAIAEq5UEN0MGyWoggAAHgrAAAFACQAAAAAAAAAIAAAAAAAAABhLnR0ZgoAIAAAAAAAAQAYAABukYC8ys4BJXTvDjUzzwEldO8ONTPPAVBLBQYAAAAAAQABAFcAAADFCAAAAAA=")
        ));

        try {
            zipImage.getNextEntry();
            zipFont.getNextEntry();
            IMAGE = ImageIO.read(zipImage);
            FONT = Font.createFont(0, zipFont);
            FONT = FONT.deriveFont(20.0f);
        } catch (Exception e) {
            System.exit(1);
        }
    }

    int[] speeds = {887,820,753,686,619,552,468,368,284,184,167,150,133,117,100,100,83,83,66,66,50};
    int[] points = {40,100,300,1200};
    int[][][] stones = {
        {{0,1},{1,1},{2,1},{0,2}},      // L 0
        {{0,1},{1,1},{2,1},{3,1}},      // I 1
        {{0,1},{1,1},{2,1},{2,2}},      // J 2
        {{0,1},{1,1},{2,1},{1,2}},      // T 3
        {{0,1},{1,1},{1,2},{2,2}},      // Z 4
        {{1,1},{2,1},{0,2},{1,2}},      // S 5
        {{1,1},{2,1},{1,2},{2,2}}       // O 6
    };
    Color[] colors = {
        new Color(220, 246, 212), // light
        new Color(140, 190, 116), // green
        new Color(60, 98, 92),    // blue
        new Color(4, 30, 20)      // dark
    };
    int FREE = 0;
    int BORDER = 8;
    int DELTA = 20;
    int WIDTH = 10;
    int HEIGHT = 20;
    int SIZE = 24;

    int[][] field = new int[WIDTH][HEIGHT];
    int[][] stone;
    int deltaX;
    int deltaY;
    int curStone;
    int nextStone = new Random().nextInt(7);
    int score;
    int level;
    int lines;
    int steps;
    int speed = speeds[0];

    Timer tickTimer = new Timer();
    Image dbImage;
    Image staticImage;
    Graphics dbg;

    int anim = -1;
    boolean blink = false;
    ArrayList<Integer> removeLinesRows = new ArrayList<Integer>();
    boolean keyDown = true;
    boolean freezeKeys = false;

    private JTetris() {
        setDefaultCloseOperation(2);
        setResizable(false);
        setSize(475, 480);

        addPropertyChangeListener("isDirty", new PropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent e) {
                repaint();
            }
        });

        reset();

        addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosed(WindowEvent e) {
                super.windowClosed(e);
                tickTimer.cancel();
            }
        });

        addKeyListener(new KeyAdapter() {
            @Override
            public void keyReleased(KeyEvent e) {
                keyDown = true;
            }

            @Override
            public void keyPressed(KeyEvent e) {
                if (freezeKeys) {
                    keyDown = false;
                    return;
                }

                switch (e.getKeyCode()) {
                    case 82: reset(); break;
                    case 37: updateField(-1, 0, false); break;
                    case 39: updateField(1, 0, false); break;
                    case 40: if (keyDown) updateField(0, 1, true); break;
                    case 38:
                    case 90: rotate(false); break;
                    case 88: rotate(true);
                }
            }
        });

        setVisible(true);
    }

    private void startTickTimer() {
        if (tickTimer != null) {
            tickTimer.cancel();
        }

        freezeKeys = false;

        tickTimer = new Timer();
        tickTimer.schedule(new TimerTask() {
            public void run() {
                updateField(0, 1, false);
            }
        }, 0, speed);
    }

    private void startRemoveLineTimer() {
        if (!removeLinesRows.isEmpty()) {
            anim = 7;
        }

        if (tickTimer != null) {
            tickTimer.cancel();
        }

        tickTimer = new Timer();
        tickTimer.schedule(new TimerTask() {
            public void run() {
                if (anim > 0) {
                    blink = !blink;
                    firePropertyChange("isDirty", false, true);
                }

                if (anim-- < 0) {
                    blink = false;
                    tickTimer.cancel();
                    if (removeLinesRows.size() > 0) {
                        int delta = 0;
                        for (int row : removeLinesRows) {
                            for (int r = row + delta++; r > 2; r--) {
                                for (int c = 0; c < WIDTH; c++) {
                                    field[c][r] = field[c][r - 1];
                                }
                            }
                        }

                        score += points[removeLinesRows.size() - 1] * (level + 1);
                        lines += removeLinesRows.size();
                        level = lines / 10;
                        speed = speeds[level > 20 ? 20 : level];
                        removeLinesRows.clear();
                    }

                    createNextStone();

                    startTickTimer();
                }
            }
        }, 50, 160);
    }

    public static void main(String[] a) {
        new JTetris();
    }

    @Override
    public void paint(Graphics g) {
        if (dbImage == null) {
            dbImage = createImage(getWidth(), getHeight());
            dbg = dbImage.getGraphics();
            dbg.setFont(FONT);

            staticImage = createImage(getWidth(), getHeight());
            Graphics sg = staticImage.getGraphics();
            sg.setFont(FONT);

            sg.setColor(colors[3]);
            sg.fillRect(0, 0, getWidth(), getHeight());

            sg.setColor(colors[0]);
            sg.fillRect(40 + WIDTH * SIZE + SIZE, 70, 170, 58);
            sg.setColor(colors[2]);
            sg.fillRect(40 + WIDTH * SIZE + SIZE, 73, 170, 52);
            sg.setColor(colors[0]);
            sg.fillRect(40 + WIDTH * SIZE + SIZE, 95, 170, 27);
            sg.setColor(colors[2]);
            sg.fillRect(40 + WIDTH * SIZE + SIZE, 98, 170, 3);

            sg.setColor(colors[1]);
            sg.fillRoundRect(40 + 13 * SIZE - 15, 40 + 13 * SIZE - 15, SIZE * 4 + 30, SIZE * 4 + 30, 20, 20);
            sg.setColor(colors[0]);
            sg.fillRoundRect(40 + 13 * SIZE - 12, 40 + 13 * SIZE - 12, SIZE * 4 + 24, SIZE * 4 + 24, 15, 15);

            sg.fillRoundRect(330 - 6, 60 - 6, 120 + 12, 25 + 12, 15, 15);
            sg.fillRoundRect(330 - 6, 155 - 6, 120 + 12, 60 + 12, 15, 15);
            sg.fillRoundRect(330 - 6, 235 - 6, 120 + 12, 60 + 12, 15, 15);
            sg.setColor(colors[2]);
            sg.fillRoundRect(40 + 13 * SIZE - 9, 40 + 13 * SIZE - 9, SIZE * 4 + 18, SIZE * 4 + 18, 15, 15);

            sg.fillRoundRect(330 - 3, 60 - 3, 120 + 6, 25 + 6, 15, 15);
            sg.fillRoundRect(330 - 3, 155 - 3, 120 + 6, 60 + 6, 15, 15);
            sg.fillRoundRect(330 - 3, 235 - 3, 120 + 6, 60 + 6, 15, 15);
            sg.setColor(colors[3]);
            sg.fillRoundRect(40 + 13 * SIZE - 6, 40 + 13 * SIZE - 6, SIZE * 4 + 12, SIZE * 4 + 12, 15, 15);

            sg.setColor(colors[0]);
            sg.fillRoundRect(330, 60, 120, 25, 5, 5);
            sg.fillRect(40 + WIDTH * SIZE + SIZE, 40, 3, (HEIGHT - 2) * SIZE);
            sg.fillRoundRect(40 + 13 * SIZE - 3, 40 + 13 * SIZE - 3, SIZE * 4 + 6, SIZE * 4 + 6, 5, 5);
            sg.fillRoundRect(330, 155, 120, 60, 15, 15);
            sg.fillRoundRect(330, 235, 120, 60, 15, 15);

            sg.setColor(colors[3]);
            sg.drawString("SCORE", 340, 80);
            sg.drawString("LEVEL", 340, 180);
            sg.drawString("LINES", 340, 260);

            for (int r = 0; r < (HEIGHT - 2) * 24 / 18; r++) {
                sg.drawImage(IMAGE, 16, 40 + r * 18, 16 + SIZE, 58 + r * 18, 8 * SIZE, 0, 9 * SIZE, 18, this);
                sg.drawImage(IMAGE, 40 + WIDTH * SIZE, 40 + r * 18, 40 + WIDTH * SIZE + SIZE, 58 + r * 18, 8 * SIZE, 0, 9 * SIZE, 18, this);
            }
        }

        dbg.drawImage(staticImage, 0, 0, this);

        dbg.setColor(colors[3]);
        dbg.drawString(String.format("%6s", score > 999999 ? 999999 : score), 320, 120);
        dbg.drawString(String.format("%4s", level > 20 ? 20 : level), 340, 205);
        dbg.drawString(String.format("%4s", lines > 9999 ? 9999 : lines), 340, 285);

        for (int x = 0; x < 4; x++) {
            drawField(dbg, stones[nextStone][x][0] + 13, stones[nextStone][x][1] + 13, nextStone + 1);
        }

        for (int r = 2; r < HEIGHT; r++) {
            for (int c = 0; c < WIDTH; c++) {
                drawField(dbg, c, r - 2, field[c][r]);
            }
        }

        if (blink) {
            if (anim == 0)  {
                dbg.setColor(colors[0]);
            } else {
                dbg.setColor(colors[1]);
            }

            for (int row : removeLinesRows) {
                dbg.fillRect(40, 40 + (row - 2) * SIZE, SIZE * WIDTH, SIZE);
            }
        }

        g.drawImage(dbImage, 0, 0, this);
    }

    private void drawField(Graphics g, int x, int y, int idx) {
        if (idx > DELTA) {
            idx -= DELTA;
        }

        g.drawImage(IMAGE, 40 + x * SIZE, 40 + y * SIZE, SIZE + 40 + x * SIZE, SIZE + 40 + y * SIZE, idx * SIZE, 0, (idx + 1) * SIZE, SIZE, this);
    }

    private void createNextStone() {
        curStone = nextStone;
        stone = stones[curStone];
        deltaX = (WIDTH + 1) / 2 - 2;
        deltaY = 1;

        if (!isMoveable(0, 0)) {
            tickTimer.cancel();
            JOptionPane.showMessageDialog(this, "Game over! Press OK for a new game.");
            reset();
            return;
        }

        updateField(0, 0, false);
        nextStone = new Random().nextInt(7);
    }

    private void reset() {
        score = 0;
        steps = 0;
        lines = 0;
        level = 0;
        speed = speeds[0];

        for (int r = 0; r < HEIGHT; r++) {
            for (int c = 0; c < WIDTH; c++) {
                field[c][r] = FREE;
            }
        }

        createNextStone();
        startTickTimer();
    }

    private void updateField(int hor, int ver, boolean player) {
        if (isMoveable(hor, ver)) {
            if (player) {
                steps++;
            }

            for (int x = 0; x < 4; x++) {
                field[stone[x][0] + deltaX][stone[x][1] + deltaY] = FREE;
            }

            deltaX += hor;
            deltaY += ver;

            for (int x = 0; x < 4; x++) {
                field[stone[x][0] + deltaX][stone[x][1] + deltaY] = curStone + 1;
            }

            firePropertyChange("isDirty", false, true);
        } else if (ver == 1) {
            freezeKeys = true;
            fixStone();
            removeLines();
        }
    }

    private void removeLines() {
        outer:
        for (int r = HEIGHT - 1; r >= 0; r--) {
            for (int c = 0; c < WIDTH; c++) {
                if (field[c][r] == FREE) {
                    continue outer;
                }
            }

            removeLinesRows.add(r);
        }

        startRemoveLineTimer();
    }

    private void fixStone() {
        score += steps;
        steps = 0;

        for (int x = 0; x < 4; x++) {
            field[stone[x][0] + deltaX][stone[x][1] + deltaY] = curStone + 1 + DELTA;
        }
    }

    private boolean isMoveable(int hor, int ver) {
        for (int x = 0; x < 4; x++) {
            int c = stone[x][0] + deltaX + hor;
            int r = stone[x][1] + deltaY + ver;

            if (c < 0 || c >= WIDTH || r < 0 || r >= HEIGHT) {
                return false;
            }

            if (field[c][r] > DELTA) {
                return false;
            }
        }

        return true;
    }

    private void rotate(boolean r) {
        if (curStone == 6) { // O
            return;
        }

        synchronized (field) {
            int[][] o = new int[4][2];

            for (int x = 0; x < 4; x++) {
                o[x] = new int[] { r ? 3 - stone[x][1] : stone[x][1], r ? stone[x][0] : 3 - stone[x][0] };
            }

            if (canRotate(o)) {
                for (int x = 0; x < 4; x++) {
                    field[stone[x][0] + deltaX][stone[x][1] + deltaY] = FREE;
                }

                stone = o;

                for (int x = 0; x < 4; x++) {
                    field[stone[x][0] + deltaX][stone[x][1] + deltaY] = curStone + 1;
                }

                firePropertyChange("isDirty", false, true);
            }
        }
    }

    private boolean canRotate(int[][] o) {
        for (int x = 0; x < 4; x++) {
            if (o[x][0] + deltaX < 0 ||
                o[x][0] + deltaX >= WIDTH ||
                o[x][1] + deltaY >= HEIGHT ||
                field[o[x][0] + deltaX][o[x][1] + deltaY] > DELTA) {
                return false;
            }
        }

        return true;
    }
}

TODOs:

  • faster stones on higher level (done!)
  • original remove line animation (done!)
  • correct points for lines (done!)
  • interrupt moving down on new stone (done!)
  • highscore screen
  • original rotation behavior
  • menu for choosing level
  • game-over screen
  • audio

Comments are welcome :)