Making of Tetris Game in Java

Here in this post, i will share a Java program to make a Tetris game. I have already wrote a post on how to make a tetris game in C language. I have discussed the data structures used in the program in that post. The Java program is almost similar to it. The description is available in this post: Making of Tetris Game in C.

The following video shows the java code in action:


The tetris game Java source code is as follows:

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JOptionPane;



public class Tetris extends JFrame{

boolean stopthread=false;
int SIZE_HORIZ=13;
int SIZE_VERTI=35;
Graphics g;
boolean waitnow=false;
int[][] board=new int[SIZE_VERTI][SIZE_HORIZ];
int t_[]={1,0,1,1,1,2,2,1};
int t_90[]={0,1,1,0,1,1,2,1};
int t_180[]={0,1,1,0,1,1,1,2};
int t_270[]={0,1,1,1,1,2,2,1};
int l_[]={0,2,1,0,1,1,1,2};
int l_90[]={0,1,1,1,2,1,2,2};
int l_180[]={1,0,1,1,1,2,2,0};
int l_270[]={0,0,0,1,1,1,2,1};
int s_[]={0,0,0,1,1,0,1,1};
int z_[]={1,1,1,2,2,0,2,1};
int z_90[]={0,1,1,1,1,2,2,2};
int i_ver[]={0,1,1,1,2,1,3,1};
int i_hor[]={1,0,1,1,1,2,1,3};
String scorestr;
Random rand=new Random(System.currentTimeMillis());
Color colors[]={Color.BLUE,Color.GREEN,Color.MAGENTA,Color.RED,Color.YELLOW};
File HighScore;
Color bgcolor=Color.WHITE;
/*
Numbering for blocks:
(values of fallingBlockNumber)
0=T
1=L
2=S
3=Z
4=I
*/
int [] blockarray;
int fallingblockNum;
int fallingBlockVersion=0;
int fallingBlockRow=0;
int fallingBlockCol=0;
int startdelay=200;
int motiondelay;
int scoreInc=5;
int myscore=0;
int tversion;
boolean spawn=true;
int scorespeedctrl=0;
int timehalving=0;
String highscoreholder;
int highscore;
KeyListener kl;

public Tetris()
{
int i,j;
startdelay=250;
scoreInc=5;
myscore=0;
motiondelay=startdelay;
NextBlock();
for(i=0;i<35;i++)
    for(j=0;j<13;j++)
 board[i][j]=0;
setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(480,500);
setResizable(false);
setLocationRelativeTo(null);
HighScore=new File(System.getProperty("java.io.tmpdir")+File.separator+"TetrisHighScore");
try{
if(HighScore.exists())
    {
    BufferedReader br=new BufferedReader(new FileReader(HighScore));
    highscoreholder=br.readLine();
    highscore=Integer.parseInt(br.readLine());
    br.close();
    }
else
    {
    highscoreholder=null;
    highscore=0;
    }
}catch(Exception ex){}
kl=new KeyListener() {
    @Override
    public void keyTyped(KeyEvent e) {}

    @Override
    public void keyPressed(KeyEvent e) {
    
        if(!spawn&&!waitnow)
 {
            waitnow=true;
            int key=e.getKeyCode();
     if(key==KeyEvent.VK_UP)//up
  {
  if(fallingblockNum==0||fallingblockNum==1)
      tversion=(fallingBlockVersion+1)%4;
  else if(fallingblockNum==4||fallingblockNum==3)
      tversion=(fallingBlockVersion+1)%2;

  if(fallingblockNum!=2&&isDrawable(fallingBlockRow,fallingBlockCol,tversion))
      {
      clearOldBlockVersion(g);
      fallingBlockVersion=tversion;
      blockarray=getFallingBlockArray();
      drawNewBlockVersion(g);
      }
  }
     else if(key==KeyEvent.VK_LEFT)//left
  {
  if(isDrawable(fallingBlockRow,fallingBlockCol-1,fallingBlockVersion))
      {
      clearOldBlockVersion(g);
      fallingBlockCol--;
      drawNewBlockVersion(g);
      }
  }
     else if(key==KeyEvent.VK_RIGHT)//right
  {
  if(isDrawable(fallingBlockRow,fallingBlockCol+1,fallingBlockVersion))
      {
      clearOldBlockVersion(g);
      fallingBlockCol++;
      drawNewBlockVersion(g);
      }
  }
     else if(key==KeyEvent.VK_DOWN)//down
  {
  if(isDrawable(fallingBlockRow+1,fallingBlockCol,fallingBlockVersion))
      {
      clearOldBlockVersion(g);
      fallingBlockRow++;
      drawNewBlockVersion(g);
      }
  }
            waitnow=false;
 }
    }
    @Override
    public void keyReleased(KeyEvent e) {}
};
th.start();
addKeyListener(kl);
}

void NextBlock()
{
fallingblockNum=rand.nextInt(5);
if(fallingblockNum==0||fallingblockNum==1)
 fallingBlockVersion=rand.nextInt(4);
else if(fallingblockNum==4||fallingblockNum==3)
 fallingBlockVersion=rand.nextInt(2);
else
 fallingBlockVersion=0;
fallingBlockRow=0;
fallingBlockCol=5;
blockarray=getFallingBlockArray();
}

int[] getFallingBlockArray()
{
int a=fallingblockNum*10+fallingBlockVersion;
switch(a)
    {
    case 0:return (t_);
    case 1:return (t_90);
    case 2:return (t_180);
    case 3:return (t_270);
    case 10:return (l_);
    case 11:return (l_90);
    case 12:return (l_180);
    case 13:return (l_270);
    case 20:return (s_);
    case 30:return (z_);
    case 31:return (z_90);
    case 40:return (i_hor);
    case 41:return (i_ver);
    }
return (i_ver);
}

boolean isDrawable(int newrow,int newcol,int blockversion)
{
int i,tempversion;
boolean flag=true;
tempversion=fallingBlockVersion;
fallingBlockVersion=blockversion;
blockarray=getFallingBlockArray();
for(i=0;i<8;i+=2)
    {
    if(newrow+blockarray[i]>34||newrow+blockarray[i]<0)
 {
 flag=false;
 break;
 }
    if(newcol+blockarray[i+1]>12||newcol+blockarray[i+1]<0)
 {
 flag=false;
 break;
 }
    if(board[(newrow+blockarray[i])][(newcol+blockarray[i+1])]==2)
 {
 flag=false;
 break;
 }
    }
fallingBlockVersion=tempversion;
blockarray=getFallingBlockArray();
return flag;
}

void clearOldBlockVersion(Graphics g)
{
int i,r,c;
for(i=0;i<8;i+=2)
 {
 r=fallingBlockRow+blockarray[i];
 c=fallingBlockCol+blockarray[i+1];
 board[r][c]=0;
 g.setColor(bgcolor);
        g.fillRect(8+c*13,32+r*13,14,14);
 }
}

void drawNewBlockVersion(Graphics g)
{
int i,r,c;
for(i=0;i<8;i+=2)
 {
 r=fallingBlockRow+blockarray[i];
 c=fallingBlockCol+blockarray[i+1];
 board[r][c]=1;
        g.setColor(colors[fallingblockNum]);
 g.fillRect(8+c*13,32+r*13,13,13);
        g.setColor(Color.BLACK);//cyan,orange
 g.drawRect(8+c*13,32+r*13,13,13);
 }
}
boolean isGameOver(Graphics g)
{
if(isDrawable(0,5,fallingBlockVersion)==false)
    return true;
drawNewBlockVersion(g);
if(isAtBottom())
    return true;
return false;
}

boolean isAtBottom()
{
int i,max=0,ti,tj;
for(i=0;i<8;i+=2)
    if(blockarray[i]>max)
 max=blockarray[i];
if(fallingBlockRow+max>=34)
 return true;
for(i=0;i<8;i+=2)
    {
    ti=blockarray[i]+fallingBlockRow;
    tj=blockarray[i+1]+fallingBlockCol;
    if(board[ti+1][tj]==2)
       return true;
    }
return false;
}

void showScore(Graphics g)
{
int left,top;
left=getWidth()-100;
top=getHeight()/2;
g.setColor(bgcolor);
g.fillRect(left,top,80,70);
g.setColor(Color.RED);
g.setFont(new Font("Arial",Font.BOLD,14));
g.drawString("Score: "+Integer.toString(myscore),left,top+20);
}

void CollapseFilledRow(Graphics g)
{
int i,j,k,sum,copyskipover=0,r;
for(i=34;i>=0;)
    {
    sum=0;//full flag
    for(j=0;j<13;j++)
 sum+=board[i][j];
    if(sum==2*13)//row full
 {
 myscore+=scoreInc;
 copyskipover++;
 }
    if(sum==0)
 break;
    i--;
    if(copyskipover>0)
 {
 for(j=0;j<13;j++)
     {
     r=i+copyskipover;
     board[r][j]=board[i][j];
     if(board[i][j]==0)
  {
                g.setColor(bgcolor);
                g.fillRect(8+j*13,32+r*13,14,14);
  }
     else
  {
                g.setColor(Color.GREEN);
                g.fillRect(8+j*13,32+r*13,13,13);
                g.setColor(Color.BLACK);
                g.drawRect(8+j*13,32+r*13,13,13);
  }
     }
 }
    }
for(k=0;k<copyskipover;k++)
    {
    r=i+k;
    for(j=0;j<13;j++)
 {
 board[r][j]=0;
        g.setColor(bgcolor);
 g.fillRect(8+j*13,32+r*13,14,14);
 }
    }
showScore(g);
}


public static void main(String[] args)
{
Tetris tt=new Tetris();
tt.setVisible(true);
}

void GameOver(Graphics g)
{
stopthread=true;
g.setColor(Color.RED);
g.setFont(new Font("Arial",Font.BOLD,28));
String str="Game Over.";
g.drawString(str,getWidth()/2-10, getHeight()/2);
if(highscore>0)
    str="Highscore : "+highscoreholder+" - "+Integer.toString(highscore);
g.setFont(new Font("Arial",Font.BOLD,16));
g.drawString(str,getWidth()/2-30, getHeight()/2+80);
if(myscore>highscore)
    {
        highscoreholder=JOptionPane.showInputDialog("New high score. Enter your name:");
        highscore=myscore;
        try{
        if(!HighScore.exists())
            HighScore.createNewFile();
        BufferedWriter bw=new BufferedWriter(new FileWriter(HighScore));
        bw.write(highscoreholder);
        bw.newLine();
        bw.write(Integer.toString(highscore));
        bw.close();
        }catch(Exception ee){}
    }
}


Thread th=new Thread()
{
int i;
public void run()

{
try {
    while(!isShowing())
        Thread.sleep(1000);
    } catch (InterruptedException ex) {}
setOpacity(1f);
setBackground(bgcolor);
getContentPane().setBackground(bgcolor);
g=getGraphics();
g.setColor(Color.RED);
g.drawRect(6,30,13*13+6,35*13+6);
showScore(g);
while(!stopthread)
{
g.setColor(Color.RED);
g.drawRect(6,30,13*13+6,35*13+6);
while (waitnow)
    {
    try {
        Thread.sleep(20);
    } catch (InterruptedException ex) {}
    }
waitnow=true;
if(isAtBottom()&&!spawn)
 {
 for(i=0;i<8;i+=2)
     {
     board[fallingBlockRow+blockarray[i]][fallingBlockCol+blockarray[i+1]]=2;
     }
 spawn=true;
 CollapseFilledRow(g);
 }
    if(spawn)
 {
 NextBlock();
 blockarray=getFallingBlockArray();
 spawn=false;
 if(isGameOver(g))
     {
     GameOver(g);
     return;
     }
 }
    else
 {
 timehalving=(timehalving+1)%3;
 if(timehalving==2)
  {
  clearOldBlockVersion(g);
  fallingBlockRow++;
  drawNewBlockVersion(g);
  }
 }
    scorespeedctrl=(scorespeedctrl+1)%140;
    if(scorespeedctrl==0&&motiondelay>0)
 {
 motiondelay-=12;
 scoreInc+=2;
        if(motiondelay<0)
            motiondelay=0;
 }
    waitnow=false;
    try {
        Thread.sleep(motiondelay);
            } catch (InterruptedException ex) {}
}
}
};
}

TCP Server Client Two Person Chat Program in Java with GUI

Server-Client chat program or two way chat using TCP connection is a common problem for java practical labs or networking labs. Here this post introduces a simple lightweight Server client two person chat program using java. The program uses ServerSocket and Socket classes available in java.net package. This program is written so as to use the same as server or as client. Both the persons who chat use the same program. One should select hosting (acting as server) while the other could connect to him by entering the server ip address. I have added screenshots of the program also.
See Screenshots

Clock Application using Java - Java Source Code for Analog Clock Application

For my java practical lab experiments, i had to create an analog clock using java. So, i created a

Analog Clock Application using Java.

simple analog clock using java. The program source code is added below. It makes use of java 2D Graphics Object and draws the clock in the screen. The clock displays all the three hands (hour hand, second hand and minute hand). The program source code is as follows. The screenshot of the java analog clock application is also added.

Simple Java Calculator Program Using Java Applet

Screenshot of Simple calculator applet in java

This post shows a sample Calculator Program using Java Applet. This program uses the JApplet Class and Swing components in the program. The full source code is given below. This is a java Applet program for a simple calculator with operations addition, subtraction, division and multiplication on floating point numbers. It also have the C (clear) button. This Java Calculator applet was created by myself for my practical lab experiment. I think this may be useful for beginners in java.