I made a new example in Jcreator. The example applet size should be 320*240.
I formatted the code with a site tool that I found. No applets anymore since they do not seem to work anymore with my google site.
There is not a lot of comment in the code. I want to keep it clean.
/**
* @(#)SpaceInvadersExample003.java
*
* SpaceInvadersExample003 Applet application
*
* @author Rudy van Etten
* @version 1.00 2013/10/28
*/
import java.awt.*;
import java.applet.*;
public class SpaceInvadersExample003 extends Applet implements Runnable{
Graphics bufferGraphics;
Image offscreen;
double px = 160-8;
double py = 200;
int pwidth = 16;
int pheight = 16;
boolean ismovingright = false;
boolean ismovingleft = false;
int wavedirection = 1; // 1 = right 0 = left
long firedelay = 0;
double bullet[][] = new double[ 32 ][ 5 ]; //active,x,y,my
double alien[][] = new double[10*5][5];//active,x,y
public void init() {
setBackground(Color.black);
offscreen = createImage(getSize().width,getSize().height);
bufferGraphics = offscreen.getGraphics();
int x=0;
int y=0;
for(int i=0;i<10*5;i++){
alien[i][0]=1;
alien[i][1]=x;
alien[i][2]=y;
x+=32;
if(x>getSize().width-32){
x=0;
y+=32;
}
}
new Thread(this).start();
}
public void run() {
for(;;) { // animation loop never ends
if (ismovingright==true){
if (px<getSize().width-pwidth)
px+=1;
}
if (ismovingleft==true){
if(px>0)
px-=1;
}
// move the bullets and remove them if they get above the screen
for(int i=0 ;i<32;i++){
if(bullet[i][0]==1){
bullet[i][2]+=bullet[i][3];
if(bullet[i][2]<0){
bullet[i][0]=0;
}
}
}
// Collision with the bullets and the aliens.
for(int i=0; i<32;i++){
if(bullet[i][0]==1){
for (int ii=0;ii<10*5;ii++){
if (alien[ii][0]==1){
Rectangle rec1 = new Rectangle((int)bullet[i][1],(int)bullet[i][2],16,16);
Rectangle rec2 = new Rectangle((int)alien[ii][1],(int)alien[ii][2],16,16);
if(rec1.intersects(rec2)){
//g.drawString("Filled Rectangle Collision", 50, 60 );
bullet[i][0]=0;
alien[ii][0]=0;
}
}
}
}
}
// Move the alien wave
for(int i=0;i<10*5;i++){
if(alien[i][0]==1){
if(wavedirection==0){
alien[i][1]-=0.1;
}else{
alien[i][1]+=0.1;
}
if(alien[i][1]>getSize().width-16){
wavedirection=0;
}
if(alien[i][1]<0){
wavedirection=1;
}
}
}
repaint();
try {
Thread.sleep(16);
}
catch (InterruptedException e) {
}
}
}
public void update(Graphics g){
bufferGraphics.clearRect(0,0,getSize().width,getSize().width);
bufferGraphics.setColor(Color.red);
bufferGraphics.drawString("Space Invaders Example.",20,30);
// draw player ship
bufferGraphics.setColor(Color.white);
bufferGraphics.fillRect((int)px,(int)py,pwidth,pheight);
//draw aliens
for(int i=0;i<10*5;i++){
if(alien[i][0]==1){
bufferGraphics.fillRect((int)alien[i][1],(int)alien[i][2],16,16);
}
}
// Draw bullets
for(int i=0;i<32;i++){
if(bullet[i][0]==1){
bufferGraphics.fillRect((int)bullet[i][1],(int)bullet[i][2],3,3);
}
}
g.drawImage(offscreen,0,0,this);
}
public void createBullet(){
for(int i=0;i<32;i++){
if(bullet[i][0]==0){
bullet[i][0]=1;
bullet[i][1]=px+8;
bullet[i][2]=py-16;
bullet[i][3]=-2;
return;
}
}
}
public boolean keyDown (Event e, int key){
if( key == Event.LEFT )
{
ismovingleft = true;
}
if(key==Event.RIGHT)
{
ismovingright = true;
}
if( key == 32 ) // space bar for jump
{
if(firedelay<System.currentTimeMillis()){
firedelay = System.currentTimeMillis() + 200;
createBullet();
}
}
System.out.println (" Integer Value: " + key);
return true;
}
public boolean keyUp (Event e, int key){
if( key == Event.LEFT )
{
ismovingleft = false;
}
if( key == Event.RIGHT )
{
ismovingright = false;
}
return true;
}
}
