Develop Reference

Java Asteroids game how to be able to fire multiple shots without having the first shot disappear?

So for my final in Java class, we are making an Asteroid game (except a simpler version that the official one, because not enough time).
The problem is when our ship fires a shot (SPACE bar) we add(shot, x, y), but then when we click SPACE bar again it just takes that shot and puts it back to original x, y. So right now we can only fire off one shot at a time to be on the screen. We would like to be able to be able to fire off multiple shots and have them all be visible and stuff.
Not sure how to do that though. Any help is welcome thank you.
P.S. if needed i will add our code.
P.S.S. sorry for posting this again i thought i could edit the post later, thats why i didn't include the code but apparently not.
package week7Homework;
import acm.program.GraphicsProgram;
import java.util.*;
import java.awt.event.*;
import acm.graphics.*;
import java.awt.Color;
import java.awt.Image;
public class space8bit extends GraphicsProgram
{
/* Initialize everything that is needed */
final int WIN_HEIGHT = 800;
final int WIN_WIDTH = 1900;
GImage space = new GImage("/College/IT219/Week7/src/week7Homework/outerspace.png");
GImage ship = new GImage("/College/IT219/Week7/src/week7Homework/ship.png");
GImage explosion = new GImage("/College/IT219/Week7/src/week7Homework/explosion.png");
GImage [] ast = new GImage[6];
Random rand = new Random();
pewpew shots = new pewpew();
int shipx;
int shipy;
public void init()
{
setSize(WIN_WIDTH, WIN_HEIGHT);
add(space);
ship.setLocation(50,330);
ship.scale(.8);
add(ship);
addKeyListeners( );
//scale explosion
explosion.scale(.5);
}
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode( );
if (key == KeyEvent.VK_UP)
{ ship.move(0, -15); }
/*else if (key == KeyEvent.VK_SPACE)
{ xMove = MV_AMT; }*/
else if (key == KeyEvent.VK_DOWN)
{ ship.move(0, 15); }
else if (key == KeyEvent.VK_SPACE)
{shipx = (int)ship.getX()+195;
shipy = (int)ship.getY() + 80;
add(shots,shipx,shipy);
}
}
public void asteriods()
{
GImage ast1 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1300,100);
GImage ast2 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1750,250);
GImage ast3 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1650,350);
GImage ast4 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1550,650);
GImage ast5 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1450,600);
GImage ast6 = new GImage("/College/IT219/Week7/src/week7Homework/asteriod.png",1350,750);
ast [0] = ast1;
ast [1] = ast2;
ast [2] = ast3;
ast [3] = ast4;
ast [4] = ast5;
ast [5] = ast6;
add(ast[0]);
add(ast[1]);
add(ast[2]);
add(ast[3]);
add(ast[4]);
add(ast[5]);
}
public void run()
{
asteriods();
while(true)
{
pause(120);
int random1x = rand.nextInt(-1+1+6)-9;
int random2x = rand.nextInt(-1+1+6)-15;
int random3x = rand.nextInt(-1+1+6)-25;
int random4x = rand.nextInt(-1+1+6)-16;
int random5x = rand.nextInt(-1+1+6)-8;
int random6x = rand.nextInt(-1+1+6)-13;
ast[0].move(random1x, 0);
ast[1].move(random2x, 0);
ast[2].move(random3x, 0);
ast[3].move(random4x, 0);
ast[4].move(random5x, 0);
ast[5].move(random6x, 0);
shots.move(50, 0);
for (int i = 0; i < ast.length; i++)
{
//integer that gets bounds of all rectangles and ovals in the arrays.
GRectangle asteroidBounds = ast[i].getBounds();
//check for collision with other objects
if (shots.getBounds().intersects(asteroidBounds))
{
int shotX = (int)shots.getX();
int shotY = (int)shots.getY();
pause(10);
remove(ast[i]);
add(explosion, shotX-100, shotY - 50);
remove(shots);
pause(25);
remove(explosion);
}
else if (ship.getY() <= 0)
{
ship.move(0, 15);
}
else if (ship.getY() >= WIN_HEIGHT - 168)
{
ship.move(0, -15);
}
}
}
}
}
ALSO HERE IS A SAMPLE CODE, much shorter but does the same thing. Just press SPACEBAR and you will see what im talking about.
package week7Homework;
import acm.graphics.*;
import acm.program.*;
import java.awt.*;
import java.awt.event.*;
public class collisionTry extends GraphicsProgram
{
final int WIN_WIDTH = 500;
final int WIN_HEIGHT = 500;
GOval ship = new GOval(100, 250, 50, 50);
GImage bullet = new GImage("/College/IT219/Week7/src/week7Homework/bullet.gif", 50, 50);
GImage bullet2;
boolean bulletFired;
public void init()
{
setSize(WIN_WIDTH, WIN_HEIGHT);
addKeyListeners();
}
public void run()
{
GRect rect = new GRect(400, 200, 50, 150);
add(rect);
rect.setColor(Color.BLACK);
rect.setFilled(true);
add(ship);
ship.setColor(Color.BLACK);
ship.setFilled(true);
while (true)
{
pause(50);
rect.move(-1, 0);
//bullet.move(5, 0);
if (bulletFired == true)
{
bullet.move(5, 0);
}
if (bullet.getBounds().intersects(rect.getBounds()))
{
remove(rect);
remove(bullet);
}
}
}//run
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if(key == KeyEvent.VK_SPACE)
{
int shipX = (int)ship.getX();
int shipY = (int)ship.getY();
add(bullet, shipX+50, shipY+25);
bulletFired = true;
}
else if (key == KeyEvent.VK_UP){
ship.move(0, -5);
}
}
}

It's 'cause you only have 1 bullet in the entire game
if (bulletFired == true) {
bullet.move(5, 0);
}
You're telling that one bullet to go back to (5, 0)
You need to find some way of making a new bullet object each time you press space:
if (key == KeyEvent.VK_SPACE) {
int shipX = (int)ship.getX();
int shipY = (int)ship.getY();
Bullet firedBullet = new Bullet(/* params if any, x? y? */);
add(firedBullet, shipX+50, shipY+25);
bulletFired = true;
}
Though this is my vision of how I'd do things, which probably won't work with your game (I don't know what classes you have, their roles etc). But hopefully you can see what I'm getting at and adapt it.
Now because you have multiple bullets, you also have to take care of their lifetimes. You fired 1000 bullets at the start of the game, they go off-screen. You don't want to waste time drawing them for the rest of the game. So whatever list/array you're using to keep track of objects to draw, you gotta periodically find and remove the ones that have gone off-screen.

Make an image change on hero direction, Simple 2D game

Hi every one i am having a bit of trouble with my java game, it is very simply made as i am new to java. and the game works fine well as good as i can achieve. But i am stuck on how i can change the images in real time. I am trying to figure out how to make my Monsters face me "the hero frylark" when they chase me. i have made 2 simple methods in my monster class. left and right How could i apply these methods to make the image change from image = getImage("/Game/images/police-right.png"); to image = getImage("/Game/images/police-left.png");.
Oh and in my project library is golden_0_2_3.jar which contains some game engine stuff.
Please.
Many thanks from edwin.
import com.golden.gamedev.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;
import java.awt.event.KeyEvent;
public class MyGame extends Game {
// set the values
public Random random;
private Hero frylark;
private Monster[] monsters = new Monster[3];
private Token coin;
private GameBackGround grass;
private BufferedImage image;
public void initResources() {
// set a new random number
random = new Random();
// get the background image.
image = getImage("/Game/images/background.png");
// set the name "grass" to background and given the image from the image set above.
grass = new GameBackGround("grass", image);
// get the monsters image.
image = getImage("/Game/images/police.png");
// give the monsters their names "" and set them their image from the image set above.
monsters[0] = new Monster("Monster", image);
monsters[1] = new Monster("Monster2", image);
monsters[2] = new Monster("Monster3", image);
// get the tokens image.
image = getImage("/Game/images/donut.png");
// set the name "coin" for the token, then its x and y position, and set the image from the image set above.
coin = new Token("coin", 400, 300, image);
// get the heros image.
image = getImage("/Game/images/snake.png");
// set the name "frylark" for the hero, then his score "0" and lives "5".
frylark = new Hero("Frylark", 0, 5);
//set the monsters random x and y positions.
monsters[0].setX(random.nextInt(750));
monsters[0].setY(random.nextInt(550));
monsters[1].setX(random.nextInt(750));
monsters[1].setY(random.nextInt(550));
monsters[2].setX(random.nextInt(750));
monsters[2].setY(random.nextInt(550));
}
// update method
public void update(long elapsedTime) {
// Pause the hero "frylark" on hold of the space bar.
if (!keyDown(KeyEvent.VK_SPACE)){
// if dead stop frylark moving on the 5 second game over sequence, being displays details and playing the game over sound.
if (Hero.dead(frylark)){
if(keyDown(KeyEvent.VK_LEFT))
{
// Move left
frylark.moveLeft();
}
if (keyDown(KeyEvent.VK_RIGHT))
{
// Move right
frylark.moveRight();
}
if (keyDown(KeyEvent.VK_UP))
{
// Move up on press of up key
frylark.moveUp();
}
if (keyDown(KeyEvent.VK_DOWN))
{
// Move down on press of down key
frylark.moveDown();
}
}
if (keyDown(KeyEvent.VK_ESCAPE))
{
// Exit game on press of esc key.
System.exit(0);
}
}
if (!keyDown(KeyEvent.VK_SPACE))
{
// Pause the monsters on hold of the space bar
monsters[0].chase(frylark);
monsters[1].chase(frylark);
monsters[2].chase(frylark);
}
// if monster 0 has eaten frylark move to a random position and lose a life, plus play the lose life sound.
if (monsters[0].eaten(frylark)) {
monsters[0].setX(random.nextInt(750));
monsters[0].setY(random.nextInt(550));
frylark.loseLife();
playSound("/Game/sounds/lost_a_life.wav");
}
// if monster 1 has eaten frylark move to a random position and lose a life, plus play the lose life sound.
if (monsters[1].eaten(frylark)) {
monsters[1].setX(random.nextInt(750));
monsters[1].setY(random.nextInt(550));
frylark.loseLife();
playSound("/Game/sounds/lost_a_life.wav");
}
// if monster 2 has eaten frylark move to a random position and lose a life, plus play the lose life sound.
if (monsters[2].eaten(frylark)) {
monsters[2].setX(random.nextInt(750));
monsters[2].setY(random.nextInt(550));
frylark.loseLife();
playSound("/Game/sounds/lost_a_life.wav");
}
// if coin is collected increase score and move to a random position, and play the coin collect sound.
if (coin.collected(frylark)) {
coin.setX (random.nextInt(750));
coin.setY (random.nextInt(550));
frylark.increaseScore();
playSound("/Game/sounds/coin.wav");
}
}
public void render(Graphics2D g) {
// draw all the monsters, hero, and coin and background.
g.drawImage(grass.getImage(),grass.getX(),grass.getY(),null);
g.drawImage(monsters[0].getImage(), monsters[0].GetX(), monsters[0].GetY(), null);
g.drawImage(monsters[1].getImage(), monsters[1].GetX(), monsters[1].GetY(), null);
g.drawImage(monsters[2].getImage(), monsters[2].GetX(), monsters[2].GetY(), null);
g.drawImage(image,frylark.getX(),frylark.getY(),null);
g.drawImage(coin.getImage(),coin.getX(),coin.getY(),null);
// if monster 0 overlaps another monster mover him back
if (monsters[0].overlap(monsters)){
monsters[0].x -=20;
monsters[0].y -=70;
}
// if monster 1 overlaps another monster mover him back
if (monsters[1].overlap(monsters)){
monsters[1].x -=21;
monsters[1].y -=70;
}
// if monster 2 overlaps another monster mover him back
if (monsters[2].overlap(monsters)){
monsters[2].x -=22;
monsters[2].y -=70;
}
// draw the lives bar, and set the font colour and size
g.setColor(Color.RED);
g.setFont(new Font("default", Font.BOLD, 18));
for (int i = 0; i < frylark.getLives(); i++) {
g.fillRect( (i + 1) * 15, 10, 10, 10);
}
// draw the score
g.setColor(Color.GREEN);
g.drawString("Score: " + frylark.getScore(), 10, 50);
// draw the level
g.setColor(Color.YELLOW);
g.drawString("level: " + frylark.getScoreNum(), 10, 80);
// game over sequence, changes the font to size 40 and displays game over, as well as the payers score and level reached plus the game over sound.
if (frylark.getLives() ==0){
g.setColor(Color.RED);
g.setFont(new Font("override", Font.BOLD, 40));
g.drawString("Game over !", 280, 290);
playSound("/Game/sounds/game_over.wav");
g.drawString("You reached Level " + frylark.getScoreNum() + " Your Score: " + frylark.getScore(), 60, 330);
}
}
// main method which after all classes have been read and checked, "Game development environment OK! " will be printed to the console.
// then a new game is created and given dimensions and launched.
public static void main(String args[]) {
System.out.println("Game development environment OK! ");
GameLoader gameLoader = new GameLoader();
MyGame myGame = new MyGame();
gameLoader.setup(myGame,new Dimension(800,600),false);
gameLoader.start();
}
}
and my Monster class
import java.util.Random;
import java.awt.image.BufferedImage;
public class Monster {
private String name;
int x;
int y;
private BufferedImage image;
Random rand;
public Monster (String nameIn, BufferedImage imageIn)
{
name = nameIn;
x = 0;
y = 0;
image = imageIn;
}
public void chase(Hero hero) {
if (hero.getX() < x) { // if hero is to the left
x--;
}
if (hero.getX() > x) { // if hero is to the right
x++ ;
}
if (hero.getY() < y) { // if hero is to the above
y--;
}
if (hero.getY() > y) { // if hero is to the below
y++;
}
}
public boolean overlap(Monster monsters[]){
if (monsters[0].x == monsters[1].x && monsters[0].y == monsters[1].y || monsters[0].x == monsters[2].x && monsters[0].y == monsters[2].y ||
monsters[1].x == monsters[0].x && monsters[1].y == monsters[0].y || monsters[1].x == monsters[2].x && monsters[1].y == monsters[2].y ||
monsters[2].x == monsters[0].x && monsters[2].y == monsters[0].y || monsters[2].x == monsters[1].x && monsters[2].y == monsters[1].y) {
return true;
}
else{
return false;
}
}
public boolean eaten(Hero hero) {
if (hero.getX() == x && hero.getY() == y) {
return true;
}
else {
return false;
}
}
public BufferedImage getImage() {
return image;
}
public int GetX(){
return x;
}
public int GetY(){
return y;
}
public String getName()
{
return this.name;
}
public void setX(int xIn) {
x = xIn;
}
public void setY(int yIn) {
y = yIn;
}
public boolean left(Hero hero) {
if (hero.getX() < x) {
return true;
}
else {
return false;
}
}
public boolean right(Hero hero) {
if (hero.getX() > x) {
return true;
}
else {
return false;
}
}
}

I would modify your Monster constructor to accept both images. Then modify Monster.getImage() to call left() and return the correct one based on the result. You probably don't need to call right() as well, since if the monster is not facing left then you know it needs to face right. Unless you want to get more sophisticated and also add a view facing straight forward or backward.

libgdx textanimation(one letter by one)

I'm trying to make visual novel game but i'm stuck with text animation
I tried to make it on console application for example so help me with making it on libgdx.
here's my sample code
public class TestC {
private static String message = "help me with textanimation";
public static void main(String[] args) {
for (int i = 0; i < message.length(); i++) {
System.out.print(message.charAt(i));
try {
Thread.sleep(50);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
Thanks in advance

Why don't you try to make it work with LibGDX and then ask help? It goes basicaly the same except instead of letting the program sleep you have to count time passed.
final float letterSpawnTime = .2f;
float timer = 0;
String completeText = "The complete text."
String drawText = "";
int stringIndex = 0;
public void update(float delta) {
timer += delta;
if (timer >= letterSpawnTime) {
drawText = drawText + completeText.charAt(stringIndex);
stringIndex++;
timer -= letterSpawnTime;
}
font.draw(someFont, drawText, x, y, etc...);
}
Something like that (written out of my head). To be a bit more efficient initialize the StringBuilder in the constructor once and just keep appending a single character to it instead of creating a new StringBuilder instance each time the you need to append a letter.

Error: Syntax error on token "(", ; expected

I have two issues on the same line the first is
Error: Syntax error on token "(", ; expected
Error: Syntax error on token ")", ; expected
I have no idea why its telling me that error, the noob mode is kicking in right now so I cant figure it out.
import java.awt.*;//for graphics class
import java .util.*;// for scanner class
//start of class
public class bouncingball {
// public static final int CENTER = 300;
//start of main
public static void main(String[] args) {
System.out.println("Project 2 modified by Jordan Spicer");
DrawingPanel panel = new DrawingPanel(400, 400);
Graphics g = panel.getGraphics();
Scanner input = new Scanner(System.in);
ball(g);
int test = 0;
String colors = "";
System.out.println(" this program prints out a bouncing ball");
System.out.println("please pick a color for the ball either red or blue ");
colors = input.nextLine();
if( (colors.compareTo("blue") == 0) ||colors.compareTo("red") == 0){
System.out.println("that wasnt a good color try again only put red or blue");
colors = input.nextLine();
System.out.println(colors);
}
else{
System.out.println(colors);
}
public static void ball (Graphics g){ <======= the errors are at this line here
g.setcolor(Color.RED);
g.drawcircle(50,50,50,50);
}
}
}

It seems you method inside another method. Move it to outside. Move following method declarationt to outside.
public static void ball (Graphics g){....}

A little rusty with java right now, but I don't think you can have the method
public static void ball (Graphics g)
inside of the main method. Try declaring it before the main method?

2D Scrolling Game: Firing Bullets. Everything runs properly theres just no image

So heres some code to begin. I first created a class called Bullet. This is where the image should be loaded.
package gameLibrary;
import java.awt.*;
import javax.swing.ImageIcon;
public class Bullet {
int x,y;
Image img;
boolean visible;
public Bullet(int startX, int startY) {
x = startX;
y = startY;
ImageIcon newBullet = new ImageIcon("/resources/bullet.png");
img = newBullet.getImage();
System.out.println("constructor Bullet is called");
visible = true;
}
public void move(){
x = x + 1;
if(x > 854){
System.out.println("Bullet is moving at X = " + x);
visible = false;
}
}
public int getX(){
return x;
}
public int getY() {
return y;
}
public boolean getVisible(){
return visible;
}
public Image getImage(){
return img;
}
}
when the space bar is pressed it calls a method called fire() where a new Bullet(X, Y); is called and then stores it in an ArrayList.
public void fire(){
if(ammo > 0) {
Bullet z = new Bullet(left + 60, y + 70);
bullets.add(z);
ammo--;
}
}
public static ArrayList getBullets(){
return bullets;
}
This code moves the bullet across the screen.
ArrayList bullets = Character.getBullets();
for(int i = 0; i < bullets.size(); i++){
Bullet m = (Bullet) bullets.get(i);
if(m.getVisible() == true){
m.move();
}if(m.getVisible() == false) {
bullets.remove(i);
}
}
And Finally code for the print method.
ArrayList bullets = Character.getBullets();
for(int i = 0; i < bullets.size(); i++){
Bullet m = (Bullet) bullets.get(0);
g2d.drawImage(m.getImage(),m.getX(),m.getY(), null);
}
I cant find where I went wrong. the functioning of the bullet is all working as far as I can tell its just the printing of the image on the screenAny suggestions is much appreciated.

Normally resources are loaded with Class.getResource
ImageIcon newBullet = new ImageIcon(Bullet.class.getResource("resources/bullet.png"));
Of course the resources folder should be in the same package (i.e. in the same folder) as your Bullet class.
That code should always work whether your game is in a jar or not.

I think your resource path is not in the good format.
ImageIcon icon = new ImageIcon("gameLibrary.resources.bullet.png");
if this doesn't work try this code to get your png path:
import java.io.File;
public class GetPath
{
public static void main(String[] args)
{
System.out.println("The user directory: " + System.getProperty("user.dir"));
File fubar = new File("Fubar.txt");
System.out.println("Where Java thinks file is located: " + fubar.getAbsolutePath());
}
}
Tell me what happens.