Help writing RTS game

Question

I have been writing a RTS game, and need help. Can anyone tell me how to, when one of my units gets in range of a foe, to attack that foe and destroy it? It should attack the closest target in its weapons range. Here is my code so far...
Main.java
package rixor;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.net.URL;
import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JViewport;
public class Main extends JFrame implements ActionListener, KeyListener, Runnable, MouseListener,
        MouseMotionListener {
    Image map;
    int mouseX, mouseY;
    int counter = 0;
    Thread game = new Thread(this);
    int mode = 0;
    Point p = new Point(0,0);
    JViewport port = new JViewport();
    //Create my resources
    int resources = 10000;
    int aiResources = 10000;
    unit[] units = new unit[600];
    unit[] aiUnits = new unit[600];
    SoundClip music;
    SoundClip transferScreen;
    //Declare faction variables
    int playerFaction = 0;
    int computerFaction = 0;
    int mouseXa;
    int mouseYa;
    boolean enterGameSetupScreen = false;
    public Main() {
        super("Rixos");
        setSize(1024,768);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        draw drawer = new draw();
        Container content = getContentPane();
        content.add(drawer);
        setContentPane(content);
        addKeyListener(this);
        addMouseListener(this);
        addMouseMotionListener(this);
        game.start();
        music = new SoundClip("music.wav");
        transferScreen = new SoundClip("0000.wav");
        music.setLooping(true);
        this.setResizable(false);
        this.setDefaultLookAndFeelDecorated(true);
        FlowLayout flow = new FlowLayout();
        content.setLayout(flow);
        music.play();
    public class draw extends JPanel {
        public void paintComponent(Graphics g) {
            Image image;
            //Draw the mouse
            if(mode == 0) {
                g.setColor(Color.black);
                g.fillRect(0,0,1024,768);
                g.setColor(Color.white);
                g.setFont(new Font("Axaxax",Font.PLAIN,40));
                Toolkit tk = Toolkit.getDefaultToolkit();
                image = tk.getImage(getURL("splash.png"));
                g.drawImage(image,0,0,null);
                g.drawString("Press B to Begin",100,100);
                g.setColor(Color.GREEN);
                g.fillRect(mouseX-10,mouseY-29,20,20);
                repaint();
            if(mode == 1) {
                g.setColor(Color.black);
                g.fillRect(0,0,1024,768);
                Toolkit tk = Toolkit.getDefaultToolkit();
                image = tk.getImage(getURL("back.png"));
                g.drawImage(image,0,0,null);
                image = tk.getImage(getURL("earth.jpg"));
                g.drawImage(image,700,200,null);
                image = tk.getImage(getURL("planet.jpg"));
                g.drawImage(image,690,450,null);
                g.setFont(new Font("Axaxax",Font.PLAIN,80));
                g.drawString("Operations Center Menu",40,80);
                g.setColor(Color.RED);
                g.fillRect(73,200,300,50);
                g.fillRect(73,300,300,50);
                g.setFont(new Font("Axaxax",Font.PLAIN,35));
                g.setColor(Color.black);
                g.drawString("About This Game",75,240);
                g.setColor(Color.GREEN);
                g.fillRect(70,170,20,20);
                checkImage(70,270,20,20,mouseX-10,mouseY-29,20,20);
                g.fillRect(70,270,20,20);
                g.setColor(Color.black);
                g.drawString("Start a Game",75,340);
                g.setColor(Color.GREEN);
                g.fillRect(mouseX-10,mouseY-29,20,20);
                repaint();
            if(mode == 4) {
                //The select map screen
                g.setColor(Color.green);
                g.fillRect(0,0,1024,768);
            if(mode == 2) {
                //The game mode (Under construction)
                Toolkit tk = Toolkit.getDefaultToolkit();
                image = tk.getImage(getURL("back.png"));
                g.drawImage(image,0,0,null);
                Color transparency = null;
                if(playerFaction == 0) {
                    //Each faction gets a different HUD Color
                    transparency = new Color(10,10,10,50);
                g.setColor(transparency);
                g.fillRect(900,50,100,680);
                g.fillRect(10,20,990,25);
                g.setColor(Color.BLACK);
                g.setFont(new Font("Axaxax",Font.PLAIN,20));
                if(playerFaction == 0) {
                    //Each faction gets a different TEXT Color
                    g.setColor(Color.BLUE);
                g.drawString("Resources: "+resources,15,40);
                if(playerFaction == 0) {
                    g.drawString("Faction: None",215,40);
                g.setColor(transparency);
                g.fillRect(mouseX-10,mouseY-29,20,20);
                g.setColor(Color.RED);
                g.fillRect(970,22,20,20);
                g.setColor(transparency);
                for(int i = 0; i < 600; i++) {
                    if(units.getHealth() > 0) units[i].drawUnit(g,Color.BLUE);
if(aiUnits[i].getHealth() > 0) aiUnits[i].drawUnit(g,Color.RED);
g.setColor(Color.RED);
//Draw the tank option
image = tk.getImage(getURL("0000.png"));
g.drawImage(image,900,80,null);
repaint();
private URL getURL(String string) {
URL url = null;
try {
url = this.getClass().getResource(string);
} catch(Exception e) {}
return url;
public void checkImage(int i, int i0, int i1, int i2, int i3, int i4, int i5, int i6) {
Rectangle b = new Rectangle(i,i0,i1,i2);
Rectangle c = new Rectangle(i3,i4,i5,i6);
if(b.intersects(c)) {
enterGameSetupScreen = true;
public static void main(String[] args) {
Main i = new Main();
public void actionPerformed(ActionEvent e) {
public void keyTyped(KeyEvent e) {
public void keyPressed(KeyEvent e) {
if(mode == 0){
if(e.getKeyCode() == KeyEvent.VK_B) {
transferScreen.play();
mode = 1;
if(mode == 3) {
if(e.getKeyCode() == KeyEvent.VK_B) {
mode = 1;
transferScreen.play();
if(e.getKeyCode() == KeyEvent.VK_Y) {
mode = 2;
//Create player's construction vehicle
for(int i = 0; i < 600; i++) {
units[i] = new unit(0,0,0,0,0,0,0);
aiUnits[i] = new unit(0,0,0,0,0,0,0);
units[0].setController(1);
units[0].setType(1);
units[0].setX(500);
units[0].setY(680);
units[0].setHealth(80000);
units[0].setSpeed(0);
aiUnits[0].setController(2);
aiUnits[0].setType(1);
aiUnits[0].setX(500);
aiUnits[0].setY(30);
aiUnits[0].setHealth(80000);
aiUnits[0].setSpeed(0);
//TODO: ADD AI UNITS
transferScreen.play();
if(mode == 2) {
for(int i = 0; i < 600; i++) {
if(e.getKeyCode() == KeyEvent.VK_DELETE) {
if(units[i].isSelected()) {
if(units[i].getType() == 2) { resources = resources + 600; }
units[i].setType(0);
public void keyReleased(KeyEvent e) {
public void run() {
while(game == Thread.currentThread()) {
if(mode == 2) {
if(counter < 90) {
//Count the time for a resource addition
counter = counter + 1;
if(counter == 90) {
//Allot resources to the player
resources = resources + 5;
aiResources = resources + 5;
counter = 0;
moveCheck();
if(mode == 1) {
counter = 0;
try {
Thread.sleep(20);
} catch(Exception e) {}
repaint();
public void mouseClicked(MouseEvent e) {
public void mousePressed(MouseEvent e) {
if(mode == 1) {
if(e.getX() > 70) {
if(e.getX() < 120) {
if(e.getY() > 200) {
if(e.getY() < 500) {
mode = 3;
transferScreen.play();
if(enterGameSetupScreen) {
mode = 4;
enterGameSetupScreen = false;
if(mode == 2) {
//Does in-game mouse detection
Rectangle Quit = new Rectangle(970,22,20,20);
Rectangle mouseTest = new Rectangle(mouseX-10,mouseY-29,20,20);
if(Quit.intersects(mouseTest)) {
transferScreen.play();
mode = 1;
aiResources = 10000;
resources = 10000;
for(int i = 0; i < 600; i++) {
//Deletes the units
try {
units[i].setController(0);
units[i].setType(0);
aiUnits[i].setController(0);
aiUnits[i].setType(0);
} catch(Exception ex) {}
//Creates a new Human tank if player is human
if(mouseTest.intersects((new Rectangle(900,80,50,50)))) {
int offset = 0;
boolean found = false;
if(playerFaction == 0) {
if(resources > 700) {
resources = resources - 700;
for(int i = 0; i < 600; i++) {
if(found == false) {
if(units[i].getType() == 0) {
offset = offset - 10;
found = true;
units[i].setType(2);
units[i].setFirepower(800);
units[i].setX(550+offset);
units[i].setY(650+offset);
units[i].setSpeed(1);
units[i].setHealth(800);
units[i].setController(1);
for(int i = 0; i < 600; i++) {
if(mouseTest.intersects(units[i].getBounds())) {
units[i].setSelected(true);
if(!mouseTest.intersects(units[i].getBounds())) {
units[i].setSelected(false);
public void mouseReleased(MouseEvent e) {
public void mouseEntered(MouseEvent e) {
public void mouseExited(MouseEvent e) {
public void mouseDragged(MouseEvent e) {
for(int i = 0; i < units.length; i++) {
if(units[i].isSelected()) {
//The moving!
if(units[i].getType() == 2) {
units[i].setState(3);
if(units[i].isSelected()) {
//The moving!
if(units[i].getType() == 2) {
units[i].setState(0);
units[i].setDistance(new Point(e.getX(),e.getY()));
units[i].setTraveled(0);
public void mouseMoved(MouseEvent e) {
//Moves our mouse collision sensor accross screen
mouseX = e.getX();
mouseY = e.getY();
private void moveCheck() {
if(mode == 2) {
for(int i = 0; i < units.length; i++) {
if(units[i].getDistance() != new Point(units[i].getX(),units[i].getY())) {
if(units[i].getX() > units[i].getDistance().getX()) {
units[i].setX(units[i].getX() - units[i].getSpeed());
if(units[i].getX() < units[i].getDistance().getX()) {
units[i].setX(units[i].getX() + units[i].getSpeed());
if(units[i].getY() > units[i].getDistance().getY()) {
units[i].setY(units[i].getY() - units[i].getSpeed());
if(units[i].getY() < units[i].getDistance().getY()) {
units[i].setY(units[i].getY() + units[i].getSpeed());
And here is my unit.java file...
package rixor;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.net.URL;
public class unit {
    //This class controlls the units and structures and allows them to be declared.
    int type = 0;
    int controller = 0;
    //1 is player, 2 is computer
    int health = 0;
    int firepower = 0;
    int speed = 0;
    int x;
    int y;
    int traveled;
    Point distance = new Point(x,y);
    int sizeX;;
    int sizeY;
    int state = 0;
    //0 is being places, 1 is placed.
    boolean selected = false;
    public unit(int type, int controller, int health, int firepower, int speed, int x, int y) {
        this.type = type;
        this.controller = controller;
        this.health = health;
        this.firepower = firepower;
        this.speed = speed;
        this.x = x;
        this.y = y;
    public int getHealth() {
        return health;
    public int getType() {
        return type;
    public int getController() {
        return controller;
    public int getSpeed() {
        return speed;
    public int getFirepower() {
        return firepower;
    public int getX() {
        return x;
    public int getY() {
        return y;
    public void setX(int x) {
        this.x = x;
    public void setY(int y) {
        this.y = y;
    public void setHealth(int health) {
        this.health = health;
    public void setFirepower(int firepower) {
        this.firepower = firepower;
    public void setController(int controller) {
        this.controller = controller;
    public void setSpeed(int speed) {
        this.speed = speed;
    public void setType(int type) {
        this.type = type;
    public void setState(int state) {
        this.state = state;
    public int getState() {
        return state;
    public void drawUnit(Graphics g, Color color) {
        Image image;
        Toolkit tk = Toolkit.getDefaultToolkit();
        if(type == 1) {
            sizeX = 30;
            sizeY = 30;
            //Draw A Construction Vehicle
            g.setColor(color);
            g.fillRect(x,y,sizeX,sizeY);
            g.setFont(new Font("Axaxax",Font.PLAIN,36));
            g.setColor(Color.green);
            g.drawString("C",x+5,y+30);
            if(selected == true) {
                g.setColor(Color.PINK);
                g.drawRect(x,y,sizeX,sizeY);
        if(type == 2) {
            sizeX = 40;
            sizeY = 40;
            image = tk.getImage(getURL("0000.png"));
            g.drawImage(image,x,y,null);
            if(selected == true) {
                g.setColor(Color.PINK);
                g.drawRect(x,y,50,50);
    private URL getURL(String string) {
        URL url = null;
        try {
            url = this.getClass().getResource(string);
        } catch(Exception e) {}
        return url;
    public Rectangle getBounds() {
        Rectangle bounds = new Rectangle(x,y,sizeX,sizeY);
        return bounds;
    public void setSelected(boolean selected) {
        this.selected = selected;
    public boolean isSelected() {
        return selected;
    public void setTraveled(int traveled) {
        this.traveled = traveled;
    public void setDistance(Point distance) {
        this.distance = distance;
    public int getTraveled() {
        return traveled;
    public Point getDistance() {
        return distance;
//TODO: Implement collision testing systemThat's all you should need to help. Thanks in advance.

Answer 1

pardon me jwenting,
But you cannot triangulate with 2 (x,y) pairs.
TRI-angulation involves 3 coordinates.
The method our peer needs is a simple distance formula:
dist = sqrt( ( x1-x2 )^2 + ( y1-y2 )^2 )
Now...
All you need for range detection is a little "for-each loop"
Place something like this in your unit class's update method:
for ( each unit in unit list )
   if ( unit.isNotMine() && unit.isWithinMyRange() )
      this.attack( unit );
}The attack( Unit u ) function should do as follows:
double dx = this.getX()-u.getX(); //you may need to flip these i did not test
double dy = this.getY()-u.getY();
double angle = Math.atan2(dy,dx);
// here define what "attacking" even means???
if ( this.isMelee() )
   this.x += Math.cos(angle)*this.getSpeed(); //this will move your unit
   this.y += Math.sin(angle)*this.getSpeed();
   if ( this.getDistance( u ) <= this.meleeAttackRange() )
      this.causeDamage( u );
else
   load++;
   if ( load>this.loadingTime() )
      this.shootToward( unit );
}Ok, get started with that...
If that doesn't help then we cant help you!!
Show us what you're trying to do, then tell us what errors.
Dont just post all your code and say "fix-me".
Good luck though, hope this gave you some ideas.
Message was edited by:
ArikArikArik