SOLVED - Enemy class

Newbie & Debugging Questions
#1

I am trying to use the same enemy class to create two enemies. How can i do this? If I try to just call it twice, it makes two different ones, but they follow the exact same patter.

Here is the class -

package main;

import java.awt.Image;

import javax.swing.ImageIcon;

public class Enemy1 {
	int x, y;
	int dx, dy;
	Image enemy;
	boolean starting;
	boolean newDirection = false;
	
	public Enemy1()
	{
		ImageIcon i = new ImageIcon(getClass().getResource("/textures/enemy.png"));
		enemy = i.getImage();
		x = 100 + (int) (Math.random() * ((200 - 100) + 1));
		y = 100 + (int) (Math.random() * ((200 - 100) + 1));
		starting = true;
	}
	
	public void move()
	{
		if (starting)
		{
			int movement = 1 + (int) (Math.random() * ((2 - 1) + 1));
			
			if (movement == 1) dx = 1;
			if (movement == 2) dx = -1;
			
			movement = 3 + (int) (Math.random() * ((4 - 3) + 1));
			
			if (movement == 3) dy = 1;
			if (movement == 4) dy = -1;
			
			dx = 1;
			dy = 1;
			
			starting = false;
		}
		
		if (x == 750) 
		{
			x = 749;
			newDirection = true;
		}
		
		if (x == 10) 
		{
			x = 11;
			newDirection = true;
		}
		
		if (y == 480) 
		{
			y = 479;
			newDirection = true;
		}
		
		if (y == 10)
		{
			y = 11;
			newDirection = true;
		}
		
		if (newDirection)
		{			
			if ((dx == 1) && (dy == 1))
			{
				if (y == 479) dy = -1;
				if (x == 749) dx = -1;
			}
			
			else if ((dx == 1) && (dy == -1))
			{
				if (y == 11) dy = 1;
				if (x == 749) dx = -1;
			}
			
			else if ((dx == -1) && (dy == 1))
			{
				if (y == 479) dy = -1;
				if (x == 11) dx = 1;
			}
			
			else if ((dx == -1) && (dy == -1))
			{
				if (y == 11) dy = 1;
				if (x == 11) dx = 1;
			}
			
			newDirection = false;
		}
		
		x = x + dx;
		y = y + dy;
	}
	
	public int getX() {return x;}
	public int getY() {return y;}
	public Image getImage() {return enemy;}
}

Here’s the Board class where the enemy is drawn -

public class Board extends JPanel implements ActionListener
{
	private static final long serialVersionUID = -6045447081410695806L;
	
	Player p;
	Enemy1 en, en2;
	Image background;
	Timer time;
	Player playerGetX;
	
	public Board()
	{
		p = new Player();
		en = new Enemy1();
		en2 = new Enemy1();
		addKeyListener(new AL());
		setFocusable(true);
		ImageIcon i = new ImageIcon(getClass().getResource("/textures/Moldy_Background.png"));
		background = i.getImage();
		time = new Timer(5, this);
		time.start();
	}
	
	public void actionPerformed(ActionEvent e)
	{
		p.move();
		en.move();
		en2.move();
		checkCollision();
		repaint();
	}
	
	public void paint(Graphics g)
	{
		super.paint(g);
		Graphics2D g2d = (Graphics2D) g;
		
		g2d.drawImage(background, 0, 0, null);
		g2d.drawImage(p.getImage(), p.getX(), p.getY(), null);
		g2d.drawImage(en.getImage(), en.getX(), en.getY(), null);
		g2d.drawImage(en2.getImage(), en2.getX(), en2.getY(), null);
	}
	
	private class AL extends KeyAdapter
	{
		public void keyReleased(KeyEvent e)
		{
			p.keyReleased(e);
		}
		
		public void keyPressed(KeyEvent e)
		{
			p.keyPressed(e);
		}
	}
	
	public void checkCollision()
	{
		
	}
}

Thanks.

#2

Have you tried stepping through it in a debugger? My guess is that the (int) rounding is actually cancelling out whatever effect Math.random() is having, so they both follow the same non-random path. What happens if you do all your movement as floats and just cast the position back to ints to draw?

#3

Thanks. It works now.

#4

sry for asking,
but what were you thinking when you wrote this code?

if (starting)
      {
         int movement = 1 + (int) (Math.random() * ((2 - 1) + 1));
         
         if (movement == 1) dx = 1;
         if (movement == 2) dx = -1;
         
         movement = 3 + (int) (Math.random() * ((4 - 3) + 1));


         
         if (movement == 3) dy = 1;
         if (movement == 4) dy = -1;
         
         dx = 1;
         dy = 1;
         
         starting = false;
      }

first of all, why is this not in the constructor ???
and second what is it with this movment field?


dx = Math.random() < 0.5 ? -1 : 1;
dy = Math.random() < 0.5 ? -1 : 1;
#5

Because I am new and have NO idea what that points up even means.

#6

It’s a ternary operator, or a simplified if-else. For example, the below code sets x to 5 if 0 is less than 1 and -5 if 0 is not less than 1.

int x = 0 < 1 ? 5 : -5;
#7 
int x = booleanExpression ? 5 : -5;

is equal to

int x;
if(booleanExpression){
    x = 5;
}else{
    x = -5;
}

It’s just a convenience method.