I am making a game for a school project.
I need help a random spawn function
it is should spawn an asteroid in top for the screen and move down and i cant make them spawn and move
my code look in line 27 to 42
import greenfoot.*; // (World, Actor, GreenfootImage, and Greenfoot) public class ScrollWorld extends World { private static final GreenfootImage bgImage = new GreenfootImage("space1.gif"); private static final int scrollSpeed = -4; private GreenfootImage scrollingImage; private int scrollPosition = 0; private int startAsteroid = 1; public int pause = 10; public ScrollWorld() { super(400, 600, 1); GreenfootImage background = new GreenfootImage(400, 600); scrollingImage = getScrollingImage(400, 600); background.drawImage(scrollingImage, 0, 0); setBackground(background); addObject(new SpaceShip(), 200, 570); //addAsteroids(startAsteroid); prepare(); } public void addAsteroid () { Asteroid asteroid = new Asteroid(); if (pause>0) { pause--; return; } if (pause ==0) { int x = Greenfoot.getRandomNumber(400); int y = (2); addObject(new Asteroid(), x, y); //asteroid.setRotation(); } } public void act() { if(scrollSpeed < 0 && scrollPosition <= 0) { scrollPosition = getHeight(); } if(scrollSpeed < 0 && scrollPosition >= getHeight()) { scrollPosition = 0; } scrollPosition -= scrollSpeed; paint(scrollPosition); } /** * Paint scrolling image at given position and make sure the rest of * the background is also painted with the same image. */ private void paint(int position) { GreenfootImage bg = getBackground(); bg.drawImage(scrollingImage, 0, position); bg.drawImage(scrollingImage, 0, position - scrollingImage.getWidth()); } /** * Returns an image with the given dimensions. */ private GreenfootImage getScrollingImage(int width, int height) { GreenfootImage image = new GreenfootImage(width, height); for(int x = 0; x < width; x += bgImage.getWidth()) { for(int y = 0; y < height; y += bgImage.getHeight()) { image.drawImage(bgImage, x, y); } } return image; } /** * Prepare the world for the start of the program. That is: create the initial * objects and add them to the world. */ private void prepare() { } }