My background scrolls horizontally and i need to add objects that come after into the screen but you cant see them before. I will be happy to share my coding. Please help
Hamza_Abdulla03 wrote ...
2017/3/27
How do you add objects that come onto the screen later in a moving background?
If the scrolling implementation was done optimally, then you should be able to just add the actor, 'actor', with one of the following statement types:
Your world constructor should be one of:
super(int, int, int, false);
addObject(actor, -30, Greenfoot.getRandomNumber(getHeight()); // or addObject(actor, getWidth()+30, Greenfoot.getRandomNumber(getHeight());
invalid method declaration
import greenfoot.*; // (World, Actor, GreenfootImage, Greenfoot and MouseInfo)
/**
* Write a description of class MyWorld here.
*
* @author (your name)
* @version (a version number or a date)
*/
public class Background extends World
{
private static final String bgImageName = "space1.jpg";
private static final double scrollSpeed = 2.5;
private static final int picWidth = (new GreenfootImage(bgImageName)).getWidth();
private GreenfootImage bgImage, bgBase;
private int scrollPosition = 0;
public Background()
{
super(800, 400, 1);
setBackground(bgImageName);
bgImage = new GreenfootImage(getBackground());
bgBase = new GreenfootImage(picWidth, getHeight());
bgBase.drawImage(bgImage, 0, 0);
prepare();
}
public void act()
{
scrollPosition -= scrollSpeed;
while(scrollSpeed > 0 && scrollPosition < -picWidth) scrollPosition += picWidth;
while(scrollSpeed < 0 && scrollPosition > 0) scrollPosition -= picWidth;
paint(scrollPosition);
}
private void paint(int position)
{
GreenfootImage bg = getBackground();
bg.drawImage(bgBase, position, 0);
bg.drawImage(bgImage, position + picWidth, 0);
}
private void prepare()
{
Airplane airplane = new Airplane();
addObject(airplane,75,203);
}
}
Please use code tags, so you can say in which line you get your error.
Change
to
super(800, 400, 1);
super(800, 400, 1, false);
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