Hi.
I want to place 4 instances of my Obstacle class in the world at random locations.
When I've tried doing it I only see one object, but I want them at different locations.
How would I go about doing this?
Wavesludge wrote ...
2012/11/25
Mutliple random placements
1
2
You probably have done this:
but then x and y are the same values in all cases.
So you better do it like this:
int x = Greenfoot.getRandomNumber(1000);//the width of your world; int y = Greenfoot.getRandomNumber(1000);//the heigth of your world; addObject(new Obstacle(), x, y); addObject(new Obstacle(), x, y); //...
for (int i = 0; i < 4; i++) {
addObject(new Obstacle(), Greenfoot.getRandomNumber(getWidth()), Greenfoot.getRandomNumber(getHeight()));
}Thank you very much!
One more thing.
I have 4 images that I want the obstacles to randomly get, so every one isn't the same. I have used this:
But it acts like a loop, so every obstacles goes through every 4 images, it looks like a gif.
How would I do to make it so it's not like a loop, the obstacles just get one of the four images?
setImage("Obstacle" + Greenfoot.getRandomNumber(4) + ".png"); 
Sounds like you put that statement in the act method, instead of the constructor of the class.
it looks like a loop because the image changes every act because you have put this code in the act method.
If you just get it out if the act method and put it into the constructor it'll work.
If I put it in the constructor I get an error:
Invalid method declaration; return type required
that just means your declaration of the constructor is wrong.
A constructor has to look like this:
public class AnyClass {
public AnyClass() {
//your code you want to put in the constructor;
}
}Your soloution worked Gevater, thanks!
I forgot to do the public AnyClass()
One problem I've been having. I'm having two classes placing randomly, and sometimes they land ontop of eachother.
How could you make so that doesn't happen?
private void ritem()
{
if (getObjects(Obstacle.class).isEmpty())
{
for (int i = 0; i < 7; i++) {
addObject(new Obstacle(), Greenfoot.getRandomNumber(getWidth()), Greenfoot.getRandomNumber(getHeight()));
}
}
if (getObjects(Food.class).isEmpty())
{
for (int i = 0; i < 1; i++) {
addObject(new Food(), Greenfoot.getRandomNumber(getWidth()), Greenfoot.getRandomNumber(getHeight()));
}
}
}Change your addObject so that it generates the positions within itself and validates that nothing else exists at that location (if something does then it should generate a new position pair)
OK, I don't know how to do that. Still new to greenfoot. Could you give an example?
I think an easyer way would be to change the locations of the objects if they intersect each other.
You could do it like this:
//in the class you want to add some objects of;
private boolean initialised = false;//you need this because you cant write it in your constructor;
public void act() {
if (!initialised) {
while (!getIntersectingObjects(ClassA.class).isEmpty() || !getIntersectingObjects(CalssB.class).isEmpty()) {// you need to check for every class you don't want this object to intersect with;
setLocation(Greenfoot.getRandomNumber(getWorld().getWidth()), Greenfoot.getRandomNumber(getWorld().getHeight()));
}
initialised = true;
}
}Worked like a charm, thanks!
There are more replies on the next page.
1
2