Greenfoot

h35am

2015/1/9

#

Hi All, I need to generate objects in greenfoot world, this must be complitly random but in specific locations. How can I achieve this? This is what I have done so far but I dont know how to complete this.

public void spawnContainer()
    {    
      
        ContainerRoodDek1 containerRoodDek1 = new ContainerRoodDek1();
        ContainerGeelDek1 containerGeelDek1 = new ContainerGeelDek1();
        ContainerGroenDek1 containerGroenDek1 = new ContainerGroenDek1();
        ContainerBlauwDek1 containerBlauwDek1 = new ContainerBlauwDek1();
        
        addObject(containerRoodDek1, 255,206);
    }

thnx for helping

Ruvero

2015/1/9

#

Make an array of all your specific locations. Use Greenfoot.random() to get the coordinates of a random location.

danpost

2015/1/9

#

Ruvero is on the right track; however, the method is 'Greenfoot.getRandomNumber(int)'. Also, there is the problem of a location being chosen more than once (or having two or more containers end up at the same location). Any ideas, Ruvero?

Ruvero

2015/1/9

#

Remove the used location from the array, be sure to use the size of the array as the maximum for Greenfoot.getRandomNumber to avoid errors. Edit: and by the way: use English for all your variables and object names. You will be judged by your teacher on that too ;).

danpost

2015/1/9

#

Ruvero wrote...

Remove the used location from the array, be sure to use the size of the array as the maximum for Greenfoot.getRandomNumber to avoid errors.

Arrays have a set size. You can remove a location from the array by making the element the location was at 'null'; but, you cannot remove the position within the array the location was at. Want to try again?

Ruvero

2015/1/9

#

Not very effective: if position == null, try again.

danpost

2015/1/9

#

Ruvero wrote...

Not very effective: if position == null, try again.

More effective would be to track the number of remaining locations and move the last choice to the position of the one used after each choice.

Super_Hippo

2015/1/9

#

You can also have the code in the 'addedToWorld' method and have a while loop to choose a new location until an empty one is found.

h35am

2015/1/9

#

Thanx a lot people :) I will try to fix this, Thnx Ruvero, Ive got a dutch teacher so he dont mind but I will certainly consider your suggestion ;)

h35am

2015/1/9

#

Ive used this solution and it works fine:

public void spawnContainerDek1(int x, int y)
    {   
        Dek1 containerRoodDek1 = new ContainerRoodDek1();
        Dek1 containerGeelDek1 = new ContainerGeelDek1();
        Dek1 containerGroenDek1 = new ContainerGroenDek1();
        Dek1 containerBlauwDek1 = new ContainerBlauwDek1();
        
        //array maken van containers
        Dek1[] containerArray = new Dek1[4];
        
        containerArray[0] = containerRoodDek1;
        containerArray[1] = containerGeelDek1;
        containerArray[2] = containerGroenDek1;
        containerArray[3] = containerBlauwDek1;
        
        //de identifier van de containerArray
        int i;
        
        //procent kans aanmaken
        int precentage = ((int)(Math.random() * 100));
        
        if(precentage >= 0 && precentage < 25){
        // kans tot 25%
            i=0;
        } else if (precentage >= 25 && precentage < 50){
            i=1;
        } else if (precentage >= 50 && precentage < 75){
            i=2;
        } else{
            i=3;
        }
        
        
        addObject(containerArray[i], x,y);
        
    }

Thnx all for helping me out :)

Ruvero

2015/1/9

#

Greenfoot has an own random number generator. For example:

Greenfoot.getRandomNumber(3)

Will generate a number between 0 and 3. So if you replace line 17 with:

int i = Greenfoot.getRandomNumber(3)

Then you can delete line 19-31.

danpost

2015/1/9

#

Ruvero wrote...

For example:

Greenfoot.getRandomNumber(3)

Will generate a number between 0 and 3.

That is not correct. That line of code will only generate a number between 0 and 2, giving the 3 possibilities { 0, 1, 2 }.

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Generate random objects on specific locations