Question

Now, I have been looking for the answer to this for a while, but Google and all my power seems to fail me.

I got this Class. (MyWorld).
Within MyWorld I have an Array of objects

GameUnit m_MyUnits[] = new GameUnit[maxUnits];

Right now m_MyUnits are filled up with GameUnits and subclasses here off, and the are walking around the screen happy as cheesecake.
I have even written my own little collision detection for each of them, so they won’t bump into each other.

And all works fine, BUT!
For my collision detection to work I have chosen the slowest of ways (and most memory requiring I think)

In MyWorld I first loop trough each GameUnit and gets its X and Y position for an array
private int[][] Positions = new int[2][maxUnits]);

I then loop trough each and every GameUnit and assigns this array to it. (GameUnit has its own array called Positions for this)

Now, while this works, I can’t help but think that this is stupid like …. Well, I won’t use those words here.

Is there a way for GameUnit to Call the Positions in MyWorld, or even better, for the game unit to call the Array m_MyUnits[].getX() and m_MyUnits[].getY() in MyWorld
Some thing like this (I use Parent to refer to MyWorld from the GameUnit)

For(int i = 0;i < Parent.maxUnits;i++) {
  int targetX = Parent. m_MyUnits[i].getX();
  int targetY = Parent. m_MyUnits[i].getX();
  //Do some thing like collition detection with the data.
}

Is this possible, or?

Yours JavaApprentis.

Answer 1

When you create a GameUnit, you could pass the MyWorld as a constructor argument. The GameUnit constructor could then store the MyWorld object in a member variable. Then when it needed to do collsion detection, it could ask the MyWorld for a list of potential partners by calling a method on that object.

In GameUnit:

private MyWorld myWorld;

public GameUnit(int,int,double, MyWorld m) {
    myWorld = m;
}

And then in MyWorld, when you make a GameUnit:

new GameUnit(1, 2, 1.0, this);

Then in all the methods of GameUnit, you have the MyWorld object in myWorld available for use.