Question

Apologies if this is a duplicate and my google-fu weak.

I have two options for method routing in my code:

Use a local method that calls a bunch of object attributes:

/* public class Manager */
public void onTouchEvent( Event event )
{
    Vec2 touch = new Vec2( event.getX(), event.getY() );
    for( GameObject o : mGameObjectList )
    {
        if ( isColliding( touch, o ) )
                o.onTouchEvent(event);
    }
}

public boolean isColliding( Vec2 touch, GameObject obj )
{
    if ( ( obj.mPosition[ 0 ] - obj.mScale[ 0 ] ) < touch.x && touch.x < ( obj.mPosition[ 0 ] +  obj.mScale[ 0 ] ) )
    {
        if ( ( obj.mPosition[ 1 ] - obj.mScale[ 1 ] ) < touch.y && touch.y < ( obj.mPosition[ 1 ] +  obj.mScale[ 1 ] ) )
        {
            return true;
        }
    }

    return false;
}

Call an object method which then uses local attributes:

/* public class Manager */
public void onTouchEvent( Event event )
{
    for( GameObject o : mGameObjectList )
    {
        o.isColliding(event);
    }
}

/* public class GameObject */
public boolean isColliding( Event event )
{
    // code here to get touch from event ( or maybe pass in touch? )

    if ( ( mPosition[ 0 ] - mScale[ 0 ] ) < touch.x && touch.x < mPosition[ 0 ] + ( mScale[ 0 ] ) )
    {
        if ( ( mPosition[ 1 ] - mScale[ 1 ] ) < touch.y && touch.y < mPosition[ 1 ] + ( mScale[ 1 ] ) )
        {
            onTouchEvent(event)
        }
    }

    return false;
}

Which set of methods would be better programmatically ( optimal, elegant, simple, etc. )?

Update: fixed code sections. Sorry about that all.

Answer 1

I would write this in terms of a GameObject::containsPoint(x, y) method. That way, it does not need to know about touch events, but nor does your touch class need to know about calculating intersections.

EDIT:

Here’s how I’d do it.

/* class GameObject */
public boolean contains(int x, int y)
{  
    //Your use of parentheses here was really confusing!  
    return mPosition[0] - mScale[0] < x && x < mPosition[0] + mScale[0]
        && mPosition[1] - mScale[1] < y && y < mPosition[1] + mScale[1];

    /* alternatively:
    return Math.abs(x - mPosition[0]) < mScale[0]
        && Math.abs(y - mPosition[1]) < mScale[1];
    */
}

/* class Manager */
public void onTouchEvent( Event event )
{
    for( GameObject o : mGameObjectList )
    {
        if(o.contains(event.getX(), event.getY()))
        {
            o.onTouchEvent(event);
        }
    }
}

I’m not sure the conversion to Vec2 is productive (or consistent) here. Why is the the touch point promoted to a Vec2, yet GameObject::mPosition is an array?