HaxeFlixel. Nape. DistanceJoint debugging. Drag sprite to area - debugging

Question

I have a sprite that I can drag around on screen. I want to be able to drag this sprite into an area (box). As it stands now I can only drop the sprite into the box, but when I drag it directly inn, the program crashes.
I have debugged in FlashDevelop using the Adobe Flash debugger. When I place the sprite into the box the debugger points to this line of code in the DistanceJoint.hx file:
if(b1.space!=space||b2.space!=space)throw "Error: Constraints must have each body within the same space to which the constraint has been assigned";
I think I understand what I have to do, but I am having a hard time finding a way to make a proper exception in my Drag class.
My idea is to break the mouseJoint in the Drag class when the collideLightBox function in Playstate is used. But I do not know how to do that, or if it is the right idea. Please help.
Relevant code:
class Drag extends FlxGroup {
var mouseJoint:DistanceJoint;
public inline function registerPhysSprite(spr:FlxNapeSprite)
{
MouseEventManager.add(spr, createMouseJoint);
}
function createMouseJoint(spr:FlxSprite)
{
var body:Body = cast(spr, FlxNapeSprite).body;
mouseJoint = new DistanceJoint(FlxNapeState.space.world, body,
new Vec2(FlxG.mouse.x, FlxG.mouse.y),
body.worldPointToLocal(new Vec2(FlxG.mouse.x, FlxG.mouse.y)),
0, 0);
mouseJoint.space = FlxNapeState.space;
}
override public function update():Void
{
super.update();
if (mouseJoint != null)
{
mouseJoint.anchor1 = new Vec2(FlxG.mouse.x, FlxG.mouse.y);
if (FlxG.mouse.justReleased)
{
mouseJoint.space = null;
}
}
}
}
class PlayState extends FlxNapeState {
override public function create()
{
super.create();
bgColor = FlxColor.BLACK;
napeDebugEnabled = true;
var light = new Light(10, 10);
var box = new Box(100, 100);
var drag:Drag;
createWalls(1, 1, 1024, 768, 10, new Material(1, 1, 2, 1, 0.001));
add(light);
add(box);
drag = new Drag();
add(drag);
drag.registerPhysSprite(light);
light.body.velocity.y = 200;
FlxNapeState.space.listeners.add(new InteractionListener(
CbEvent.BEGIN,
InteractionType.COLLISION,
Light.CB_TYPE,
Box.CB_TYPE,
collideLightBox));
}
function collideLightBox(callback:InteractionCallback)
{
var light:Light = cast callback.int1.castBody.userData.sprite;
light.kill();
}
}
class Light extends FlxNapeSprite {
public static var CB_TYPE(default, null) = new CbType();
public function new(x:Float, y:Float)
{
super(x, y);
makeGraphic(10, 10, FlxColor.TRANSPARENT);
var radius = 5;
drawCircle(5, 5, radius, FlxColor.WHITE);
createCircularBody(radius);
body.cbTypes.add(CB_TYPE);
body.userData.sprite = this;
}
}
class Box extends FlxNapeSprite {
public static var CB_TYPE(default, null) = new CbType();
public function new(x:Float, y:Float)
{
super(x, y);
makeGraphic(100, 50, FlxColor.GREEN);
createRectangularBody(width, height);
body.cbTypes.add(CB_TYPE);
body.type = BodyType.STATIC;
}
}

Answer 1

Give Drag a function like "destroyConstraints()" and set mouseJoint.space = null inside that function. In collideLightBox, call drag.destroyConstraints().