setDraggable does not work without adding a mouse joint

[catmanjan]

Not sure if this is how Box2D works, but adding
add(new B2FlxMouseJoint());

Makes setDraggable actually work. Why not just always add a mouse joint in B2FlxState?

[WingEraser]

I didn't added that because of performance. Once you click on a box2d object it will go through some calculations. You can see it in B2FlxMouseJoint::mouseDown(). It needs to query all fixtures that may overlap the provided AABB. After that it needs to know whether the body is draggable or not.

My game uses box2d with a lot of bodies. The controls are just FlxButtons, but every time I press on the screen, it doesn't have to query all the fixtures.

[catmanjan]

How about automatically adding a mouse joint (if one doesn't already exist) as soon as setDraggable is set to true on any body?

[WingEraser]

Nope, ain't going to happen. I don't want any specific joint to be in B2FlxShape. It will also have some problem with multitouch support (if I ever managed to get that working properly). I need multiple mouse joints for that.