Does OnMouseUp() require OnMouseDown() to be triggered first?

Questions & Answers
1

This might be a bug, or I may just be looking at this wrong, but here's the behavior I'm seeing. I want to be able to click the mouse somewhere on the screen (not over my target) and drag the mouse over the target object. When I let go of the mouse button, I'd like things to happen. On my target object I have a script attached with this:

function OnMouseUp() {
   print("Your Mouse button is up!");
}

Pretty simple. Yet, when I click somewhere on the screen, drag my mouse on top of the object, and then let the button go nothing happens. If I click the mouse down on top of my target and then let it go it works correctly. I assume this is because when my mouse is clicked while over the target it fires the OnMouseDown() function.

I've worked around the issue by setting a variable to true when OnMouseEnter() is triggered, and then in the update() I test is the variable is true && the GetMouseButtonUp(0).

function OnMouseEnter() {
   mouseIsOver = true;
}

function Update() {
   if(mouseIsOver) {
      if(Input.GetMouseButtonUp(0)) {
         print("Your mouse button is up!");
      }
   }
}

Is this a bug, or am I missing something really obvious?

2

From the documentation:

"OnMouseUp is only called if the mouse was pressed down while over the same GUIElement or Collider."

http://unity3d.com/support/documentation/ScriptReference/MonoBehaviour.OnMouseUp.html

So perhaps it's because you're moving the mouse before releasing the mouse button that you're not getting the expected behavior?