Issue with constraining a crosshair to an actor

HappyKat78

Hi All,

I have an actor and a crosshair (ok, that's another actor, but I'm differentiating them for you!). I am trying to set it up so that when you click on the crosshair it's X and Y will constrain to the mouse coordinates. However, I don't want the crosshair from being more than a magnitude of 100 from the actor regardless of whether the mouse is further away from the actor. In that case, the crosshair will still follow the direction of the mouse but will be locked within a boundary so it's always within a magnitude of 100.

I can almost get this to work, but for some reason it locks the crosshair to Mag 100 as I would expect when the mouse is beyond a magnitude of 100 from the actor, but it then seems to duplicate another copy of the crosshair under the mouse wherever it is on the screen. To best show this I've attached a link to a file. There isn't actually much code used. The code that is setting these rules is in the CrossHair prototype.

If any of you would be kind enough to have a look at the file in the link below and offer some advice that would be great. I've double-checked the math and the magnitude function looks right, so I'm not sure if it's a bug or I've missed something obvious.

Thanks a million in advance!

http://dl.dropbox.com/u/45687190/Actor Targeting Issue.gameproj.zip

tatiang

Pretty sure you're going to want to use a max/min function here instead of the way you're doing it.

Here's an example, although it limits movement to a square rather than a circle.



(Just turn off your existing rule and add that code to test it)

HappyKat78

Thanks tatiang. I really want a circle to be honest, I initially coded it with max/min and got the square border that didn't look good for what I wanted. Do you not think the circle using Magnitude is possible? It seems like it is, I just can't work out why it's duplicating the crosshair after 100 mag.

RThurman

@HappyKat78 -- Very close. All you need to do is add a second condition to the rule:

When (All)
--Attribute (self.DistanceFromMaster) < 100
--Attribute (self.MouseFromMaster) < 100

tatiang

And I was just about to quote @RThurman!

http://forums.gamesalad.com/discussion/comment/238467/#Comment_238467

HappyKat78

This works great. Wow, I was close, I knew it! Thanks so much for the help!

RThurman

@HappyKat78 -- Glad its working for you!

@tatiang -- Yes, there are several ways to do this. HappyKat78 has created a method that is probably less processor intensive. It only requires multiplication and no trig. functions!