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Thread: angle conversion?

  1. #1
    Join Date
    Jun 2011

    Question angle conversion?

    Hi folks,

    when I'd like to know the angle between two vectors, sometimes I get negative values (radian or degree). How do you convert them so I always get positive values?

    Flash seems to have a strange system for calculating angles. I used the following code for doing this, but sometimes I get negative values. Please - can someone help me with this problem?

    public function rangedAngleBetween(otherVector:EuclideanVector):Number
        var firstAngle:Number;
        var secondAngle:Number;
        var angle:Number;
        firstAngle = Math.atan2(otherVector.position.y, otherVector.position.x);
        secondAngle = Math.atan2(position.y, position.x);
        angle = secondAngle - firstAngle;
        while (angle > Math.PI)
            angle -= Math.PI * 2;
        while (angle < -Math.PI)
            angle += Math.PI * 2;
        return angle;

  2. #2
    Moderator enpstudios's Avatar
    Join Date
    Jun 2001
    Tampa, Fl.
    Try setting: var angle:Number; to var angle:uint;

  3. #3
    Join Date
    Jun 2011
    I'll try that. But I'm not sure if that's gonna work...thanks anyway!

  4. #4
    Join Date
    Dec 2009
    Don't know if you are still having trouble with this, but if you are you can always use Math.abs(angle) to change any negative angle into a positive. Also, if you are trying to convert the angle from radians to degrees, you need
    Actionscript Code:
    var angleInDegrees:Number = angle*180/Math.PI
    However, if you are going to do something with the angle later, I would suggest not changing it to degrees since you will just have to change it back to radians to use it again. Hope this helps.

  5. #5
    Registered User
    Join Date
    Jul 2011

    Thumbs up rotating knob control

    Hi David Bernier,

    I believe that you can help me with one of the simple Flash AS3 technique, My problem is as follows...........

    I want to create a Rotating Control Knob(Circular Dial) to control some paramater using values 0% to 100%.....

    I must get the values displayed in a text field when the Knob is rotated ............

    Please Reply me ASAP.........Eagerly waiting............Thank you........by RANJAN ----ranjan.superman@gmail.com

  6. #6
    Ө_ө sleepy mod
    Join Date
    Mar 2003
    Oregon, USA
    Here's a writeup of how Flash handles angles: http://www.calypso88.com/?p=512
    Please use [php] or [code] tags, and mark your threads resolved 8)

  7. #7
    Join Date
    Jun 2011
    Thanks for your answer. But I got the problem solved and now it works like a charm. Problem was that I didn't understand HOW the cos works. So I took an old maths school book where cos was explained. I was confused that it outputs a value between 1 and -1 because I thought it outputs values in radians. That was the mistake I made.

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