Flash AS3 - Click, drag and spin - check direction of spin

Question

I'm using greensock tweenlite to click, drag and rotate a circular movieclip and have the following so far.

What I need to do is determine the direction of the rotation and the speed, i.e. if the user is spinning the wheel to the right, store this direction in a string variable say and the rotation speed in a number variable.

I've tried numerous different things with the mousestart and move coordinates and with the vinyl_mc rotation coordinates but can't get anything reliable. Is there a way I can determine the direction and speed and store these in variables?

The app can be viewed at: http://s46264.gridserver.com/dev/dave/rotate/rotate.html and source fla is at: http://s46264.gridserver.com/dev/dave/rotate/rotate.fla.zip if this helps at all.

Thanks.

import com.greensock.*;
import com.greensock.easing.*;
import com.greensock.plugins.*;
import flash.events.*;

TweenPlugin.activate([ShortRotationPlugin]);
var oldRotation,ax,ay,bx,by,thetaA,thetaB,delTheta,newTheta:Number;

var direction:String;

function dragger(evt:MouseEvent)
{
    if (evt.type == MouseEvent.MOUSE_DOWN)
    {
        stage.addEventListener(MouseEvent.MOUSE_MOVE, dragger);
        stage.addEventListener(MouseEvent.MOUSE_UP, dragger);
        oldRotation = vinyl_mc.rotation;
        ax = stage.mouseX - vinyl_mc.x;
        ay = stage.mouseY - vinyl_mc.y;
        thetaA = Math.atan2(ay,ax) * 180 / Math.PI;
        if (thetaA < 0)
        {
            thetaA =  -  thetaA;
        }
        else
        {
            thetaA = 360 - thetaA;
        }

    }
    else if (evt.type == MouseEvent.MOUSE_MOVE)
    {

        bx = stage.mouseX - vinyl_mc.x;
        by = stage.mouseY - vinyl_mc.y;
        thetaB = Math.atan2(by,bx) * 180 / Math.PI;

        if (thetaB < 0)
        {
            thetaB =  -  thetaB;
        }
        else
        {
            thetaB = 360 - thetaB;
        }

        delTheta = thetaB - thetaA;
        newTheta = oldRotation - delTheta;

        TweenLite.to(vinyl_mc, 1, {shortRotation:{rotation:newTheta}, overwrite:true, ease:Cubic.easeOut});

    }
    else if (evt.type == MouseEvent.MOUSE_UP)
    {
        stage.removeEventListener(MouseEvent.MOUSE_MOVE, dragger);
        stage.removeEventListener(MouseEvent.MOUSE_UP, dragger);
    }
}


vinyl_mc.addEventListener(MouseEvent.MOUSE_DOWN, dragger);

Sam Sam · Accepted Answer · 2011-03-15T23:38:43

What about creating a marker object on the edge of the circle, do some trig to get the angle, check it again compare the two. angle over time would give you speed, angle1-angle2 would give you direction.

Flash AS3 - Click, drag and spin - check direction of spin

1 Answers