rotating sprite from it's current angle as3 - actionscript-3

Question

i created an object that is rotated with the mouse, however each time after rotating, when mouse is clicked again the object "jump" right to it's new angle i would like that the object will continue to rotate from it's current location no matter where the mouse being clicked.
this is my code that rotates the object.
public function _mouseclick(me:MouseEvent):void
{
addEventListener(Event.ENTER_FRAME, UpdateGame);
IsButtonClicked = true;
}
public function UpdateGame(e:Event):void
{
if (IsButtonClicked)
{
var dist_Y:Number = mouseY - PlayerSprite.y ;
var dist_X:Number = mouseX - PlayerSprite.x ;
var angle:Number = Math.atan2(dist_Y, dist_X);
var degrees:Number = angle * 180/ Math.PI;
PlayerSprite.rotation = degrees;
}
}
how can i reset the angle to the current sprite angle and prevent that "jump"?

Answer 1

It looks like maybe you are trying to make some sort of knob or dial. Finding the angle between the mouse and sprite and applying it the way you are, will always face that direction. I think you are looking for something a little more simple.
First I would set up 2 variables, one to be the amount to increment the rotation, the other to store the mouse position.
var increment:int = 5;
var mousePos:Point;
Then in your mouse click function:
mousePos = new Point( mouseX, mouseY );
Lastly in your UpdateGame():
private function UpdateGame( e:Event ):void {
if ( IsButtonClicked ) {
var increment:int = 5;
if ( mousePos.y < mouseY ) {
spr.rotation += increment;
}
else {
spr.rotation -= increment;
}
mousePos = new Point( mouseX, mouseY );
}
}
That seems to be more the effect you are looking for. In this case when you move the mouse up, the sprite rotates counter clockwise. Moving the mouse down, rotates it clockwise.

Answer 2

If you want to change the rotation smoothly, you want to base it on the change from last rotation as the delta.
The delta is based on the initial rotation from mouse click relative to the current rotation.
current_rotation += (atan2 - last_rotation);
last_rotation = atan2;
And the full pseudo example.
private var current_rotation:Number;
private var last_rotation:Number;
private var mouse_down:Boolean;
public function MouseClick(e:MouseEvent):void
{
var dX:Number = Mouse.X - 400;
var dY:Number = Mouse.Y - 300;
var atan2:Number = Math.atan2(dY, dX);
last_rotation = atan2;
mouse_down = true;
}
public function UpdateGame(e:Event):void
{
if (mouse_down)
{
var dX:Number = Mouse.X - 400;
var dY:Number = Mouse.Y - 300;
var atan2:Number = Math.atan2(dY, dX);
current_rotation += (atan2 - last_rotation);
last_rotation = atan2;
}
}