Hey, I've got 2 apps that I'm working on, both that use atan2 as a base. The first one seemed to be having a very slight problem, but it was very slight and seemed a very small "rounding issue", since the issue was marginal. However, in my second app, the problem is very clear.

When using atan2, I find the angle between two points, and use this angle to find the adjacent and opposite of the angle (the hypotenuse is the given "moveSpeed", which I have defined as 10). Here is the code.
Code:
                var adjside = pointX-clip._x;
		var oppside = pointY-clip._y;
		var angle = Math.atan2(oppside, adjside)/Math.PI;
		var moveX = Math.cos(angle)*moveSpeed;
		var moveY = Math.sin(angle)*moveSpeed;
		trace("x " +moveX)
		trace("y " +moveY)
		moveX += decX;
		moveY += decY;
		var moveX1 = Math.floor(moveX);
		var moveY1 = Math.floor(moveY);
		decX = moveX-moveX1;
		decY = moveY-moveY1;
		moveX = moveX1;
		moveY = moveY1;
		
		if(pointX > clip._x) {
			clip._x += moveX;
		}
		if(pointX < clip._x) {
			clip._x -= moveX;
		}
		if(pointY > clip._y) {
			clip._y += moveY;
		}
		if(pointY < clip._y) {
			clip._y += moveY;
		}
After tracing moveX and moveY, I used these to solve, and found that they do in fact form a right triangle with movespeed. The x coordinate seems to move just fine, but the y coordinate, blast it, goes wack. I'll upload the swf in a zip.

If your suggestion is to make this change:

Code:
                var adjside = pointX-clip._x;
		var oppside = pointY-clip._y;
		var angle = Math.atan2(oppside, adjside)/Math.PI;
		var moveX = Math.cos(angle)*moveSpeed;
		var moveY = Math.sin(angle)*moveSpeed;
		trace("x " +moveX)
		trace("y " +moveY)
		moveX += decX;
		moveY += decY;
		var moveX1 = Math.floor(moveX);
		var moveY1 = Math.floor(moveY);
		decX = moveX-moveX1;
		decY = moveY-moveY1;
		moveX = moveX1;
		moveY = moveY1;
		
		clip._x += moveX;
		clip._y += moveY;
Don't bother, because this doesn't work.

I don't fully understand what the atan2 function is supposed to do, I was just told to use it in this manner to find the angle. Any help is appreciated.

Nathan Gibson