Building a Better D-Pad

Okay, here is something I'll turn into a resource for everyone once I get it finished - a better D-Pad GuiObject. Well, 'better' is subjective, as iTGB doesn't have one at all right now - so I built a simple one for most of the Shinobi Ninja development. Though, by simple, I mean a 9 space grid. Worked great, but not awesome for hardcore playability - for that, I want an angular based D-Pad like most other iPhone games have.

What I have done so far is created a GuiCtrl that displays an image. The player touches it, and the C++ code determines the angle from the center that was touched, then uses that to determine how to move the player. Problem is, it's pretty flakey right now. Hopefully someone out there with a better understanding of angular math might be able to point out my problem. Here is the code:

Point2I pos = globalToLocalCoord(event.mousePoint);	
	
	t2dVector controlDiscCenter;
	t2dVector controlDiscTouchPos;
	
	controlDiscCenter.mX = 68.5;
	controlDiscCenter.mY = 68.5;
	
	controlDiscTouchPos.mX = pos.x;
	controlDiscTouchPos.mY = pos.y;
	
	// find angle
	F32 angleOut = mDegToRad(mFmod(mAtan( controlDiscTouchPos.mX - controlDiscCenter.mX , controlDiscCenter.mY - controlDiscTouchPos.mY), 360.0f));  
	
	// normalize to 0 - 360
	if ( angleOut < 0.0f ) angleOut += 360.0f;

    F32 sin, cos;
	F32 speed = 35;
    mSinCos( angleOut, sin, cos );
	
    // Set Gross Linear Velocity.
    gCurrentPlayer->setLinearVelocity( t2dVector( cos*speed, sin*speed ) );

What happens is, no matter where you touch the GuiObject, the player moves in an almost random direction. Hopefully I just swapped something somewhere in my math, but any help would be greatly appreciated!