[Resolved]Getting angle of movement in radians via mouse

[Cander]

Hey guys. I am really trying to wrap my head around this. What I am trying to get done is when the mouse is moved, I need to calculate the degree in radians it moved based on the local coordinate space of a sprite the mouse is moving. Basically I need to fire a bullet in that direction when I hit the fire button. I know how to animate it and all that, but just can't figure out how to get the radians based on mouse movement.

Hope I explained that well enough. Think Geometry Wars as far as how I need to be firing the bullets. Any tips?

I will eventually be using a 360 controller using the left stick for this, but for the time being I need to do this with a mouse for testing stuff at work where I don't dare bring in a game controller.