Detecting the Mouse Angle - Easily - Page 2

Theory

Skip this if you want...

The basic concept is that the mouse angle will fall into 1 of the 4 quadrants, they are:

    0 -  90    (right and down)    +x +y
   90 - 180    (left and down)     -x +y
  180 - 270      (left and up)     -x -y
  270 - 360      (right and up)    +x -y

The "mouse coordinate" is the "coordinate of the mouse" minus the "coordinate of the origin"
ie. if origin(10,10) & mouse(20, -20), then the mouse coordinate becomes (10, -30). This is right and up or +x -y.

The angle is then APPROXIMATED using a simple algorithm. The algorithm will not be explained as approximations never really make "sense" - just look at the code. The movement for a bullet from the origin to the mouse is calculated EXACTLY. So for the purpose of games this is usually ok.