title: Calculating a line from a starting point and angle in 3d
body: <p>I have a point in 3D space and two angles, I want to calculate the resulting line from this information. I have found how to do this with 2D lines, but not 3D.  How can this be calculated?</p>
  
  <p>If it helps: I'm using C++ &amp; OpenGL and have the location of the user's mouse click and the angle of the camera, I want to trace this line for intersections.</p>