title: How to check if vectors are facing same direction
body: <p>I am working on a question where I am working within a right-handed coordinate system where the y-axis is straight up. I am supplied a structure that represents a 3-dimensional vector that looks like this:</p>
  
  <pre><code>struct vec{float x; float y; float z; };
  </code></pre>
  
  <p>I need to write a function that takes in a unit vector representing north and a unit vector represent a player's forward vector, and return if they are facing more north than south. Unfortunatly I have no idea where to go from here, I believe I have to do something like:</p>
  
  <pre><code>PlayerDirection = sqrt((PlayerVector.x *= PlayerVector.x)
                       + (PlayerVector.y *= PlayerVector.y)
                       + (PlayerVector.z *= PlayerVector.z));
  </code></pre>
  
  <p>But I do not know where to go from here. Any help/explanation would help, thanks.</p>