title: OpenGL C++ Circle vs Circle Collision
body: <p>I am making a 2D game and I have created two circles, one named player and one named enemy. The circles are drawn by calling a drawPlayerCircle and drawEnemyCircle function, both which are called in my display() function. At the moment my project isn't Object Orientated which you can already probably tell. My collision works for both circles as I have calculated penetration vectors and normalised vectors etc... However my question is, expanding this game further by having 10-20 enemies in the game, how can I work out the collision to every single enemy quickly rather than calculating manually the penetration and normalised vectors between my player and every enemy in the game which is obviously very inefficient. I'm guessing splitting my player and enemy entities into their own class but I'm still struggling to visualise how the collision will work.</p>
  
  <p>Any help will be greatly appreciated! :)</p>