title: MonoGame - Have an object circle around a point
body: <p>I have an object with a <code>Vector2 Position</code>, and a cursor with <code>Vector2 Position</code>.</p>
  
  <p>When I hold a certain key, I want the object to circle around the object, but I'm having trouble calculating the correct coordinates.</p>
  
  <p>I've managed to make the object circle around the cursor (but it's not going in a perfect circle, but more of a spiral) with this code:</p>
  
  <pre><code>Vector2 diff= Vector2.Normalize(cursor.Location - this.Location);
  
  float angle = (float)Math.Atan2(diff.Y, diff.X) + (float)(90 * (Math.PI / 180));
  this.Position += new Vector2((float)(speed * Math.Cos(angle)), (float)(speed* Math.Sin(angle)));
  </code></pre>
  
  <p>I calculate the angle between cursor's and object's locations, and add 90° (in radians) to that value, which, by my logic, should make the object travel in a perfect circle. However, the distance between the cursor and the object quickly spreads.</p>
  
  <p>What am I calculating wrong here?</p>