title: Pitch, Yaw, Roll calculation confusion
body: <p>I am reading the <a href="https://learnopengl.com/Getting-started/Camera" rel="nofollow noreferrer">this</a> tutorial and I got a bit confused. Why is the x value changing with the pitch when the pitch is a rotation about the x axis.</p>
  
  <pre><code>direction.x = cos(glm::radians(pitch)) * cos(glm::radians(yaw));
  direction.y = sin(glm::radians(pitch));
  direction.z = cos(glm::radians(pitch)) * sin(glm::radians(yaw));
  </code></pre>
  
  <p>I get how the rest are changing, but not the <code>cos(glm::radians(pitch))</code> in <code>direction.x</code>. How come this is the case ?</p>