title: glm::perspective explanation
body: <p>I am trying to understand what the following code does:</p>
  
  <pre><code>glm::mat4 Projection = glm::perspective(35.0f, 1.0f, 0.1f, 100.0f);
  </code></pre>
  
  <p>Does it create a <a href="http://en.wikipedia.org/wiki/Projection_%28linear_algebra%29" rel="noreferrer">projection matrix</a>? Clips off anything that is not in the user's view?
  I wasn't able to find anything on the <a href="http://glm.g-truc.net/0.9.5/api/index.html" rel="noreferrer">API page</a>, and the only thing I could find in the pdf on their website was this:</p>
  
  <p>gluPerspective:</p>
  
  <pre><code>glm::mat4 perspective(float fovy, float aspect, float zNear,
  float zFar);
  glm::dmat4 perspective(
  double fovy, double aspect, double zNear,
  double zFar);
  From GLM_GTC_matrix_transform extension: &lt;glm/gtc/matrix_transform.hpp&gt;
  </code></pre>
  
  <p>But it doesn't explain the parameters. Maybe I missed something.</p>