title: Updating vertex data in a VBO (glBufferSubData vs glMapBuffer)
body: <p>I want to update an object's list of vertices after a VBO has been created. I've seen both <code>glBufferSubData</code> and <code>glMapBuffer</code> and they both appear to do similar things, which means I'm now unsure which one to use.</p>
  
  <p>My pseudo workflow is:</p>
  
  <blockquote>
    <p>Create object<br>
    Begin vertex update (calls glBufferData with data = nullptr)<br>
    Update object's vertices<br>
    End vertex update (takes the updated vertices and either calls <code>glBufferSubData</code> or <code>glMapBuffer</code>)  </p>
  </blockquote>