title: Orthographic Projection in Modern OpenGL
body: <p>I'd like to set up an orthographic projection using only modern OpenGL techniques (i.e. no immediate-mode stuff). I'm seeing conflicting info on the web about how to approach this.</p>
  
  <p>Some people are saying that it's still OK to call <code>glMatrixMode(GL_PROJECTION)</code> and then <code>glOrtho</code>. This has always worked for me in the past, but I'm wondering if this has been deprecated in modern OpenGL.</p>
  
  <p>If so, are vertex shaders the standard way to do an orthographic projection nowadays? Does GLSL provide a handy built-in function to set up an orthographic projection, or do I need to write that math myself in the vertex shader?</p>