title: What is a renderpass?
body: <p>I'm currently trying to learn to use uniform buffers and instanced rendering.<br>
  I know the concept of both, but in each Tutorial I read the term "renderpass" or "draw-call" comes up.<br>
  Can someone explain to me what that means in Programming terms? 
  is it each time and individual object, Mesh is drawn?<br>
  is it each time a shader is executed?<br>
  So what exactly is a renderpass? Is it the same as a draw call?<br>
  Is it maybe basicly this?:  </p>
  
  <pre><code>Gl_Color(xyz);
  gl_uniform("a",1);
  gl_uniform("a",1);
  gl_uniform("a",1);
  //I know this is deprected as balls, but just to help me understand
  Gl_Begin(GL_VERTEX_STRIP);
  GL_Vertex(xyz);
  GL_TEXCOORD(xy);
  GL_End();
  </code></pre>