title: Is it possible to copy data from one framebuffer to another in OpenGL?
body: <p>I guess it is somehow possible since this:</p>
  
  <pre><code>glBindFramebuffer(GL_READ_FRAMEBUFFER_APPLE, _multisampleFramebuffer);
  glBindFramebuffer(GL_DRAW_FRAMEBUFFER_APPLE, _framebuffer);
  glResolveMultisampleFramebufferAPPLE();
  </code></pre>
  
  <p>does exactly that, and on top resolves the multisampling. However, it's an Apple extension and I was wondering if there is something similar that copies all the logical buffers from one framebuffer to another and doesn't do the multisampling part in the vanilla implementation. <code>GL_READ_FRAMEBUFFER</code> doesn't seem to be a valid target, so I'm guessing there is no direct way? How about workarounds?</p>
  
  <p>EDIT: Seems it's possible to use <code>glCopyImageSubData</code> in OpenGL 4, unfortunately not in my case since I'm using OpenGL ES 2.0 on iPhone, which seems to be lacking that function. Any other way?</p>