message: Ensure pixel pack/unpack buffers don't break overlays on GL
diff: @@ -232,6 +232,12 @@ void main()
  glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, subtex, 3, 2);
  + // keep a trash buffer bound to pixel pack/unpack
  + GLuint trash = MakeBuffer();
  + glBindBuffer(GL_PIXEL_UNPACK_BUFFER, trash);
  + glBufferStorage(GL_PIXEL_UNPACK_BUFFER, 1024, 0, 0);
  + glBindBuffer(GL_PIXEL_PACK_BUFFER, trash);
  +
  while(Running())
  {
  glBindVertexArray(vao);
  