Drawing in 3D

 Depth buffer
   Allows scene to remove hidden surfaces. Use glEnable(GL_DEPTH_TEST) to enable it.
   1-glPolygonMode( Face, Mode )
       Face: GL_FRONT, GL_BACK, GL_FRONT_AND_BACK
      Mode: GL_LINE, GL_POINT, GL_FILL
  2-glCullFace( Mode )
      Mode: GL_FRONT, GL_BACK, GL_FRONT_AND_BACK
  3-glFrontFace( Vertex_Ordering )
      Vertex Ordering: GL_CW or GL_CCW