Adds a shape node to the current scene. These low-level functions should not normally be called by users.
rgl.points(x, y = NULL, z = NULL, ... )
rgl.lines(x, y = NULL, z = NULL, ... )
rgl.linestrips(x, y = NULL, z = NULL, ...)
rgl.triangles(x, y = NULL, z = NULL, normals = NULL, texcoords = NULL, ... )
rgl.quads(x, y = NULL, z = NULL, normals = NULL, texcoords = NULL, ... )coordinates.  Any reasonable way of defining the
    coordinates is acceptable.  See the function xyz.coords
    for details.
Normals at each point.
Texture coordinates at each point.
Material properties. See rgl.material for details.
Each primitive function returns the integer object ID of the shape that
   was added to the scene.  These can be passed to pop3d
   to remove the object from the scene.
Adds a shape node to the scene. The appearance is defined by the material properties.
  See rgl.material for details.
The names of these functions correspond to OpenGL primitives.  They
  all take a sequence of vertices in x, y, z.  The only non-obvious 
  ones are rgl.lines which draws line segments based on
  pairs of vertices, and rgl.linestrips which joins the
  vertices.
For triangles and quads, the normals at each vertex may be specified
  using normals.  These may be given in any way that would be
  acceptable as a single argument to xyz.coords.  
  These need not match the actual normals to the polygon:
  curved surfaces can be simulated by using other choices of normals.
Texture coordinates may also be specified.  These may be given in
  any way that would be acceptable as a single argument to 
  xy.coords, and are interpreted in terms
  of the bitmap specified as the material texture, with (0, 0) 
  at the lower left, (1, 1) at the upper right.  The texture
  is used to modulate the color of the polygon.
These are the lower level functions called by
  points3d, segments3d,
  lines3d, etc.  The two principal differences between
  the rgl.* functions and the *3d functions are that the
  former set all unspecified material properties to defaults, whereas
  the latter use current values as defaults; the former make
  persistent changes to material properties with each call, whereas
  the latter make temporary changes only for the duration of the call.