Class Polygon

      object --+    
               |    
common.Primitive --+
                   |
                  Polygon

Class to draw a flat polygon in OpenGL.  Will be drawn
in the current OpenGL drawable.  This includes the ability
to draw into Maestro's Workspace.  It just needs to be
the current drawable.

See doc string for __init__ for details on instantiation.

API Example
-----------
import schrodinger.maestro.maestro as maestro
import schrodinger.graphics3d.common as common
import schrodinger.graphics3d.polygon as polygon
import math

poly_grp = common.Group()
st = maestro.workspace_get()
at = st.atom[1]
vertices = []
for theta in range(0, 360, 80):
    theta_rad = theta * math.pi/180
    x = math.cos(theta_rad)
    y = math.sin(theta_rad) 
    vertices.append(
        (at.x + x, at.y + y, at.z)
    )
pgon = polygon.Polygon(
    vertices=vertices,
    color='red',
    opacity=0.8,
)

# Add the primative to the container.
poly_grp.add(pgon)

# Hide the markers.
poly_grp.hide()

# Remove the markers and the callback.
poly_grp.clear()
maestro.workspace_draw_function_remove(poly_grp.draw)

Constructor requires:

vertices: List of vertex coordinates (x, y, z).
          Specify at least 3 vertices in consecutive order.
          All vertices must be in the same plane.

color:    One of:
            Color object (Color class)
            Color name (string)
            Tuple of (R, G, B) (each a float in range 0.0-1.0)

Optional arguments:

opacity:  0.0 (invisible) through 1.0 (opaque)
               Defaults to 1.0

style:    LINE or FILL.  Default is FILL.