gluQuadricDrawStyle specifies the draw style for quadrics rendered with quad. The legal values are as follows:GLU_FILL
Quadrics are rendered with polygon primitives. The polygons are drawn in a counterclockwise fashion with respect to their normals (as defined with gluQuadricOrientation).
GLU_LINE
Quadrics are rendered as a set of lines.
GLU_SILHOUETTE
Quadrics are rendered as a set of lines, except that edges separating coplanar faces will not be drawn.
GLU_POINT
Quadrics are rendered as a set of points.