glEdgeFlag, glEdgeFlagv - flag edges as either boundary or
nonboundary

glEdgeFlag
	glEdgeFlag(flag) -> None
glEdgeFlagv
	glEdgeFlagv(flag) -> None

void glEdgeFlag( GLboolean flag )

flag	Specifies the current edge flag	value, either GL_TRUE
      or GL_FALSE. The initial value is GL_TRUE.

void glEdgeFlagv( const GLboolean *flag )

flag Specifies a pointer to an array that contains a single
     boolean element,	which replaces the current edge	flag
     value.

Each vertex of a polygon, separate triangle, or separate
quadrilateral	specified between a glBegin/glEnd pair is
marked as the	start of either	a boundary or nonboundary
edge.	 If the	current	edge flag is true when the vertex is
specified, the vertex	is marked as the start of a boundary
edge.	 Otherwise, the	vertex is marked as the	start of a
nonboundary edge.  glEdgeFlag	sets the edge flag bit to
GL_TRUE if flag is GL_TRUE, and to GL_FALSE otherwise.

The vertices of connected triangles and connected
quadrilaterals are always marked as boundary,	regardless of
the value of the edge	flag.

Boundary and nonboundary edge	flags on vertices are
significant only if GL_POLYGON_MODE is set to	GL_POINT or
GL_LINE.  See	glPolygonMode.

The current edge flag	can be updated at any time.  In
particular, glEdgeFlag can be	called between a call to
glBegin and the corresponding	call to	glEnd.

glGet	with argument GL_EDGE_FLAG

glBegin, glEdgeFlagPointer, glPolygonMode