glLineStipple	- specify the line stipple pattern

	  void glLineStipple( GLint factor,
			      GLushort pattern )

	  factor   Specifies a multiplier for each bit in the line
		   stipple pattern.  If	factor is 3, for example, each
		   bit in the pattern is used three times before the
		   next	bit in the pattern is used.  factor is clamped
		   to the range	[1, 256] and defaults to 1.

	  pattern  Specifies a 16-bit integer whose bit	pattern
		   determines which fragments of a line	will be	drawn
		   when	the line is rasterized.	 Bit zero is used
		   first; the default pattern is all 1's.

	  Line stippling masks out certain fragments produced by
	  rasterization; those fragments will not be drawn.  The
	  masking is achieved by using three parameters:  the 16-bit
	  line stipple pattern pattern,	the repeat count factor, and
	  an integer stipple counter s.

	  Counter s is reset to	0 whenever glBegin is called, and
	  before each line segment of a	glBegin(GL_LINES)/glEnd
	  sequence is generated.  It is	incremented after each
	  fragment of a	unit width aliased line	segment	is generated,
	  or after each	i fragments of an i width line segment are
	  generated.  The i fragments associated with count s are
	  masked out if

			pattern	bit (s / factor) mod 16

	  is 0,	otherwise these	fragments are sent to the frame
	  buffer.  Bit zero of pattern is the least significant	bit.

	  Antialiased lines are	treated	as a sequence of 1xwidth
	  rectangles for purposes of stippling.	 Whether rectagle s is
	  rasterized or	not depends on the fragment rule described for
	  aliased lines, counting rectangles rather than groups	of

	  To enable and	disable	line stippling,	call glEnable and
	  glDisable with argument GL_LINE_STIPPLE.  When enabled, the
	  line stipple pattern is applied as described above.  When
	  disabled, it is as if	the pattern were all 1's.  Initially,
	  line stippling is disabled.
	  GL_INVALID_OPERATION is generated if glLineStipple is
	  executed between the execution of glBegin and	the
	  corresponding	execution of glEnd.

	  glGet	with argument GL_LINE_STIPPLE_PATTERN
	  glGet	with argument GL_LINE_STIPPLE_REPEAT
	  glIsEnabled with argument GL_LINE_STIPPLE

	  glLineWidth, glPolygonStipple