glLineStipple(3G)	       OpenGL Reference		     glLineStipple(3G)

NAME    [Toc]    [Back]

     glLineStipple - specify the line stipple pattern

C SPECIFICATION    [Toc]    [Back]

     void glLineStipple( GLint factor,
			 GLushort pattern )

PARAMETERS    [Toc]    [Back]

     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.

DESCRIPTION    [Toc]    [Back]

     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 fragments.

     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.

ERRORS    [Toc]    [Back]

     GL_INVALID_OPERATION is generated if glLineStipple	is executed between
     the execution of glBegin and the corresponding execution of glEnd.






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glLineStipple(3G)	       OpenGL Reference		     glLineStipple(3G)

ASSOCIATED GETS    [Toc]    [Back]

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

SEE ALSO    [Toc]    [Back]

     glLineWidth, glPolygonStipple


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