glLineStipple

GLLINESTIPPLE(3G)					    GLLINESTIPPLE(3G)



NAME
       glLineStipple - specify the line stipple pattern


C SPECIFICATION
       void glLineStipple( GLint factor,
			   GLushort pattern )

       delim $$

PARAMETERS
       factor	Specifies  a multiplier for each bit in the line stipple pat-
		tern.  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  raster-
		ized.	Bit  zero  is  used first; the default pattern is all
		1’s.

DESCRIPTION
       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 seg-
       ment 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 $(s ~/~ "factor") ~roman mod~ 16$

       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 $1 times width$ rectan-
       gles for purposes of stippling.	Whether rectangle $s$  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
       GL_INVALID_OPERATION is generated if glLineStipple is executed between
       the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS
       glGet with argument GL_LINE_STIPPLE_PATTERN
       glGet with argument GL_LINE_STIPPLE_REPEAT
       glIsEnabled with argument GL_LINE_STIPPLE

SEE ALSO
       glLineWidth(3G), glPolygonStipple(3G)



							    GLLINESTIPPLE(3G)