---

Manual Reference Pages  - GLLINESTIPPLE (3G)

---

glLineStipple - specify the line stipple pattern

CONTENTS

C Specification
Parameters
Description
Errors
Associated Gets
See Also

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 1timeswidth rectangles 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.

 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(3G),  glPolygonStipple(3G)

Jump to page    or go to Top of page |  Section 3G |  Main Index.