glLineStipple -- specify the line stipple pattern
void glLineStipple(GLint factor,
Specifies a multiplier for each bit in the line stipple pattern. If
factor is 3, for example, each bit in the pattern will be used three
times before the next bit in the pattern is used. factor is
clamped to the range [1, 256] and defaults to one.
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, and the default pattern is all ones.
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 zero 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 zero, 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*width rectangles for
purposes of stippling. Rectangle s is rasterized or not based on the
fragment rule described for aliased lines, counting rectangles rather than
groups of fragments.
Line stippling is enabled or disabled using
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
ones. Initially, line stippling is disabled.
GL_INVALID_OPERATION is generated if glLineStipple is called
between a call to glBegin and the
corresponding call to glEnd.
glGet with argument
glGet with argument
glIsEnabled with argument
back to the OpenGL index page
© 1995 Uwe Behrens. All rights reserved.