GLLINESTIPPLE

NAME

glLineStipple - specify the line stipple pattern

C SPECIFICATION

void f3glLineStipplefP( GLint fIfactorfP,

f2factorfP
Specifies a multiplier for each bit in the line stipple pattern.
If f2factorfP is 3,
for example,
each bit in the pattern is used three times
before the next bit in the pattern is used.
f2factorfP is clamped to the range [1, 256] and defaults to 1.

f2patternfP
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

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 f2patternfP, the repeat count f2factorfP, and an integer stipple counter $s$. Counter $s$ is reset to 0 whenever %f3glBeginfP is called, and before each line segment of a %f3glBeginfP(%f3GL_LINESfP)/%f3glEndfP 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

f2patternfP bit $(s ~/~ "factor") ~roman mod~ 16$

is 0, otherwise these fragments are sent to the frame buffer. Bit zero of f2patternfP is the least significant bit. Antialiased lines are treated as a sequence of $1 times width$ 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 %f3glEnablefP and %f3glDisablefP with argument %f3GL_LINE_STIPPLEfP. 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

%f3GL_INVALID_OPERATIONfP is generated if %f3glLineStipplefP is executed between the execution of %f3glBeginfP and the corresponding execution of %f3glEndfP.

ASSOCIATED GETS

%f3glGetfP with argument %f3GL_LINE_STIPPLE_PATTERNfP
%f3glGetfP with argument %f3GL_LINE_STIPPLE_REPEATfP
%f3glIsEnabledfP with argument %f3GL_LINE_STIPPLEfP