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Manpage of GLLINEWIDTH

GLLINEWIDTH

Index
 

NAME

glLineWidth - specify the width of rasterized lines

 

C SPECIFICATION

void f3glLineWidthfP( GLfloat fIwidthfP )


delim $$  

PARAMETERS

f2widthfP
Specifies the width of rasterized lines. The initial value is 1.
 

DESCRIPTION

%f3glLineWidthfP specifies the rasterized width of both aliased and antialiased lines. Using a line width other than 1 has different effects, depending on whether line antialiasing is enabled. To enable and disable line antialiasing, call %f3glEnablefP and %f3glDisablefP with argument %f3GL_LINE_SMOOTHfP. Line antialiasing is initially disabled. If line antialiasing is disabled, the actual width is determined by rounding the supplied width to the nearest integer. (If the rounding results in the value 0, it is as if the line width were 1.) If $| DELTA x | ~>=~ | DELTA y |$, f2ifP pixels are filled in each column that is rasterized, where f2ifP is the rounded value of f2widthfP. Otherwise, f2ifP pixels are filled in each row that is rasterized. If antialiasing is enabled, line rasterization produces a fragment for each pixel square that intersects the region lying within the rectangle having width equal to the current line width, length equal to the actual length of the line, and centered on the mathematical line segment. The coverage value for each fragment is the window coordinate area of the intersection of the rectangular region with the corresponding pixel square. This value is saved and used in the final rasterization step. Not all widths can be supported when line antialiasing is enabled. If an unsupported width is requested, the nearest supported width is used. Only width 1 is guaranteed to be supported; others depend on the implementation. Likewise, there is a range for aliased line widths as well. To query the range of supported widths and the size difference between supported widths within the range, call %f3glGetfP with arguments %f3GL_ALIASED_LINE_WIDTH_RANGEfP, %f3GL_SMOOTH_LINE_WIDTH_RANGEfP, %f3GL_SMOOTH_LINE_WIDTH_GRANULARITYfP.  

NOTES

The line width specified by %f3glLineWidthfP is always returned when %f3GL_LINE_WIDTHfP is queried. Clamping and rounding for aliased and antialiased lines have no effect on the specified value. Nonantialiased line width may be clamped to an implementation-dependent maximum. Call %f3glGetfP with %f3GL_ALIASED_LINE_WIDTH_RANGEfP to determine the maximum width.  

ERRORS

%f3GL_INVALID_VALUEfP is generated if f2widthfP is less than or equal to 0. %f3GL_INVALID_OPERATIONfP is generated if %f3glLineWidthfP is executed between the execution of %f3glBeginfP and the corresponding execution of %f3glEndfP.  

ASSOCIATED GETS

%f3glGetfP with argument %f3GL_LINE_WIDTHfP
%f3glGetfP with argument %f3GL_ALIASED_LINE_WIDTH_RANGEfP
%f3glGetfP with argument %f3GL_SMOOTH_LINE_WIDTH_RANGEfP
%f3glGetfP with argument %f3GL_SMOOTH_LINE_WIDTH_GRANULARITYfP
%f3glIsEnabledfP with argument %f3GL_LINE_SMOOTHfP  

SEE ALSO

%f3glEnable(3G)fP


 

Index

NAME
C SPECIFICATION
PARAMETERS
DESCRIPTION
NOTES
ERRORS
ASSOCIATED GETS
SEE ALSO