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GLLINEWIDTH(3G)                                  OpenGL 3.3                                  GLLINEWIDTH(3G)



NAME
       glLineWidth - specify the width of rasterized lines

C SPECIFICATION
       void glLineWidth(GLfloat width);

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

DESCRIPTION
       glLineWidth 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 glEnable() and glDisable() with argument GL_LINE_SMOOTH. 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
       ^ x >= ^ y, i pixels are filled in each column that is rasterized, where i is the rounded value of
       width. Otherwise, i 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
       glGet() with arguments GL_ALIASED_LINE_WIDTH_RANGE, GL_SMOOTH_LINE_WIDTH_RANGE, and
       GL_SMOOTH_LINE_WIDTH_GRANULARITY.

NOTES
       The line width specified by glLineWidth is always returned when GL_LINE_WIDTH 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 glGet() with
       GL_ALIASED_LINE_WIDTH_RANGE to determine the maximum width.

       In OpenGL 1.2, the tokens GL_LINE_WIDTH_RANGE and GL_LINE_WIDTH_GRANULARITY were replaced by
       GL_ALIASED_LINE_WIDTH_RANGE, GL_SMOOTH_LINE_WIDTH_RANGE, and GL_SMOOTH_LINE_WIDTH_GRANULARITY. The
       old names are retained for backward compatibility, but should not be used in new code.

ERRORS
       GL_INVALID_VALUE is generated if width is less than or equal to 0.

ASSOCIATED GETS
       glGet() with argument GL_LINE_WIDTH


       glGet() with argument GL_ALIASED_LINE_WIDTH_RANGE


       glGet() with argument GL_SMOOTH_LINE_WIDTH_RANGE


       glGet() with argument GL_SMOOTH_LINE_WIDTH_GRANULARITY


       glIsEnabled() with argument GL_LINE_SMOOTH

SEE ALSO
       glEnable()


COPYRIGHT
       Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software
       B License. For details, see http://oss.sgi.com/projects/FreeB/.



OpenGL 3.3                                       03/08/2011                                  GLLINEWIDTH(3G)