*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->Tru64 Unix man pages -> glLineWidth (3)              



NAME    [Toc]    [Back]

       glLineWidth - specify the width of rasterized lines

SYNOPSIS    [Toc]    [Back]

       void glLineWidth(
               GLfloat width );

PARAMETERS    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

       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 | DELTA x | >= | DELTA 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,

NOTES    [Toc]    [Back]

       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

ERRORS    [Toc]    [Back]

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

       GL_INVALID_OPERATION is generated if glLineWidth() is executed
  between  the  execution of glBegin() and the corresponding
 execution of glEnd().

ASSOCIATED GETS    [Toc]    [Back]

       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    [Toc]    [Back]


[ Back ]
 Similar pages
Name OS Title
linewidth IRIX specifies width of lines
fold FreeBSD fold long lines for finite width output device
fold IRIX fold long lines for finite width output device
fold HP-UX fold long lines for finite width output device
fold OpenBSD fold long lines for finite width output device
glpointsize IRIX specify the diameter of rasterized points
glPointSize Tru64 specify the diameter of rasterized points
paste IRIX merge same lines of several files or subsequent lines of one file
paste Tru64 Joins corresponding lines of several files or subsequent lines in one file
paste HP-UX merge same lines of several files or subsequent lines of one file
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service