GLPOINTSIZE(3G)                                                GLPOINTSIZE(3G)



NAME
       glPointSize - specify the diameter of rasterized points


C SPECIFICATION
       void glPointSize( GLfloat size )


PARAMETERS
       size  Specifies  the  diameter of rasterized points.  The initial value
             is 1.

DESCRIPTION
       glPointSize specifies the  rasterized  diameter  of  both  aliased  and
       antialiased  points.   Using  a  point  size other than 1 has different
       effects, depending on whether point antialiasing is enabled.  To enable
       and  disable point antialiasing, call glEnable and glDisable with argu-
       ment GLPOINTSMOTH. Point antialiasing is initially disabled.

       If point antialiasing is disabled, the actual  size  is  determined  by
       rounding  the  supplied  size to the nearest integer.  (If the rounding
       results in the value 0, it is as if the point size  were  1.)   If  the
       rounded  size  is  odd,  then  the center point ( x ,  y ) of the pixel
       fragment that represents the point is computed as

                                 (xw ] .5, yw ] .5)

       where w subscripts indicate window coordinates.  All  pixels  that  lie
       within  the square grid of the rounded size centered at ( x ,  y ) make
       up the fragment.  If the size is even, the center point is

                                 (xw ] .5, yw ] .5)

       and the rasterized fragment's centers are the half-integer window coor-
       dinates  within  the square of the rounded size centered at ( x ,  y ).
       All pixel fragments produced in rasterizing a nonantialiased point  are
       assigned  the same associated data, that of the vertex corresponding to
       the point.

       If antialiasing is enabled, then point rasterization produces  a  frag-
       ment  for each pixel square that intersects the region lying within the
       circle having diameter equal to the current point size and centered  at
       the  point's  (  xw , yw).  The coverage value for each fragment is the
       window coordinate area of the intersection of the circular region  with
       the  corresponding  pixel  square.  This value is saved and used in the
       final rasterization step.  The data associated with  each  fragment  is
       the data associated with the point being rasterized.

       Not  all sizes are supported when point antialiasing is enabled.  If an
       unsupported size is requested, the  nearest  supported  size  is  used.
       Only  size 1 is guaranteed to be supported; others depend on the imple-
       mentation.  To query the range of supported sizes and the size  differ-
       ence  between  supported  sizes within the range, call glGet with argu-
       ments GLSMOTHPOINTSIZERANGE and  GLSMOTHPOINTSIZEGRANULARITY.
       For aliased points, query the supported range with glGet with arguments
       GLALIASEDPOINTSIZERANGE and

NOTES
       The point  size  specified  by  glPointSize  is  always  returned  when
       GLPOINTSIZE  is  queried.   Clamping  and  rounding  for  aliased and
       antialiased points have no effect on the specified value.

       A non-antialiased point size may be clamped to an implementation-depen-
       dent  maximum.   Although this maximum cannot be queried, it must be no
       less than the maximum value for  antialiased  points,  rounded  to  the
       nearest integer value.

       GLPOINTSIZERANGE  and GLPOINTSIZEGRANULARITY are deprecated in GL
       versions 1.2 and greater.  Their functionality  has  been  replaced  by
       GLSMOTHPOINTSIZERANGE and GLSMOTHPOINTSIZEGRANULARITY.

ERORS
       GLINVALIDVALUE is generated if size is less than or equal to 0.

       GLINVALIDOPERATION  is  generated  if glPointSize is executed between
       the execution of glBegin and the corresponding execution of glEnd.

ASOCIATED GETS
       glGet with argument GLPOINTSIZE
       glGet with argument GLALIASEDPOINTSIZERANGE
       glGet with argument GLSMOTHPOINTSIZERANGE
       glGet with argument GLSMOTHPOINTSIZEGRANULARITY
       glIsEnabled with argument GLPOINTSMOTH

SEE ALSO
       glEnable



                                                               GLPOINTSIZE(3G)