Index for Section 3G

Alphabetical listing for G

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glPointSize(3G)
NAME
  glPointSize - specify the diameter of rasterized points

SYNOPSIS
  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 argument
  GL_POINT_SMOOTH. 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

       ( x[w] + .5,  y[w] + .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

       ( x[w] + .5,  y[w] + .5 )

  and the rasterized fragment's centers are the half-integer window
  coordinates 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 fragment
  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
  ( x[w] ,  y[w] ). 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 implementation.
  To query the range of supported sizes and the size difference between
  supported sizes within the range, call glGet() with arguments
  GL_SMOOTH_POINT_SIZE_RANGE and GL_SMOOTH_POINT_SIZE_GRANULARITY. For
  aliased points, query the supported ranges and granularity with glGet()
  with arguments GL_ALIASED_POINT_SIZE_RANGE and
  GL_ALIASED_POINT_SIZE_GRANULARITY.

NOTES
  The point size specified by glPointSize() is always returned when
  GL_POINT_SIZE 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-dependent
  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.

  GL_POINT_SIZE_RANGE and GL_POINT_SIZE_GRANULARITY are deprecated in GL
  versions 1.2 and greater.  Their functionality has been replaced by
  GL_SMOOTH_POINT_SIZE_RANGE and GL_SMOOTH_POINT_SIZE_GRANULARITY.

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

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

ASSOCIATED GETS
       glGet() with argument GL_POINT_SIZE
       glGet() with argument GL_ALIASED_POINT_SIZE_RANGE
       glGet() with argument GL_ALIASED_POINT_SIZE_GRANULARITY
       glGet() with argument GL_SMOOTH_POINT_SIZE_RANGE
       glGet() with argument GL_SMOOTH_POINT_SIZE_GRANULARITY
       glIsEnabled() with argument GL_POINT_SMOOTH

SEE ALSO
  glEnable(3)

Index for Section 3G

Alphabetical listing for G

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