void glPointSize( GLfloatsize)

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

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*)

( *x _{w}* + .5,

where *w* subscripts indicate window coordinates. All pixels that lie
within the square grid of the rounded size centered at *x*,
*y*)

( *x _{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*)

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}*,

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_POINT_SIZE_RANGE` and

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.

is generated if**GL_INVALID_VALUE**is less than or equal to 0.*size*is generated if**GL_INVALID_OPERATION**`glPointSize`is executed between the execution of`glBegin`and the corresponding execution of`glEnd`.