void glPointSize(GLfloat size)
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
(| xw | + 0.5, | yw | + 0.5)
where w subscripts indicate window coordinates. All pixels
that lie within the square grid of the rounded size centered
at
(| xw + 0.5 |, | yw + 0.5 |)
and the rasterized fragment's centers are the half-integer
window coordinates within the square of the rounded size
centered at
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
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 GL_POINT_SIZE_GRANULARITY.
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_INVALID_OPERATION is generated if glPointSize is executed between the execution of glBegin and the corresponding execution of glEnd.