glLineWidth -	specify	the width of rasterized	lines

glLineWidth
	glLineWidth(width) -> None

void glLineWidth( GLfloat width )

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

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.  To query
the range of supported widths	and the	size difference
between supported widths within the range, call glGet	with
arguments GL_LINE_WIDTH_RANGE	and GL_LINE_WIDTH_GRANULARITY.

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.  Although this maximum
cannot be queried, it	must be	no less	than the maximum value
for antialiased lines, rounded to the	nearest	integer	value.

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.

glGet	with argument GL_LINE_WIDTH
glGet	with argument GL_LINE_WIDTH_RANGE
glGet	with argument GL_LINE_WIDTH_GRANULARITY
glIsEnabled with argument GL_LINE_SMOOTH

glEnable