GLPOLYGONSTIPPLE(3G)GLPOLYGONSTIPPLE(3G)NAMEglPolygonStipple - set the polygon stippling pattern
C SPECIFICATION
void glPolygonStipple( const GLubyte *mask )
delim $$
PARAMETERS
mask Specifies a pointer to a $32 ~times~ 32$ stipple pattern that
will be unpacked from memory in the same way that glDrawPixels
unpacks pixels.
DESCRIPTION
Polygon stippling, like line stippling (see glLineStipple), masks out
certain fragments produced by rasterization, creating a pattern.
Stippling is independent of polygon antialiasing.
mask is a pointer to a $32 ~times~ 32$ stipple pattern that is stored
in memory just like the pixel data supplied to a glDrawPixels call with
height and width both equal to 32, a pixel of GL_COLOR_INDEX, and data
type of GL_BITMAP. That is, the stipple pattern is represented as a
$32 ~times~ 32$ array of 1-bit color indices packed in unsigned bytes.
glPixelStore parameters like GL_UNPACK_SWAP_BYTES and
GL_UNPACK_LSB_FIRST affect the assembling of the bits into a stipple
pattern. Pixel transfer operations (shift, offset, pixel map) are not
applied to the stipple image, however.
To enable and disable polygon stippling, call glEnable and glDisable
with argument GL_POLYGON_STIPPLE. Polygon stippling is initially
disabled. If it's enabled, a rasterized polygon fragment with window
coordinates $x sub w$ and $y sub w$ is sent to the next stage of the GL
if and only if the ($x sub w~roman mod~32$)th bit in the ($y sub
w~roman mod~32$)th row of the stipple pattern is 1 (one). When polygon
stippling is disabled, it is as if the stipple pattern consists of all
1's.
ERRORS
GL_INVALID_OPERATION is generated if glPolygonStipple is executed
between the execution of glBegin and the corresponding execution of
glEnd.
ASSOCIATED GETS
glGetPolygonStipple
glIsEnabled with argument GL_POLYGON_STIPPLE
SEE ALSOglDrawPixels(3G), glLineStipple(3G), glPixelStore(3G),
glPixelTransfer(3G)
March 1, 2011
