GLPOLYGONSTIPPLE(3gl)GLPOLYGONSTIPPLE(3gl)NAME
glPolygonStipple - set the polygon stippling pattern
C SPECIFICATION
void glPolygonStipple( const GLubyte *mask )
PARAMETERS
mask Specifies a pointer to a 32×32 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. Stip‐
pling is independent of polygon antialiasing.
mask is a pointer to a 32×32 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 format of GL_COLOR_INDEX, and data
type of GL_BITMAP. That is, the stipple pattern is represented as a
32×32 array of 1-bit color indices packed in unsigned bytes. glPixel‐
Store parameters like GL_UNPACK_SWAP_BYTES and GL_UNPACK_LSB_FIRST
affect the assembling of the bits into a stipple pattern. Pixel trans‐
fer operations (shift, offset, pixel map) are not applied to the stip‐
ple image, however.
To enable and disable polygon stippling, call glEnable and glDisable
with argument GL_POLYGON_STIPPLE. Polygon stippling is initially dis‐
abled. If it's enabled, a rasterized polygon fragment with window coor‐
dinates xw and yw is sent to the next stage of the GL if and only if
the (xwmod32)th bit in the (ywmod32)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 ALSO
glDrawPixels, glLineStipple, glPixelStore, glPixelTransfer
15 Mar 97 GLPOLYGONSTIPPLE(3gl)