glPolygonStipple(3G) OpenGL Reference glPolygonStipple(3G)
NAME
glPolygonStipple - set the polygon stippling pattern
C SPECIFICATION
void glPolygonStipple( const GLubyte *mask )
PARAMETERS
mask Specifies a pointer to a 32x32 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 32x32 stipple pattern that is stored in memory
just like the pixel data supplied to a glDrawPixels with height and width
both equal to 32, a pixel format of GLCOLORINDEX, and data type of
GLBITMAP. That is, the stipple pattern is represented as a 32x32 array
of 1-bit color indices packed in unsigned bytes. glPixelStore parameters
like GLUNPACKSWAPBYTES and GLUNPACKLSBFIRST 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 GLPOLYGONSTIPPLE. If enabled, a rasterized polygon
fragment with window coordinates x and y is sent to the next stage of
w w
the GL if and only if the (x mod 32)th bit in the (y mod 32)th row of
w w
the stipple pattern is 1. When polygon stippling is disabled, it is as
if the stipple pattern were all 1's.
ERRORS
GLINVALIDOPERATION is generated if glPolygonStipple is executed between
the execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGetPolygonStipple
glIsEnabled with argument GLPOLYGONSTIPPLE
SEE ALSO
glDrawPixels, glLineStipple, glPixelStore, glPixelTransfer
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