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 32 x 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 x 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 x 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
w
and y is sent to the next stage of the GL if and only if the
w
(x mod 32)th bit in the (y mod 32)th row of the stipple pattern is 1
w w
(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
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