fglPolygonStipple(3G)

NAME
     fglPolygonStipple - set the polygon stippling pattern


FORTRAN SPECIFICATION
     SUBROUTINE fglPolygonStipple( CHARACTER*256 mask )


PARAMETERS
     mask  Specifies a pointer to a 32 x 32 stipple pattern that will be
           unpacked from memory in the same way that fglDrawPixels unpacks
           pixels.

DESCRIPTION
     Polygon stippling, like line stippling (see fglLineStipple), 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 fglDrawPixels 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.  fglPixelStore
     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 fglEnable and fglDisable
     with argument GL_POLYGON_STIPPLE. Polygon stippling is initially
     disabled. If it's enabled, a rasterized polygon fragment with window
     coordinates x  and y  is sent to the next stage of the GL if and only if
                  w      w
     the (x  mod 32)th bit in the (y  mod 32)th row of the stipple pattern is
           w                        w
     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 fglPolygonStipple is executed
     between the execution of fglBegin and the corresponding execution of
     fglEnd.

ASSOCIATED GETS
     fglGetPolygonStipple
     fglIsEnabled with argument GL_POLYGON_STIPPLE


SEE ALSO
     fglDrawPixels, fglLineStipple, fglPixelStore, fglPixelTransfer