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3.7 BitmapsBitmaps are rectangles of zeros and ones specifying a particular pattern of fragments to be produced. Each of these fragments has the same associated data. These data are those associated with the current raster position. Bitmaps are sent using
void Bitmap ( sizei w, sizei h, float
w and h comprise the integer width and height
of the rectangular bitmap,
respectively.
Like a polygon pattern, a bitmap is unpacked from memory according to the procedure given in section 3.6.3 for DrawPixels ; it is as if the width and height passed to that command were equal to w and h, respectively, the type were BITMAP, and the format were COLOR_INDEX. The unpacked values (before any conversion or arithmetic would have been performed) are bitwise ANDed with 1 to obtain a stipple pattern of zeros and ones. See Figure 3.9.
A bitmap sent using Bitmap is rasterized as follows. First, if the current raster position is invalid (the valid bit is reset), the bitmap is ignored. Otherwise, a rectangular array of fragments is constructed, with lower left corner at
and upper right corner at The z and w values of the current raster position remain unchanged.
![]() ![]() ![]() ![]() ![]() Next: 3.8 Texturing Up: 3 Rasterization Previous: Stencil Index Lookup David Blythe Sat Mar 29 02:23:21 PST 1997
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