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  man pages->Tru64 Unix man pages -> glBitmap (3)              



NAME    [Toc]    [Back]

       glBitmap - draw a bitmap

SYNOPSIS    [Toc]    [Back]

       void glBitmap(
               GLsizei width,
               GLsizei height,
               GLfloat xorig,
               GLfloat yorig,
               GLfloat xmove,
               GLfloat ymove,
               const GLubyte *bitmap );

PARAMETERS    [Toc]    [Back]

       Specify  the  pixel  width and height of the bitmap image.
       Specify the location of the origin in  the  bitmap  image.
       The  origin  is measured from the lower left corner of the
       bitmap, with right and up being the positive axes.   Specify
  the x and y offsets to be added to the current raster
       position after the bitmap is drawn.  Specifies the address
       of the bitmap image.

DESCRIPTION    [Toc]    [Back]

       A  bitmap  is  a  binary  image. When drawn, the bitmap is
       positioned relative to the current  raster  position,  and
       frame buffer pixels corresponding to 1's in the bitmap are
       written using the current raster  color  or  index.  Frame
       buffer  pixels  corresponding to 0's in the bitmap are not

       glBitmap() takes seven arguments. The first pair specifies
       the  width and height of the bitmap image. The second pair
       specifies the location of the bitmap  origin  relative  to
       the  lower left corner of the bitmap image. The third pair
       of arguments specifies x and y offsets to be added to  the
       current  raster  position after the bitmap has been drawn.
       The final argument  is  a  pointer  to  the  bitmap  image

       The  bitmap  image  is interpreted like image data for the
       glDrawPixels() command, with width and height  corresponding
 to the width and height arguments of that command, and
       with  type  set   to   GL_BITMAP   and   format   set   to
       GL_COLOR_INDEX.   Modes   specified  using  glPixelStore()
       affect the interpretation  of  bitmap  image  data;  modes
       specified using glPixelTransfer() do not.

       If  the  current raster position is invalid, glBitmap() is
       ignored. Otherwise, the lower left corner  of  the  bitmap
       image is positioned at the window coordinates
        x[w] = x[r] - x[o]

       y[w] = y[r] - y[o]

       where ( x[r] , y[r] ) is the raster position and ( x [o] ,
       y[o] ) is the bitmap origin. Fragments are then  generated
       for  each  pixel  corresponding to a 1 (one) in the bitmap
       image. These fragments are  generated  using  the  current
       raster  z  coordinate,  color  or color index, and current
       raster texture coordinates. They are then treated just  as
       if  they  had been generated by a point, line, or polygon,
       including texture mapping, fogging, and  all  per-fragment
       operations such as alpha and depth testing.

       After  the  bitmap has been drawn, the x and y coordinates
       of the current raster position are  offset  by  xmove  and
       ymove.  No  change is made to the z coordinate of the current
 raster position, or to the current raster color, texture
 coordinates, or index.

NOTES    [Toc]    [Back]

       To set a valid raster position outside the viewport, first
       set a valid raster position inside the viewport, then call
       glBitmap()  with  NULL  as  the  bitmap parameter and with
       xmove and ymove set to the offsets of the new raster position.
  This  technique  is  useful  when  panning an image
       around the viewport.

ERRORS    [Toc]    [Back]

       GL_INVALID_VALUE is generated if width or height is  negative.

       GL_INVALID_OPERATION  is  generated  if glBitmap() is executed
 between the execution of glBegin()  and  the  corresponding
 execution of glEnd().

ASSOCIATED GETS    [Toc]    [Back]

       glGet() with argument GL_CURRENT_RASTER_POSITION
       glGet() with argument GL_CURRENT_RASTER_COLOR
       glGet() with argument GL_CURRENT_RASTER_DISTANCE
       glGet() with argument GL_CURRENT_RASTER_INDEX
       glGet() with argument GL_CURRENT_RASTER_TEXTURE_COORDS
       glGet() with argument GL_CURRENT_RASTER_POSITION_VALID

SEE ALSO    [Toc]    [Back]

       glDrawPixels(3),    glPixelStore(3),   glPixelTransfer(3),

[ Back ]
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