glBitmap — draw a bitmap
void glBitmap( | GLsizei | width, |
GLsizei | height, | |
GLfloat | xorig, | |
GLfloat | yorig, | |
GLfloat | xmove, | |
GLfloat | ymove, | |
const GLubyte * | bitmap) ; |
width
, height
Specify the pixel width and height of the bitmap image.
xorig
, yorig
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.
xmove
, ymove
Specify the x and y offsets to be added to the current raster position after the bitmap is drawn.
bitmap
Specifies the address of the bitmap image.
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 modified.
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 itself.
If a non-zero named buffer object is bound to the GL_PIXEL_UNPACK_BUFFER
target
(see glBindBuffer) while a bitmap image is
specified, bitmap
is treated as a byte offset into the buffer object's data store.
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
where
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.
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.
GL_INVALID_VALUE
is generated if width
or height
is negative.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_UNPACK_BUFFER
target and the buffer object's data store is currently mapped.
GL_INVALID_OPERATION
is generated if a non-zero buffer object name is bound to the
GL_PIXEL_UNPACK_BUFFER
target and the data would be unpacked from the buffer
object such that the memory reads required would exceed the data store size.
GL_INVALID_OPERATION
is generated if glBitmap
is executed between the execution of glBegin and the corresponding execution of
glEnd.
glGet with argument GL_CURRENT_RASTER_POSITION
glGet with argument GL_CURRENT_RASTER_COLOR
glGet with argument GL_CURRENT_RASTER_SECONDARY_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
glGet with argument GL_PIXEL_UNPACK_BUFFER_BINDING
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.