GLBITMAP(3G) UNIX Programmer's Manual GLBITMAP(3G)
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 bit-
map image.
xorig, yorig Specify the location of the origin in the bit-
map 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 posi-
tioned 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 speci-
fies 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.
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.
MirOS BSD #10-current Printed 20.2.2012 1
GLBITMAP(3G) UNIX Programmer's Manual GLBITMAP(3G)
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
xw = | xr - xo |
yw = | yr - yo |
where (xr,yr) is the raster position and (xo,yo) is the bit-
map origin. Fragments are then generated for each pixel
corresponding to a 1 (one) in the bitmap image. These frag-
ments are generated using the current raster z coordinate,
color or color index, and current raster texture coordi-
nates. They are then treated just as if they had been gen-
erated by a point, line, or polygon, including texture map-
ping,
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 coordi-
nates, 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 nega-
tive.
GL_INVALID_OPERATION is generated if glBitmap is executed
between the execution of glBegin and the corresponding exe-
cution of glEnd.
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
glDrawPixels(3G), glPixelStore(3G), glPixelTransfer(3G),
glRasterPos(3G)
MirOS BSD #10-current Printed 20.2.2012 2
GLBITMAP(3G) UNIX Programmer's Manual GLBITMAP(3G)
MirOS BSD #10-current Printed 20.2.2012 3
Generated on 2012-02-20 02:47:02 by $MirOS: src/scripts/roff2htm,v 1.70 2011/12/03 18:21:12 tg Exp $
These manual pages and other documentation are copyrighted by their respective writers;
their source is available at our CVSweb,
AnonCVS, and other mirrors. The rest is Copyright © 2002‒2011 The MirOS Project, Germany.
This product includes material
provided by Thorsten Glaser.
This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report – diffs preferred.