Signature
Parameters
Variables | Description |
---|---|
x, y, z |
Specify the
,
,
coordinates for the raster position.
|
v |
Specifies a pointer to an array of two or three elements,
specifying
,
,
coordinates, respectively.
|
Description
The GL maintains a 3D position in window coordinates. This position,
called the raster position, is used to position pixel and bitmap write
operations. It is maintained with subpixel accuracy. See
glBitmap
,
glDrawPixels
, and
glCopyPixels
.
glWindowPos2
specifies the
and
coordinates, while
is
implicitly set to 0.
glWindowPos3
specifies all three coordinates.
The
coordinate of the current raster position is always set to 1.0.
glWindowPos
directly updates the
and
coordinates of the current raster
position with the values specified. That is, the values are neither
transformed by the current modelview and projection matrices, nor by
the viewport-to-window transform. The
coordinate of the current raster
position is updated in the following manner:
The specified coordinates are not clip-tested, causing the raster position
to always be valid.
The current raster position also includes some associated color data and
texture coordinates. If lighting is enabled, then
GL_CURRENT_RASTER_COLOR
(in RGBA mode) or
GL_CURRENT_RASTER_INDEX
(in color index mode) is set to the color produced by the lighting
calculation (see
glLight
,
glLightModel
, and
glShadeModel
).
If lighting is disabled, current color (in RGBA mode, state variable
GL_CURRENT_COLOR
) or color index (in color index mode, state variable
GL_CURRENT_INDEX
) is used to update the current raster color.
GL_CURRENT_RASTER_SECONDARY_COLOR
(in RGBA mode) is likewise updated.
Likewise,
GL_CURRENT_RASTER_TEXTURE_COORDS
is updated as a function of
GL_CURRENT_TEXTURE_COORDS
, based on the texture matrix and the texture
generation functions (see
glTexGen
). The
GL_CURRENT_RASTER_DISTANCE
is set to the
GL_CURRENT_FOG_COORD
.
Notes
glWindowPos
is available only if the GL version is 1.4 or greater.
Calling
glDrawElements
, or
glDrawRangeElements
may leave the
current color or index indeterminate.
If
glWindowPos
is executed while the current color or index is indeterminate, the
current raster color or current raster index remains indeterminate.
There are distinct raster texture coordinates for each texture unit. Each
texture unit's current raster texture coordinates are updated by
glWindowPos
.
Errors
GL_INVALID_OPERATION
is generated if
glWindowPos
is executed between the execution of
glBegin
and the corresponding execution of
glEnd
.
Associated Gets
glGet
with argument
GL_CURRENT_RASTER_POSITION
glGet
with argument
GL_CURRENT_RASTER_POSITION_VALID
glGet
with argument
GL_CURRENT_RASTER_DISTANCE
glGet
with argument
GL_CURRENT_RASTER_COLOR
glGet
with argument
GL_CURRENT_RASTER_SECONDARY_COLOR
glGet
with argument
GL_CURRENT_RASTER_INDEX
glGet
with argument
GL_CURRENT_RASTER_TEXTURE_COORDS
See Also
Copyright
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/
.