glRasterPos — specify the raster position for pixel operations
void glRasterPos2s( | GLshort | x, |
GLshort | y) ; |
void glRasterPos2i( | GLint | x, |
GLint | y) ; |
void glRasterPos2f( | GLfloat | x, |
GLfloat | y) ; |
void glRasterPos2d( | GLdouble | x, |
GLdouble | y) ; |
void glRasterPos3s( | GLshort | x, |
GLshort | y, | |
GLshort | z) ; |
void glRasterPos3i( | GLint | x, |
GLint | y, | |
GLint | z) ; |
void glRasterPos3f( | GLfloat | x, |
GLfloat | y, | |
GLfloat | z) ; |
void glRasterPos3d( | GLdouble | x, |
GLdouble | y, | |
GLdouble | z) ; |
void glRasterPos4s( | GLshort | x, |
GLshort | y, | |
GLshort | z, | |
GLshort | w) ; |
void glRasterPos4i( | GLint | x, |
GLint | y, | |
GLint | z, | |
GLint | w) ; |
void glRasterPos4f( | GLfloat | x, |
GLfloat | y, | |
GLfloat | z, | |
GLfloat | w) ; |
void glRasterPos4d( | GLdouble | x, |
GLdouble | y, | |
GLdouble | z, | |
GLdouble | w) ; |
x
, y
, z
, w
Specify the
void glRasterPos2sv( | const GLshort * | v) ; |
void glRasterPos2iv( | const GLint * | v) ; |
void glRasterPos2fv( | const GLfloat * | v) ; |
void glRasterPos2dv( | const GLdouble * | v) ; |
void glRasterPos3sv( | const GLshort * | v) ; |
void glRasterPos3iv( | const GLint * | v) ; |
void glRasterPos3fv( | const GLfloat * | v) ; |
void glRasterPos3dv( | const GLdouble * | v) ; |
void glRasterPos4sv( | const GLshort * | v) ; |
void glRasterPos4iv( | const GLint * | v) ; |
void glRasterPos4fv( | const GLfloat * | v) ; |
void glRasterPos4dv( | const GLdouble * | v) ; |
v
Specifies a pointer to an array of two,
three,
or four elements,
specifying
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.
The current raster position consists of three window coordinates
(glRasterPos4
specifies object coordinates
glRasterPos3
specifies object coordinate
glRasterPos2
uses the argument values for
The object coordinates presented by glRasterPos
are treated just like those
of a glVertex command:
They are transformed by the current modelview and projection matrices
and passed to the clipping stage.
If the vertex is not culled,
then it is projected and scaled to window coordinates,
which become the new current raster position,
and the GL_CURRENT_RASTER_POSITION_VALID
flag is set.
If the vertex
is
culled,
then the valid bit is cleared and the current raster position
and associated color and texture coordinates are undefined.
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).
Finally,
the distance from the origin of the eye coordinate system to the
vertex as transformed by only the modelview matrix replaces
GL_CURRENT_RASTER_DISTANCE
.
Initially, the current raster position is (0, 0, 0, 1),
the current raster distance is 0,
the valid bit is set,
the associated RGBA color is (1, 1, 1, 1),
the associated color index is 1,
and the associated texture coordinates are (0, 0, 0, 1).
In RGBA mode,
GL_CURRENT_RASTER_INDEX
is always 1;
in color index mode,
the current raster RGBA color always maintains its initial value.
The raster position is modified by glRasterPos
, glBitmap, and glWindowPos.
When the raster position coordinates are invalid, drawing commands that are based on the raster position are ignored (that is, they do not result in changes to GL state).
Calling glDrawElements or glDrawRangeElements may leave the
current color or index indeterminate.
If glRasterPos
is executed while the current color or index is indeterminate, the
current raster color or current raster index remains indeterminate.
To set a valid raster position outside the viewport, first set a valid raster position, then call glBitmap with NULL as the bitmap parameter.
When the ARB_imaging
extension is supported, there are distinct
raster texture coordinates for each texture unit. Each texture unit's
current raster texture coordinates are updated by glRasterPos
.
GL_INVALID_OPERATION
is generated if glRasterPos
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_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
glBitmap, glCopyPixels, glDrawArrays, glDrawElements, glDrawRangeElements, glDrawPixels, glMultiTexCoord, glTexCoord, glTexGen, glVertex, glWindowPos
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/.