glRasterPos.3gl







Name

  glRasterPos2d, glRasterPos2f,	glRasterPos2i, glRasterPos2s, glRasterPos3d,

  glRasterPos3f, glRasterPos3i,	glRasterPos3s, glRasterPos4d, glRasterPos4f,

  glRasterPos4i, glRasterPos4s,	glRasterPos2dv,	glRasterPos2fv,

  glRasterPos2iv, glRasterPos2sv, glRasterPos3dv, glRasterPos3fv,

  glRasterPos3iv, glRasterPos3sv, glRasterPos4dv, glRasterPos4fv,

  glRasterPos4iv, glRasterPos4sv - specify the raster position for pixel

  operations





C Specification

  void glRasterPos2d( GLdouble x,

		      GLdouble y )

  void glRasterPos2f( GLfloat x,

		      GLfloat y	)

  void glRasterPos2i( GLint x,

		      GLint y )

  void glRasterPos2s( GLshort x,

		      GLshort y	)

  void glRasterPos3d( GLdouble x,

		      GLdouble y,

		      GLdouble z )

  void glRasterPos3f( GLfloat x,

		      GLfloat y,

		      GLfloat z	)

  void glRasterPos3i( GLint x,

		      GLint y,

		      GLint z )

  void glRasterPos3s( GLshort x,

		      GLshort y,

		      GLshort z	)

  void glRasterPos4d( GLdouble x,

		      GLdouble y,

		      GLdouble z,

		      GLdouble w )

  void glRasterPos4f( GLfloat x,

		      GLfloat y,

		      GLfloat z,

		      GLfloat w	)

  void glRasterPos4i( GLint x,

		      GLint y,

		      GLint z,

		      GLint w )

  void glRasterPos4s( GLshort x,

		      GLshort y,

		      GLshort z,

		      GLshort w	)





Parameters



  x, y,	z, w

	   Specify the x, y, z,	and w object coordinates (if present) for the

	   raster position.



C Specification

  void glRasterPos2dv( const GLdouble *v )

  void glRasterPos2fv( const GLfloat *v	)

  void glRasterPos2iv( const GLint *v )

  void glRasterPos2sv( const GLshort *v	)

  void glRasterPos3dv( const GLdouble *v )

  void glRasterPos3fv( const GLfloat *v	)

  void glRasterPos3iv( const GLint *v )

  void glRasterPos3sv( const GLshort *v	)

  void glRasterPos4dv( const GLdouble *v )

  void glRasterPos4fv( const GLfloat *v	)

  void glRasterPos4iv( const GLint *v )

  void glRasterPos4sv( const GLshort *v	)





  v    Specifies a pointer to an array of two, three, or four elements,

       specifying x, y,	z, and w coordinates, respectively.





Description

  The GL maintains a 3-D position in window coordinates.  This position,

  called the raster position, is maintained with subpixel accuracy.  It	is

  used to position pixel and bitmap write operations.  See glBitmap,

  glDrawPixels,	and glCopyPixels.



  The current raster position consists of three	window coordinates (x, y, z),

  a clip coordinate w value, an	eye coordinate distance, a valid bit, and

  associated color data	and texture coordinates.  The w	coordinate is a	clip

  coordinate, because w	is not projected to window coordinates.	 glRasterPos4

  specifies object coordinates x, y, z,	and w explicitly.  glRasterPos3

  specifies object coordinate x, y, and	z explicitly, while w is implicitly

  set to one.  glRasterPos2 uses the argument values for x and y while

  implicitly setting z and w to	zero and one.



  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 the 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.



  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.



Notes

  The raster position is modified both by glRasterPos and by glBitmap.



  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).



Errors

  GL_INVALID_OPERATION is generated if glRasterPos is called between a call

  to glBegin and the corresponding call	to 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_INDEX

  glGet	with argument GL_CURRENT_RASTER_TEXTURE_COORDS



See Also

  glBitmap, glCopyPixels, glDrawPixels,	glLight, glLightModel, glShadeModel,

  glTexCoord, glTexGen,	glVertex








Introduction | Alphabetic | Specification

Last Edited: Mon, May 22, 1995

AFV