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: Fri Dec 6 11:18:03 EST 1996 by AFV
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