glClipPlane(3G)		       OpenGL Reference		       glClipPlane(3G)

NAME    [Toc]    [Back]

     glClipPlane - specify a plane against which all geometry is clipped

C SPECIFICATION    [Toc]    [Back]

     void glClipPlane( GLenum plane,
		       const GLdouble *equation	)

PARAMETERS    [Toc]    [Back]

     plane     Specifies which clipping	plane is being positioned.  Symbolic
	       names of	the form GL_CLIP_PLANEi, where i is an integer between
	       0 and GL_MAX_CLIP_PLANES-1, are accepted.

     equation  Specifies the address of	an array of four double-precision
	       floating-point values.  These values are	interpreted as a plane
	       equation.

DESCRIPTION    [Toc]    [Back]

     Geometry is always	clipped	against	the boundaries of a six-plane frustum
     in	x, y, and z. glClipPlane allows	the specification of additional
     planes, not necessarily perpendicular to the x, y,	or z axis, against
     which all geometry	is clipped.  To	determine the maximum number of
     additional	clipping planes, call glGetIntegerv with argument
     GL_MAX_CLIP_PLANES. All implementations support at	least six such
     clipping planes. Because the resulting clipping region is the
     intersection of the defined half-spaces, it is always convex.

     glClipPlane specifies a half-space	using a	four-component plane equation.
     When glClipPlane is called, equation is transformed by the	inverse	of the
     modelview matrix and stored in the	resulting eye coordinates.  Subsequent
     changes to	the modelview matrix have no effect on the stored planeequation
 components.  If the dot product of the eye coordinates of	a
     vertex with the stored plane equation components is positive or zero, the
     vertex is in with respect to that clipping	plane.	Otherwise, it is out.

     To	enable and disable clipping planes, call glEnable and glDisable	with
     the argument GL_CLIP_PLANEi, where	i is the plane number.

     All clipping planes are initially defined as (0, 0, 0, 0) in eye
     coordinates and are disabled.

NOTES    [Toc]    [Back]

     It	is always the case that	GL_CLIP_PLANEi = GL_CLIP_PLANE0	+ i.

ERRORS    [Toc]    [Back]

     GL_INVALID_ENUM is	generated if plane is not an accepted value.

     GL_INVALID_OPERATION is generated if glClipPlane is executed between the
     execution of glBegin and the corresponding	execution of glEnd.





									Page 1






glClipPlane(3G)		       OpenGL Reference		       glClipPlane(3G)

ASSOCIATED GETS    [Toc]    [Back]

     glGetClipPlane
     glIsEnabled with argument GL_CLIP_PLANEi

SEE ALSO    [Toc]    [Back]

     glEnable


									PPPPaaaaggggeeee 2222