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OpenGL 1.1 for AIX: Reference Manual

glClipPlane Subroutine


Specifies a plane against which all geometry is clipped.


OpenGL C bindings library: libGL.a

C Syntax

void glClipPlane(GLenum Plane, const GLdouble *Equation)

By default, all clipping planes are defined as (0,0,0,0) in eye coordinates and are disabled.


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.


Geometry is always clipped against the boundaries of a six-plane frustum in x, y, and z. The glClipPlane subroutine allows the specification of additional planes, not necessarily perpendicular to the x, y, or z axes, against which all geometry is clipped. Up to GL_MAX_CLIP_PLANES planes can be specified, where GL_MAX_CLIP_PLANES is at least 6 in all implementations. Because the resulting clipping region is the intersection of the defined half-spaces, it is always convex.

The glClipPlane subroutine 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 plane equation components. If the dot product of the eye coordinates of a vertex with the stored plane equation components is positive or 0 (zero), the vertex is in with respect to that clipping plane. Otherwise it is out.

Clipping planes are enabled and disabled with glEnable and glDisable, called with the argument GL_CLIP_PLANEi, where i is the plane number.


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


GL_INVALID_ENUM Plane is set to an unaccepted value.
GL_INVALID_OPERATION The glClipPlane subroutine is called between a call to glBegin and the corresponding call to glEnd.

Associated Gets

Associated gets for the glClipPlane subroutine are as follows. (See the glGet subroutine for more information.)

                          Enabled with argument GL_CLIP_PLANEi.


/usr/include/GL/gl.h Contains C language constants, variable type definitions, and ANSI function prototypes for OpenGL

Related Information

The glBegin or glEnd subroutine, glEnable or glDisable subroutine.

OpenGL Overview.

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