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Manual Reference Pages  - GLCLIPPLANE (3G)

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glClipPlane - specify a plane against which all geometry is clipped

CONTENTS

C Specification
Parameters
Description
Notes
Errors
Associated Gets
See Also

void glClipPlane( GLenum plane,

                const GLdouble *equation )

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.  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 plane-equation 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.

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

 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.

 glGetClipPlane
 glIsEnabled with argument  GL_CLIP_PLANEi

 glEnable(3G)

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