glClipPlane(3G) OpenGL Reference glClipPlane(3G)NAME
glClipPlane - specify a plane against which all geometry is clipped
C SPECIFICATION
void glClipPlane( GLenum plane,
const GLdouble *equation )
PARAMETERS
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
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.
NOTES
It is always the case that GL_CLIP_PLANEi = GL_CLIP_PLANE0 + i.
ERRORS
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.
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glClipPlane(3G) OpenGL Reference glClipPlane(3G)ASSOCIATED GETS
glGetClipPlane
glIsEnabled with argument GL_CLIP_PLANEi
SEE ALSO
glEnable
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