glClipPlane(3G)glClipPlane(3G)NAMEglClipPlane - specify a plane against which all geometry is clipped
const GLdouble *equation );
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. Specifies the address of an array
of four double-precision floating-point values. These values are inter‐
preted as a plane equation.
Geometry is always clipped against the boundaries of a six-plane frus‐
tum 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 addi‐
tional clipping planes, call glGetIntegerv() with argument
GL_MAX_CLIP_PLANES. All implementations support at least six such clip‐
ping 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 equa‐
tion. When glClipPlane() is called, equation is transformed by the
inverse of the modelview matrix and stored in the resulting eye coordi‐
nates. Subsequent changes to the modelview matrix have no effect on the
stored plane-equation components. If the dot product of the eye coordi‐
nates of a vertex with the stored plane equation components is positive
or zero, the vertex is in with respect to that clipping plane. Other‐
wise, 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 coor‐
dinates 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().
ASSOCIATED GETSglGetClipPlane()glIsEnabled() with argument GL_CLIP_PLANEi