GLCLIPPLANE(3G)GLCLIPPLANE(3G)NAMEglClipPlane - specify a plane against which all geometry is clipped
C SPECIFICATION
void glClipPlane( GLenum plane,
const GLdouble *equation )
delim $$
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_PLANE$i$ = 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.
ASSOCIATED GETS
glGetClipPlane
glIsEnabled with argument GL_CLIP_PLANEi
SEE ALSOglEnable(3G)
March 1, 2011
