Gl.ClipPlane (gb.opengl)
Static Sub ClipPlane ( Plane As Integer, Equation As Float[] )
Specify a plane against which all geometry is clipped.
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
,
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.
Gl.ClipPlane 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
Gl.GetIntegerv 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.
Gl.ClipPlane specifies a half-space using a four-component plane equation.
When
Gl.ClipPlane 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
Gl.Enable and
Gl.Disable with the argument
Gl.CLIP_PLANE
i,
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
=
Gl.CLIP_PLANE0 +
.
Errors
Gl.INVALID_ENUM is generated if
plane is not an accepted value.
Gl.INVALID_OPERATION is generated if
Gl.ClipPlane
is executed between the execution of
Gl.Begin
and the corresponding execution of
Gl.End.
Associated Gets
Gl.GetClipPlane
Gl.IsEnabled with argument Gl.CLIP_PLANE
i
See also
See original documentation on OpenGL website