Glclipplane - HP b2600 Reference Manual

glClipPlane

glClipPlane: specify a plane against which all geometry is clipped.
C Specification
void glClipPlane(
Parameters
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 \f2in\f1 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
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Chapter 3
GLenum plane,
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 interpreted as a plane equation.
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.
C
glClipPlane
57