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csPlane3 Class Reference

A plane in 3D space. More...

#include <plane3.h>

List of all members.

Public Methods

csPlane3 ()

Initialize to the xy plane (0,0,1,0).

csPlane3 (const csVector3 &plane_norm, float d=0)

Initialize the plane with the given norm and D component.

csPlane3 (float a, float b, float c, float d=0)

Initialize the plane to the given components.

csPlane3 (const csVector3 &v1, const csVector3 &v2, const csVector3 &v3)

Initialize the plane through the three given points. More...

csPlane3 (const csVector3 &v2, const csVector3 &v3)

Initialize the plane through 0 and the two given points. More...

csVector3& Normal ()

Return the normal vector of this plane.

const csVector3& Normal () const

Return the normal vector of this plane.

float A () const

Return the A component of this plane.

float B () const

Return the B component of this plane.

float C () const

Return the C component of this plane.

float D () const

Return the D component of this plane.

float& A ()

Return the A component of this plane.

float& B ()

Return the B component of this plane.

float& C ()

Return the C component of this plane.

float& D ()

Return the D component of this plane.

void Set (float a, float b, float c, float d)

Set the value of the four plane components.

void Set (const csVector3 &normal, float d)

Set the value of the plane using a normal and D component.

void Set (const csVector3 &v1, const csVector3 &v2, const csVector3 &v3)

Initialize the plane through the three given points. More...

void Set (const csVector3 &v2, const csVector3 &v3)

Initialize the plane through 0 and the two given points. More...

float Classify (const csVector3 &pt) const

Classify the given vector with regards to this plane. More...

float Distance (const csVector3 &pt) const

Compute the distance from the given vector to this plane. More...

void Invert ()

Reverses the direction of the plane while maintianing the plane itself. More...

void Normalize ()

Normalizes the plane equation so that 'norm' is a unit vector.

bool ClipPolygon (csVector3 *&pverts, int &num_verts, bool reversed=false)

Clip the polygon in pverts (having num_verts vertices) to this plane. More...

Public Attributes

csVector3 norm

The normal vector (or the (A,B,C) components).

float DD

The D component of the plane.

Static Public Methods

float Classify (float A, float B, float C, float D, const csVector3 &pt)

This static function classifies a vector with regards to four given plane components. More...

Detailed Description

A plane in 3D space.

The plane is given by the equation AAx + BBy + CCz + DD = 0, Where (AA,BB,CC) is given by the vector 'norm'.

Constructor & Destructor Documentation

csPlane3::csPlane3 ( const csVector3 & v1,

const csVector3 & v2,

const csVector3 & v3 )

Initialize the plane through the three given points.
If the plane is expressed as (N,D) with N the A,B,C components of the plane then this will initialize the plane to (N',-N'*v1) with N' equal to (v1-v2)%(v1-v3).

csPlane3::csPlane3 ( const csVector3 & v2,

const csVector3 & v3 ) [inline]

Initialize the plane through 0 and the two given points.
If the plane is expressed as (N,D) with N the A,B,C components of the plane then this will initialize the plane to (v2v3,0).

Member Function Documentation

float csPlane3::Classify ( float A,

float B,

float C,

float D,

const csVector3 & pt ) [inline, static]

This static function classifies a vector with regards to four given plane components.
This will calculate and return A*pt.x+B*pt.y+C*pt.z+D.

float csPlane3::Classify ( const csVector3 & pt ) const [inline]

Classify the given vector with regards to this plane.
If the plane is expressed as (N,D) with N the A,B,C components of the plane then this will calculate and return N*pt+D. Note that in the Crystal Space engine this function will return negative if used on the visible side of a polygon. i.e. if you take the world space plane of the polygon, then Classify() will return a negative value if the camera is located at a point from which you can see the polygon. Back-face culling will make the polygon invisible on the other side.

bool csPlane3::ClipPolygon ( csVector3 *& pverts,

int & num_verts,

bool reversed = false )

Clip the polygon in pverts (having num_verts vertices) to this plane.
The vertices are expected in camera space. Method returns true if there is something visible, false otherwise. Note that this function returns a pointer to a static array in csPlane3. The contents of this array will only be valid until the next call to ClipPolygon. Normally this function will consider the polygon visible if it is on the negative side of the plane (Classify()). If 'reversed' is set to true then the positive side will be used instead.

float csPlane3::Distance ( const csVector3 & pt ) const [inline]

Compute the distance from the given vector to this plane.
This function assumes that 'norm' is a unit vector. If not, the function returns distance times the magnitude of 'norm'. This function corresponds exactly to the absolute value of Classify().

void csPlane3::Invert ( ) [inline]

Reverses the direction of the plane while maintianing the plane itself.
This will basically reverse the result of Classify().

void csPlane3::Set ( const csVector3 & v2,

const csVector3 & v3 ) [inline]

Initialize the plane through 0 and the two given points.
If the plane is expressed as (N,D) with N the A,B,C components of the plane then this will initialize the plane to (v2v3,0).

void csPlane3::Set ( const csVector3 & v1,

const csVector3 & v2,

const csVector3 & v3 )

Initialize the plane through the three given points.
If the plane is expressed as (N,D) with N the A,B,C components of the plane then this will initialize the plane to (N',-N'*v1) with N' equal to (v1-v2)%(v1-v3).

The documentation for this class was generated from the following file:

plane3.h