---

SbViewVolume Class Reference

The SbViewVolume class is a viewing volume in 3D space. More...

#include <Inventor/SbLinear.h>

List of all members.

Public Types
enum	ProjectionType { ORTHOGRAPHIC = 0, PERSPECTIVE = 1 }
Public Methods
	SbViewVolume (void)
	~SbViewVolume (void)
void	getMatrices (SbMatrix &affine, SbMatrix &proj) const
SbMatrix	getMatrix (void) const
SbMatrix	getCameraSpaceMatrix (void) const
void	projectPointToLine (const SbVec2f &pt, SbLine &line) const
void	projectPointToLine (const SbVec2f &pt, SbVec3f &line0, SbVec3f &line1) const
void	projectToScreen (const SbVec3f &src, SbVec3f &dst) const
SbPlane	getPlane (const float distFromEye) const
SbVec3f	getSightPoint (const float distFromEye) const
SbVec3f	getPlanePoint (const float distFromEye, const SbVec2f &normPoint) const
SbRotation	getAlignRotation (SbBool rightAngleOnly=FALSE) const
float	getWorldToScreenScale (const SbVec3f &worldCenter, float normRadius) const
SbVec2f	projectBox (const SbBox3f &box) const
SbViewVolume	narrow (float left, float bottom, float right, float top) const
SbViewVolume	narrow (const SbBox3f &box) const
void	ortho (float left, float right, float bottom, float top, float nearval, float farval)
void	perspective (float fovy, float aspect, float nearval, float farval)
void	rotateCamera (const SbRotation &q)
void	translateCamera (const SbVec3f &v)
SbVec3f	zVector (void) const
SbViewVolume	zNarrow (float nearval, float farval) const
void	scale (float factor)
void	scaleWidth (float ratio)
void	scaleHeight (float ratio)
ProjectionType	getProjectionType (void) const
const SbVec3f &	getProjectionPoint (void) const
const SbVec3f &	getProjectionDirection (void) const
float	getNearDist (void) const
float	getWidth (void) const
float	getHeight (void) const
float	getDepth (void) const
void	print (FILE *fp) const
void	getViewVolumePlanes (SbPlane planes[6]) const
void	transform (const SbMatrix &matrix)
SbVec3f	getViewUp (void) const
Public Attributes
ProjectionType	type
SbVec3f	projPoint
SbVec3f	projDir
float	nearDist
float	nearToFar
SbVec3f	llf
SbVec3f	lrf
SbVec3f	ulf

---

Detailed Description

The SbViewVolume class is a viewing volume in 3D space.

This class contains the necessary information for storing a view volume. It has methods for projection of primitives from or into the 3D volume, doing camera transforms, view volume transforms etc.

See also:

SbViewportRegion.

---

Member Enumeration Documentation

enum SbViewVolume::ProjectionType

An SbViewVolume instance can represent either an orthogonal projection volume or a perspective projection volume. See also: ortho(), perspective(), getProjectionType(). Enumeration values: ORTHOGRAPHIC   Orthographic projection. PERSPECTIVE   Perspective projection.

---

Constructor & Destructor Documentation

SbViewVolume::SbViewVolume (  void )

Constructor. Note that the SbViewVolume instance will be uninitialized until you explicitly call ortho() or perspective(). See also: ortho(), perspective().

SbViewVolume::~SbViewVolume (  void )

Destructor.

---

Member Function Documentation

void SbViewVolume::getMatrices (  SbMatrix & affine, SbMatrix & proj )  const

Returns the view volume's affine matrix and projection matrix. See also: getMatrix(), getCameraSpaceMatrix()

SbMatrix SbViewVolume::getMatrix (  void )  const

Returns the combined affine and projection matrix. See also: getMatrices(), getCameraSpaceMatrix()

SbMatrix SbViewVolume::getCameraSpaceMatrix (  void )  const

Returns a matrix which will translate the view volume camera back to origo, and rotate the camera so it'll point along the negative z axis. Note that the matrix will not include the rotation necessary to make the camera up vector point along the positive y axis (i.e. camera roll is not accounted for). See also: getMatrices(), getMatrix()

void SbViewVolume::projectPointToLine (  const SbVec2f & pt, SbLine & line )  const

Project the given 2D point from the projection plane into a 3D line. pt coordinates should be normalized to be within [0, 1].

void SbViewVolume::projectPointToLine (  const SbVec2f & pt, SbVec3f & line0, SbVec3f & line1 )  const

Project the given 2D point from the projection plane into two points defining a 3D line. The first point, line0, will be the corresponding point for the projection on the near plane, while line1 will be the line endpoint, lying in the far plane.

void SbViewVolume::projectToScreen (  const SbVec3f & src, SbVec3f & dst )  const

Project the src point to a normalized set of screen coordinates in the projection plane and place the result in dst. It is safe to let src and \dst be the same SbVec3f instance. The z-coordinate of dst is monotonically increasing for points closer to the far plane. Note however that this is not a linear relationship, the dst z-coordinate is calculated as follows: Orthogonal view: DSTz = (-2 * SRCz - far - near) / (far - near), Perspective view: DSTz = (-SRCz * (far - near) - 2*far*near) / (far - near)

SbPlane SbViewVolume::getPlane (  const float distFromEye )  const

Returns an SbPlane instance which has a normal vector in the opposite direction of which the camera is pointing. This means the plane will be parallel to the near and far clipping planes. See also: getSightPoint()

SbVec3f SbViewVolume::getSightPoint (  const float distFromEye )  const

Returns the point on the center line-of-sight from the camera position with the given distance. See also: getPlane()

SbVec3f SbViewVolume::getPlanePoint (  const float distFromEye, const SbVec2f & normPoint )  const

Return the 3D point which projects to normPoint and lies on the plane perpendicular to the camera direction and distFromEye distance away from the camera position. normPoint should be given in normalized coordinates, where the visible render canvas is covered by the range [0.0, 1.0].

SbRotation SbViewVolume::getAlignRotation (  SbBool rightangleonly = FALSE )  const

This method is obsoleted in Coin. Let us know if you need it, and we'll consider implementing it.

float SbViewVolume::getWorldToScreenScale (  const SbVec3f & worldCenter, float normRadius )  const

Given a sphere with center in worldCenter and an initial radius of 1.0, return the scale factor needed to make this sphere have a normRadius radius when projected onto the near clipping plane.

SbVec2f SbViewVolume::projectBox (  const SbBox3f & box )  const

Projects the given box onto the projection plane and returns the normalized screen space it occupies.

SbViewVolume SbViewVolume::narrow (  float left, float bottom, float right, float top )  const

Returns a narrowed version of the view volume which is within the given [0, 1] normalized coordinates. The coordinates are taken to be corner points of a normalized "view window" on the near clipping plane. I.e.: SbViewVolume view; view.ortho(0, 100, 0, 100, 0.1, 1000); view = view.narrow(0.25, 0.5, 0.75, 1.0); ..will give a view volume with corner points <25, 75> and <50, 100>. See also: scale(), scaleWidth(), scaleHeight()

SbViewVolume SbViewVolume::narrow (  const SbBox3f & box )  const

Returns a narrowed version of the view volume which is within the given [0, 1] normalized coordinates. The box x and y coordinates are taken to be corner points of a normalized "view window" on the near clipping plane. The box z coordinates are used to adjust the near and far clipping planes, and should be relative to the current clipping planes. A value of 1.0 is at the current near plane. A value of 0.0 is at the current far plane.

void SbViewVolume::ortho (  float left, float right, float bottom, float top, float nearval, float farval )

Set up the view volume as a rectangular box for orthographic parallel projections. The line of sight will be along the negative z axis, through the center of the plane defined by the point <(right+left)/2, (top+bottom)/2, 0>. See also: perspective().

void SbViewVolume::perspective (  float fovy, float aspect, float nearval, float farval )

Set up the view volume for perspective projections. The line of sight will be through origo along the negative z axis. See also: ortho().

void SbViewVolume::rotateCamera (  const SbRotation & q )

Rotate the direction which the camera is pointing in. See also: translateCamera().

void SbViewVolume::translateCamera (  const SbVec3f & v )

Translate the camera position of the view volume. See also: rotateCamera().

SbVec3f SbViewVolume::zVector (  void )  const

Return the vector pointing from the center of the view volume towards the camera. This is just the vector pointing in the opposite direction of getProjectionDirection(). See also: getProjectionDirection().

SbViewVolume SbViewVolume::zNarrow (  float nearval, float farval )  const

Return a copy SbViewVolume with narrowed depth by supplying parameters for new near and far clipping planes. nearval and \farval should be relative to the current clipping planes. A value of 1.0 is at the current near plane. A value of 0.0 is at the current far plane. See also: zVector().

void SbViewVolume::scale (  float factor )

Scale width and height of viewing frustum by the given ratio around the projection plane center axis. See also: scaleWidth(), scaleHeight().

void SbViewVolume::scaleWidth (  float ratio )

Scale width of viewing frustum by the given ratio around the vertical center axis in the projection plane. See also: scale(), scaleHeight().

void SbViewVolume::scaleHeight (  float ratio )

Scale height of viewing frustum by the given ratio around the horizontal center axis in the projection plane. See also: scale(), scaleWidth().

SbViewVolume::ProjectionType SbViewVolume::getProjectionType (  void )  const

Return current view volume projection type, which can be either ORTHOGRAPHIC or PERSPECTIVE. See also: SbViewVolume::ProjectionType

const SbVec3f & SbViewVolume::getProjectionPoint (  void )  const

Returns coordinates of center point in the projection plane.

const SbVec3f & SbViewVolume::getProjectionDirection (  void )  const

Returns the direction of projection, i.e. the direction the camera is pointing. See also: getNearDist().

float SbViewVolume::getNearDist (  void )  const

Returns distance from projection plane to near clipping plane. See also: getProjectionDirection().

float SbViewVolume::getWidth (  void )  const

Returns width of viewing frustum in the projection plane. See also: getHeight(), getDepth().

float SbViewVolume::getHeight (  void )  const

Returns height of viewing frustum in the projection plane. See also: getWidth(), getDepth().

float SbViewVolume::getDepth (  void )  const

Returns depth of viewing frustum, i.e. the distance from the near clipping plane to the far clipping plane. See also: getWidth(), getHeight().

void SbViewVolume::print (  FILE * fp )  const

Dump the state of this object to the file stream. Only works in debug version of library, method does nothing in an optimized compile.

void SbViewVolume::getViewVolumePlanes (  SbPlane planes[6] )  const

Returns the six planes defining the view volume in the following order: left, bottom, right, top, near, far. Plane normals are directed into the view volume. This method is an extension for Coin, and is not available in the original Open Inventor.

void SbViewVolume::transform (  const SbMatrix & matrix )

Transform the viewing volume by matrix.

SbVec3f SbViewVolume::getViewUp (  void )  const

Returns the view up vector for this view volume. It's a vector which is perpendicular to the projection direction, and parallel and oriented in the same direction as the vector from the lower left corner to the upper left corner of the near plane.

---

Member Data Documentation

SbViewVolume::ProjectionType SbViewVolume::type

For internal use only.

SbVec3f SbViewVolume::projPoint

For internal use only.

SbVec3f SbViewVolume::projDir

For internal use only.

float SbViewVolume::nearDist

For internal use only.

float SbViewVolume::nearToFar

For internal use only.

SbVec3f SbViewVolume::llf

For internal use only.

SbVec3f SbViewVolume::lrf

For internal use only.

SbVec3f SbViewVolume::ulf

For internal use only.

---

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

• SbViewVolume.cpp
• SbViewVolume.h

---