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SbViewVolume Class Reference

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

`#include <Inventor/SbViewVolume.h>`

## Public Types | |

enum | ProjectionType { ORTHOGRAPHIC = 0, PERSPECTIVE = 1 } |

## Public Member Functions | |

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 | frustum (float left, float right, float bottom, float top, 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 |

SbBool | intersect (const SbVec3f &p) const |

SbBool | intersect (const SbVec3f &p0, const SbVec3f &p1, SbVec3f &closestpoint) const |

SbBool | intersect (const SbBox3f &box) const |

SbBox3f | intersectionBox (const SbBox3f &box) const |

SbBool | outsideTest (const SbPlane &p, const SbVec3f &bmin, const SbVec3f &bmax) const |

const SbDPViewVolume & | getDPViewVolume (void) const |

## Public Attributes | |

ProjectionType | type |

SbVec3f | projPoint |

SbVec3f | projDir |

float | nearDist |

float | nearToFar |

SbVec3f | llf |

SbVec3f | lrf |

SbVec3f | ulf |

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 into the 3D volume from 2D points in the projection plane or vice versa, doing camera transforms, view volume transforms, etc.

- See also
- SbViewportRegion

An SbViewVolume instance can represent either an orthogonal projection volume or a perspective projection volume.

- See also
- ortho(), perspective(), getProjectionType().

Enumerator | |
---|---|

ORTHOGRAPHIC | Orthographic projection. |

PERSPECTIVE | Perspective projection. |

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.

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()

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.

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)

The returned coordinates (*dst*) are normalized to be in range [0, 1].

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()

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 |

Returns a rotation that aligns an object so that its positive x-axis is to the right and its positive y-axis is up in the view volume.

If rightangleonly is TRUE, it will create a rotation that aligns the x and y-axis with the closest orthogonal axes to right and up.

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.

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.:

..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::frustum | ( | float | left, |

float | right, |
||

float | bottom, |
||

float | top, |
||

float | nearval, |
||

float | farval |
||

) |

Set up the frustum for perspective projection. This is an alternative to perspective() that lets you specify any kind of view volumes (e.g. off center volumes). It has the same arguments and functionality as the corresponding OpenGL glFrustum() function.

This function is an extension for Coin, and it is not available in the original SGI Open Inventor v2.1 API.

- Since
- Coin 2.0

- See also
- perspective()

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 the projection point, i.e. the camera position.

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.

SbBool SbViewVolume::intersect | ( | const SbVec3f & | p | ) | const |

Returns TRUE if *p* is inside the view volume.

- Since
- Coin 2.3

SbBool SbViewVolume::intersect | ( | const SbVec3f & | p0, |

const SbVec3f & | p1, |
||

SbVec3f & | closestpoint |
||

) | const |

Returns TRUE if the line segment *p0*, *p1* may intersect volume. Be aware that it's not 100% certain that the line segment intersects the volume even if this function returns TRUE.

*closestpoint* is set to the closest point on the line to the center ray of the view volume.

- Since
- Coin 2.3

SbBool SbViewVolume::intersect | ( | const SbBox3f & | box | ) | const |

Returns TRUE if *box* may be inside the view volume.

- Since
- Coin 2.3

Calculates the bbox of the intersection between *bbox* and the view volume.

- Since
- Coin 4.0

SbBool SbViewVolume::outsideTest | ( | const SbPlane & | p, |

const SbVec3f & | bmin, |
||

const SbVec3f & | bmax |
||

) | const |

Returns TRUE if all eight corner points in *bmin*, *bmax* is outside *p*.

const SbDPViewVolume & SbViewVolume::getDPViewVolume | ( | void | ) | const |

Returns the double precision version of this view volume.

SbViewVolume::ProjectionType SbViewVolume::type |

*This API member is considered internal to the library, as it is not likely to be of interest to the application programmer.*

SbVec3f SbViewVolume::projPoint |

SbVec3f SbViewVolume::projDir |

float SbViewVolume::nearDist |

float SbViewVolume::nearToFar |

SbVec3f SbViewVolume::llf |

SbVec3f SbViewVolume::lrf |

SbVec3f SbViewVolume::ulf |

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

- SbViewVolume.h
- SbViewVolume.cpp