SbViewVolume(3IV)

NAME
SbViewVolume — 3D viewing volume class

INHERITS FROM
SbViewVolume

SYNOPSIS
#include <Inventor/SbLinear.h>

enum ProjectionType {
SbViewVolume::ORTHOGRAPHIC
Orthographic projection
SbViewVolume::PERSPECTIVE
Perspective projection
}

Methods from class SbViewVolume:

SbViewVolume()

~SbViewVolume()
void
getMatrices(SbMatrix &affine, SbMatrix &proj) const
SbMatrix
getMatrix() const
SbMatrix
getCameraSpaceMatrix() 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(float distFromEye) const
SbVec3f
getSightPoint(float distFromEye) const
SbVec3f
getPlanePoint(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 near, float far)
void
perspective(float fovy, float aspect, float near, float far)
void
rotateCamera(const SbRotation &q)
void
translateCamera(const SbVec3f &v)
SbVec3f
zVector() const
SbViewVolume
zNarrow(float near, float far) const
void
scale(float factor)
void
scaleWidth(float ratio)
void
scaleHeight(float ratio)
ProjectionType
getProjectionType() const
const SbVec3f &
getProjectionPoint() const
const SbVec3f &
getProjectionDirection() const
float
getNearDist() const
float
getWidth() const
float
getHeight() const
float
getDepth() const

DESCRIPTION
Class used to represent a 3D viewing volume. This class is used to represent viewing frusta and picking volumes. For perspective projection, the view volume is a frustum. For orthographic (parallel) projection, the view volume is a rectangular prism.

METHODS

SbViewVolume()

~SbViewVolume()
Constructor and destructor.

void
getMatrices(SbMatrix &affine, SbMatrix &proj) const
Returns two matrices corresponding to the view volume. The first is a viewing matrix, which is guaranteed to be an affine transformation. The second is suitable for use as a projection matrix in OpenGL.

SbMatrix
getMatrix() const
Like the method above, but returns the affine and projection parts together in one matrix (i.e., affine.multRight( proj ) ).

SbMatrix
getCameraSpaceMatrix() const
Returns a matrix that transforms the view volume into camera space: it translates the view volume so the viewpoint is at the origin, and rotates it so the view direction is along the negative z axis.

void
projectPointToLine(const SbVec2f &pt, SbLine &line) const
void
projectPointToLine(const SbVec2f &pt, SbVec3f &line0, SbVec3f &line1) const
Maps a 2D point (in 0 <= x,y <= 1) to a 3D line.

void
projectToScreen(const SbVec3f &src, SbVec3f &dst) const
Maps the 3D point in world coordinates to a 2D point in normalized screen coordinates (0 <= x,y,z <= 1). The z-screen coordinate represents the homogenized z coordinate which goes (nonlinearly) from 0 at the near clipping plane to 1 at the far clipping plane.

SbPlane
getPlane(float distFromEye) const
Returns a plane parallel to the near (or far) plane of the view volume at a given distance from the projection point (eye).

SbVec3f
getSightPoint(float distFromEye) const
Returns the point along the line of sight at the given distance from the projection point (eye).

SbVec3f
getPlanePoint(float distFromEye, const SbVec2f &normPoint) const
Returns the projection of a given point in normalized screen coordinates (see projectToScreen()) onto the plane parallel to the near plane that is at distFromEye units from the eye.

SbRotation
getAlignRotation(SbBool rightAngleOnly = FALSE) const
Returns a rotation that would align a viewed object so that its positive x-axis (of its object space) is to the right in the view and its positive y-axis is up. If rightAngleOnly is TRUE, it will come as close as it can to this goal by using only 90 degree rotations.

float
getWorldToScreenScale(const SbVec3f &worldCenter, float normRadius) const
Returns a scale factor that would scale a unit sphere centered at worldCenter so that it would appear to have the given radius in normalized screen coordinates when projected onto the near plane.

SbVec2f
projectBox(const SbBox3f &box) const
Projects the given 3D bounding box onto the near plane and returns the size (in normalized screen coordinates) of the rectangular region that encloses it.

SbViewVolume
narrow(float left, float bottom, float right, float top) const
Given a view volume, narrows the view to the given sub-rectangle of the near plane. The coordinates of the rectangle are between 0 and 1, where (0,0) is the lower-left corner of the near plane and (1,1) is the upper-right corner.

SbViewVolume
narrow(const SbBox3f &box) const
Narrows a view volume by the given box. The box must lie inside the unit cube, and the view will be shrunk according to the size of the box.

void
ortho(float left, float right, float bottom, float top, float near, float far)
Sets up an orthographic view volume with the given sides. The parameters are the same as for the OpenGL glOrtho() routine.

void
perspective(float fovy, float aspect, float near, float far)
Sets up a perspective view volume with the given field of view and aspect ratio. The parameters are the same as for the OpenGL gluPerspective() routine, except that the field of view angle is specified in radians.

void
rotateCamera(const SbRotation &q)
Rotate the camera view direction. Note that this accomplishes the reverse of doing an OpenGL glRotate() command after defining a camera, which rotates the scene viewed by the camera.

void
translateCamera(const SbVec3f &v)
Translate the camera viewpoint. Note that this accomplishes the reverse of doing an OpenGL glTranslate() command after defining a camera, which translates the scene viewed by the camera.

SbVec3f
zVector() const
Returns the positive z axis in eye space. In this coordinate system, the z value of the near plane should be GREATER than the z value of the far plane.

SbViewVolume
zNarrow(float near, float far) const
Returns a narrowed view volume which contains as tightly as possible the given interval on the z axis (in eye space). The returned view volume will never be larger than the current volume, however. near and far are given in terms of zVector(): this means that near > far must hold.

void
scale(float factor)
Scales width and height of view volume by given factor.

void
scaleWidth(float ratio)
void
scaleHeight(float ratio)
Scales view volume to be the given ratio of its current width or height, leaving the resulting view volume centered about the same point (in the near plane) as the current one.

ProjectionType
getProjectionType() const
const SbVec3f &
getProjectionPoint() const
const SbVec3f &
getProjectionDirection() const
Returns projection information.

float
getNearDist() const
Returns distance from projection point to near plane.

float
getWidth() const
float
getHeight() const
float
getDepth() const
Returns bounds of viewing frustum.

SEE ALSO
SbVec3f, SbVec2f, SbBox3f, SbMatrix, SbRotation