man SbViewVolume () - 3D viewing volume class
NAME
SbViewVolume - 3D viewing volume class
INHERITS FROM
SbViewVolume
SYNOPSIS
#include <Inventor/SbLinear.h>
enum ProjectionType {
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Orthographic projection
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Perspective projection
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Methods from class SbViewVolume:
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SbViewVolume()
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~SbViewVolume()
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getMatrices(SbMatrix &affine, SbMatrix &proj) const
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getMatrix() const
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getCameraSpaceMatrix() const
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projectPointToLine(const SbVec2f &pt, SbLine &line) const
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projectPointToLine(const SbVec2f &pt, SbVec3f &line0, SbVec3f &line1) const
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projectToScreen(const SbVec3f &src, SbVec3f &dst) const
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getPlane(float distFromEye) const
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getSightPoint(float distFromEye) const
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getPlanePoint(float distFromEye, const SbVec2f &normPoint) const
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getAlignRotation(SbBool rightAngleOnly = FALSE) const
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getWorldToScreenScale(const SbVec3f &worldCenter, float normRadius) const
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projectBox(const SbBox3f &box) const
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narrow(float left, float bottom, float right, float top) const
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narrow(const SbBox3f &box) const
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ortho(float left, float right, float bottom, float top, float near, float far)
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perspective(float fovy, float aspect, float near, float far)
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rotateCamera(const SbRotation &q)
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translateCamera(const SbVec3f &v)
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zVector() const
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zNarrow(float near, float far) const
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scale(float factor)
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scaleWidth(float ratio)
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scaleHeight(float ratio)
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getProjectionType() const
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getProjectionPoint() const
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getProjectionDirection() const
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getNearDist() const
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getWidth() const
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getHeight() const
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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
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SbViewVolume()
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~SbViewVolume()
Constructor and destructor.
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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.
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getMatrix() const
Like the method above, but returns the affine and projection parts together in one matrix (i.e., affine.multRight( proj ) ).
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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.
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projectPointToLine(const SbVec2f &pt, SbLine &line) const
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projectPointToLine(const SbVec2f &pt, SbVec3f &line0, SbVec3f &line1) const
Maps a 2D point (in 0 <= x,y <= 1) to a 3D line.
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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.
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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).
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getSightPoint(float distFromEye) const
Returns the point along the line of sight at the given distance from the projection point (eye).
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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scale(float factor)
Scales width and height of view volume by given factor.
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scaleWidth(float ratio)
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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.
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getProjectionType() const
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getProjectionPoint() const
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getProjectionDirection() const
Returns projection information.
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getNearDist() const
Returns distance from projection point to near plane.
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getWidth() const
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getHeight() const
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getDepth() const
Returns bounds of viewing frustum.
SEE ALSO
SbVec3f, SbVec2f, SbBox3f, SbMatrix, SbRotation