NAME
SbDPViewVolume -
The SbDPViewVolume class is a double precision 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.
SYNOPSIS
#include <Inventor/SbLinear.h>
Public Types
enum ProjectionType { ORTHOGRAPHIC = 0, PERSPECTIVE = 1 }
Public Member Functions
SbDPViewVolume (void)
~SbDPViewVolume (void)
void getMatrices (SbDPMatrix &affine, SbDPMatrix &proj) const
SbDPMatrix getMatrix (void) const
SbDPMatrix getCameraSpaceMatrix (void) const
void projectPointToLine (const SbVec2d &pt, SbDPLine &line) const
void projectPointToLine (const SbVec2d &pt, SbVec3d &line0, SbVec3d
&line1) const
void projectToScreen (const SbVec3d &src, SbVec3d &dst) const
SbPlane getPlane (const double distFromEye) const
SbVec3d getSightPoint (const double distFromEye) const
SbVec3d getPlanePoint (const double distFromEye, const SbVec2d
&normPoint) const
SbDPRotation getAlignRotation (SbBool rightAngleOnly=0) const
double getWorldToScreenScale (const SbVec3d &worldCenter, double
normRadius) const
SbVec2d projectBox (const SbBox3f &box) const
SbDPViewVolume narrow (double left, double bottom, double right, double
top) const
SbDPViewVolume narrow (const SbBox3f &box) const
void ortho (double left, double right, double bottom, double top,
double nearval, double farval)
void perspective (double fovy, double aspect, double nearval, double
farval)
void frustum (double left, double right, double bottom, double top,
double nearval, double farval)
void rotateCamera (const SbDPRotation &q)
void translateCamera (const SbVec3d &v)
SbVec3d zVector (void) const
SbDPViewVolume zNarrow (double nearval, double farval) const
void scale (double factor)
void scaleWidth (double ratio)
void scaleHeight (double ratio)
ProjectionType getProjectionType (void) const
const SbVec3d & getProjectionPoint (void) const
const SbVec3d & getProjectionDirection (void) const
double getNearDist (void) const
double getWidth (void) const
double getHeight (void) const
double getDepth (void) const
void print (FILE *fp) const
void getViewVolumePlanes (SbPlane planes[6]) const
void transform (const SbDPMatrix &matrix)
SbVec3d getViewUp (void) const
void copyValues (SbViewVolume &vv)
Detailed Description
The SbDPViewVolume class is a double precision 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.
Be aware that this class is an extension for Coin, and it is not
available in the original SGI Open Inventor v2.1 API.
See also:
SbViewportRegion
Since:
Coin 2.0
Member Enumeration Documentation
enum SbDPViewVolume::ProjectionType An SbDPViewVolume 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.
Constructor & Destructor Documentation
SbDPViewVolume::SbDPViewVolume (void) Constructor. Note that the
SbDPViewVolume instance will be uninitialized until you explicitly call
ortho() or perspective().
See also:
ortho(), perspective().
SbDPViewVolume::~SbDPViewVolume (void) Destructor.
Member Function Documentation
void SbDPViewVolume::getMatrices (SbDPMatrix & affine, SbDPMatrix & proj)
const Returns the view volume’s affine matrix and projection matrix.
See also:
getMatrix(), getCameraSpaceMatrix()
SbDPMatrix SbDPViewVolume::getMatrix (void) const Returns the combined
affine and projection matrix.
See also:
getMatrices(), getCameraSpaceMatrix()
SbDPMatrix SbDPViewVolume::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 SbDPViewVolume::projectPointToLine (const SbVec2d & pt, SbDPLine &
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 SbDPViewVolume::projectPointToLine (const SbVec2d & pt, SbVec3d &
line0, SbVec3d & 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 SbDPViewVolume::projectToScreen (const SbVec3d & src, SbVec3d & 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 be the same SbVec3d 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 SbDPViewVolume::getPlane (const double 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()
SbVec3d SbDPViewVolume::getSightPoint (const double distFromEye) const
Returns the point on the center line-of-sight from the camera position
with the given distance.
See also:
getPlane()
SbVec3d SbDPViewVolume::getPlanePoint (const double distFromEye, const
SbVec2d & 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].
SbDPRotation SbDPViewVolume::getAlignRotation (SbBool rightangleonly = 0)
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.
double SbDPViewVolume::getWorldToScreenScale (const SbVec3d & worldCenter,
double 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.
SbVec2d SbDPViewVolume::projectBox (const SbBox3f & box) const Projects the
given box onto the projection plane and returns the normalized screen
space it occupies.
SbDPViewVolume SbDPViewVolume::narrow (double left, double bottom, double
right, double 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.:
SbDPViewVolume view;
view.ortho(0, 100, 0, 100, 0.1, 1000);
view = view.narrow(0.25, 0.5, 0.75, 1.0);
See also:
scale(), scaleWidth(), scaleHeight()
SbDPViewVolume SbDPViewVolume::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 SbDPViewVolume::ortho (double left, double right, double bottom,
double top, double nearval, double 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 SbDPViewVolume::perspective (double fovy, double aspect, double
nearval, double 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 SbDPViewVolume::frustum (double left, double right, double bottom,
double top, double nearval, double 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.
See also:
perspective()
void SbDPViewVolume::rotateCamera (const SbDPRotation & q) Rotate the
direction which the camera is pointing in.
See also:
translateCamera().
void SbDPViewVolume::translateCamera (const SbVec3d & v) Translate the
camera position of the view volume.
See also:
rotateCamera().
SbVec3d SbDPViewVolume::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().
SbDPViewVolume SbDPViewVolume::zNarrow (double nearval, double farval)
const Return a copy SbDPViewVolume with narrowed depth by supplying
parameters for new near and far clipping planes.
nearval 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.
See also:
zVector().
void SbDPViewVolume::scale (double factor) Scale width and height of
viewing frustum by the given ratio around the projection plane center
axis.
See also:
scaleWidth(), scaleHeight().
void SbDPViewVolume::scaleWidth (double ratio) Scale width of viewing
frustum by the given ratio around the vertical center axis in the
projection plane.
See also:
scale(), scaleHeight().
void SbDPViewVolume::scaleHeight (double ratio) Scale height of viewing
frustum by the given ratio around the horizontal center axis in the
projection plane.
See also:
scale(), scaleWidth().
SbDPViewVolume::ProjectionType SbDPViewVolume::getProjectionType (void)
const Return current view volume projection type, which can be either
ORTHOGRAPHIC or PERSPECTIVE.
See also:
SbDPViewVolume::ProjectionType
const SbVec3d & SbDPViewVolume::getProjectionPoint (void) const Returns
coordinates of center point in the projection plane.
const SbVec3d & SbDPViewVolume::getProjectionDirection (void) const Returns
the direction of projection, i.e. the direction the camera is pointing.
See also:
getNearDist().
double SbDPViewVolume::getNearDist (void) const Returns distance from
projection plane to near clipping plane.
See also:
getProjectionDirection().
double SbDPViewVolume::getWidth (void) const Returns width of viewing
frustum in the projection plane.
See also:
getHeight(), getDepth().
double SbDPViewVolume::getHeight (void) const Returns height of viewing
frustum in the projection plane.
See also:
getWidth(), getDepth().
double SbDPViewVolume::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 SbDPViewVolume::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 SbDPViewVolume::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 SbDPViewVolume::transform (const SbDPMatrix & matrix) Transform the
viewing volume by matrix.
SbVec3d SbDPViewVolume::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.
Author
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