OpenSceneGraph  3.0.1
Public Types | Public Member Functions | Protected Member Functions | Protected Attributes
osg::Transform Class Reference

A Transform is a group node for which all children are transformed by a 4x4 matrix. More...

Inheritance diagram for osg::Transform:
Inheritance graph
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List of all members.

Public Types

enum  ReferenceFrame { RELATIVE_RF, ABSOLUTE_RF, ABSOLUTE_RF_INHERIT_VIEWPOINT }

Public Member Functions

 Transform ()
 Transform (const Transform &, const CopyOp &copyop=CopyOp::SHALLOW_COPY)
 Copy constructor using CopyOp to manage deep vs shallow copy.
 META_Node (osg, Transform)
virtual TransformasTransform ()
 Convert 'this' into a Transform pointer if Node is a Transform, otherwise return 0.
virtual const TransformasTransform () const
 convert 'const this' into a const Transform pointer if Node is a Transform, otherwise return 0.
virtual MatrixTransformasMatrixTransform ()
virtual const MatrixTransformasMatrixTransform () const
virtual PositionAttitudeTransformasPositionAttitudeTransform ()
virtual const
PositionAttitudeTransform
asPositionAttitudeTransform () const
void setReferenceFrame (ReferenceFrame rf)
 Set the transform's ReferenceFrame, either to be relative to its parent reference frame, or relative to an absolute coordinate frame.
ReferenceFrame getReferenceFrame () const
virtual bool computeLocalToWorldMatrix (Matrix &matrix, NodeVisitor *) const
virtual bool computeWorldToLocalMatrix (Matrix &matrix, NodeVisitor *) const
virtual BoundingSphere computeBound () const
 Overrides Group's computeBound.

Protected Member Functions

virtual ~Transform ()

Protected Attributes

ReferenceFrame _referenceFrame

Detailed Description

A Transform is a group node for which all children are transformed by a 4x4 matrix.

It is often used for positioning objects within a scene, producing trackball functionality or for animation.

Transform itself does not provide set/get functions, only the interface for defining what the 4x4 transformation is. Subclasses, such as MatrixTransform and PositionAttitudeTransform support the use of an osg::Matrix or a osg::Vec3/osg::Quat respectively.

Note: If the transformation matrix scales the subgraph then the normals of the underlying geometry will need to be renormalized to be unit vectors once more. This can be done transparently through OpenGL's use of either GL_NORMALIZE and GL_RESCALE_NORMAL modes. For further background reading see the glNormalize documentation in the OpenGL Reference Guide (the blue book). To enable it in the OSG, you simply need to attach a local osg::StateSet to the osg::Transform, and set the appropriate mode to ON via stateset->setMode(GL_NORMALIZE, osg::StateAttribute::ON);


Member Enumeration Documentation

Enumerator:
RELATIVE_RF 
ABSOLUTE_RF 
ABSOLUTE_RF_INHERIT_VIEWPOINT 

Constructor & Destructor Documentation

osg::Transform::Transform ( )
osg::Transform::Transform ( const Transform ,
const CopyOp copyop = CopyOp::SHALLOW_COPY 
)

Copy constructor using CopyOp to manage deep vs shallow copy.

virtual osg::Transform::~Transform ( ) [protected, virtual]

Member Function Documentation

virtual MatrixTransform* osg::Transform::asMatrixTransform ( ) [inline, virtual]

Reimplemented in osg::MatrixTransform.

virtual const MatrixTransform* osg::Transform::asMatrixTransform ( ) const [inline, virtual]

Reimplemented in osg::MatrixTransform.

virtual PositionAttitudeTransform* osg::Transform::asPositionAttitudeTransform ( ) [inline, virtual]

Reimplemented in osg::PositionAttitudeTransform.

virtual const PositionAttitudeTransform* osg::Transform::asPositionAttitudeTransform ( ) const [inline, virtual]

Reimplemented in osg::PositionAttitudeTransform.

virtual Transform* osg::Transform::asTransform ( ) [inline, virtual]

Convert 'this' into a Transform pointer if Node is a Transform, otherwise return 0.

Equivalent to dynamic_cast<Transform*>(this).

Reimplemented from osg::Node.

virtual const Transform* osg::Transform::asTransform ( ) const [inline, virtual]

convert 'const this' into a const Transform pointer if Node is a Transform, otherwise return 0.

Equivalent to dynamic_cast<const Transform*>(this).

Reimplemented from osg::Node.

virtual BoundingSphere osg::Transform::computeBound ( ) const [virtual]

Overrides Group's computeBound.

There is no need to override in subclasses from osg::Transform since this computeBound() uses the underlying matrix (calling computeMatrix if required).

Reimplemented from osg::Group.

Reimplemented in osg::AutoTransform.

virtual bool osg::Transform::computeLocalToWorldMatrix ( Matrix matrix,
NodeVisitor  
) const [inline, virtual]
virtual bool osg::Transform::computeWorldToLocalMatrix ( Matrix matrix,
NodeVisitor  
) const [inline, virtual]
ReferenceFrame osg::Transform::getReferenceFrame ( ) const [inline]
osg::Transform::META_Node ( osg  ,
Transform   
)
void osg::Transform::setReferenceFrame ( ReferenceFrame  rf)

Set the transform's ReferenceFrame, either to be relative to its parent reference frame, or relative to an absolute coordinate frame.

RELATIVE_RF is the default. Note: Setting the ReferenceFrame to be ABSOLUTE_RF will also set the CullingActive flag on the transform, and hence all of its parents, to false, thereby disabling culling of it and all its parents. This is necessary to prevent inappropriate culling, but may impact cull times if the absolute transform is deep in the scene graph. It is therefore recommended to only use absolute Transforms at the top of the scene, for such things as heads up displays. ABSOLUTE_RF_INHERIT_VIEWPOINT is the same as ABSOLUTE_RF except it adds the ability to use the parents view points position in world coordinates as its local viewpoint in the new coordinates frame. This is useful for Render to texture Cameras that wish to use the main views LOD range computation (which uses the viewpoint rather than the eye point) rather than use the local eye point defined by the this Transforms' absolute view matrix.


Member Data Documentation


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

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Generated at Mon Oct 3 2011 12:39:45 for the OpenSceneGraph by doxygen 1.7.5.