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OpenSceneGraph/include/osg/Transform
2002-01-29 14:04:06 +00:00

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//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.
#ifndef OSG_TRANSFORM
#define OSG_TRANSFORM 1
#include <osg/Group>
#include <osg/Matrix>
namespace osg {
/** Transform - is group which all children
* are transformed by the the Transform's osg::Matrix. Typical uses
* of the Transform is for positioning objects within a scene or
* producing trackball functionality or for animation.
* 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. One can done transparently through OpenGL's
* use of either GL_NORMALIZE and GL_SCALE_NORMALIZE modes. Further
* background reading see the glNormalize documentation in the OpenGL Reference
* Guide (the blue book). To enable it in the OSG, you simple 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);.
*/
class SG_EXPORT Transform : public Group
{
public :
Transform();
/** Copy constructor using CopyOp to manage deep vs shallow copy.*/
Transform(const Transform&,const CopyOp& copyop=CopyOp::SHALLOW_COPY);
Transform(const Matrix& matix);
META_Node(Transform);
/** Range of types that the Transform can be.*/
enum Type
{
DYNAMIC,
STATIC
};
/** Set the Transform Type, which can be DYNAMIC - the Matrix
* value is updated during the main loop, or STATIC - the Matrix
* is constant throughout the life of the main loop. STATIC
* Transforms can be optimized away is some instances, which
* can improve performance so unless you plan to modify the
* Matrix explicitly set the Matrix to STATIC. The default
* value is DYNAMIC.*/
inline void setType(Type type) { _type = type; }
/** Get the Transform Type.*/
inline const Type getType() const { return _type; }
enum Mode
{
VIEW,
MODEL
};
inline void setMode(Mode mode) { _mode = mode; }
inline const Mode getMode() const { return _mode; }
/** Get the transformation matrix which moves from local coords to world coords.*/
inline const Matrix& getLocalToWorldMatrix() const { if (_localToWorldDirty) computeLocalToWorld(); return *_localToWorld; }
/** Get the transformation matrix which moves from world coords to local coords.*/
inline const Matrix& getWorldToLocalMatrix() const { if (_worldToLocalDirty) computeWorldToLocal(); return *_worldToLocal; }
/** Set the transform's matrix.*/
void setMatrix(const Matrix& mat);
/** Get the transform's matrix. */
inline const Matrix& getMatrix() const { if (_mode==MODEL) return *_localToWorld; else return *_worldToLocal; }
/** preMult transform.*/
void preMult(const Matrix& mat);
/** postMult transform.*/
void postMult(const Matrix& mat);
protected :
virtual ~Transform();
/** Override's 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.) */
virtual const bool computeBound() const;
/** If you subclass from osg::Transform you must override computeLocalToWorld() to provide your own mechanism for
* setting up the 4x4 matrix. An example of a subclass might a PositionAttitudeTransfrom which is its own
* Vec3 and Quat to calculate the matrix.*/
virtual void computeLocalToWorld() const;
/** If you subclass from osg::Transform it must also override computeWorldToLocal() to provide your own mechanism for
* setting up the 4x4 matrix.*/
virtual void computeWorldToLocal() const;
Type _type;
Mode _mode;
mutable bool _localToWorldDirty;
mutable ref_ptr<Matrix> _localToWorld;
mutable bool _worldToLocalDirty;
mutable ref_ptr<Matrix> _worldToLocal;
};
};
#endif