113 lines
3.2 KiB
C++
113 lines
3.2 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2010 Robert Osfield
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*
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* This library is open source and may be redistributed and/or modified under
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
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* (at your option) any later version. The full license is in LICENSE file
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* included with this distribution, and on the openscenegraph.org website.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* OpenSceneGraph Public License for more details.
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*/
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// Written by Wang Rui, (C) 2010
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#ifndef OSGPARTICLE_ORBITOPERATOR
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#define OSGPARTICLE_ORBITOPERATOR
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#include <osgParticle/ModularProgram>
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#include <osgParticle/Operator>
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#include <osgParticle/Particle>
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namespace osgParticle
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{
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/** An orbit operator forces particles in the orbit around a point.
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Refer to David McAllister's Particle System API (http://www.particlesystems.org)
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*/
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class OrbitOperator : public Operator
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{
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public:
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OrbitOperator()
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: Operator(), _magnitude(1.0f), _epsilon(1e-3), _maxRadius(FLT_MAX)
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{}
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OrbitOperator( const OrbitOperator& copy, const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY )
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: Operator(copy, copyop), _center(copy._center), _magnitude(copy._magnitude),
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_epsilon(copy._epsilon), _maxRadius(copy._maxRadius)
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{}
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META_Object( osgParticle, OrbitOperator );
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/// Set the center of orbit
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void setCenter( const osg::Vec3& c ) { _center = c; }
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/// Get the center of orbit
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const osg::Vec3& getCenter() const { return _center; }
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/// Set the acceleration scale
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void setMagnitude( float mag ) { _magnitude = mag; }
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/// Get the acceleration scale
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float getMagnitude() const { return _magnitude; }
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/// Set the acceleration epsilon
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void setEpsilon( float eps ) { _epsilon = eps; }
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/// Get the acceleration epsilon
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float getEpsilon() const { return _epsilon; }
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/// Set max radius between the center and the particle
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void setMaxRadius( float max ) { _maxRadius = max; }
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/// Get max radius between the center and the particle
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float getMaxRadius() const { return _maxRadius; }
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/// Apply the acceleration to a particle. Do not call this method manually.
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inline void operate( Particle* P, double dt );
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/// Perform some initializations. Do not call this method manually.
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inline void beginOperate( Program* prg );
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protected:
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virtual ~OrbitOperator() {}
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OrbitOperator& operator=( const OrbitOperator& ) { return *this; }
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osg::Vec3 _center;
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osg::Vec3 _xf_center;
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float _magnitude;
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float _epsilon;
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float _maxRadius;
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};
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// INLINE METHODS
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inline void OrbitOperator::operate( Particle* P, double dt )
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{
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osg::Vec3 dir = _xf_center - P->getPosition();
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float length = dir.length();
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if ( length<_maxRadius )
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{
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P->addVelocity( dir * ((_magnitude * dt) /
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(length * (_epsilon+length*length))) );
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}
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}
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inline void OrbitOperator::beginOperate( Program* prg )
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{
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if ( prg->getReferenceFrame()==ModularProgram::RELATIVE_RF )
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{
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_xf_center = prg->transformLocalToWorld(_center);
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}
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else
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{
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_xf_center = _center;
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}
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}
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}
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#endif
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