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94 lines
3.2 KiB
94 lines
3.2 KiB
/* -*-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_DAMPINGOPERATOR |
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#define OSGPARTICLE_DAMPINGOPERATOR |
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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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/** A damping operator applies damping constant to particle's velocity. |
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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 DampingOperator : public Operator |
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{ |
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public: |
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DampingOperator() : Operator(), _cutoffLow(0.0f), _cutoffHigh(FLT_MAX) |
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{ _damping.set(1.0f, 1.0f, 1.0f); } |
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DampingOperator( const DampingOperator& copy, const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY ) |
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: Operator(copy, copyop), _damping(copy._damping), |
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_cutoffLow(copy._cutoffLow), _cutoffHigh(copy._cutoffHigh) |
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{} |
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META_Object( osgParticle, DampingOperator ); |
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/// Set the damping factors |
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void setDamping( float x, float y, float z ) { _damping.set(x, y, z); } |
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void setDamping( const osg::Vec3& damping ) { _damping = damping; } |
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/// Set the damping factors to one value |
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void setDamping( float x ) { _damping.set(x, x, x); } |
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/// Get the damping factors |
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void getDamping( float& x, float& y, float& z ) const |
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{ x = _damping.x(); y = _damping.y(); z = _damping.z(); } |
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const osg::Vec3& getDamping() const { return _damping; } |
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/// Set the velocity cutoff factors |
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void setCutoff( float low, float high ) { _cutoffLow = low; _cutoffHigh = high; } |
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void setCutoffLow( float low ) { _cutoffLow = low; } |
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void setCutoffHigh( float low ) { _cutoffHigh = low; } |
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/// Get the velocity cutoff factors |
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void getCutoff( float& low, float& high ) const { low = _cutoffLow; high = _cutoffHigh; } |
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float getCutoffLow() const { return _cutoffLow; } |
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float getCutoffHigh() const { return _cutoffHigh; } |
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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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protected: |
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virtual ~DampingOperator() {} |
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DampingOperator& operator=( const DampingOperator& ) { return *this; } |
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osg::Vec3 _damping; |
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float _cutoffLow; |
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float _cutoffHigh; |
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}; |
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// INLINE METHODS |
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inline void DampingOperator::operate( Particle* P, double dt ) |
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{ |
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const osg::Vec3& vel = P->getVelocity(); |
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float length2 = vel.length2(); |
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if ( length2>=_cutoffLow && length2<=_cutoffHigh ) |
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{ |
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osg::Vec3 newvel( vel.x() * (1.0f - (1.0f - _damping.x()) * dt), |
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vel.y() * (1.0f - (1.0f - _damping.y()) * dt), |
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vel.z() * (1.0f - (1.0f - _damping.z()) * dt) ); |
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P->setVelocity( newvel ); |
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} |
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} |
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} |
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#endif
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