RandomRateCounter
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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* OpenSceneGraph Public License for more details.
*/
//osgParticle - Copyright (C) 2002 Marco Jez
#ifndef OSGPARTICLE_RANDOMRATE_COUNTER
#define OSGPARTICLE_RANDOMRATE_COUNTER 1
#include <osgParticle/VariableRateCounter>
#include <osg/CopyOp>
#include <osg/Object>
namespace osgParticle
{
class RandomRateCounter: public VariableRateCounter {
public:
inline RandomRateCounter();
inline RandomRateCounter(const RandomRateCounter& copy, const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY);
META_Object(osgParticle, RandomRateCounter);
inline int numParticlesToCreate(double dt) const;
protected:
virtual ~RandomRateCounter() {}
mutable float _np;
};
// INLINE FUNCTIONS
inline RandomRateCounter::RandomRateCounter()
: VariableRateCounter(), _np(0)
{
}
inline RandomRateCounter::RandomRateCounter(const RandomRateCounter& copy, const osg::CopyOp& copyop)
: VariableRateCounter(copy, copyop), _np(copy._np)
{
}
inline int RandomRateCounter::numParticlesToCreate(double dt) const
{
// compute the number of new particles, clamping it to 1 second of particles at the maximum rate
float numNewParticles = osg::minimum(static_cast<float>(dt * getRateRange().get_random()), getRateRange().maximum);
// add the number of new particles to value carried over from the previous call
_np += numNewParticles;
// round down the number of particles.
int n = static_cast<int>(_np);
// take away the number of rounded number of particles leaving the decimal place
// this is done so that two frames of 0.5's will results in first frame 0 new particles, second frame 1
_np -= n;
// return the rounded number of particles to be created
return n;
}
}
#endif
CopyOp
Object
VariableRateCounter
osgParticle::RandomRateCounter::~RandomRateCounter
virtual ~RandomRateCounter()
Definition RandomRateCounter:37
osgParticle::RandomRateCounter::_np
float _np
Definition RandomRateCounter:39
osgParticle::RandomRateCounter::numParticlesToCreate
int numParticlesToCreate(double dt) const
Return the number of particles to be created in this frame.
Definition RandomRateCounter:54
osgParticle::RandomRateCounter::RandomRateCounter
RandomRateCounter()
Definition RandomRateCounter:44
osgParticle::RandomRateCounter::META_Object
META_Object(osgParticle, RandomRateCounter)
osgParticle::VariableRateCounter::VariableRateCounter
VariableRateCounter()
Definition VariableRateCounter:51
osgParticle::VariableRateCounter::getRateRange
const rangef & getRateRange() const
Definition VariableRateCounter:61
osg::CopyOp
Definition CopyOp:41
osg::CopyOp::SHALLOW_COPY
@ SHALLOW_COPY
Definition CopyOp:47
osgParticle
Definition AccelOperator:27
osg::minimum
T minimum(T lhs, T rhs)
Definition Math:78