India/cocos2d-x/extensions/Particle3D/PU/CCPUGravityAffector.cpp

/****************************************************************************
 Copyright (C) 2013 Henry van Merode. All rights reserved.
 Copyright (c) 2015-2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.
 
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 of this software and associated documentation files (the "Software"), to deal
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 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.
 
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 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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#include "CCPUGravityAffector.h"
#include "extensions/Particle3D/PU/CCPUParticleSystem3D.h"

NS_CC_BEGIN

// Constants
const float PUGravityAffector::DEFAULT_GRAVITY = 1.0f;

//-----------------------------------------------------------------------
PUGravityAffector::PUGravityAffector(void) : 
    PUAffector(),
    _gravity(DEFAULT_GRAVITY)
{
}
//-----------------------------------------------------------------------
PUGravityAffector::~PUGravityAffector( void )
{

}
//-----------------------------------------------------------------------
float PUGravityAffector::getGravity(void) const
{
    return _gravity;
}
//-----------------------------------------------------------------------
void PUGravityAffector::setGravity(float gravity)
{
    _gravity = gravity;
}

void PUGravityAffector::updatePUAffector( PUParticle3D *particle, float deltaTime )
{
    //for (auto iter : _particleSystem->getParticles())
    {
        //PUParticle3D *particle = iter;
        // Applied scaling in V1.3.1
        /** Applying Newton's law of universal gravitation.	*/
        Vec3 distance = _derivedPosition - particle->position;
        float length = distance.lengthSquared();
        float scaleVelocity = 1.0f;
        //if (mParentTechnique)
        {
            scaleVelocity = (static_cast<PUParticleSystem3D *>(_particleSystem))->getParticleSystemScaleVelocity();
        }
        if (length > 0/* && mParentTechnique*/)
        {
            //Real force = (mGravity * particle->mass * mass) / length;
            float force = (scaleVelocity * _gravity * particle->mass * _mass) / length;
            particle->direction += force * distance * deltaTime * calculateAffectSpecialisationFactor(particle);
        }
    }
}

void PUGravityAffector::preUpdateAffector( float /*deltaTime*/ )
{
    getDerivedPosition();
}

PUGravityAffector* PUGravityAffector::create()
{
    auto pga = new (std::nothrow) PUGravityAffector();
    pga->autorelease();
    return pga;
}

void PUGravityAffector::copyAttributesTo( PUAffector* affector )
{
    PUAffector::copyAttributesTo(affector);

    PUGravityAffector* gravityAffector = static_cast<PUGravityAffector*>(affector);
    gravityAffector->_gravity = _gravity;
}

NS_CC_END