axmol/extensions/Particle3D/PU/CCPUOnVelocityObserver.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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#include "extensions/Particle3D/PU/CCPUOnVelocityObserver.h"
#include "extensions/Particle3D/PU/CCPUParticleSystem3D.h"

NS_CC_BEGIN

static bool almostEquals(float a, float b, float epsilon = std::numeric_limits<float>::epsilon())
{
    return fabs(a - b) <= ((fabs(a) < fabs(b) ? fabs(b) : fabs(a)) * epsilon);
};

// Constants
const float PUOnVelocityObserver::DEFAULT_VELOCITY_THRESHOLD = 0.0f;

//-----------------------------------------------------------------------
PUOnVelocityObserver::PUOnVelocityObserver()
    : PUObserver(), _threshold(DEFAULT_VELOCITY_THRESHOLD), _compare(CO_LESS_THAN){};
//-----------------------------------------------------------------------
bool PUOnVelocityObserver::observe(PUParticle3D* particle, float /*timeElapsed*/)
{
    if (!particle)
        return false;

    // Compensate for the scaled velocity
    float scaleVelocity = _particleSystem->getParticleSystemScaleVelocity();
    if (_compare == CO_GREATER_THAN)
    {
        // Changed in V 1.3.1
        return (particle->calculateVelocity()) > (scaleVelocity * _threshold);
    }
    else if (_compare == CO_LESS_THAN)
    {
        return (particle->calculateVelocity()) < (scaleVelocity * _threshold);
    }
    else
    {
        // Equals
        return almostEquals(particle->calculateVelocity(), (scaleVelocity * _threshold), 0.01f);
    }

    return false;
}

PUOnVelocityObserver* PUOnVelocityObserver::create()
{
    auto pvo = new PUOnVelocityObserver();
    pvo->autorelease();
    return pvo;
}

void PUOnVelocityObserver::copyAttributesTo(PUObserver* observer)
{
    PUObserver::copyAttributesTo(observer);

    PUOnVelocityObserver* onVelocityObserver = static_cast<PUOnVelocityObserver*>(observer);
    onVelocityObserver->_threshold           = _threshold;
    onVelocityObserver->_compare             = _compare;
}

NS_CC_END