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#include "qquickparticlesystem_p.h"
#include <QtQuick/qsgnode.h>
#include "qquickparticleemitter_p.h"
#include "qquickparticleaffector_p.h"
#include "qquickparticlepainter_p.h"
#include <private/qquickspriteengine_p.h>
#include <private/qquicksprite_p.h>
#include "qquickv8particledata_p.h"
#include "qquickparticlegroup_p.h"

#include "qquicktrailemitter_p.h"//###For auto-follow on states, perhaps should be in emitter?
#include <private/qdeclarativeengine_p.h>
#include <cmath>
#include <QDebug>

QT_BEGIN_NAMESPACE
//###Switch to define later, for now user-friendly (no compilation) debugging is worth it
DEFINE_BOOL_CONFIG_OPTION(qmlParticlesDebug, QML_PARTICLES_DEBUG)
/*!
    \qmlclass ParticleSystem QQuickParticleSystem
    \inqmlmodule QtQuick.Particles 2
    \brief The ParticleSystem brings together ParticlePainter, Emitter and Affector elements.

*/

/*!
    \qmlproperty bool QtQuick.Particles2::ParticleSystem::running

    If running is set to false, the particle system will stop the simulation. All particles
    will be destroyed when the system is set to running again.

    It can also be controlled with the start() and stop() methods.
*/


/*!
    \qmlproperty bool QtQuick.Particles2::ParticleSystem::paused

    If paused is set to true, the particle system will not advance the simulation. When
    paused is set to false again, the simulation will resume from the same point it was
    paused.

    The simulation will automatically pause if it detects that there are no live particles
    left, and unpause when new live particles are added.

    It can also be controlled with the pause() and resume() methods.
*/

/*!
    \qmlproperty bool QtQuick.Particles2::ParticleSystem::empty

    empty is set to true when there are no live particles left in the system.

    You can use this to pause the system, keeping it from spending any time updating,
    but you will need to resume it in order for additional particles to be generated
    by the system.

    To kill all the particles in the system, use a Kill affector.
*/

/*!
    \qmlproperty list<Sprite> QtQuick.Particles2::ParticleSystem::particleStates

    You can define a sub-set of particle groups in this property in order to provide them
    with stochastic state transitions.

    Each QtQuick2::Sprite in this list is interpreted as corresponding to the particle group
    with ths same name. Any transitions defined in these sprites will take effect on the particle
    groups as well. Additionally TrailEmitters, Affectors and ParticlePainters definined
    inside one of these sprites are automatically associated with the corresponding particle group.
*/

/*!
    \qmlmethod void QtQuick.Particles2::ParticleSystem::pause

    Pauses the simulation if it is running.

    \sa resume, paused
*/

/*!
    \qmlmethod void QtQuick.Particles2::ParticleSystem::resume

    Resumes the simulation if it is paused.

    \sa pause, paused
*/

/*!
    \qmlmethod void QtQuick.Particles2::ParticleSystem::start

    Starts the simulation if it has not already running.

    \sa stop, restart, running
*/

/*!
    \qmlmethod void QtQuick.Particles2::ParticleSystem::stop

    Stops the simulation if it is running.

    \sa start, restart, running
*/

/*!
    \qmlmethod void QtQuick.Particles2::ParticleSystem::restart

    Stops the simulation if it is running, and then starts it.

    \sa stop, restart, running
*/
/*!
    \qmlmethod void QtQuick.Particles2::ParticleSystem::reset

    Discards all currently existing particles.

*/
const qreal EPSILON = 0.001;
//Utility functions for when within 1ms is close enough
bool timeEqualOrGreater(qreal a, qreal b)
{
    return (a+EPSILON >= b);
}

bool timeLess(qreal a, qreal b)
{
    return (a-EPSILON < b);
}

bool timeEqual(qreal a, qreal b)
{
    return (a+EPSILON > b) && (a-EPSILON < b);
}

int roundedTime(qreal a)
{// in ms
    return (int)qRound(a*1000.0);
}

QQuickParticleDataHeap::QQuickParticleDataHeap()
    : m_data(0)
{
    m_data.reserve(1000);
    clear();
}

void QQuickParticleDataHeap::grow() //###Consider automatic growth vs resize() calls from GroupData
{
    m_data.resize(1 << ++m_size);
}

void QQuickParticleDataHeap::insert(QQuickParticleData* data)
{
    insertTimed(data, roundedTime(data->t + data->lifeSpan));
}

void QQuickParticleDataHeap::insertTimed(QQuickParticleData* data, int time)
{
    //TODO: Optimize 0 lifespan (or already dead) case
    if (m_lookups.contains(time)) {
        m_data[m_lookups[time]].data << data;
        return;
    }
    if (m_end == (1 << m_size))
        grow();
    m_data[m_end].time = time;
    m_data[m_end].data.clear();
    m_data[m_end].data.insert(data);
    m_lookups.insert(time, m_end);
    bubbleUp(m_end++);
}

int QQuickParticleDataHeap::top()
{
    if (m_end == 0)
        return 1 << 30;
    return m_data[0].time;
}

QSet<QQuickParticleData*> QQuickParticleDataHeap::pop()
{
    if (!m_end)
        return QSet<QQuickParticleData*> ();
    QSet<QQuickParticleData*> ret = m_data[0].data;
    m_lookups.remove(m_data[0].time);
    if (m_end == 1) {
        --m_end;
    } else {
        m_data[0] = m_data[--m_end];
        bubbleDown(0);
    }
    return ret;
}

void QQuickParticleDataHeap::clear()
{
    m_size = 0;
    m_end = 0;
    //m_size is in powers of two. So to start at 0 we have one allocated
    m_data.resize(1);
    m_lookups.clear();
}

bool QQuickParticleDataHeap::contains(QQuickParticleData* d)
{
    for (int i=0; i<m_end; i++)
        if (m_data[i].data.contains(d))
            return true;
    return false;
}

void QQuickParticleDataHeap::swap(int a, int b)
{
    m_tmp = m_data[a];
    m_data[a] = m_data[b];
    m_data[b] = m_tmp;
    m_lookups[m_data[a].time] = a;
    m_lookups[m_data[b].time] = b;
}

void QQuickParticleDataHeap::bubbleUp(int idx)//tends to be called once
{
    if (!idx)
        return;
    int parent = (idx-1)/2;
    if (m_data[idx].time < m_data[parent].time) {
        swap(idx, parent);
        bubbleUp(parent);
    }
}

void QQuickParticleDataHeap::bubbleDown(int idx)//tends to be called log n times
{
    int left = idx*2 + 1;
    if (left >= m_end)
        return;
    int lesser = left;
    int right = idx*2 + 2;
    if (right < m_end) {
        if (m_data[left].time > m_data[right].time)
            lesser = right;
    }
    if (m_data[idx].time > m_data[lesser].time) {
        swap(idx, lesser);
        bubbleDown(lesser);
    }
}

QQuickParticleGroupData::QQuickParticleGroupData(int id, QQuickParticleSystem* sys):index(id),m_size(0),m_system(sys)
{
    initList();
}

QQuickParticleGroupData::~QQuickParticleGroupData()
{
    foreach (QQuickParticleData* d, data)
        delete d;
}

int QQuickParticleGroupData::size()
{
    return m_size;
}

QString QQuickParticleGroupData::name()//### Worth caching as well?
{
    return m_system->groupIds.key(index);
}

void QQuickParticleGroupData::setSize(int newSize)
{
    if (newSize == m_size)
        return;
    Q_ASSERT(newSize > m_size);//XXX allow shrinking
    data.resize(newSize);
    for (int i=m_size; i<newSize; i++) {
        data[i] = new QQuickParticleData(m_system);
        data[i]->group = index;
        data[i]->index = i;
        reusableIndexes << i;
    }
    int delta = newSize - m_size;
    m_size = newSize;
    foreach (QQuickParticlePainter* p, painters)
        p->setCount(p->count() + delta);
}

void QQuickParticleGroupData::initList()
{
    dataHeap.clear();
}

void QQuickParticleGroupData::kill(QQuickParticleData* d)
{
    Q_ASSERT(d->group == index);
    d->lifeSpan = 0;//Kill off
    foreach (QQuickParticlePainter* p, painters)
        p->reload(d);
    reusableIndexes << d->index;
}

QQuickParticleData* QQuickParticleGroupData::newDatum(bool respectsLimits)
{
    //recycle();//Extra recycler round to be sure?

    while (!reusableIndexes.empty()) {
        int idx = *(reusableIndexes.begin());
        reusableIndexes.remove(idx);
        if (data[idx]->stillAlive()) {// ### This means resurrection of 'dead' particles. Is that allowed?
            prepareRecycler(data[idx]);
            continue;
        }
        return data[idx];
    }
    if (respectsLimits)
        return 0;

    int oldSize = m_size;
    setSize(oldSize + 10);//###+1,10%,+10? Choose something non-arbitrarily
    reusableIndexes.remove(oldSize);
    return data[oldSize];
}

bool QQuickParticleGroupData::recycle()
{
    while (dataHeap.top() <= m_system->timeInt) {
        foreach (QQuickParticleData* datum, dataHeap.pop()) {
            if (!datum->stillAlive()) {
                reusableIndexes << datum->index;
            } else {
                prepareRecycler(datum); //ttl has been altered mid-way, put it back
            }
        }
    }

    //TODO: If the data is clear, gc (consider shrinking stack size)?
    return reusableIndexes.count() == m_size;
}

void QQuickParticleGroupData::prepareRecycler(QQuickParticleData* d)
{
    if (d->lifeSpan*1000 < m_system->maxLife) {
        dataHeap.insert(d);
    } else {
        while ((roundedTime(d->t) + 2*m_system->maxLife/3) <= m_system->timeInt)
            d->extendLife(m_system->maxLife/3000.0);
        dataHeap.insertTimed(d, roundedTime(d->t) + 2*m_system->maxLife/3);
    }
}

QQuickParticleData::QQuickParticleData(QQuickParticleSystem* sys)
    : group(0)
    , e(0)
    , system(sys)
    , index(0)
    , systemIndex(-1)
    , colorOwner(0)
    , rotationOwner(0)
    , deformationOwner(0)
    , animationOwner(0)
    , v8Datum(0)
{
    x = 0;
    y = 0;
    t = -1;
    lifeSpan = 0;
    size = 0;
    endSize = 0;
    vx = 0;
    vy = 0;
    ax = 0;
    ay = 0;
    xx = 1;
    xy = 0;
    yx = 0;
    yy = 1;
    rotation = 0;
    rotationSpeed = 0;
    autoRotate = 0;
    animIdx = 0;
    frameDuration = 1;
    frameCount = 1;
    animT = -1;
    animX = 0;
    animY = 0;
    animWidth = 1;
    animHeight = 1;
    color.r = 255;
    color.g = 255;
    color.b = 255;
    color.a = 255;
    r = 0;
    delegate = 0;
    modelIndex = -1;
}

QQuickParticleData::~QQuickParticleData()
{
    delete v8Datum;
}

void QQuickParticleData::clone(const QQuickParticleData& other)
{
    x = other.x;
    y = other.y;
    t = other.t;
    lifeSpan = other.lifeSpan;
    size = other.size;
    endSize = other.endSize;
    vx = other.vx;
    vy = other.vy;
    ax = other.ax;
    ay = other.ay;
    xx = other.xx;
    xy = other.xy;
    yx = other.yx;
    yy = other.yy;
    rotation = other.rotation;
    rotationSpeed = other.rotationSpeed;
    autoRotate = other.autoRotate;
    animIdx = other.animIdx;
    frameDuration = other.frameDuration;
    frameCount = other.frameCount;
    animT = other.animT;
    animX = other.animX;
    animY = other.animY;
    animWidth = other.animWidth;
    animHeight = other.animHeight;
    color.r = other.color.r;
    color.g = other.color.g;
    color.b = other.color.b;
    color.a = other.color.a;
    r = other.r;
    delegate = other.delegate;
    modelIndex = other.modelIndex;

    colorOwner = other.colorOwner;
    rotationOwner = other.rotationOwner;
    deformationOwner = other.deformationOwner;
    animationOwner = other.animationOwner;
}

QDeclarativeV8Handle QQuickParticleData::v8Value()
{
    if (!v8Datum)
        v8Datum = new QQuickV8ParticleData(QDeclarativeEnginePrivate::getV8Engine(qmlEngine(system)), this);
    return v8Datum->v8Value();
}
//sets the x accleration without affecting the instantaneous x velocity or position
void QQuickParticleData::setInstantaneousAX(qreal ax)
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    qreal vx = (this->vx + t*this->ax) - t*ax;
    qreal ex = this->x + this->vx * t + 0.5 * this->ax * t * t;
    qreal x = ex - t*vx - 0.5 * t*t*ax;

    this->ax = ax;
    this->vx = vx;
    this->x = x;
}

//sets the x velocity without affecting the instantaneous x postion
void QQuickParticleData::setInstantaneousVX(qreal vx)
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    qreal evx = vx - t*this->ax;
    qreal ex = this->x + this->vx * t + 0.5 * this->ax * t * t;
    qreal x = ex - t*evx - 0.5 * t*t*this->ax;

    this->vx = evx;
    this->x = x;
}

//sets the instantaneous x postion
void QQuickParticleData::setInstantaneousX(qreal x)
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    this->x = x - t*this->vx - 0.5 * t*t*this->ax;
}

//sets the y accleration without affecting the instantaneous y velocity or position
void QQuickParticleData::setInstantaneousAY(qreal ay)
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    qreal vy = (this->vy + t*this->ay) - t*ay;
    qreal ey = this->y + this->vy * t + 0.5 * this->ay * t * t;
    qreal y = ey - t*vy - 0.5 * t*t*ay;

    this->ay = ay;
    this->vy = vy;
    this->y = y;
}

//sets the y velocity without affecting the instantaneous y position
void QQuickParticleData::setInstantaneousVY(qreal vy)
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    qreal evy = vy - t*this->ay;
    qreal ey = this->y + this->vy * t + 0.5 * this->ay * t * t;
    qreal y = ey - t*evy - 0.5 * t*t*this->ay;

    this->vy = evy;
    this->y = y;
}

//sets the instantaneous Y position
void QQuickParticleData::setInstantaneousY(qreal y)
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    this->y = y - t*this->vy - 0.5 * t*t*this->ay;
}

qreal QQuickParticleData::curX() const
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    return this->x + this->vx * t + 0.5 * this->ax * t * t;
}

qreal QQuickParticleData::curVX() const
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    return this->vx + t*this->ax;
}

qreal QQuickParticleData::curY() const
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    return y + vy * t + 0.5 * ay * t * t;
}

qreal QQuickParticleData::curVY() const
{
    qreal t = (system->timeInt / 1000.0) - this->t;
    return vy + t*ay;
}

void QQuickParticleData::debugDump()
{
    qDebug() << "Particle" << systemIndex << group << "/" << index << stillAlive()
             << "Pos: " << x << "," << y
             << "Vel: " << vx << "," << vy
             << "Acc: " << ax << "," << ay
             << "Size: " << size << "," << endSize
             << "Time: " << t << "," <<lifeSpan << ";" << (system->timeInt / 1000.0) ;
}

bool QQuickParticleData::stillAlive()
{
    if (!system)
        return false;
    return (t + lifeSpan - EPSILON) > ((qreal)system->timeInt/1000.0);
}

bool QQuickParticleData::alive()
{
    if (!system)
        return false;
    qreal st = ((qreal)system->timeInt/1000.0);
    return (t + EPSILON) < st && (t + lifeSpan - EPSILON) > st;
}

float QQuickParticleData::curSize()
{
    if (!system || !lifeSpan)
        return 0.0f;
    return size + (endSize - size) * (1 - (lifeLeft() / lifeSpan));
}

float QQuickParticleData::lifeLeft()
{
    if (!system)
        return 0.0f;
    return (t + lifeSpan) - (system->timeInt/1000.0);
}

void QQuickParticleData::extendLife(float time)
{
    qreal newX = curX();
    qreal newY = curY();
    qreal newVX = curVX();
    qreal newVY = curVY();

    t += time;
    animT += time;

    qreal elapsed = (system->timeInt / 1000.0) - t;
    qreal evy = newVY - elapsed*ay;
    qreal ey = newY - elapsed*evy - 0.5 * elapsed*elapsed*ay;
    qreal evx = newVX - elapsed*ax;
    qreal ex = newX - elapsed*evx - 0.5 * elapsed*elapsed*ax;

    x = ex;
    vx = evx;
    y = ey;
    vy = evy;
}

QQuickParticleSystem::QQuickParticleSystem(QQuickItem *parent) :
    QQuickItem(parent),
    stateEngine(0),
    m_running(true),
    particleCount(0),
    m_nextIndex(0),
    m_componentComplete(false),
    m_paused(false)
{
    connect(&m_painterMapper, SIGNAL(mapped(QObject*)),
            this, SLOT(loadPainter(QObject*)));

    m_debugMode = qmlParticlesDebug();
}

QQuickParticleSystem::~QQuickParticleSystem()
{
    foreach (QQuickParticleGroupData* gd, groupData)
        delete gd;
}

void QQuickParticleSystem::initGroups()
{
    m_reusableIndexes.clear();
    m_nextIndex = 0;

    qDeleteAll(groupData);
    groupData.clear();
    groupIds.clear();

    QQuickParticleGroupData* gd = new QQuickParticleGroupData(0, this);//Default group
    groupData.insert(0,gd);
    groupIds.insert(QString(), 0);
    m_nextGroupId = 1;
}

void QQuickParticleSystem::registerParticlePainter(QQuickParticlePainter* p)
{
    //TODO: a way to Unregister emitters, painters and affectors
    m_painters << QPointer<QQuickParticlePainter>(p);//###Set or uniqueness checking?
    connect(p, SIGNAL(groupsChanged(QStringList)),
            &m_painterMapper, SLOT(map()));
    loadPainter(p);
}

void QQuickParticleSystem::registerParticleEmitter(QQuickParticleEmitter* e)
{
    m_emitters << QPointer<QQuickParticleEmitter>(e);//###How to get them out?
    connect(e, SIGNAL(particleCountChanged()),
            this, SLOT(emittersChanged()));
    connect(e, SIGNAL(groupChanged(QString)),
            this, SLOT(emittersChanged()));
    emittersChanged();
    e->reset();//Start, so that starttime factors appropriately
}

void QQuickParticleSystem::registerParticleAffector(QQuickParticleAffector* a)
{
    m_affectors << QPointer<QQuickParticleAffector>(a);
}

void QQuickParticleSystem::registerParticleGroup(QQuickParticleGroup* g)
{
    m_groups << QPointer<QQuickParticleGroup>(g);
    createEngine();
}

void QQuickParticleSystem::setRunning(bool arg)
{
    if (m_running != arg) {
        m_running = arg;
        emit runningChanged(arg);
        setPaused(false);
        if (m_animation)//Not created until componentCompleted
            m_running ? m_animation->start() : m_animation->stop();
        reset();
    }
}

void QQuickParticleSystem::setPaused(bool arg) {
    if (m_paused != arg) {
        m_paused = arg;
        if (m_animation && m_animation->state() != QAbstractAnimation::Stopped)
            m_paused ? m_animation->pause() : m_animation->resume();
        if (!m_paused) {
            foreach (QQuickParticlePainter *p, m_painters)
                p->update();
        }
        emit pausedChanged(arg);
    }
}

void QQuickParticleSystem::statePropertyRedirect(QDeclarativeListProperty<QObject> *prop, QObject *value)
{
    //Hooks up automatic state-associated stuff
    QQuickParticleSystem* sys = qobject_cast<QQuickParticleSystem*>(prop->object->parent());
    QQuickParticleGroup* group = qobject_cast<QQuickParticleGroup*>(prop->object);
    if (!group || !sys || !value)
        return;
    stateRedirect(group, sys, value);
}

void QQuickParticleSystem::stateRedirect(QQuickParticleGroup* group, QQuickParticleSystem* sys, QObject *value)
{
    QStringList list;
    list << group->name();
    QQuickParticleAffector* a = qobject_cast<QQuickParticleAffector*>(value);
    if (a) {
        a->setParentItem(sys);
        a->setGroups(list);
        a->setSystem(sys);
        return;
    }
    QQuickTrailEmitter* fe = qobject_cast<QQuickTrailEmitter*>(value);
    if (fe) {
        fe->setParentItem(sys);
        fe->setFollow(group->name());
        fe->setSystem(sys);
        return;
    }
    QQuickParticleEmitter* e = qobject_cast<QQuickParticleEmitter*>(value);
    if (e) {
        e->setParentItem(sys);
        e->setGroup(group->name());
        e->setSystem(sys);
        return;
    }
    QQuickParticlePainter* p = qobject_cast<QQuickParticlePainter*>(value);
    if (p) {
        p->setParentItem(sys);
        p->setGroups(list);
        p->setSystem(sys);
        return;
    }
    qWarning() << value << " was placed inside a particle system state but cannot be taken into the particle system. It will be lost.";
}

void QQuickParticleSystem::componentComplete()

{
    QQuickItem::componentComplete();
    m_componentComplete = true;
    m_animation = new QQuickParticleSystemAnimation(this);
    reset();//restarts animation as well
}

void QQuickParticleSystem::reset()
{
    if (!m_componentComplete)
        return;

    timeInt = 0;
    //Clear guarded pointers which have been deleted
    int cleared = 0;
    cleared += m_emitters.removeAll(0);
    cleared += m_painters.removeAll(0);
    cleared += m_affectors.removeAll(0);

    bySysIdx.resize(0);
    initGroups();//Also clears all logical particles

    if (!m_running)
        return;

    foreach (QQuickParticleEmitter* e, m_emitters)
        e->reset();

    emittersChanged();

    foreach (QQuickParticlePainter *p, m_painters) {
        loadPainter(p);
        p->reset();
    }

    //### Do affectors need reset too?
    if (m_animation) {//Animation is explicitly disabled in benchmarks
        //reset restarts animation (if running)
        if ((m_animation->state() == QAbstractAnimation::Running))
            m_animation->stop();
        m_animation->start();
        if (m_paused)
            m_animation->pause();
    }

    initialized = true;
}


void QQuickParticleSystem::loadPainter(QObject *p)
{
    if (!m_componentComplete)
        return;

    QQuickParticlePainter* painter = qobject_cast<QQuickParticlePainter*>(p);
    Q_ASSERT(painter);//XXX
    foreach (QQuickParticleGroupData* sg, groupData)
        sg->painters.remove(painter);
    int particleCount = 0;
    if (painter->groups().isEmpty()) {//Uses default particle
        QStringList def;
        def << QString();
        painter->setGroups(def);
        particleCount += groupData[0]->size();
        groupData[0]->painters << painter;
    } else {
        foreach (const QString &group, painter->groups()) {
            if (group != QLatin1String("") && !groupIds[group]) {//new group
                int id = m_nextGroupId++;
                QQuickParticleGroupData* gd = new QQuickParticleGroupData(id, this);
                groupIds.insert(group, id);
                groupData.insert(id, gd);
            }
            particleCount += groupData[groupIds[group]]->size();
            groupData[groupIds[group]]->painters << painter;
        }
    }
    painter->setCount(particleCount);
    painter->update();//Initial update here
    return;
}

void QQuickParticleSystem::emittersChanged()
{
    if (!m_componentComplete)
        return;

    m_emitters.removeAll(0);


    QList<int> previousSizes;
    QList<int> newSizes;
    for (int i=0; i<m_nextGroupId; i++) {
        previousSizes << groupData[i]->size();
        newSizes << 0;
    }

    foreach (QQuickParticleEmitter* e, m_emitters) {//Populate groups and set sizes.
        if (!groupIds.contains(e->group())
                || (!e->group().isEmpty() && !groupIds[e->group()])) {//or it was accidentally inserted by a failed lookup earlier
            int id = m_nextGroupId++;
            QQuickParticleGroupData* gd = new QQuickParticleGroupData(id, this);
            groupIds.insert(e->group(), id);
            groupData.insert(id, gd);
            previousSizes << 0;
            newSizes << 0;
        }
        newSizes[groupIds[e->group()]] += e->particleCount();
        //###: Cull emptied groups?
    }

    //TODO: Garbage collection?
    particleCount = 0;
    for (int i=0; i<m_nextGroupId; i++) {
        groupData[i]->setSize(qMax(newSizes[i], previousSizes[i]));
        particleCount += groupData[i]->size();
    }

    if (m_debugMode)
        qDebug() << "Particle system emitters changed. New particle count: " << particleCount;

    if (particleCount > bySysIdx.size())//New datum requests haven't updated it
        bySysIdx.resize(particleCount);

    foreach (QQuickParticlePainter *p, m_painters)
        loadPainter(p);

    if (!m_groups.isEmpty())
        createEngine();

}

void QQuickParticleSystem::createEngine()
{
    if (!m_componentComplete)
        return;
    if (stateEngine && m_debugMode)
        qDebug() << "Resetting Existing Sprite Engine...";
    //### Solve the losses if size/states go down
    foreach (QQuickParticleGroup* group, m_groups) {
        bool exists = false;
        foreach (const QString &name, groupIds.keys())
            if (group->name() == name)
                exists = true;
        if (!exists) {
            int id = m_nextGroupId++;
            QQuickParticleGroupData* gd = new QQuickParticleGroupData(id, this);
            groupIds.insert(group->name(), id);
            groupData.insert(id, gd);
        }
    }

    if (m_groups.count()) {
        //Reorder groups List so as to have the same order as groupData
        QList<QQuickParticleGroup*> newList;
        for (int i=0; i<m_nextGroupId; i++) {
            bool exists = false;
            QString name = groupData[i]->name();
            foreach (QQuickParticleGroup* existing, m_groups) {
                if (existing->name() == name) {
                    newList << existing;
                    exists = true;
                }
            }
            if (!exists) {
                newList << new QQuickParticleGroup(this);
                newList.back()->setName(name);
            }
        }
        m_groups = newList;
        QList<QQuickStochasticState*> states;
        foreach (QQuickParticleGroup* g, m_groups)
            states << (QQuickStochasticState*)g;

        if (!stateEngine)
            stateEngine = new QQuickStochasticEngine(this);
        stateEngine->setCount(particleCount);
        stateEngine->m_states = states;

        connect(stateEngine, SIGNAL(stateChanged(int)),
                this, SLOT(particleStateChange(int)));

    } else {
        if (stateEngine)
            delete stateEngine;
        stateEngine = 0;
    }

}

void QQuickParticleSystem::particleStateChange(int idx)
{
    moveGroups(bySysIdx[idx], stateEngine->curState(idx));
}

void QQuickParticleSystem::moveGroups(QQuickParticleData *d, int newGIdx)
{
    if (!d || newGIdx == d->group)
        return;

    QQuickParticleData* pd = newDatum(newGIdx, false, d->systemIndex);
    if (!pd)
        return;

    pd->clone(*d);
    finishNewDatum(pd);

    d->systemIndex = -1;
    groupData[d->group]->kill(d);
}

int QQuickParticleSystem::nextSystemIndex()
{
    if (!m_reusableIndexes.isEmpty()) {
        int ret = *(m_reusableIndexes.begin());
        m_reusableIndexes.remove(ret);
        return ret;
    }
    if (m_nextIndex >= bySysIdx.size()) {
        bySysIdx.resize(bySysIdx.size() < 10 ? 10 : bySysIdx.size()*1.1);//###+1,10%,+10? Choose something non-arbitrarily
        if (stateEngine)
            stateEngine->setCount(bySysIdx.size());

    }
    return m_nextIndex++;
}

QQuickParticleData* QQuickParticleSystem::newDatum(int groupId, bool respectLimits, int sysIndex)
{
    Q_ASSERT(groupId < groupData.count());//XXX shouldn't really be an assert

    QQuickParticleData* ret = groupData[groupId]->newDatum(respectLimits);
    if (!ret) {
        return 0;
    }
    if (sysIndex == -1) {
        if (ret->systemIndex == -1)
            ret->systemIndex = nextSystemIndex();
    } else {
        if (ret->systemIndex != -1) {
            if (stateEngine)
                stateEngine->stop(ret->systemIndex);
            m_reusableIndexes << ret->systemIndex;
            bySysIdx[ret->systemIndex] = 0;
        }
        ret->systemIndex = sysIndex;
    }
    bySysIdx[ret->systemIndex] = ret;

    if (stateEngine)
        stateEngine->start(ret->systemIndex, ret->group);

    m_empty = false;
    return ret;
}

void QQuickParticleSystem::emitParticle(QQuickParticleData* pd)
{// called from prepareNextFrame()->emitWindow - enforce?
    //Account for relative emitter position
    QPointF offset = this->mapFromItem(pd->e, QPointF(0, 0));
    if (!offset.isNull()) {
        pd->x += offset.x();
        pd->y += offset.y();
    }

    finishNewDatum(pd);
}

void QQuickParticleSystem::finishNewDatum(QQuickParticleData *pd)
{
    Q_ASSERT(pd);
    groupData[pd->group]->prepareRecycler(pd);

    foreach (QQuickParticleAffector *a, m_affectors)
        if (a && a->m_needsReset)
            a->reset(pd);
    foreach (QQuickParticlePainter* p, groupData[pd->group]->painters)
        if (p)
            p->load(pd);
}

void QQuickParticleSystem::updateCurrentTime( int currentTime )
{
    if (!initialized)
        return;//error in initialization

    //### Elapsed time never shrinks - may cause problems if left emitting for weeks at a time.
    qreal dt = timeInt / 1000.;
    timeInt = currentTime;
    qreal time =  timeInt / 1000.;
    dt = time - dt;
    needsReset.clear();

    m_emitters.removeAll(0);
    m_painters.removeAll(0);
    m_affectors.removeAll(0);

    bool oldClear = m_empty;
    m_empty = true;
    foreach (QQuickParticleGroupData* gd, groupData)//Recycle all groups and see if they're out of live particles
        m_empty = gd->recycle() && m_empty;

    if (stateEngine)
        stateEngine->updateSprites(timeInt);

    foreach (QQuickParticleEmitter* emitter, m_emitters)
        emitter->emitWindow(timeInt);
    foreach (QQuickParticleAffector* a, m_affectors)
        a->affectSystem(dt);
    foreach (QQuickParticleData* d, needsReset)
        foreach (QQuickParticlePainter* p, groupData[d->group]->painters)
            p->reload(d);

    if (oldClear != m_empty)
        emptyChanged(m_empty);
}

int QQuickParticleSystem::systemSync(QQuickParticlePainter* p)
{
    if (!m_running)
        return 0;
    if (!initialized)
        return 0;//error in initialization
    p->performPendingCommits();
    return timeInt;
}


QT_END_NAMESPACE