qquickitemparticle.cpp

Go to the documentation of this file.

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#undef QT_NO_FOREACH // this file contains unported legacy Q_FOREACH uses
 
#include "qquickitemparticle_p.h"
#include <QtQuick/qsgnode.h>
#include <QTimer>
#include <QQmlComponent>
#include <QDebug>
 
QT_BEGIN_NAMESPACE
 
QQuickItemParticle::QQuickItemParticle(QQuickItem *parent) :
    QQuickParticlePainter(parent), m_fade(true), m_lastT(0), m_activeCount(0), m_delegate(nullptr)
{
    setFlag(QQuickItem::ItemHasContents);
    clock = new Clock(this);
    connect(this, &QQuickItemParticle::systemChanged, this, &QQuickItemParticle::reconnectSystem);
    connect(this, &QQuickItemParticle::parentChanged, this, &QQuickItemParticle::reconnectParent);
    connect(this, &QQuickItemParticle::enabledChanged, this, &QQuickItemParticle::updateClock);
    reconnectSystem(m_system);
    reconnectParent(parent);
}
 
QQuickItemParticle::~QQuickItemParticle()
{
    delete clock;
    qDeleteAll(m_managed);
}
 
void QQuickItemParticle::freeze(QQuickItem* item)
{
    m_stasis << item;
}
 
 
void QQuickItemParticle::unfreeze(QQuickItem* item)
{
    m_stasis.remove(item);
}
 
void QQuickItemParticle::take(QQuickItem *item, bool prioritize)
{
    if (prioritize)
        m_pendingItems.push_front(item);
    else
        m_pendingItems.push_back(item);
}
 
void QQuickItemParticle::give(QQuickItem *item)
{
    for (auto groupId : groupIds()) {
        for (QQuickParticleData* data : std::as_const(m_system->groupData[groupId]->data)) {
            if (data->delegate == item){
                m_deletables << item;
                data->delegate = nullptr;
                m_system->groupData[groupId]->kill(data);
                return;
            }
        }
    }
}
 
void QQuickItemParticle::initialize(int gIdx, int pIdx)
{
    Q_UNUSED(gIdx);
    Q_UNUSED(pIdx);
}
 
void QQuickItemParticle::commit(int, int)
{
}
 
void QQuickItemParticle::processDeletables()
{
    foreach (QQuickItem* item, m_deletables){
        if (m_fade)
            item->setOpacity(0.);
        item->setVisible(false);
        QQuickItemParticleAttached* mpa;
        if ((mpa = qobject_cast<QQuickItemParticleAttached*>(qmlAttachedPropertiesObject<QQuickItemParticle>(item)))) {
            if (mpa->m_parentItem != nullptr)
                item->setParentItem(mpa->m_parentItem);
            mpa->detach();
        }
        int idx = -1;
        if ((idx = m_managed.indexOf(item)) != -1) {
            m_managed.takeAt(idx);
            delete item;
        }
        m_activeCount--;
    }
    m_deletables.clear();
}
 
void QQuickItemParticle::tick(int time)
{
    Q_UNUSED(time);//only needed because QTickAnimationProxy expects one
    processDeletables();
    for (auto groupId : groupIds()) {
        for (QQuickParticleData* d : std::as_const(m_system->groupData[groupId]->data)) {
            if (!d->delegate && d->t != -1 && d->stillAlive(m_system)) {
                QQuickItem* parentItem = nullptr;
                if (!m_pendingItems.isEmpty()){
                    QQuickItem *item = m_pendingItems.front();
                    m_pendingItems.pop_front();
                    parentItem = item->parentItem();
                    d->delegate = item;
                }else if (m_delegate){
                    d->delegate = qobject_cast<QQuickItem*>(m_delegate->create(qmlContext(this)));
                    if (d->delegate)
                        m_managed << d->delegate;
                }
                if (d && d->delegate){//###Data can be zero if creating an item leads to a reset - this screws things up.
                    d->delegate->setX(d->curX(m_system) - d->delegate->width() / 2); //TODO: adjust for system?
                    d->delegate->setY(d->curY(m_system) - d->delegate->height() / 2);
                    QQuickItemParticleAttached* mpa = qobject_cast<QQuickItemParticleAttached*>(qmlAttachedPropertiesObject<QQuickItemParticle>(d->delegate));
                    if (mpa){
                        mpa->m_parentItem = parentItem;
                        mpa->m_mp = this;
                        mpa->attach();
                    }
                    d->delegate->setParentItem(this);
                    if (m_fade)
                        d->delegate->setOpacity(0.);
                    d->delegate->setVisible(false);//Will be set to true when we prepare the next frame
                    m_activeCount++;
                }
            }
        }
    }
}
 
void QQuickItemParticle::reset()
{
    QQuickParticlePainter::reset();
 
    // delete all managed items which had their logical particles cleared
    // but leave it alone if the logical particle is maintained
    QSet<QQuickItem*> lost = QSet<QQuickItem*>(m_managed.cbegin(), m_managed.cend());
    for (auto groupId : groupIds()) {
        for (QQuickParticleData* d : std::as_const(m_system->groupData[groupId]->data)) {
            lost.remove(d->delegate);
        }
    }
    m_deletables.unite(lost);
    //TODO: This doesn't yet handle calling detach on taken particles in the system reset case
    processDeletables();
}
 
 
QSGNode* QQuickItemParticle::updatePaintNode(QSGNode* n, UpdatePaintNodeData* d)
{
    //Dummy update just to get painting tick
    if (m_pleaseReset)
        m_pleaseReset = false;
 
    if (clockShouldUpdate()) {
        prepareNextFrame();
        update(); //Get called again
    }
    if (n)
        n->markDirty(QSGNode::DirtyMaterial);
    return QQuickItem::updatePaintNode(n,d);
}
 
void QQuickItemParticle::prepareNextFrame()
{
    if (!m_system)
        return;
    qint64 timeStamp = m_system->systemSync(this);
    qreal curT = timeStamp/1000.0;
    qreal dt = curT - m_lastT;
    m_lastT = curT;
    if (!m_activeCount)
        return;
 
    //TODO: Size, better fade?
    for (auto groupId : groupIds()) {
        for (QQuickParticleData* data : std::as_const(m_system->groupData[groupId]->data)) {
            QQuickItem* item = data->delegate;
            if (!item)
                continue;
            float t = ((timeStamp / 1000.0f) - data->t) / data->lifeSpan;
            if (m_stasis.contains(item)) {
                data->t += dt;//Stasis effect
                continue;
            }
            if (t >= 1.0f){//Usually happens from load
                m_deletables << item;
                data->delegate = nullptr;
            }else{//Fade
                data->delegate->setVisible(true);
                if (m_fade){
                    float o = 1.f;
                    if (t <0.2f)
                        o = t * 5;
                    if (t > 0.8f)
                        o = (1-t)*5;
                    item->setOpacity(o);
                }
            }
            item->setX(data->curX(m_system) - item->width() / 2 - m_systemOffset.x());
            item->setY(data->curY(m_system) - item->height() / 2 - m_systemOffset.y());
        }
    }
}
 
QQuickItemParticleAttached *QQuickItemParticle::qmlAttachedProperties(QObject *object)
{
    return new QQuickItemParticleAttached(object);
}
 
bool QQuickItemParticle::clockShouldUpdate() const
{
    QQuickItem *parentItem = qobject_cast<QQuickItem *>(parent());
    return (m_system && m_system->isRunning() && !m_system->isPaused() && m_system->isEnabled()
            && ((parentItem && parentItem->isEnabled()) || !parentItem) && isEnabled());
}
 
void QQuickItemParticle::reconnectParent(QQuickItem *parentItem)
{
    updateClock();
    disconnect(m_parentEnabledStateConnection);
    if (parentItem) {
        m_parentEnabledStateConnection = connect(parentItem, &QQuickParticleSystem::enabledChanged,
                                                 this, &QQuickItemParticle::updateClock);
    }
}
 
void QQuickItemParticle::reconnectSystem(QQuickParticleSystem *system)
{
    updateClock();
    disconnect(m_systemRunStateConnection);
    disconnect(m_systemPauseStateConnection);
    disconnect(m_systemEnabledStateConnection);
    if (system) {
        m_systemRunStateConnection = connect(m_system, &QQuickParticleSystem::runningChanged, this, [this](){
            QQuickItemParticle::updateClock();
        });
        m_systemPauseStateConnection = connect(m_system, &QQuickParticleSystem::pausedChanged, this, [this](){
            QQuickItemParticle::updateClock();
        });
        m_systemEnabledStateConnection = connect(m_system, &QQuickParticleSystem::enabledChanged, this,
                                                 &QQuickItemParticle::updateClock);
    }
}
 
void QQuickItemParticle::updateClock()
{
    if (clockShouldUpdate()) {
        if (!clock->isRunning())
            clock->start();
    } else {
        if (clock->isRunning())
            clock->pause();
    }
}
 
QT_END_NAMESPACE
 
#include "moc_qquickitemparticle_p.cpp"