qquick3dparticletrailemitter.cpp

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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
 
#include "qquick3dparticletrailemitter_p.h"
 
QT_BEGIN_NAMESPACE
 
QQuick3DParticleTrailEmitter::QQuick3DParticleTrailEmitter(QQuick3DNode *parent)
    : QQuick3DParticleEmitter(parent)
{
}
 
QQuick3DParticle *QQuick3DParticleTrailEmitter::follow() const
{
    return m_follow;
}
 
void QQuick3DParticleTrailEmitter::setFollow(QQuick3DParticle *follow)
{
    if (m_follow == follow)
        return;
 
    m_follow = follow;
    Q_EMIT followChanged();
}
 
void QQuick3DParticleTrailEmitter::burst(int count)
{
    if (!system())
        return;
    QQuick3DParticleEmitBurstData burst;
    burst.time = system()->currentTime();
    burst.amount = count;
    m_bursts << burst;
}
 
// Returns true if there are any dynamic bursts
bool QQuick3DParticleTrailEmitter::hasBursts() const
{
    bool dynamicBursts = false;
    for (auto *burst : std::as_const(m_emitBursts)) {
        if (qobject_cast<QQuick3DParticleDynamicBurst *>(burst)) {
            dynamicBursts = true;
            break;
        }
    }
    return !m_bursts.empty() || dynamicBursts;
}
 
// Called to emit set of particles
void QQuick3DParticleTrailEmitter::emitTrailParticles(const QVector3D &centerPos, int emitAmount, int triggerType)
{
    if (!system())
        return;
 
    if (!enabled())
        return;
 
    const int systemTime = system()->currentTime();
    for (auto particle : std::as_const(m_system->m_particles)) {
        if (particle == m_particle) {
            emitAmount += getEmitAmountFromDynamicBursts(triggerType);
            emitAmount = std::min(emitAmount, int(particle->maxAmount()));
            float addTime = ((systemTime - m_prevEmitTime) / 1000.0f) / emitAmount;
            for (int i = 0; i < emitAmount; i++) {
                // Distribute evenly between previous and current time, important especially
                // when time has jumped a lot (like a starttime).
                float startTime = (m_prevEmitTime / 1000.0f) + addTime * float(i);
                emitParticle(particle, startTime, QMatrix4x4(), QQuaternion(), centerPos);
            }
            // Emit bursts, if any
            for (auto burst : std::as_const(m_bursts)) {
                int burstAmount = std::min(burst.amount, int(particle->maxAmount()));
                float burstTime = float(burst.time / 1000.0f);
                for (int i = 0; i < burstAmount; i++)
                    emitParticle(particle, burstTime, QMatrix4x4(), QQuaternion(), centerPos);
            }
        }
    }
 
    m_prevEmitTime = systemTime;
}
 
void QQuick3DParticleTrailEmitter::clearBursts()
{
    // After bursts have been emitted, clear the list
    m_bursts.clear();
}
 
QT_END_NAMESPACE