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// 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
#include <QtCore/qtconfigmacros.h>
#undef QT_NO_FOREACH // this file contains unported legacy Q_FOREACH uses
#include "qquicktrailemitter_p.h"
#include <private/qqmlglobal_p.h>
#include <private/qquickv4particledata_p.h>
#include <QtCore/qrandom.h>
#include <cmath>
QT_BEGIN_NAMESPACE
/*!
\qmltype TrailEmitter
\nativetype QQuickTrailEmitter
\inqmlmodule QtQuick.Particles
\inherits Emitter
\brief Emits logical particles from other logical particles.
\ingroup qtquick-particles
This element emits logical particles into the ParticleSystem, with the
starting positions based on those of other logical particles.
*/
QQuickTrailEmitter::QQuickTrailEmitter(QQuickItem *parent) :
QQuickParticleEmitter(parent)
, m_particlesPerParticlePerSecond(0)
, m_lastTimeStamp(0)
, m_emitterXVariation(0)
, m_emitterYVariation(0)
, m_followCount(0)
, m_emissionExtruder(nullptr)
, m_defaultEmissionExtruder(new QQuickParticleExtruder(this))
{
//TODO: If followed increased their size
connect(this, &QQuickTrailEmitter::followChanged,
this, &QQuickTrailEmitter::recalcParticlesPerSecond);
connect(this, &QQuickTrailEmitter::particleDurationChanged,
this, &QQuickTrailEmitter::recalcParticlesPerSecond);
connect(this, &QQuickTrailEmitter::particlesPerParticlePerSecondChanged,
this, &QQuickTrailEmitter::recalcParticlesPerSecond);
}
/*!
\qmlproperty string QtQuick.Particles::TrailEmitter::follow
The type of logical particle which this is emitting from.
*/
/*!
\qmlproperty real QtQuick.Particles::TrailEmitter::velocityFromMovement
If this value is non-zero, then any movement of the emitter will provide additional
starting velocity to the particles based on the movement. The additional vector will be the
same angle as the emitter's movement, with a magnitude that is the magnitude of the emitters
movement multiplied by velocityFromMovement.
Default value is 0.
*/
/*!
\qmlproperty Shape QtQuick.Particles::TrailEmitter::emitShape
As the area of a TrailEmitter is the area it follows, a separate shape can be provided
to be the shape it emits out of. This shape has width and height specified by emitWidth
and emitHeight, and is centered on the followed particle's position.
The default shape is a filled Rectangle.
*/
/*!
\qmlproperty real QtQuick.Particles::TrailEmitter::emitWidth
The width in pixels the emitShape is scaled to. If set to TrailEmitter.ParticleSize,
the width will be the current size of the particle being followed.
Default is 0.
*/
/*!
\qmlproperty real QtQuick.Particles::TrailEmitter::emitHeight
The height in pixels the emitShape is scaled to. If set to TrailEmitter.ParticleSize,
the height will be the current size of the particle being followed.
Default is 0.
*/
/*!
\qmlproperty real QtQuick.Particles::TrailEmitter::emitRatePerParticle
*/
/*!
\qmlsignal QtQuick.Particles::TrailEmitter::emitFollowParticles(Array particles, Particle followed)
This signal is emitted when particles are emitted from the \a followed particle. \a particles contains an array of particle objects which can be directly manipulated.
If you use this signal handler, emitParticles will not be emitted.
*/
bool QQuickTrailEmitter::isEmitFollowConnected()
{
IS_SIGNAL_CONNECTED(
this, QQuickTrailEmitter, emitFollowParticles,
(const QList<QQuickV4ParticleData> &, const QQuickV4ParticleData &));
}
void QQuickTrailEmitter::recalcParticlesPerSecond(){
if (!m_system)
return;
m_followCount = m_system->groupData[m_system->groupIds[m_follow]]->size();
if (!m_followCount){
setParticlesPerSecond(1);//XXX: Fix this horrendous hack, needed so they aren't turned off from start (causes crashes - test that when gone you don't crash with 0 PPPS)
}else{
setParticlesPerSecond(m_particlesPerParticlePerSecond * m_followCount);
m_lastEmission.resize(m_followCount);
m_lastEmission.fill(m_lastTimeStamp);
}
}
void QQuickTrailEmitter::reset()
{
m_followCount = 0;
}
void QQuickTrailEmitter::emitWindow(int timeStamp)
{
if (m_system == nullptr)
return;
if (!m_enabled && !m_pulseLeft && m_burstQueue.isEmpty())
return;
if (m_followCount != m_system->groupData[m_system->groupIds[m_follow]]->size()){
qreal oldPPS = m_particlesPerSecond;
recalcParticlesPerSecond();
if (m_particlesPerSecond != oldPPS)
return;//system may need to update
}
if (m_pulseLeft){
m_pulseLeft -= timeStamp - m_lastTimeStamp * 1000.;
if (m_pulseLeft < 0){
timeStamp += m_pulseLeft;
m_pulseLeft = 0;
}
}
//TODO: Implement startTime and velocityFromMovement
qreal time = timeStamp / 1000.;
qreal particleRatio = 1. / m_particlesPerParticlePerSecond;
qreal pt;
qreal maxLife = (m_particleDuration + m_particleDurationVariation)/1000.0;
//Have to map it into this system, because particlesystem automaps it back
QPointF offset = m_system->mapFromItem(this, QPointF(0, 0));
qreal sizeAtEnd = m_particleEndSize >= 0 ? m_particleEndSize : m_particleSize;
int gId = m_system->groupIds[m_follow];
int gId2 = groupId();
for (int i=0; i<m_system->groupData[gId]->data.size(); i++) {
QQuickParticleData *d = m_system->groupData[gId]->data[i];
if (!d->stillAlive(m_system)){
m_lastEmission[i] = time; //Should only start emitting when it returns to life
continue;
}
pt = m_lastEmission[i];
if (pt < d->t)
pt = d->t;
if (pt + maxLife < time)//We missed so much, that we should skip emiting particles that are dead by now
pt = time - maxLife;
if ((width() || height()) && !effectiveExtruder()->contains(QRectF(offset.x(), offset.y(), width(), height()),
QPointF(d->curX(m_system), d->curY(m_system)))) {
m_lastEmission[d->index] = time;//jump over this time period without emitting, because it's outside
continue;
}
QList<QQuickParticleData*> toEmit;
while (pt < time || !m_burstQueue.isEmpty()){
QQuickParticleData* datum = m_system->newDatum(gId2, !m_overwrite);
if (datum){//else, skip this emission
// Particle timestamp
datum->t = pt;
datum->lifeSpan =
(m_particleDuration
+ (QRandomGenerator::global()->bounded((m_particleDurationVariation*2) + 1) - m_particleDurationVariation))
/ 1000.0;
// Particle position
// Note that burst location doesn't get used for follow emitter
qreal followT = pt - d->t;
qreal followT2 = followT * followT * 0.5;
qreal eW = m_emitterXVariation < 0 ? d->curSize(m_system) : m_emitterXVariation;
qreal eH = m_emitterYVariation < 0 ? d->curSize(m_system) : m_emitterYVariation;
//Subtract offset, because PS expects this in emitter coordinates
QRectF boundsRect(d->x - offset.x() + d->vx * followT + d->ax * followT2 - eW/2,
d->y - offset.y() + d->vy * followT + d->ay * followT2 - eH/2,
eW, eH);
QQuickParticleExtruder* effectiveEmissionExtruder = m_emissionExtruder ? m_emissionExtruder : m_defaultEmissionExtruder;
const QPointF &newPos = effectiveEmissionExtruder->extrude(boundsRect);
datum->x = newPos.x();
datum->y = newPos.y();
// Particle velocity
const QPointF &velocity = m_velocity->sample(newPos);
datum->vx = velocity.x()
+ m_velocity_from_movement * d->vx;
datum->vy = velocity.y()
+ m_velocity_from_movement * d->vy;
// Particle acceleration
const QPointF &accel = m_acceleration->sample(newPos);
datum->ax = accel.x();
datum->ay = accel.y();
// Particle size
float sizeVariation = -m_particleSizeVariation
+ QRandomGenerator::global()->generateDouble() * m_particleSizeVariation * 2;
float size = qMax((qreal)0.0, m_particleSize + sizeVariation);
float endSize = qMax((qreal)0.0, sizeAtEnd + sizeVariation);
datum->size = size * float(m_enabled);
datum->endSize = endSize * float(m_enabled);
toEmit << datum;
m_system->emitParticle(datum, this);
}
if (!m_burstQueue.isEmpty()){
m_burstQueue.first().first--;
if (m_burstQueue.first().first <= 0)
m_burstQueue.pop_front();
}else{
pt += particleRatio;
}
}
foreach (QQuickParticleData* d, toEmit)
m_system->emitParticle(d, this);
if (isEmitConnected() || isEmitFollowConnected()) {
QList<QQuickV4ParticleData> particles;
particles.reserve(toEmit.size());
for (QQuickParticleData *particle : std::as_const(toEmit))
particles.push_back(particle->v4Value(m_system));
if (isEmitFollowConnected()) {
//A chance for many arbitrary JS changes
emit emitFollowParticles(particles, d->v4Value(m_system));
} else if (isEmitConnected()) {
emit emitParticles(particles);//A chance for arbitrary JS changes
}
}
m_lastEmission[d->index] = pt;
}
m_lastTimeStamp = time;
}
QT_END_NAMESPACE
#include "moc_qquicktrailemitter_p.cpp"