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#include "swarmaffector.h"
#include "particle.h"
#include <cmath>
#include <QDebug>
QT_BEGIN_NAMESPACE
SwarmAffector::SwarmAffector(QSGItem *parent) :
ParticleAffector(parent), m_strength(1), m_inited(false)
{
connect(this, SIGNAL(leadersChanged(QStringList)),
this, SLOT(updateGroupList()));
}
void SwarmAffector::ensureInit()
{
if(m_inited)
return;
m_inited = true;
updateGroupList();
m_lastPos.resize(m_system->count());
}
const qreal epsilon = 0.0000001;
bool SwarmAffector::affectParticle(ParticleData *d, qreal dt)
{
ensureInit();
QPointF curPos(d->curX(), d->curY());
if(m_leaders.isEmpty() || m_leadGroups.contains(d->group)){
m_lastPos[d->systemIndex] = curPos;
if(m_leadGroups.contains(d->group))
return false;
}
qreal fx = 0.0;
qreal fy = 0.0;
for(int i=0; i < m_lastPos.count(); i++){
if(m_lastPos[i].isNull())
continue;
QPointF diff = m_lastPos[i] - curPos;
qreal r = sqrt(diff.x() * diff.x() + diff.y() * diff.y());
if(r == 0.0)
continue;
qreal f = m_strength * (1/r);
if(f < epsilon)
continue;
qreal theta = atan2(diff.y(), diff.x());
fx += cos(theta) * f;
fy += sin(theta) * f;
}
if(!fx && !fy)
return false;
d->setInstantaneousSX(d->curSX()+fx * dt);
d->setInstantaneousSY(d->curSY()+fy * dt);
return true;
}
void SwarmAffector::reset(int systemIdx)
{
if(!m_system)
return;
if(!m_lastPos[systemIdx].isNull())
m_lastPos[systemIdx] = QPointF();
}
void SwarmAffector::updateGroupList()
{
if(!m_system || !m_system->m_initialized)
return;
m_leadGroups.clear();
foreach(const QString &s, m_leaders)
m_leadGroups << m_system->m_groupIds[s];
}
QT_END_NAMESPACE
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