1 files changed, 114 insertions, 0 deletions
diff --git a/src/imports/particles/swarmaffector.cpp b/src/imports/particles/swarmaffector.cpp
new file mode 100644
index 0000000000..513e8a17a7
--- /dev/null
+++ b/src/imports/particles/swarmaffector.cpp
@@ -0,0 +1,114 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the Declarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#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