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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the QtQuick module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 3 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL3 included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qquickgravity_p.h"
#include <cmath>
QT_BEGIN_NAMESPACE
const qreal CONV = 0.017453292520444443;
/*!
\qmltype Gravity
\instantiates QQuickGravityAffector
\inqmlmodule QtQuick.Particles
\ingroup qtquick-particles
\inherits Affector
\brief For applying acceleration in an angle
This element will accelerate all affected particles to a vector of
the specified magnitude in the specified angle. If the angle and acceleration do
not vary, it is more efficient to set the specified acceleration on the Emitter.
This element models the gravity of a massive object whose center of
gravity is far away (and thus the gravitational pull is effectively constant
across the scene). To model the gravity of an object near or inside the scene,
use PointAttractor.
*/
/*!
\qmlproperty real QtQuick.Particles::Gravity::magnitude
Pixels per second that objects will be accelerated by.
*/
/*!
\qmlproperty real QtQuick.Particles::Gravity::acceleration
Name changed to magnitude, will be removed soon.
*/
/*!
\qmlproperty real QtQuick.Particles::Gravity::angle
Angle of acceleration.
*/
QQuickGravityAffector::QQuickGravityAffector(QQuickItem *parent) :
QQuickParticleAffector(parent), m_magnitude(-10), m_angle(90), m_needRecalc(true)
{
}
bool QQuickGravityAffector::affectParticle(QQuickParticleData *d, qreal dt)
{
if (!m_magnitude)
return false;
if (m_needRecalc) {
m_needRecalc = false;
m_dx = m_magnitude * std::cos(m_angle * CONV);
m_dy = m_magnitude * std::sin(m_angle * CONV);
}
d->setInstantaneousVX(d->curVX(m_system) + m_dx*dt, m_system);
d->setInstantaneousVY(d->curVY(m_system) + m_dy*dt, m_system);
return true;
}
QT_END_NAMESPACE
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