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Diffstat (limited to 'src/quick/particles/qquickpointattractor.cpp')
| -rw-r--r-- | src/quick/particles/qquickpointattractor.cpp | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/src/quick/particles/qquickpointattractor.cpp b/src/quick/particles/qquickpointattractor.cpp new file mode 100644 index 0000000000..d96458c8bb --- /dev/null +++ b/src/quick/particles/qquickpointattractor.cpp @@ -0,0 +1,162 @@ +/**************************************************************************** +** +** 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. +** +** $QT_BEGIN_LICENSE:LGPL$ +** GNU Lesser General Public License Usage +** 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. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU General +** Public License version 3.0 as published by the Free Software Foundation +** and appearing in the file LICENSE.GPL included in the packaging of this +** file. Please review the following information to ensure the GNU General +** Public License version 3.0 requirements will be met: +** http://www.gnu.org/copyleft/gpl.html. +** +** Other Usage +** Alternatively, this file may be used in accordance with the terms and +** conditions contained in a signed written agreement between you and Nokia. +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qquickpointattractor_p.h" +#include <cmath> +#include <QDebug> +QT_BEGIN_NAMESPACE +/*! + \qmlclass Attractor QQuickAttractorAffector + \inqmlmodule QtQuick.Particles 2 + \inherits Affector + \brief The Attractor allows you to attract particles towards a specific point. + + Note that the size and position of this element affects which particles it affects. + The size of the point attracted to is always 0x0, and the location of that point + is specified by the pointX and pointY properties. + + Note that Attractor has the standard Item x,y,width and height properties. + Like other affectors, these represent the affected area. They + do not represent the 0x0 point which is the target of the attraction. +*/ + + +/*! + \qmlproperty real QtQuick.Particles2::PointAttractor::pointX + + The x coordinate of the attracting point. This is relative + to the x coordinate of the Attractor. +*/ +/*! + \qmlproperty real QtQuick.Particles2::PointAttractor::pointY + + The y coordinate of the attracting point. This is relative + to the y coordinate of the Attractor. +*/ +/*! + \qmlproperty real QtQuick.Particles2::PointAttractor::strength + + The pull, in units per second, to be exerted on an item one pixel away. + + Depending on how the attraction is proportionalToDistance this may have to + be very high or very low to have a reasonable effect on particles at a + distance. +*/ +/*! + \qmlproperty AffectableParameter QtQuick.Particles2::Attractor::affectedParameter + + What attribute of particles is directly affected. + \list + \o Attractor.Position + \o Attractor.Velocity + \o Attractor.Acceleration + \endlist +*/ +/*! + \qmlproperty Proportion QtQuick.Particles2::Attractor::proportionalToDistance + + How the distance from the particle to the point affects the strength of the attraction. + + \list + \o Attractor.Constant + \o Attractor.Linear + \o Attractor.InverseLinear + \o Attractor.Quadratic + \o Attractor.InverseQuadratic + \endlist +*/ + + +QQuickAttractorAffector::QQuickAttractorAffector(QQuickItem *parent) : + QQuickParticleAffector(parent), m_strength(0.0), m_x(0), m_y(0) + , m_physics(Velocity), m_proportionalToDistance(Linear) +{ +} + +bool QQuickAttractorAffector::affectParticle(QQuickParticleData *d, qreal dt) +{ + if (m_strength == 0.0) + return false; + qreal dx = m_x+m_offset.x() - d->curX(); + qreal dy = m_y+m_offset.y() - d->curY(); + qreal r = sqrt((dx*dx) + (dy*dy)); + qreal theta = atan2(dy,dx); + qreal ds = 0; + switch (m_proportionalToDistance){ + case InverseQuadratic: + ds = (m_strength / qMax<qreal>(1.,r*r)); + break; + case InverseLinear: + ds = (m_strength / qMax<qreal>(1.,r)); + break; + case Quadratic: + ds = (m_strength * qMax<qreal>(1.,r*r)); + break; + case Linear: + ds = (m_strength * qMax<qreal>(1.,r)); + break; + default: //also Constant + ds = m_strength; + } + ds *= dt; + dx = ds * cos(theta); + dy = ds * sin(theta); + qreal vx,vy; + switch (m_physics){ + case Position: + d->x = (d->x + dx); + d->y = (d->y + dy); + break; + case Acceleration: + d->setInstantaneousAX(d->ax + dx); + d->setInstantaneousAY(d->ay + dy); + break; + case Velocity: //also default + default: + vx = d->curVX(); + vy = d->curVY(); + d->setInstantaneousVX(vx + dx); + d->setInstantaneousVY(vy + dy); + } + + return true; +} +QT_END_NAMESPACE |