From: Alan Alpert Date: Thu, 20 Oct 2011 11:01:28 +0000 (+1000) Subject: Add threshold property to Friction X-Git-Tag: qt-v5.0.0-alpha1~1314 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=89fb0fb65d0071e88f24b8022eb7070956a7a1a7;p=profile%2Fivi%2Fqtdeclarative.git Add threshold property to Friction So much easier than calculating exact counterbalancing acceleration. Change-Id: I7cc43cc2e4d0ad39d1996d432f0e29ccf7bff554 Reviewed-by: Martin Jones --- diff --git a/src/declarative/particles/qsgfriction.cpp b/src/declarative/particles/qsgfriction.cpp index 85a586b..9e32fc2 100644 --- a/src/declarative/particles/qsgfriction.cpp +++ b/src/declarative/particles/qsgfriction.cpp @@ -54,13 +54,23 @@ QT_BEGIN_NAMESPACE A drag will be applied to moving objects which is this factor of their current velocity. */ +/*! + \qmlproperty real QtQuick.Particles2::Friction::threshold + + The drag will only be applied to objects with a velocity above the threshold velocity. The + drag applied will bring objects down to the threshold velocity, but no further. + + The default threshold is 0 +*/ static qreal sign(qreal a) { return a >= 0 ? 1 : -1; } +static const qreal epsilon = 0.00001; + QSGFrictionAffector::QSGFrictionAffector(QQuickItem *parent) : - QSGParticleAffector(parent), m_factor(0.0) + QSGParticleAffector(parent), m_factor(0.0), m_threshold(0.0) { } @@ -70,14 +80,29 @@ bool QSGFrictionAffector::affectParticle(QSGParticleData *d, qreal dt) return false; qreal curVX = d->curVX(); qreal curVY = d->curVY(); + if (!curVX && !curVY) + return false; qreal newVX = curVX + (curVX * m_factor * -1 * dt); qreal newVY = curVY + (curVY * m_factor * -1 * dt); - //Since we're modelling a continuous function, it will never pass 0. - if (sign(curVX) != sign(newVX)) - newVX = 0; - if (sign(curVY) != sign(newVY)) - newVY = 0; + if (!m_threshold) { + if (sign(curVX) != sign(newVX)) + newVX = 0; + if (sign(curVY) != sign(newVY)) + newVY = 0; + } else { + qreal curMag = sqrt(curVX*curVX + curVY*curVY); + if (curMag <= m_threshold + epsilon) + return false; + qreal newMag = sqrt(newVX*newVX + newVY*newVY); + if (newMag <= m_threshold + epsilon || //went past the threshold, stop there instead + sign(curVX) != sign(newVX) || //went so far past maybe it came out the other side! + sign(curVY) != sign(newVY)) { + qreal theta = atan2(curVY, curVX); + newVX = m_threshold * cos(theta); + newVY = m_threshold * sin(theta); + } + } d->setInstantaneousVX(newVX); d->setInstantaneousVY(newVY); diff --git a/src/declarative/particles/qsgfriction_p.h b/src/declarative/particles/qsgfriction_p.h index e2b3a0c..9965b14 100644 --- a/src/declarative/particles/qsgfriction_p.h +++ b/src/declarative/particles/qsgfriction_p.h @@ -54,6 +54,7 @@ class QSGFrictionAffector : public QSGParticleAffector { Q_OBJECT Q_PROPERTY(qreal factor READ factor WRITE setFactor NOTIFY factorChanged) + Q_PROPERTY(qreal threshold READ threshold WRITE setThreshold NOTIFY thresholdChanged) public: explicit QSGFrictionAffector(QQuickItem *parent = 0); @@ -61,24 +62,41 @@ public: { return m_factor; } + + qreal threshold() const + { + return m_threshold; + } + protected: virtual bool affectParticle(QSGParticleData *d, qreal dt); + signals: void factorChanged(qreal arg); + void thresholdChanged(qreal arg); public slots: -void setFactor(qreal arg) -{ - if (m_factor != arg) { - m_factor = arg; - emit factorChanged(arg); + void setFactor(qreal arg) + { + if (m_factor != arg) { + m_factor = arg; + emit factorChanged(arg); + } + } + + void setThreshold(qreal arg) + { + if (m_threshold != arg) { + m_threshold = arg; + emit thresholdChanged(arg); + } } -} private: -qreal m_factor; + qreal m_factor; + qreal m_threshold; }; QT_END_NAMESPACE diff --git a/tests/auto/particles/qsgfriction/data/threshold.qml b/tests/auto/particles/qsgfriction/data/threshold.qml new file mode 100644 index 0000000..27990c3 --- /dev/null +++ b/tests/auto/particles/qsgfriction/data/threshold.qml @@ -0,0 +1,73 @@ +/**************************************************************************** +** +** 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 test suite 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. +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +import QtQuick 2.0 +import QtQuick.Particles 2.0 + +Rectangle { + color: "black" + width: 320 + height: 320 + + ParticleSystem { + id: sys + objectName: "system" + anchors.fill: parent + + ImageParticle { + groups: ["","notdefault"] + source: "../../shared/star.png" + } + + Friction { + factor: 1000 //speed limit 50 + threshold: 50 + } + + Emitter{ + //0,0 position + speed: PointDirection{x:1000} + size: 32 + emitRate: 1000 + lifeSpan: 500 + } + } +} diff --git a/tests/auto/particles/qsgfriction/tst_qsgfriction.cpp b/tests/auto/particles/qsgfriction/tst_qsgfriction.cpp index ad37c3e..3237c92 100644 --- a/tests/auto/particles/qsgfriction/tst_qsgfriction.cpp +++ b/tests/auto/particles/qsgfriction/tst_qsgfriction.cpp @@ -52,6 +52,7 @@ public: private slots: void test_basic(); + void test_threshold(); }; tst_qsgfriction::tst_qsgfriction() @@ -102,6 +103,32 @@ void tst_qsgfriction::test_basic() } } +void tst_qsgfriction::test_threshold() +{ + QQuickView* view = createView(QCoreApplication::applicationDirPath() + "/data/threshold.qml", 600); + QSGParticleSystem* system = view->rootObject()->findChild("system"); + ensureAnimTime(600, system->m_animation); + + //Speed capped at 50, but it might take a frame or two to get there + QCOMPARE(system->groupData[0]->size(), 500); + foreach (QSGParticleData *d, system->groupData[0]->data) { + if (d->t == -1.0f) + continue; //Particle data unused + if (myFuzzyGEQ(d->t, ((qreal)system->timeInt/1000.0) - 0.1)) + continue; //Particle data too young + + QVERIFY(myFuzzyLEQ(d->vx, 50.f)); + QCOMPARE(d->y, 0.f); + QCOMPARE(d->vy, 0.f); + QCOMPARE(d->ax, 0.f); + QCOMPARE(d->ay, 0.f); + QCOMPARE(d->lifeSpan, 0.5f); + QCOMPARE(d->size, 32.f); + QCOMPARE(d->endSize, 32.f); + QVERIFY(myFuzzyLEQ(d->t, ((qreal)system->timeInt/1000.0))); + } +} + QTEST_MAIN(tst_qsgfriction); #include "tst_qsgfriction.moc"