qquicktargetdirection.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qquicktargetdirection_p.h"
#include "qquickparticleemitter_p.h"
#include <cmath>
#include <QDebug>
#include <QRandomGenerator>
 
QT_BEGIN_NAMESPACE
QQuickTargetDirection::QQuickTargetDirection(QObject *parent) :
    QQuickDirection(parent)
  , m_targetX(0)
  , m_targetY(0)
  , m_targetVariation(0)
  , m_proportionalMagnitude(false)
  , m_magnitude(0)
  , m_magnitudeVariation(0)
  , m_targetItem(nullptr)
{
}
 
QPointF QQuickTargetDirection::sample(const QPointF &from)
{
    //###This approach loses interpolating the last position of the target (like we could with the emitter) is it worthwhile?
    QPointF ret;
    qreal targetX;
    qreal targetY;
    if (m_targetItem){
        QQuickParticleEmitter* parentEmitter = qobject_cast<QQuickParticleEmitter*>(parent());
        targetX = m_targetItem->width()/2;
        targetY = m_targetItem->height()/2;
        if (!parentEmitter){
            qWarning() << "Directed vector is not a child of the emitter. Mapping of target item coordinates may fail.";
            targetX += m_targetItem->x();
            targetY += m_targetItem->y();
        }else{
            ret = parentEmitter->mapFromItem(m_targetItem, QPointF(targetX, targetY));
            targetX = ret.x();
            targetY = ret.y();
        }
    }else{
        targetX = m_targetX;
        targetY = m_targetY;
    }
    targetX += 0 - from.x() - m_targetVariation + QRandomGenerator::global()->generateDouble() * m_targetVariation*2;
    targetY += 0 - from.y() - m_targetVariation + QRandomGenerator::global()->generateDouble() * m_targetVariation*2;
    qreal theta = std::atan2(targetY, targetX);
    qreal mag = m_magnitude + QRandomGenerator::global()->generateDouble() * m_magnitudeVariation * 2 - m_magnitudeVariation;
    if (m_proportionalMagnitude)
        mag *= qHypot(targetX, targetY);
    ret.setX(mag * std::cos(theta));
    ret.setY(mag * std::sin(theta));
    return ret;
}
 
QT_END_NAMESPACE
 
#include "moc_qquicktargetdirection_p.cpp"