/****************************************************************************
**
** Copyright (C) 2021 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of Qt Quick 3D.
**
** $QT_BEGIN_LICENSE:GPL$
** 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 General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 or (at your option) 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.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-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qquick3dparticlevectordirection_p.h"
#include "qquick3dparticlerandomizer_p.h"
#include "qquick3dparticlesystem_p.h"

QT_BEGIN_NAMESPACE

/*!
    \qmltype VectorDirection3D
    \inherits Direction3D
    \inqmlmodule QtQuick3D.Particles3D
    \brief For specifying a direction towards the target direction.

    This element sets emitted particle velocity towards the target direction vector.
    The length of the direction vector is used as the velocity magnitude.

    For example, to emit particles towards some random direction within
    x: 50..150, y: -20..20, z: 0:

    \qml
    ParticleEmitter3D {
        ...
        velocity: VectorDirection3D {
            direction: Qt.vector3d(100, 0, 0)
            directionVariation: Qt.vector3d(50, 20, 0)
        }
    }
    \endqml

*/

QQuick3DParticleVectorDirection::QQuick3DParticleVectorDirection(QObject *parent)
    : QQuick3DParticleDirection(parent)
{
}

/*!
    \qmlproperty vector3d VectorDirection3D::direction

    This property defines the direction for particles target.

    The default value is \c (0, 100, 0) (upwards on the y-axis).

    \sa directionVariation
*/
QVector3D QQuick3DParticleVectorDirection::direction() const
{
    return m_direction;
}

/*!
    \qmlproperty vector3d VectorDirection3D::directionVariation

    This property defines the direction variation for particles target.

    The default value is \c (0, 0, 0) (no variation).

    \sa direction
*/
QVector3D QQuick3DParticleVectorDirection::directionVariation() const
{
    return m_directionVariation;
}

void QQuick3DParticleVectorDirection::setDirection(const QVector3D &direction)
{
    if (m_direction == direction)
        return;

    m_direction = direction;
    Q_EMIT directionChanged();
}

void QQuick3DParticleVectorDirection::setDirectionVariation(const QVector3D &directionVariation)
{
    if (m_directionVariation == directionVariation)
        return;

    m_directionVariation = directionVariation;
    Q_EMIT directionVariationChanged();
}

QVector3D QQuick3DParticleVectorDirection::sample(const QQuick3DParticleData &d)
{
    QVector3D ret;
    if (!m_system)
        return ret;
    auto rand = m_system->rand();
    ret.setX(m_direction.x() - m_directionVariation.x() + rand->get(d.index, QPRand::VDirXV) * m_directionVariation.x() * 2.0f);
    ret.setY(m_direction.y() - m_directionVariation.y() + rand->get(d.index, QPRand::VDirYV) * m_directionVariation.y() * 2.0f);
    ret.setZ(m_direction.z() - m_directionVariation.z() + rand->get(d.index, QPRand::VDirZV) * m_directionVariation.z() * 2.0f);
    return ret;
}

QT_END_NAMESPACE
