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** Copyright (C) 2016 Klaralvdalens Datakonsult AB (KDAB).
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****************************************************************************/

#include "qfirstpersoncameracontroller.h"
#include "qfirstpersoncameracontroller_p.h"

#include <Qt3DInput/QAction>
#include <Qt3DInput/QActionInput>
#include <Qt3DInput/QAnalogAxisInput>
#include <Qt3DInput/QAxis>
#include <Qt3DInput/QButtonAxisInput>
#include <Qt3DLogic/QFrameAction>
#include <Qt3DInput/QKeyboardDevice>
#include <Qt3DInput/QLogicalDevice>
#include <Qt3DInput/QMouseDevice>
#include <Qt3DInput/QMouseEvent>
#include <Qt3DRender/QCamera>

QT_BEGIN_NAMESPACE

namespace Qt3DExtras {

QFirstPersonCameraControllerPrivate::QFirstPersonCameraControllerPrivate()
    : Qt3DCore::QEntityPrivate()
    , m_camera(nullptr)
    , m_leftMouseButtonAction(new Qt3DInput::QAction())
    , m_fineMotionAction(new Qt3DInput::QAction())
    , m_rxAxis(new Qt3DInput::QAxis())
    , m_ryAxis(new Qt3DInput::QAxis())
    , m_txAxis(new Qt3DInput::QAxis())
    , m_tyAxis(new Qt3DInput::QAxis())
    , m_tzAxis(new Qt3DInput::QAxis())
    , m_leftMouseButtonInput(new Qt3DInput::QActionInput())
    , m_fineMotionKeyInput(new Qt3DInput::QActionInput())
    , m_mouseRxInput(new Qt3DInput::QAnalogAxisInput())
    , m_mouseRyInput(new Qt3DInput::QAnalogAxisInput())
    , m_mouseTzXInput(new Qt3DInput::QAnalogAxisInput())
    , m_mouseTzYInput(new Qt3DInput::QAnalogAxisInput())
    , m_keyboardTxPosInput(new Qt3DInput::QButtonAxisInput())
    , m_keyboardTyPosInput(new Qt3DInput::QButtonAxisInput())
    , m_keyboardTzPosInput(new Qt3DInput::QButtonAxisInput())
    , m_keyboardTxNegInput(new Qt3DInput::QButtonAxisInput())
    , m_keyboardTyNegInput(new Qt3DInput::QButtonAxisInput())
    , m_keyboardTzNegInput(new Qt3DInput::QButtonAxisInput())
    , m_keyboardDevice(new Qt3DInput::QKeyboardDevice())
    , m_mouseDevice(new Qt3DInput::QMouseDevice())
    , m_logicalDevice(new Qt3DInput::QLogicalDevice())
    , m_frameAction(new Qt3DLogic::QFrameAction())
    , m_linearSpeed(10.0f)
    , m_lookSpeed(180.0f)
    , m_acceleration(-1.0f)
    , m_deceleration(-1.0f)
    , m_firstPersonUp(QVector3D(0.0f, 1.0f, 0.0f))
{}

void QFirstPersonCameraControllerPrivate::init()
{
    //// Actions

    // Left Mouse Button Action
    m_leftMouseButtonInput->setButtons(QVector<int>() << Qt::LeftButton);
    m_leftMouseButtonInput->setSourceDevice(m_mouseDevice);
    m_leftMouseButtonAction->addInput(m_leftMouseButtonInput);

    // Fine Motion Action
    m_fineMotionKeyInput->setButtons(QVector<int>() << Qt::Key_Shift);
    m_fineMotionKeyInput->setSourceDevice(m_keyboardDevice);
    m_fineMotionAction->addInput(m_fineMotionKeyInput);

    //// Axes

    // Mouse X
    m_mouseRxInput->setAxis(Qt3DInput::QMouseDevice::X);
    m_mouseRxInput->setSourceDevice(m_mouseDevice);
    m_rxAxis->addInput(m_mouseRxInput);

    // Mouse Y
    m_mouseRyInput->setAxis(Qt3DInput::QMouseDevice::Y);
    m_mouseRyInput->setSourceDevice(m_mouseDevice);
    m_ryAxis->addInput(m_mouseRyInput);

    // Mouse Wheel X
    m_mouseTzXInput->setAxis(Qt3DInput::QMouseDevice::WheelX);
    m_mouseTzXInput->setSourceDevice(m_mouseDevice);
    m_tzAxis->addInput(m_mouseTzXInput);

    // Mouse Wheel Y
    m_mouseTzYInput->setAxis(Qt3DInput::QMouseDevice::WheelY);
    m_mouseTzYInput->setSourceDevice(m_mouseDevice);
    m_tzAxis->addInput(m_mouseTzYInput);

    // Keyboard Pos Tx
    m_keyboardTxPosInput->setButtons(QVector<int>() << Qt::Key_Right);
    m_keyboardTxPosInput->setScale(1.0f);
    m_keyboardTxPosInput->setSourceDevice(m_keyboardDevice);
    m_txAxis->addInput(m_keyboardTxPosInput);

    // Keyboard Pos Ty
    m_keyboardTyPosInput->setButtons(QVector<int>() << Qt::Key_PageUp);
    m_keyboardTyPosInput->setScale(1.0f);
    m_keyboardTyPosInput->setSourceDevice(m_keyboardDevice);
    m_tyAxis->addInput(m_keyboardTyPosInput);

    // Keyboard Pos Tz
    m_keyboardTzPosInput->setButtons(QVector<int>() << Qt::Key_Up);
    m_keyboardTzPosInput->setScale(1.0f);
    m_keyboardTzPosInput->setSourceDevice(m_keyboardDevice);
    m_tzAxis->addInput(m_keyboardTzPosInput);

    // Keyboard Neg Tx
    m_keyboardTxNegInput->setButtons(QVector<int>() << Qt::Key_Left);
    m_keyboardTxNegInput->setScale(-1.0f);
    m_keyboardTxNegInput->setSourceDevice(m_keyboardDevice);
    m_txAxis->addInput(m_keyboardTxNegInput);

    // Keyboard Neg Ty
    m_keyboardTyNegInput->setButtons(QVector<int>() << Qt::Key_PageDown);
    m_keyboardTyNegInput->setScale(-1.0f);
    m_keyboardTyNegInput->setSourceDevice(m_keyboardDevice);
    m_tyAxis->addInput(m_keyboardTyNegInput);

    // Keyboard Neg Tz
    m_keyboardTzNegInput->setButtons(QVector<int>() << Qt::Key_Down);
    m_keyboardTzNegInput->setScale(-1.0f);
    m_keyboardTzNegInput->setSourceDevice(m_keyboardDevice);
    m_tzAxis->addInput(m_keyboardTzNegInput);

    //// Logical Device

    m_logicalDevice->addAction(m_fineMotionAction);
    m_logicalDevice->addAction(m_leftMouseButtonAction);
    m_logicalDevice->addAxis(m_rxAxis);
    m_logicalDevice->addAxis(m_ryAxis);
    m_logicalDevice->addAxis(m_txAxis);
    m_logicalDevice->addAxis(m_tyAxis);
    m_logicalDevice->addAxis(m_tzAxis);

    applyAccelerations();

    Q_Q(QFirstPersonCameraController);
    //// FrameAction

    QObject::connect(m_frameAction, SIGNAL(triggered(float)),
                     q, SLOT(_q_onTriggered(float)));

    // Disable the logical device when the entity is disabled
    QObject::connect(q, &Qt3DCore::QEntity::enabledChanged,
                     m_logicalDevice, &Qt3DInput::QLogicalDevice::setEnabled);

    q->addComponent(m_frameAction);
    q->addComponent(m_logicalDevice);
}

void QFirstPersonCameraControllerPrivate::applyAccelerations()
{
    const auto inputs = {
        m_keyboardTxPosInput,
        m_keyboardTyPosInput,
        m_keyboardTzPosInput,
        m_keyboardTxNegInput,
        m_keyboardTyNegInput,
        m_keyboardTzNegInput
    };

    for (auto input : inputs) {
        input->setAcceleration(m_acceleration);
        input->setDeceleration(m_deceleration);
    }
}

void QFirstPersonCameraControllerPrivate::_q_onTriggered(float dt)
{
    if (m_camera != nullptr) {
        m_camera->translate(QVector3D(m_txAxis->value() * m_linearSpeed,
                                      m_tyAxis->value() * m_linearSpeed,
                                      m_tzAxis->value() * m_linearSpeed) * dt);
        if (m_leftMouseButtonAction->isActive()) {
            float lookSpeed = m_lookSpeed;
            if (m_fineMotionAction->isActive())
                lookSpeed *= 0.2f;
            m_camera->pan(m_rxAxis->value() * lookSpeed * dt, m_firstPersonUp);
            m_camera->tilt(m_ryAxis->value() * lookSpeed * dt);
        }
    }
}

/*!
    \class Qt3DExtras::QFirstPersonCameraController
    \brief The QFirstPersonCameraController class allows controlling the scene camera
    from the first person perspective.
    \inmodule Qt3DExtras
    \since 5.7
    \inherits Qt3DCore::QEntity

    The controls are:
    \table
    \header
        \li Input
        \li Action
    \row
        \li Left mouse button
        \li While the left mouse button is pressed, mouse movement along x-axis pans the camera and
        movement along y-axis tilts it.
    \row
        \li Mouse scroll wheel
        \li Zooms the camera in and out without changing the view center.
    \row
        \li Shift key
        \li Turns the fine motion control active while pressed. Makes mouse pan and tilt less
        sensitive.
    \row
        \li Arrow keys
        \li Move the camera horizontally relative to camera viewport.
    \row
        \li Page up and page down keys
        \li Move the camera vertically relative to camera viewport.
    \endtable
*/

QFirstPersonCameraController::QFirstPersonCameraController(Qt3DCore::QNode *parent)
    : Qt3DCore::QEntity(*new QFirstPersonCameraControllerPrivate, parent)
{
    Q_D(QFirstPersonCameraController);
    d->init();
}

QFirstPersonCameraController::~QFirstPersonCameraController()
{
}

/*!
    \property QFirstPersonCameraController::camera

    Holds the currently controlled camera.
*/
Qt3DRender::QCamera *QFirstPersonCameraController::camera() const
{
    Q_D(const QFirstPersonCameraController);
    return d->m_camera;
}

/*!
    \property QFirstPersonCameraController::linearSpeed

    Holds the current linear speed of the camera controller. Linear speed determines the
    movement speed of the camera.
*/
float QFirstPersonCameraController::linearSpeed() const
{
    Q_D(const QFirstPersonCameraController);
    return d->m_linearSpeed;
}

/*!
    \property QFirstPersonCameraController::lookSpeed

    Holds the current look speed of the camera controller. The look speed determines the turn rate
    of the camera pan and tilt.
*/
float QFirstPersonCameraController::lookSpeed() const
{
    Q_D(const QFirstPersonCameraController);
    return d->m_lookSpeed;
}

/*!
    \property QFirstPersonCameraController::acceleration

    Holds the current acceleration of the camera controller.
*/
float QFirstPersonCameraController::acceleration() const
{
    Q_D(const QFirstPersonCameraController);
    return d->m_acceleration;
}

/*!
    \property QFirstPersonCameraController::deceleration

    Holds the current deceleration of the camera controller.
*/
float QFirstPersonCameraController::deceleration() const
{
    Q_D(const QFirstPersonCameraController);
    return d->m_deceleration;
}

void QFirstPersonCameraController::setCamera(Qt3DRender::QCamera *camera)
{
    Q_D(QFirstPersonCameraController);
    if (d->m_camera != camera) {

        if (d->m_camera)
            d->unregisterDestructionHelper(d->m_camera);

        if (camera && !camera->parent())
            camera->setParent(this);

        d->m_camera = camera;

        // Ensures proper bookkeeping
        if (d->m_camera)
            d->registerDestructionHelper(d->m_camera, &QFirstPersonCameraController::setCamera, d->m_camera);

        emit cameraChanged();
    }
}

void QFirstPersonCameraController::setLinearSpeed(float linearSpeed)
{
    Q_D(QFirstPersonCameraController);
    if (d->m_linearSpeed != linearSpeed) {
        d->m_linearSpeed = linearSpeed;
        emit linearSpeedChanged();
    }
}

void QFirstPersonCameraController::setLookSpeed(float lookSpeed)
{
    Q_D(QFirstPersonCameraController);
    if (d->m_lookSpeed != lookSpeed) {
        d->m_lookSpeed = lookSpeed;
        emit lookSpeedChanged();
    }
}

void QFirstPersonCameraController::setAcceleration(float acceleration)
{
    Q_D(QFirstPersonCameraController);
    if (d->m_acceleration != acceleration) {
        d->m_acceleration = acceleration;
        d->applyAccelerations();
        emit accelerationChanged(acceleration);
    }
}

void QFirstPersonCameraController::setDeceleration(float deceleration)
{
    Q_D(QFirstPersonCameraController);
    if (d->m_deceleration != deceleration) {
        d->m_deceleration = deceleration;
        d->applyAccelerations();
        emit decelerationChanged(deceleration);
    }
}

} // Qt3DExtras

QT_END_NAMESPACE

#include "moc_qfirstpersoncameracontroller.cpp"