// Copyright (C) 2019 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

#include "qquick3dperspectivecamera_p.h"

#include <QtQuick3DRuntimeRender/private/qssgrendercamera_p.h>

#include <QtMath>
#include <QtQuick3DUtils/private/qssgutils_p.h>

#include "qquick3dutils_p.h"

#include "qquick3dnode_p_p.h"

QT_BEGIN_NAMESPACE

/*!
    \qmltype PerspectiveCamera
    \inherits Camera
    \inqmlmodule QtQuick3D
    \brief Defines a Perspective Camera for viewing the content of a 3D scene.

    A \l Camera defines how the content of the 3D scene is projected onto a 2D surface,
    such as a View3D. A scene needs at least one \l Camera in order to visualize its
    contents.

    It is possible to position and rotate the \l Camera like any other spatial \l{QtQuick3D::Node}{Node} in
    the scene. The \l{QtQuick3D::Node}{Node}'s location and orientation determines where the \l Camera is in
    the scene, and what direction it is facing. The default orientation of the \l Camera
    has its forward vector pointing along the negative Z axis and its up vector along
    the positive Y axis.

    \image perspectivecamera.png

    PerspectiveCamera is the standard \l Camera type. It gives a realistic projection of the
    scene, where distant objects are perceived as smaller. The frustum is defined by
    the fieldOfView property as well as near and far clip planes.

    The following example creates a PerspectiveCamera at position [0, 200, 300] in the scene, a
    field of view of 90 degrees and with a 30 degree downward pitch.
    \code
    PerspectiveCamera {
        position: Qt.vector3d(0, 200, 300)
        eulerRotation.x: -30
        fieldOfView: 90
    }
    \endcode

    \sa {Qt Quick 3D - View3D Example}, OrthographicCamera, FrustumCamera, CustomCamera
*/

/*!
    \internal
*/
QQuick3DPerspectiveCamera::QQuick3DPerspectiveCamera(QQuick3DNodePrivate &dd, QQuick3DNode *parent)
    : QQuick3DCamera(dd, parent)
{}

/*!
    \internal
*/
QQuick3DPerspectiveCamera::QQuick3DPerspectiveCamera(QQuick3DNode *parent)
    : QQuick3DPerspectiveCamera(*(new QQuick3DNodePrivate(QQuick3DNodePrivate::Type::PerspectiveCamera)), parent)
{}

/*!
    \qmlproperty real PerspectiveCamera::clipNear

    This property defines the near clip plane of the PerspectiveCamera's frustum. Geometry which
    is closer to the \l Camera than the near clip plane will not be visible.

    The default value is 10.0. The unit depends on the user's geometry units,
    and the value is relative to the global camera position.
*/

float QQuick3DPerspectiveCamera::clipNear() const
{
    return m_clipNear;
}

/*!
    \qmlproperty real PerspectiveCamera::clipFar

    This property defines the far clip plane of the PerspectiveCamera's frustum. Geometry which
    is further away from the \l Camera than the far clip plane will not be visible.

    The default value is 10000.0. The unit depends on the user's geometry units,
    and the value is relative to the global camera position.
*/

float QQuick3DPerspectiveCamera::clipFar() const
{
    return m_clipFar;
}

/*!
   \qmlproperty enumeration PerspectiveCamera::fieldOfViewOrientation

   This property holds the orientation in which camera field of view is given.

   \value PerspectiveCamera.Vertical
          The provided field of view is vertical, meaning the field of view is the angle between
          the line traced from the camera to the center top of the viewport and the line from
          the camera to the center bottom of the viewport. The horizontal aspect ratio will be
          adjusted to maintain aspect ratio.
   \value PerspectiveCamera.Horizontal
          The provided field of view is horizontal, meaning the field of view is the angle between
          the line traced from the camera to the center left side of the viewport and the line from
          the camera to the center right side of the viewport. The vertical aspect ratio will be
          adjusted to maintain aspect ratio.


   The default value is \c {PerspectiveCamera.Vertical}.
 */

/*!
    \qmlproperty real PerspectiveCamera::fieldOfView

    This property holds the field of view of the camera in degrees. This can be either the
    vertical or horizontal field of view depending on whether the fieldOfViewOrientation property
    is set to \c {PerspectiveCamera.Vertical} or \c {PerspectiveCamera.Horizontal}.

    The default value is 60.0.
 */

float QQuick3DPerspectiveCamera::fieldOfView() const
{
    return m_fieldOfView;
}

QQuick3DPerspectiveCamera::FieldOfViewOrientation QQuick3DPerspectiveCamera::fieldOfViewOrientation() const
{
    return m_fieldOfViewOrientation;
}

void QQuick3DPerspectiveCamera::setClipNear(float clipNear)
{
    if (qFuzzyCompare(m_clipNear, clipNear))
        return;

    m_clipNear = clipNear;
    emit clipNearChanged();
    update();
}

void QQuick3DPerspectiveCamera::setClipFar(float clipFar)
{
    if (qFuzzyCompare(m_clipFar, clipFar))
        return;

    m_clipFar = clipFar;
    emit clipFarChanged();
    update();
}

void QQuick3DPerspectiveCamera::setFieldOfView(float fieldOfView)
{
    if (qFuzzyCompare(m_fieldOfView, fieldOfView))
        return;

    m_fieldOfView = fieldOfView;
    emit fieldOfViewChanged();
    update();
}

void QQuick3DPerspectiveCamera::setFieldOfViewOrientation(QQuick3DPerspectiveCamera::FieldOfViewOrientation
                                                          fieldOfViewOrientation)
{
    if (m_fieldOfViewOrientation == fieldOfViewOrientation)
        return;

    m_fieldOfViewOrientation = fieldOfViewOrientation;
    emit fieldOfViewOrientationChanged();
    update();
}

QSSGRenderGraphObject *QQuick3DPerspectiveCamera::updateSpatialNode(QSSGRenderGraphObject *node)
{
    QSSGRenderCamera *camera = static_cast<QSSGRenderCamera *>(QQuick3DCamera::updateSpatialNode(node));
    if (camera) {
        QSSGRenderCamera::FieldOfView fov;
        switch (m_fieldOfViewOrientation) {
        case QQuick3DPerspectiveCamera::Vertical:
            fov = QSSGRenderCamera::FieldOfView::fromDegrees(m_fieldOfView);
            break;
        case QQuick3DPerspectiveCamera::Horizontal:
            fov = QSSGRenderCamera::FieldOfView::fromDegrees<QSSGRenderCamera::FieldOfView::Orientation::Horizontal>(m_fieldOfView);
            break;
        }

        const bool changed = ((int(qUpdateIfNeeded(camera->clipPlanes, {m_clipNear, m_clipFar}))
                               | int(qUpdateIfNeeded(camera->fov, fov))) != 0);
        if (changed)
            camera->markDirty(QSSGRenderCamera::DirtyFlag::CameraDirty);
    }

    return camera;
}

QT_END_NAMESPACE
