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#ifndef QT3DRENDER_RENDER_PICKBOUNDINGVOLUMEUTILS_H
#define QT3DRENDER_RENDER_PICKBOUNDINGVOLUMEUTILS_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of other Qt classes.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <Qt3DCore/QNodeId>
#include <Qt3DRender/private/qray3d_p.h>
#include <Qt3DRender/private/trianglesvisitor_p.h>
#include <Qt3DRender/private/qraycastingservice_p.h>


QT_BEGIN_NAMESPACE

class QSurface;

namespace Qt3DRender {
namespace RayCasting {
class QAbstractCollisionQueryService;
}

namespace Render {

class Entity;
class Renderer;
class FrameGraphNode;

namespace PickingUtils {

struct Q_AUTOTEST_EXPORT ViewportCameraAreaDetails
{
    Qt3DCore::QNodeId cameraId;
    QRectF viewport;
    QSize area;
    QSurface *surface = nullptr;
};
QT3D_DECLARE_TYPEINFO_3(Qt3DRender, Render, PickingUtils, ViewportCameraAreaDetails, Q_PRIMITIVE_TYPE)

class Q_AUTOTEST_EXPORT ViewportCameraAreaGatherer
{
public:
    ViewportCameraAreaGatherer(const Qt3DCore::QNodeId &nodeId = Qt3DCore::QNodeId()) : m_targetCamera(nodeId) { }
    QVector<ViewportCameraAreaDetails> gather(FrameGraphNode *root);

private:
    Qt3DCore::QNodeId m_targetCamera;
    QVector<FrameGraphNode *> m_leaves;

    void visit(FrameGraphNode *node);
    ViewportCameraAreaDetails gatherUpViewportCameraAreas(Render::FrameGraphNode *node) const;
    bool isUnique(const QVector<ViewportCameraAreaDetails> &vcaList, const ViewportCameraAreaDetails &vca) const;
};

class Q_AUTOTEST_EXPORT EntityGatherer
{
public:
    explicit EntityGatherer(Entity *root);

    QVector<Entity *> entities() const;

private:
    Entity *m_root;
    mutable QVector<Entity *> m_entities;
    mutable bool m_needsRefresh;
};

class Q_AUTOTEST_EXPORT CollisionVisitor : public TrianglesVisitor
{
public:
    typedef QVector<RayCasting::QCollisionQueryResult::Hit> HitList;
    HitList hits;

    CollisionVisitor(NodeManagers* manager, const Entity *root, const RayCasting::QRay3D& ray,
                     bool frontFaceRequested, bool backFaceRequested)
        : TrianglesVisitor(manager), m_root(root), m_ray(ray), m_triangleIndex(0)
        , m_frontFaceRequested(frontFaceRequested), m_backFaceRequested(backFaceRequested)
    {
    }

private:
    const Entity *m_root;
    RayCasting::QRay3D m_ray;
    uint m_triangleIndex;
    bool m_frontFaceRequested;
    bool m_backFaceRequested;

    void visit(uint andx, const QVector3D &a,
               uint bndx, const QVector3D &b,
               uint cndx, const QVector3D &c) Q_DECL_OVERRIDE;
    bool intersectsSegmentTriangle(uint andx, const QVector3D &a,
                                   uint bndx, const QVector3D &b,
                                   uint cndx, const QVector3D &c);
};

class Q_AUTOTEST_EXPORT HierarchicalEntityPicker
{
public:
    explicit HierarchicalEntityPicker(const RayCasting::QRay3D &ray);

    bool collectHits(Entity *root);
    inline CollisionVisitor::HitList hits() const { return m_hits; }
    inline QVector<Entity *> entities() const { return m_entities; }

private:
    RayCasting::QRay3D m_ray;
    CollisionVisitor::HitList m_hits;
    QVector<Entity *> m_entities;
};

struct Q_AUTOTEST_EXPORT AbstractCollisionGathererFunctor
{
    AbstractCollisionGathererFunctor();
    virtual ~AbstractCollisionGathererFunctor();

    NodeManagers *m_manager;
    RayCasting::QRay3D m_ray;

    // This define is required to work with QtConcurrent
    typedef CollisionVisitor::HitList result_type;
    result_type operator ()(const Entity *entity) const;
    virtual result_type pick(RayCasting::QAbstractCollisionQueryService *rayCasting, const Entity *entity) const = 0;

    static void sortHits(CollisionVisitor::HitList &results);
};

struct Q_AUTOTEST_EXPORT EntityCollisionGathererFunctor : public AbstractCollisionGathererFunctor
{
    result_type pick(RayCasting::QAbstractCollisionQueryService *rayCasting, const Entity *entity) const Q_DECL_OVERRIDE;
};

struct Q_AUTOTEST_EXPORT TriangleCollisionGathererFunctor : public AbstractCollisionGathererFunctor
{
    bool m_frontFaceRequested;
    bool m_backFaceRequested;

    result_type pick(RayCasting::QAbstractCollisionQueryService *rayCasting, const Entity *entity) const Q_DECL_OVERRIDE;

    bool rayHitsEntity(RayCasting::QAbstractCollisionQueryService *rayCasting, const Entity *entity) const;
};

Q_AUTOTEST_EXPORT QVector<Entity *> gatherEntities(Entity *entity, QVector<Entity *> entities);

Q_AUTOTEST_EXPORT CollisionVisitor::HitList reduceToFirstHit(CollisionVisitor::HitList &result, const CollisionVisitor::HitList &intermediate);

// Unordered
Q_AUTOTEST_EXPORT CollisionVisitor::HitList reduceToAllHits(CollisionVisitor::HitList &results, const CollisionVisitor::HitList &intermediate);

} // PickingUtils

} // Render

} // Qt3DRender

QT_END_NAMESPACE

#endif // QT3DRENDER_RENDER_PICKBOUNDINGVOLUMEUTILS_H