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  ** Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
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  ** This file is part of the Qt3D module of the Qt Toolkit.
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  ****************************************************************************/
  
  #ifndef QT3DRENDER_RENDER_SPHERE_H
  #define QT3DRENDER_RENDER_SPHERE_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 <Qt3DRender/private/qt3drender_global_p.h>
  #include <Qt3DCore/qnodeid.h>
  #include <Qt3DCore/private/matrix4x4_p.h>
  #include <Qt3DRender/private/boundingsphere_p.h>
  
  #include <QMatrix4x4>
  
  QT_BEGIN_NAMESPACE
  
  namespace Qt3DRender {
  
  namespace Render {
  
  class Q_3DRENDERSHARED_PRIVATE_EXPORT Sphere : public RayCasting::BoundingSphere
  {
  public:
      inline Sphere(Qt3DCore::QNodeId i = Qt3DCore::QNodeId())
          : m_center()
          , m_radius(-1.0f)
          , m_id(i)
      {}
  
      inline Sphere(const Vector3D &c, float r, Qt3DCore::QNodeId i = Qt3DCore::QNodeId())
          : m_center(c)
          , m_radius(r)
          , m_id(i)
      {}
  
      void setCenter(const Vector3D &c);
      Vector3D center() const override;
  
      bool isNull() const { return m_center == Vector3D() && m_radius == -1.0f; }
  
      void setRadius(float r);
      float radius() const override;
  
      void clear();
      void initializeFromPoints(const QVector<Vector3D> &points);
      void expandToContain(const Vector3D &point);
      inline void expandToContain(const QVector<Vector3D> &points)
      {
          for (const Vector3D &p : points)
              expandToContain(p);
      }
  
      void expandToContain(const Sphere &sphere);
  
      Sphere transformed(const Matrix4x4 &mat) const;
      inline Sphere &transform(const Matrix4x4 &mat)
      {
          *this = transformed(mat);
          return *this;
      }
  
      Qt3DCore::QNodeId id() const final;
      bool intersects(const RayCasting::QRay3D &ray, Vector3D *q, Vector3D *uvw = nullptr) const final;
      Type type() const final;
  
      static Sphere fromPoints(const QVector<Vector3D> &points);
  
  private:
      Vector3D m_center;
      float m_radius;
      Qt3DCore::QNodeId m_id;
  
      static const float ms_epsilon;
  };
  
  inline void Sphere::setCenter(const Vector3D &c)
  {
      m_center = c;
  }
  
  inline Vector3D Sphere::center() const
  {
      return m_center;
  }
  
  inline void Sphere::setRadius(float r)
  {
      Q_ASSERT(r >= 0.0f);
      if (r >= 0.0f)
          m_radius = r;
  }
  
  inline float Sphere::radius() const
  {
      return m_radius;
  }
  
  inline void Sphere::clear()
  {
      m_center = Vector3D();
      m_radius = -1.0f;
  }
  
  inline bool intersects(const Sphere &a, const Sphere &b)
  {
      if (a.isNull() || b.isNull())
          return false;
  
      // Calculate squared distance between sphere centers
      const Vector3D d = a.center() - b.center();
      const float distSq = Vector3D::dotProduct(d, d);
  
      // Spheres intersect if squared distance is less than squared
      // sum of radii
      const float sumRadii = a.radius() + b.radius();
      return distSq <= sumRadii * sumRadii;
  }
  
  #ifndef QT_NO_DEBUG_STREAM
  Q_3DRENDERSHARED_EXPORT QDebug operator<<(QDebug dbg, const Sphere &sphere);
  #endif
  
  } // Render
  
  } // Qt3DRender
  
  QT_END_NAMESPACE
  
  Q_DECLARE_METATYPE(Qt3DRender::Render::Sphere) // LCOV_EXCL_LINE
  
  #endif // QT3DRENDER_RENDER_SPHERE_H
  