////  EntitySimulation.h//  libraries/entities/src////  Created by Andrew Meadows on 2014.11.24//  Copyright 2014 High Fidelity, Inc.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html// #ifndef hifi_EntitySimulation_h#define hifi_EntitySimulation_h #include <limits>#include <unordered_set> #include <QtCore/QObject>#include <QVector> #include <PerfStat.h> #include "EntityItem.h"#include "EntityTree.h" using EntitySimulationPointer = std::shared_ptr<EntitySimulation>;using VectorOfEntities = QVector<EntityItemPointer>; // the EntitySimulation needs to know when these things change on an entity,// so it can sort EntityItem or relay its state to the PhysicsEngine.const int DIRTY_SIMULATION_FLAGS =        Simulation::DIRTY_POSITION |        Simulation::DIRTY_ROTATION |        Simulation::DIRTY_LINEAR_VELOCITY |        Simulation::DIRTY_ANGULAR_VELOCITY |        Simulation::DIRTY_MASS |        Simulation::DIRTY_COLLISION_GROUP |        Simulation::DIRTY_MOTION_TYPE |        Simulation::DIRTY_SHAPE |        Simulation::DIRTY_LIFETIME |        Simulation::DIRTY_UPDATEABLE |        Simulation::DIRTY_MATERIAL |        Simulation::DIRTY_SIMULATOR_ID; class EntitySimulation : public QObject, public std::enable_shared_from_this<EntitySimulation> {public:    EntitySimulation() : _mutex(), _nextExpiry(std::numeric_limits<uint64_t>::max()), _entityTree(nullptr) { }    virtual ~EntitySimulation() { setEntityTree(nullptr); }     inline EntitySimulationPointer getThisPointer() const {        return std::const_pointer_cast<EntitySimulation>(shared_from_this());    }     /// \param tree pointer to EntityTree which is stored internally    void setEntityTree(EntityTreePointer tree);     virtual void updateEntities();     // FIXME: remove these    virtual void addDynamic(EntityDynamicPointer dynamic) {}    virtual void removeDynamic(const QUuid dynamicID) {}    virtual void applyDynamicChanges() {};     /// \param entity pointer to EntityItem to be added    /// \sideeffect sets relevant backpointers in entity, but maybe later when appropriate data structures are locked    void addEntity(EntityItemPointer entity);     /// \param entity pointer to EntityItem that may have changed in a way that would affect its simulation    /// call this whenever an entity was changed from some EXTERNAL event (NOT by the EntitySimulation itself)    void changeEntity(EntityItemPointer entity);     virtual void clearEntities();     void moveSimpleKinematics(uint64_t now);     EntityTreePointer getEntityTree() { return _entityTree; }     virtual void prepareEntityForDelete(EntityItemPointer entity);     void processChangedEntities();    virtual void queueEraseDomainEntity(const QUuid& id) const { } protected:    virtual void addEntityToInternalLists(EntityItemPointer entity);    virtual void removeEntityFromInternalLists(EntityItemPointer entity);    virtual void processChangedEntity(const EntityItemPointer& entity);    virtual void processDeadEntities();     void expireMortalEntities(uint64_t now);    void callUpdateOnEntitiesThatNeedIt(uint64_t now);    virtual void sortEntitiesThatMoved();     QRecursiveMutex _mutex;     SetOfEntities _entitiesToSort; // entities moved by simulation (and might need resort in EntityTree)    SetOfEntities _simpleKinematicEntities; // entities undergoing non-colliding kinematic motion    SetOfEntities _deadEntitiesToRemoveFromTree; private:    void moveSimpleKinematics();     // We maintain multiple lists, each for its distinct purpose.    // An entity may be in more than one list.    std::unordered_set<EntityItemPointer> _changedEntities; // all changes this frame    SetOfEntities _allEntities; // tracks all entities added the simulation    SetOfEntities _entitiesToUpdate; // entities that need to call EntityItem::update()    SetOfEntities _mortalEntities; // entities that have an expiry    uint64_t _nextExpiry;     // back pointer to EntityTree structure    EntityTreePointer _entityTree;}; #endif // hifi_EntitySimulation_h