nrg_snapshot.h

Go to the documentation of this file.

/*
  LibNRG - Networking for Real-time Games
  
  Copyright (C) 2012-2014 Alex Baines <alex@abaines.me.uk>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#ifndef NRG_SNAPSHOT_H
#define NRG_SNAPSHOT_H
#include "nrg_core.h"
#include "nrg_entity.h"
#include "nrg_event.h"
#include "nrg_ringbuffer.h"
#include <functional>
#include <vector>
#include <map>

namespace nrg {

class Snapshot {
public:
    Snapshot();
    Snapshot(uint16_t id);
    uint16_t getID() const { return id; }
    void setID(uint16_t id){ this->id = id; }
    void addEntity(Entity* e);
    void removeEntityById(uint16_t id);
    void writeToPacket(Packet& p) const;
    void reset();
private:
    struct EntityData {
        uint16_t eid, etype;
        std::vector<size_t> field_sizes;
        Packet field_data;
        off_t getFieldOffset(int num) const;
        size_t getTotalBytes() const;
    };
    uint16_t id;
    std::map<uint16_t, EntityData> edata;
    Packet buffer;
};

struct DeltaSnapshot {
    DeltaSnapshot() : DeltaSnapshot(0){}
    DeltaSnapshot(int i);
    uint16_t getID() const { return id; }
    void setID(uint16_t id){ this->id = id; }
    void addEntity(Entity* e);
    void removeEntityById(uint16_t id);
    void mergeWithNext(const DeltaSnapshot& next);
    void writeToPacket(Packet& p) const;
    void reset();
private:
    struct  FieldInfo {
        uint16_t entity;
        uint16_t number;
        size_t size;
        size_t offset;
        const uint8_t* get(const Packet& p) const {
            return p.getBasePointer() + offset;
        }
        bool operator<(uint16_t v) const { return entity < v; }
        bool operator==(uint16_t v) const { return entity == v; }
    };
    struct  EntityInfo {
        size_t num_fields;
        uint16_t id;
        uint16_t type;
        bool full;
        bool operator<(const EntityInfo& other) const { return id < other.id; }
        bool operator==(const EntityInfo& other) const { return id == other.id; }
        bool operator==(uint16_t v) const { return id == v; }
    };
    
    uint16_t id;
    std::vector<EntityInfo> entities;
    std::vector<FieldInfo> fields, tmp_fields;
    size_t full_count, del_count, upd_count;
    Packet field_data, buffer;
};

struct ClientSnapshot {
    enum class Action { Get, Create, Destroy, Update };
    typedef std::function<Entity*(Action, uint16_t eid, uint16_t etype)> CSnapFunc;

    bool readFromPacket(Packet& p, const CSnapFunc& f);
};

typedef RingBuffer<DeltaSnapshot, NRG_NUM_PAST_SNAPSHOTS> DeltaSnapshotBuffer;

}

#endif