OgreTerrainLodManager.h

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/*
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This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2013 Torus Knot Software Ltd

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all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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THE SOFTWARE.
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*/

#ifndef __Ogre_TerrainLodManager_H__
#define __Ogre_TerrainLodManager_H__

#include "OgreTerrainPrerequisites.h"
#include "OgreWorkQueue.h"


namespace Ogre
{
    class Terrain;
    class _OgreTerrainExport TerrainLodManager : public WorkQueue::RequestHandler, public WorkQueue::ResponseHandler, public TerrainAlloc
    {
    public:
        static const uint32 TERRAINLODDATA_CHUNK_ID;
        static const uint16 TERRAINLODDATA_CHUNK_VERSION;
        typedef vector<float>::type LodData;
        typedef vector<LodData>::type LodsData;

        struct LoadLodRequest
        {
            LoadLodRequest( TerrainLodManager* r, uint16 preparedLod, uint16 loadedLod, uint16 target )
                : requestee(r)
                , currentPreparedLod(preparedLod)
                , currentLoadedLod(loadedLod)
                , requestedLod(target)
            {
            }
            TerrainLodManager* requestee;
            uint16 currentPreparedLod;
            uint16 currentLoadedLod;
            uint16 requestedLod;
            _OgreTerrainExport friend std::ostream& operator<<(std::ostream& o, const LoadLodRequest& r)
            { return o; }
        };

        struct LodInfo
        {
            uint treeStart;
            uint treeEnd;
            bool isLast;
            uint16 resolution;
            uint size;
        };
    public:
        TerrainLodManager(Terrain* t, DataStreamPtr& stream);
        TerrainLodManager(Terrain* t, const String& filename = "");
        virtual ~TerrainLodManager();

        static const uint16 WORKQUEUE_LOAD_LOD_DATA_REQUEST;
        virtual bool canHandleRequest(const WorkQueue::Request* req, const WorkQueue* srcQ);
        virtual bool canHandleResponse(const WorkQueue::Response* res, const WorkQueue* srcQ);
        virtual WorkQueue::Response* handleRequest(const WorkQueue::Request* req, const WorkQueue* srcQ);
        virtual void handleResponse(const WorkQueue::Response* res, const WorkQueue* srcQ);

        void updateToLodLevel(int lodLevel, bool synchronous = false);
        static void saveLodData(StreamSerialiser& stream, Terrain* terrain);

        void fillBufferAtLod(uint lodLevel, const float* data, uint dataSize );
        void readLodData(uint16 lowerLodBound, uint16 higherLodBound);
        void waitForDerivedProcesses();

        int getHighestLodPrepared(){ return mHighestLodPrepared; }
        int getHighestLodLoaded(){ return mHighestLodLoaded; }
        int getTargetLodLevel(){ return mTargetLodLevel; }

        LodInfo& getLodInfo(uint lodLevel)
        {
            if(!mLodInfoTable)
                buildLodInfoTable();
            return mLodInfoTable[lodLevel];
        }
    private:
        void init();
        void buildLodInfoTable();

        static void separateData(float* data, uint16 size, uint16 numLodLevels, LodsData& lods );
    private:
        Terrain* mTerrain;
        DataStreamPtr mDataStream;
        size_t mStreamOffset;
        uint16 mWorkQueueChannel;

        LodInfo* mLodInfoTable;
        int mTargetLodLevel;    
        int mHighestLodPrepared;  
        int mHighestLodLoaded;  

        bool mIncreaseLodLevelInProgress;  
        bool mLastRequestSynchronous;
    };
}

#endif