landscape_face_vector_manager.cpp

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/* Copyright, 2001 Nevrax Ltd.
 *
 * This file is part of NEVRAX NEL.
 * NEVRAX NEL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.

 * NEVRAX NEL is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with NEVRAX NEL; see the file COPYING. If not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#include "std3d.h"

#include "nel/3d/landscape_face_vector_manager.h"
#include "nel/misc/debug.h"


using namespace std;
using namespace NLMISC;


namespace NL3D
{


// ***************************************************************************
#define NL3D_FACE_VECTOR_NUMBLOCK   33

// ***************************************************************************
CLandscapeFaceVectorManager::CLandscapeFaceVectorManager()
{
    // Allow 2^32 triangles at max. each list has at max 2^i triangles.
    _Blocks.resize(NL3D_FACE_VECTOR_NUMBLOCK, NULL);
}

// ***************************************************************************
CLandscapeFaceVectorManager::~CLandscapeFaceVectorManager()
{
    purge();
}

// ***************************************************************************
void                    CLandscapeFaceVectorManager::purge()
{
    for(uint i=0; i<NL3D_FACE_VECTOR_NUMBLOCK; i++)
    {
        TLandscapeIndexType *ptr= _Blocks[i];
        // For each node in list, delete.
        while(ptr)
        {
            // Get the ptr on next free list.
            TLandscapeIndexType *next= *(TLandscapeIndexType**)ptr;
            delete []  ptr;
            ptr= next;
        }
        // list is empty.
        _Blocks[i]= NULL;
    }
}

// ***************************************************************************
uint    CLandscapeFaceVectorManager::getBlockIdFromNumTri(uint numTris)
{
    return getPowerOf2(numTris);
}

// ***************************************************************************
TLandscapeIndexType *CLandscapeFaceVectorManager::createFaceVector(uint numTri)
{
    // get the BlockId from the number of tri in this fv
    uint    blockId= getBlockIdFromNumTri(numTri);

    // If no more free FaceVector, allocate.
    if(_Blocks[blockId]==NULL)
    {
        // Allocate a block of max tris. +1 is for the NumTris entry at index 0.
        uint    numTriMax= 1<<blockId;
        // allocate max of (sizeof(uint32*), (numTriMax*3+1)*sizeof(uint32));
        uint    sizeInByteToAllocate= max(sizeof(TLandscapeIndexType*), (numTriMax*3 + 1)*sizeof(TLandscapeIndexType));
        _Blocks[blockId]= new TLandscapeIndexType[(sizeInByteToAllocate + (sizeof(TLandscapeIndexType) - 1)) /sizeof(TLandscapeIndexType)];
        // Init it as a free faceVector, with no Next.
        *(TLandscapeIndexType**)_Blocks[blockId]= NULL;
    }

    // Pop a FaceVector from the free list.
    TLandscapeIndexType     *ret= _Blocks[blockId];
    // Make the head list point to next
    _Blocks[blockId]= *(TLandscapeIndexType**)ret;

    // There is numTri triangles.
    *ret= numTri;

    return ret;
}

// ***************************************************************************
void                    CLandscapeFaceVectorManager::deleteFaceVector(TLandscapeIndexType   *fv)
{
    // get the BlockId from the number of tri in this fv (ie *fv)
    uint    blockId= getBlockIdFromNumTri(*fv);

    // Append this block to the free list. Write the ptr directly on fv.
    *(TLandscapeIndexType**)fv= _Blocks[blockId];
    _Blocks[blockId]= fv;
}


} // NL3D