source: downloads/OgreMain/src/OgreProgressiveMesh.cpp @ 6

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

Copyright (c) 2000-2006 Torus Knot Software Ltd
Also see acknowledgements in Readme.html

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.

You may alternatively use this source under the terms of a specific version of
the OGRE Unrestricted License provided you have obtained such a license from
Torus Knot Software Ltd.
-----------------------------------------------------------------------------
*/
#include "OgreStableHeaders.h"

// The algorithm in this file is based heavily on:
/*
*  Progressive Mesh type Polygon Reduction Algorithm
*  by Stan Melax (c) 1998
*/

#include "OgreProgressiveMesh.h"
#include "OgreString.h"
#include "OgreHardwareBufferManager.h"
#include <algorithm>

#include <iostream>

#if OGRE_DEBUG_MODE 
std::ofstream ofdebug;
#endif 

namespace Ogre {
        #define NEVER_COLLAPSE_COST 99999.9f


    /** Comparator for unique vertex list
    */
    struct vectorLess
    {
                _OgreExport bool operator()(const Vector3& v1, const Vector3& v2) const
        {
                        if (v1.x < v2.x) return true;
                        if (v1.x == v2.x && v1.y < v2.y) return true;
                        if (v1.x == v2.x && v1.y == v2.y && v1.z < v2.z) return true;

                        return false;
                }
        };
    //---------------------------------------------------------------------
    ProgressiveMesh::ProgressiveMesh(const VertexData* vertexData, 
        const IndexData* indexData)
    {
        addWorkingData(vertexData, indexData);
        mpVertexData = vertexData;
        mpIndexData = indexData;
        mWorstCosts.resize(vertexData->vertexCount);



    }
    //---------------------------------------------------------------------
    ProgressiveMesh::~ProgressiveMesh()
    {
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::addExtraVertexPositionBuffer(const VertexData* vertexData)
    {
        addWorkingData(vertexData, mpIndexData);
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::build(ushort numLevels, LODFaceList* outList, 
                        VertexReductionQuota quota, Real reductionValue)
    {
        IndexData* newLod;

        computeAllCosts();

#if OGRE_DEBUG_MODE
                dumpContents("pm_before.log");
#endif

        // Init
        mCurrNumIndexes = mpIndexData->indexCount;
        size_t numVerts, numCollapses;
        // Use COMMON vert count, not original vert count
        // Since collapsing 1 common vert position is equivalent to collapsing them all
        numVerts = mNumCommonVertices;
                
#if OGRE_DEBUG_MODE 
                ofdebug.open("progressivemesh.log");
#endif
                numCollapses = 0;
                bool abandon = false;
                while (numLevels--)
        {
            // NB idf 'abandon' is set, we stop reducing 
            // However, we still bake the number of LODs requested, even if it 
            // means they are the same
            if (!abandon)
            {
                            if (quota == VRQ_PROPORTIONAL)
                            {
                                    numCollapses = static_cast<size_t>(numVerts * reductionValue);
                            }
                            else 
                            {
                                    numCollapses = static_cast<size_t>(reductionValue);
                            }
                // Minimum 3 verts!
                if ( (numVerts - numCollapses) < 3) 
                    numCollapses = numVerts - 3;
                            // Store new number of verts
                            numVerts = numVerts - numCollapses;

                            while(numCollapses-- && !abandon)
                {
                    size_t nextIndex = getNextCollapser();
                    // Collapse on every buffer
                    WorkingDataList::iterator idata, idataend;
                    idataend = mWorkingData.end();
                    for (idata = mWorkingData.begin(); idata != idataend; ++idata)
                    {
                        PMVertex* collapser = &( idata->mVertList.at( nextIndex ) );
                        // This will reduce mCurrNumIndexes and recalc costs as required
                                            if (collapser->collapseTo == NULL)
                                            {
                                                    // Must have run out of valid collapsables
                                                    abandon = true;
                                                    break;
                                            }
#if OGRE_DEBUG_MODE 
                                            ofdebug << "Collapsing index " << (unsigned int)collapser->index << "(border: "<< collapser->isBorder() <<
                                                    ") to " << (unsigned int)collapser->collapseTo->index << "(border: "<< collapser->collapseTo->isBorder() <<
                                                    ")" << std::endl;
#endif
                                            assert(collapser->collapseTo->removed == false);

                        collapse(collapser);
                    }

                }
            }
#if OGRE_DEBUG_MODE
                        StringUtil::StrStreamType logname;
                        logname << "pm_level" << numLevels << ".log";
                        dumpContents(logname.str());
#endif

            // Bake a new LOD and add it to the list
            newLod = new IndexData();
            bakeNewLOD(newLod);
            outList->push_back(newLod);
                        
        }



    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::addWorkingData(const VertexData * vertexData, 
        const IndexData * indexData)
    {
        // Insert blank working data, then fill 
        mWorkingData.push_back(PMWorkingData());

        PMWorkingData& work = mWorkingData.back();

        // Build vertex list
                // Resize face list (this will always be this big)
                work.mFaceVertList.resize(vertexData->vertexCount);
                // Also resize common vert list to max, to avoid reallocations
                work.mVertList.resize(vertexData->vertexCount);

                // locate position element & hte buffer to go with it
                const VertexElement* posElem = vertexData->vertexDeclaration->findElementBySemantic(VES_POSITION);
                HardwareVertexBufferSharedPtr vbuf = 
                        vertexData->vertexBufferBinding->getBuffer(posElem->getSource());
                // lock the buffer for reading
                unsigned char* pVertex = static_cast<unsigned char*>(
                        vbuf->lock(HardwareBuffer::HBL_READ_ONLY));
                float* pFloat;
                Vector3 pos;
                // Map for identifying duplicate position vertices
                typedef std::map<Vector3, size_t, vectorLess> CommonVertexMap;
                CommonVertexMap commonVertexMap;
                CommonVertexMap::iterator iCommonVertex;
                size_t numCommon = 0;
        size_t i = 0;
        for (i = 0; i < vertexData->vertexCount; ++i, pVertex += vbuf->getVertexSize())
        {
                        posElem->baseVertexPointerToElement(pVertex, &pFloat);

            pos.x = *pFloat++;
            pos.y = *pFloat++;
            pos.z = *pFloat++;

                        // Try to find this position in the existing map 
                        iCommonVertex = commonVertexMap.find(pos);
                        if (iCommonVertex == commonVertexMap.end())
                        {
                                // Doesn't exist, so create it
                                PMVertex* commonVert = &(work.mVertList[numCommon]);
                                commonVert->setDetails(pos, numCommon);
                                commonVert->removed = false;
                                commonVert->toBeRemoved = false;
                                commonVert->seam = false;

                                // Enter it in the map
                                commonVertexMap.insert(CommonVertexMap::value_type(pos, numCommon) );
                                // Increment common index
                                ++numCommon;

                                work.mFaceVertList[i].commonVertex = commonVert;
                                work.mFaceVertList[i].realIndex = i;
                        }
                        else
                        {
                                // Exists already, reference it
                                PMVertex* existingVert = &(work.mVertList[iCommonVertex->second]);
                                work.mFaceVertList[i].commonVertex = existingVert;
                                work.mFaceVertList[i].realIndex = i;

                                // Also tag original as a seam since duplicates at this location
                                work.mFaceVertList[i].commonVertex->seam = true;

                        }
                        
        }
                vbuf->unlock();

                mNumCommonVertices = numCommon;

        // Build tri list
        size_t numTris = indexData->indexCount / 3;
                unsigned short* pShort;
                unsigned int* pInt;
                HardwareIndexBufferSharedPtr ibuf = indexData->indexBuffer;
                bool use32bitindexes = (ibuf->getType() == HardwareIndexBuffer::IT_32BIT);
                if (use32bitindexes)
                {
                        pInt = static_cast<unsigned int*>(
                                ibuf->lock(HardwareBuffer::HBL_READ_ONLY));
                }
                else
                {
                        pShort = static_cast<unsigned short*>(
                                ibuf->lock(HardwareBuffer::HBL_READ_ONLY));
                }
        work.mTriList.resize(numTris); // assumed tri list
        for (i = 0; i < numTris; ++i)
        {
                        PMFaceVertex *v0, *v1, *v2;
                        // use 32-bit index always since we're not storing
                        unsigned int vindex = use32bitindexes? *pInt++ : *pShort++;
                        v0 = &(work.mFaceVertList[vindex]);
                        vindex = use32bitindexes? *pInt++ : *pShort++;
                        v1 = &(work.mFaceVertList[vindex]);
                        vindex = use32bitindexes? *pInt++ : *pShort++;
                        v2 = &(work.mFaceVertList[vindex]);

                        work.mTriList[i].setDetails(i, v0, v1, v2);

            work.mTriList[i].removed = false;

        }
                ibuf->unlock();

    }
    //---------------------------------------------------------------------
    Real ProgressiveMesh::computeEdgeCollapseCost(PMVertex *src, PMVertex *dest)
    {
        // if we collapse edge uv by moving src to dest then how 
        // much different will the model change, i.e. how much "error".
        // The method of determining cost was designed in order 
        // to exploit small and coplanar regions for
        // effective polygon reduction.
        Vector3 edgeVector = src->position - dest->position;

        Real cost;
                Real curvature = 0.001f;

        // find the "sides" triangles that are on the edge uv
        PMVertex::FaceList sides;
        PMVertex::FaceList::iterator srcface, srcfaceEnd;
        srcfaceEnd = src->face.end();
        // Iterate over src's faces and find 'sides' of the shared edge which is being collapsed
        for(srcface = src->face.begin(); srcface != srcfaceEnd; ++srcface)
        {
            // Check if this tri also has dest in it (shared edge)
            if( (*srcface)->hasCommonVertex(dest) )
            {
                sides.insert(*srcface);
            }
        }

                // Special cases
                // If we're looking at a border vertex
        if(src->isBorder())
        {
                        if (sides.size() > 1) 
                        {
                                // src is on a border, but the src-dest edge has more than one tri on it
                                // So it must be collapsing inwards
                                // Mark as very high-value cost
                                // curvature = 1.0f;
                                cost = 1.0f;
                        }
                        else
                        {
                                // Collapsing ALONG a border
                                // We can't use curvature to measure the effect on the model
                                // Instead, see what effect it has on 'pulling' the other border edges
                                // The more colinear, the less effect it will have
                                // So measure the 'kinkiness' (for want of a better term)
                                // Normally there can be at most 1 other border edge attached to this
                                // However in weird cases there may be more, so find the worst
                                Vector3 collapseEdge, otherBorderEdge;
                                Real kinkiness, maxKinkiness;
                                PMVertex::NeighborList::iterator n, nend;
                                nend = src->neighbor.end();
                                maxKinkiness = 0.0f;
                                edgeVector.normalise();
                                collapseEdge = edgeVector;
                                for (n = src->neighbor.begin(); n != nend; ++n)
                                {
                                        if (*n != dest && (*n)->isManifoldEdgeWith(src))
                                        {
                                                otherBorderEdge = src->position - (*n)->position;
                                                otherBorderEdge.normalise();
                                                // This time, the nearer the dot is to -1, the better, because that means
                                                // the edges are opposite each other, therefore less kinkiness
                                                // Scale into [0..1]
                                                kinkiness = (otherBorderEdge.dotProduct(collapseEdge) + 1.002f) * 0.5f;
                                                maxKinkiness = std::max(kinkiness, maxKinkiness);

                                        }
                                }

                                cost = maxKinkiness; 

                        }
        } 
                else // not a border
                {

                        // Standard inner vertex
                        // Calculate curvature
                        // use the triangle facing most away from the sides 
                        // to determine our curvature term
                        // Iterate over src's faces again
                        for(srcface = src->face.begin(); srcface != srcfaceEnd; ++srcface) 
                        {
                                Real mincurv = 1.0f; // curve for face i and closer side to it
                                // Iterate over the sides
                                PMVertex::FaceList::iterator sidesFace, sidesFaceEnd;
                                sidesFaceEnd = sides.end();
                                for(sidesFace = sides.begin(); sidesFace != sidesFaceEnd; ++sidesFace) 
                                {
                                        // Dot product of face normal gives a good delta angle
                                        Real dotprod = (*srcface)->normal.dotProduct( (*sidesFace)->normal );
                                        // NB we do (1-..) to invert curvature where 1 is high curvature [0..1]
                                        // Whilst dot product is high when angle difference is low
                                        mincurv =  std::min(mincurv,(1.002f - dotprod) * 0.5f);
                                }
                                curvature = std::max(curvature, mincurv);
                        }
                        cost = curvature;
                }

        // check for texture seam ripping
                if (src->seam && !dest->seam)
                {
                        cost = 1.0f;
                }

        // Check for singular triangle destruction
        // If src and dest both only have 1 triangle (and it must be a shared one)
        // then this would destroy the shape, so don't do this
        if (src->face.size() == 1 && dest->face.size() == 1)
        {
            cost = NEVER_COLLAPSE_COST;
        }


                // Degenerate case check
                // Are we going to invert a face normal of one of the neighbouring faces?
                // Can occur when we have a very small remaining edge and collapse crosses it
                // Look for a face normal changing by > 90 degrees
                for(srcface = src->face.begin(); srcface != srcfaceEnd; ++srcface) 
                {
                        // Ignore the deleted faces (those including src & dest)
                        if( !(*srcface)->hasCommonVertex(dest) )
                        {
                                // Test the new face normal
                                PMVertex *v0, *v1, *v2;
                                // Replace src with dest wherever it is
                                v0 = ( (*srcface)->vertex[0]->commonVertex == src) ? dest : (*srcface)->vertex[0]->commonVertex;
                                v1 = ( (*srcface)->vertex[1]->commonVertex == src) ? dest : (*srcface)->vertex[1]->commonVertex;
                                v2 = ( (*srcface)->vertex[2]->commonVertex == src) ? dest : (*srcface)->vertex[2]->commonVertex;

                                // Cross-product 2 edges
                                Vector3 e1 = v1->position - v0->position; 
                                Vector3 e2 = v2->position - v1->position;

                                Vector3 newNormal = e1.crossProduct(e2);
                                newNormal.normalise();

                                // Dot old and new face normal
                                // If < 0 then more than 90 degree difference
                                if (newNormal.dotProduct( (*srcface)->normal ) < 0.0f )
                                {
                                        // Don't do it!
                                        cost = NEVER_COLLAPSE_COST;
                                        break; // No point continuing
                                }


                        }
                }
                

                assert (cost >= 0);
                return cost;
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::initialiseEdgeCollapseCosts(void)
    {
        WorkingDataList::iterator i, iend;
        iend = mWorkingData.end();
        for (i = mWorkingData.begin(); i != iend; ++i)
        {
            CommonVertexList::iterator v, vend;
            vend = i->mVertList.end();
            for (v = i->mVertList.begin(); v != vend; ++v)
            {
                v->collapseTo = NULL;
                v->collapseCost = NEVER_COLLAPSE_COST;
            }
        }

        
    }
    //---------------------------------------------------------------------
    Real ProgressiveMesh::computeEdgeCostAtVertexForBuffer(WorkingDataList::iterator idata, size_t vertIndex)
    {
        // compute the edge collapse cost for all edges that start
        // from vertex v.  Since we are only interested in reducing
        // the object by selecting the min cost edge at each step, we
        // only cache the cost of the least cost edge at this vertex
        // (in member variable collapse) as well as the value of the 
        // cost (in member variable objdist).

        CommonVertexList::iterator v = idata->mVertList.begin();
        v += vertIndex;

        if(v->neighbor.empty()) {
            // v doesn't have neighbors so nothing to collapse
            v->notifyRemoved();
            return v->collapseCost;
        }

        // Init metrics
        v->collapseCost = NEVER_COLLAPSE_COST;
        v->collapseTo = NULL;

        // search all neighboring edges for "least cost" edge
        PMVertex::NeighborList::iterator n, nend;
        nend = v->neighbor.end();
        Real cost;
        for(n = v->neighbor.begin(); n != nend; ++n) 
        {
            cost = computeEdgeCollapseCost(&(*v), *n);
            if( (!v->collapseTo) || cost < v->collapseCost) 
            {
                v->collapseTo = *n;  // candidate for edge collapse
                v->collapseCost = cost;             // cost of the collapse
            }
        }

        return v->collapseCost;
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::computeAllCosts(void)
    {
        initialiseEdgeCollapseCosts();
        size_t i;
        for (i = 0; i < mpVertexData->vertexCount; ++i)
        {
            computeEdgeCostAtVertex(i);
        }
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::collapse(ProgressiveMesh::PMVertex *src)
    {
        PMVertex *dest = src->collapseTo;
                std::set<PMVertex*> recomputeSet;

                // Abort if we're never supposed to collapse
                if (src->collapseCost == NEVER_COLLAPSE_COST) 
                        return;

                // Remove this vertex from the running for the next check
                src->collapseTo = NULL;
                src->collapseCost = NEVER_COLLAPSE_COST;
                mWorstCosts[src->index] = NEVER_COLLAPSE_COST;

                // Collapse the edge uv by moving vertex u onto v
            // Actually remove tris on uv, then update tris that
            // have u to have v, and then remove u.
            if(!dest) {
                    // src is a vertex all by itself 
#if OGRE_DEBUG_MODE 
                        ofdebug << "Aborting collapse, orphan vertex. " << std::endl;
#endif
                        return;
            }

                // Add dest and all the neighbours of source and dest to recompute list
                recomputeSet.insert(dest);
                PMVertex::NeighborList::iterator n, nend;
        nend = src->neighbor.end();

                PMVertex* temp;

            for(n = src->neighbor.begin(); n != nend; ++n)
        {
                        temp = *n;
                        recomputeSet.insert( *n );
                }
        nend = dest->neighbor.end();
            for(n = dest->neighbor.begin(); n != nend; ++n)
        {
                        temp = *n;
                        recomputeSet.insert( *n );
                }

            // delete triangles on edge src-dest
        // Notify others to replace src with dest
        PMVertex::FaceList::iterator f, fend;
        fend = src->face.end();
                // Queue of faces for removal / replacement
                // prevents us screwing up the iterators while we parse
                PMVertex::FaceList faceRemovalList, faceReplacementList;
            for(f = src->face.begin(); f != fend; ++f) 
        {
                    if((*f)->hasCommonVertex(dest)) 
            {
                // Tri is on src-dest therefore is gone
                                faceRemovalList.insert(*f);
                // Reduce index count by 3 (useful for quick allocation later)
                mCurrNumIndexes -= 3;
                    }
            else
            {
                // Only src involved, replace with dest
                                faceReplacementList.insert(*f);
            }
            }

                src->toBeRemoved = true;
                // Replace all the faces queued for replacement
            for(f = faceReplacementList.begin(); f != faceReplacementList.end(); ++f) 
                {
                        /* Locate the face vertex which corresponds with the common 'dest' vertex
                        To to this, find a removed face which has the FACE vertex corresponding with
                        src, and use it's FACE vertex version of dest.
                        */
                        PMFaceVertex* srcFaceVert = (*f)->getFaceVertexFromCommon(src);
                        PMFaceVertex* destFaceVert = NULL;
                        PMVertex::FaceList::iterator iremoved;
                        for(iremoved = faceRemovalList.begin(); iremoved != faceRemovalList.end(); ++iremoved) 
                        {
                                //if ( (*iremoved)->hasFaceVertex(srcFaceVert) )
                                //{
                                        destFaceVert = (*iremoved)->getFaceVertexFromCommon(dest); 
                                //}
                        }
                        
                        assert(destFaceVert);

#if OGRE_DEBUG_MODE 
                        ofdebug << "Replacing vertex on face " << (unsigned int)(*f)->index << std::endl;
#endif
            (*f)->replaceVertex(srcFaceVert, destFaceVert);
                }
                // Remove all the faces queued for removal
            for(f = faceRemovalList.begin(); f != faceRemovalList.end(); ++f) 
                {
#if OGRE_DEBUG_MODE 
                        ofdebug << "Removing face " << (unsigned int)(*f)->index << std::endl;
#endif
                        (*f)->notifyRemoved();
                }

        // Notify the vertex that it is gone
        src->notifyRemoved();

        // recompute costs
                std::set<PMVertex*>::iterator irecomp, irecompend;
                irecompend = recomputeSet.end();
                for (irecomp = recomputeSet.begin(); irecomp != irecompend; ++irecomp)
                {
                        temp = (*irecomp);
                        computeEdgeCostAtVertex( (*irecomp)->index );
                }
                
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::computeEdgeCostAtVertex(size_t vertIndex)
    {
                // Call computer for each buffer on this vertex
        Real worstCost = -0.01f;
        WorkingDataList::iterator i, iend;
        iend = mWorkingData.end();
        for (i = mWorkingData.begin(); i != iend; ++i)
        {
            worstCost = std::max(worstCost, 
                computeEdgeCostAtVertexForBuffer(i, vertIndex));
        }
        // Save the worst cost
        mWorstCosts[vertIndex] = worstCost;
    }
    //---------------------------------------------------------------------
    size_t ProgressiveMesh::getNextCollapser(void)
    {
        // Scan
        // Not done as a sort because want to keep the lookup simple for now
        Real bestVal = NEVER_COLLAPSE_COST;
        size_t i, bestIndex;
                bestIndex = 0; // NB this is ok since if nothing is better than this, nothing will collapse
        for (i = 0; i < mNumCommonVertices; ++i)
        {
            if (mWorstCosts[i] < bestVal)
            {
                bestVal = mWorstCosts[i];
                bestIndex = i;
            }
        }
        return bestIndex;
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::bakeNewLOD(IndexData* pData)
    {
        assert(mCurrNumIndexes > 0 && "No triangles to bake!");
        // Zip through the tri list of any working data copy and bake
        pData->indexCount = mCurrNumIndexes;
                pData->indexStart = 0;
                // Base size of indexes on original 
                bool use32bitindexes = 
                        (mpIndexData->indexBuffer->getType() == HardwareIndexBuffer::IT_32BIT);

                // Create index buffer, we don't need to read it back or modify it a lot
                pData->indexBuffer = HardwareBufferManager::getSingleton().createIndexBuffer(
                        use32bitindexes? HardwareIndexBuffer::IT_32BIT : HardwareIndexBuffer::IT_16BIT,
                        pData->indexCount, HardwareBuffer::HBU_STATIC_WRITE_ONLY, false);

        unsigned short* pShort;
                unsigned int* pInt;
                if (use32bitindexes)
                {
                        pInt = static_cast<unsigned int*>(
                                pData->indexBuffer->lock( 0,
                                        pData->indexBuffer->getSizeInBytes(),
                                        HardwareBuffer::HBL_DISCARD));
                }
                else
                {
                        pShort = static_cast<unsigned short*>(
                                pData->indexBuffer->lock( 0,
                                        pData->indexBuffer->getSizeInBytes(),
                                        HardwareBuffer::HBL_DISCARD));
                }
        TriangleList::iterator tri, triend;
        // Use the first working data buffer, they are all the same index-wise
        WorkingDataList::iterator pWork = mWorkingData.begin();
        triend = pWork->mTriList.end();
        for (tri = pWork->mTriList.begin(); tri != triend; ++tri)
        {
            if (!tri->removed)
            {
                                if (use32bitindexes)
                                {
                                        *pInt++ = static_cast<unsigned int>(tri->vertex[0]->realIndex);
                                        *pInt++ = static_cast<unsigned int>(tri->vertex[1]->realIndex);
                                        *pInt++ = static_cast<unsigned int>(tri->vertex[2]->realIndex);
                                }
                                else
                                {
                                        *pShort++ = static_cast<unsigned short>(tri->vertex[0]->realIndex);
                                        *pShort++ = static_cast<unsigned short>(tri->vertex[1]->realIndex);
                                        *pShort++ = static_cast<unsigned short>(tri->vertex[2]->realIndex);
                                }
            }
        }
                pData->indexBuffer->unlock();

    }
    //---------------------------------------------------------------------
    ProgressiveMesh::PMTriangle::PMTriangle() : removed(false)
    {
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::PMTriangle::setDetails(size_t newindex, 
                ProgressiveMesh::PMFaceVertex *v0, ProgressiveMesh::PMFaceVertex *v1, 
        ProgressiveMesh::PMFaceVertex *v2)
    {
        assert(v0!=v1 && v1!=v2 && v2!=v0);

        index = newindex;
                vertex[0]=v0;
        vertex[1]=v1;
        vertex[2]=v2;

        computeNormal();

        // Add tri to vertices
        // Also tell vertices they are neighbours
        for(int i=0;i<3;i++) {
            vertex[i]->commonVertex->face.insert(this);
            for(int j=0;j<3;j++) if(i!=j) {
                vertex[i]->commonVertex->neighbor.insert(vertex[j]->commonVertex);
            }
        }
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::PMTriangle::notifyRemoved(void)
    {
        int i;
        for(i=0; i<3; i++) {
            // remove this tri from the vertices
            if(vertex[i]) vertex[i]->commonVertex->face.erase(this);
        }
        for(i=0; i<3; i++) {
            int i2 = (i+1)%3;
            if(!vertex[i] || !vertex[i2]) continue;
            // Check remaining vertices and remove if not neighbours anymore
            // NB May remain neighbours if other tris link them
            vertex[i ]->commonVertex->removeIfNonNeighbor(vertex[i2]->commonVertex);
            vertex[i2]->commonVertex->removeIfNonNeighbor(vertex[i ]->commonVertex);
        }

        removed = true;
    }
    //---------------------------------------------------------------------
    bool ProgressiveMesh::PMTriangle::hasCommonVertex(ProgressiveMesh::PMVertex *v) const
    {
        return (v == vertex[0]->commonVertex ||
                        v == vertex[1]->commonVertex || 
                        v == vertex[2]->commonVertex);
    }
    //---------------------------------------------------------------------
        bool ProgressiveMesh::PMTriangle::hasFaceVertex(ProgressiveMesh::PMFaceVertex *v) const
        {
                return (v == vertex[0] ||
                                v == vertex[1] || 
                                v == vertex[2]);
        }
    //---------------------------------------------------------------------
        ProgressiveMesh::PMFaceVertex* 
        ProgressiveMesh::PMTriangle::getFaceVertexFromCommon(ProgressiveMesh::PMVertex* commonVert)
        {
                if (vertex[0]->commonVertex == commonVert) return vertex[0];
                if (vertex[1]->commonVertex == commonVert) return vertex[1];
                if (vertex[2]->commonVertex == commonVert) return vertex[2];

                return NULL;

        }
    //---------------------------------------------------------------------
    void ProgressiveMesh::PMTriangle::computeNormal()
    {
        Vector3 v0=vertex[0]->commonVertex->position;
        Vector3 v1=vertex[1]->commonVertex->position;
        Vector3 v2=vertex[2]->commonVertex->position;
        // Cross-product 2 edges
        Vector3 e1 = v1 - v0; 
        Vector3 e2 = v2 - v1;

        normal = e1.crossProduct(e2);
        normal.normalise();
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::PMTriangle::replaceVertex(
                ProgressiveMesh::PMFaceVertex *vold, ProgressiveMesh::PMFaceVertex *vnew) 
    {
        assert(vold && vnew);
        assert(vold==vertex[0] || vold==vertex[1] || vold==vertex[2]);
        assert(vnew!=vertex[0] && vnew!=vertex[1] && vnew!=vertex[2]);
        if(vold==vertex[0]){
            vertex[0]=vnew;
        }
        else if(vold==vertex[1]){
            vertex[1]=vnew;
        }
        else {
            assert(vold==vertex[2]);
            vertex[2]=vnew;
        }
        int i;
        vold->commonVertex->face.erase(this);
        vnew->commonVertex->face.insert(this);
        for(i=0;i<3;i++) {
            vold->commonVertex->removeIfNonNeighbor(vertex[i]->commonVertex);
            vertex[i]->commonVertex->removeIfNonNeighbor(vold->commonVertex);
        }
        for(i=0;i<3;i++) {
            assert(vertex[i]->commonVertex->face.find(this) != vertex[i]->commonVertex->face.end());
            for(int j=0;j<3;j++) if(i!=j) {
#if OGRE_DEBUG_MODE 
                                ofdebug << "Adding vertex " << (unsigned int)vertex[j]->commonVertex->index << " to the neighbor list "
                                        "of vertex " << (unsigned int)vertex[i]->commonVertex->index << std::endl;
#endif 
                vertex[i]->commonVertex->neighbor.insert(vertex[j]->commonVertex);
            }
        }
        computeNormal();
    }
    //---------------------------------------------------------------------
    ProgressiveMesh::PMVertex::PMVertex() : removed(false)
    {
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::PMVertex::setDetails(const Vector3& v, size_t newindex)
    {
        position = v;
        index = newindex;
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::PMVertex::notifyRemoved(void)
    {
        NeighborList::iterator i, iend;
        iend = neighbor.end();
        for (i = neighbor.begin(); i != iend; ++i)
        {
            // Remove me from neighbor
            (*i)->neighbor.erase(this);
        }
        removed = true;
                this->collapseTo = NULL;
        this->collapseCost = NEVER_COLLAPSE_COST;
    }
    //---------------------------------------------------------------------
    bool ProgressiveMesh::PMVertex::isBorder() 
    {
        // Look for edges which only have one tri attached, this is a border

        NeighborList::iterator i, iend;
        iend = neighbor.end();
        // Loop for each neighbor
        for(i = neighbor.begin(); i != iend; ++i) 
        {
            // Count of tris shared between the edge between this and neighbor
            ushort count = 0;
            // Loop over each face, looking for shared ones
            FaceList::iterator j, jend;
            jend = face.end();
            for(j = face.begin(); j != jend; ++j) 
            {
                if((*j)->hasCommonVertex(*i))
                {
                    // Shared tri
                    count ++;
                }
            }
            //assert(count>0); // Must be at least one!
            // This edge has only 1 tri on it, it's a border
            if(count == 1) 
                                return true;
        }
        return false;
    } 
        //---------------------------------------------------------------------
        bool ProgressiveMesh::PMVertex::isManifoldEdgeWith(ProgressiveMesh::PMVertex* v)
        {
                // Check the sides involving both these verts
                // If there is only 1 this is a manifold edge
                ushort sidesCount = 0;
                FaceList::iterator i, iend;
                iend = face.end();
                for (i = face.begin(); i != iend; ++i)
                {
                        if ((*i)->hasCommonVertex(v))
                        {
                                sidesCount++;
                        }
                }

                return (sidesCount == 1);
        }
        //---------------------------------------------------------------------
    void ProgressiveMesh::PMVertex::removeIfNonNeighbor(ProgressiveMesh::PMVertex *n) 
    {
        // removes n from neighbor list if n isn't a neighbor.
        NeighborList::iterator i = neighbor.find(n);
        if (i == neighbor.end())
            return; // Not in neighbor list anyway

        FaceList::iterator f, fend;
        fend = face.end();
        for(f = face.begin(); f != fend; ++f) 
        {
            if((*f)->hasCommonVertex(n)) return; // Still a neighbor
        }

#if OGRE_DEBUG_MODE 
                ofdebug << "Vertex " << (unsigned int)n->index << " is no longer a neighbour of vertex " << (unsigned int)this->index <<
                        " so has been removed from the latter's neighbor list." << std::endl;
#endif
        neighbor.erase(n);

                if (neighbor.empty() && !toBeRemoved)
                {
                        // This vertex has been removed through isolation (collapsing around it)
                        this->notifyRemoved();
                }
    }
    //---------------------------------------------------------------------
    void ProgressiveMesh::dumpContents(const String& log)
        {
                std::ofstream ofdump(log.c_str());

                // Just dump 1st working data for now
                WorkingDataList::iterator worki = mWorkingData.begin();

                CommonVertexList::iterator vi, vend;
                vend = worki->mVertList.end();
                ofdump << "-------== VERTEX LIST ==-----------------" << std::endl;
                size_t i;
                for (vi = worki->mVertList.begin(), i = 0; i < mNumCommonVertices; ++vi, ++i)
                {
                        ofdump << "Vertex " << (unsigned int)vi->index << " pos: " << vi->position << " removed: " 
                                << vi->removed << " isborder: " << vi->isBorder() << std::endl;
                        ofdump << "    Faces:" << std::endl;
                        PMVertex::FaceList::iterator f, fend;
                        fend = vi->face.end();
                        for(f = vi->face.begin(); f != fend; ++f)
                        {
                                ofdump << "    Triangle index " << (unsigned int)(*f)->index << std::endl;
                        }
                        ofdump << "    Neighbours:" << std::endl;
                        PMVertex::NeighborList::iterator n, nend;
                        nend = vi->neighbor.end();
                        for (n = vi->neighbor.begin(); n != nend; ++n)
                        {
                                ofdump << "    Vertex index " << (unsigned int)(*n)->index << std::endl;
                        }

                }

                TriangleList::iterator ti, tend;
                tend = worki->mTriList.end();
                ofdump << "-------== TRIANGLE LIST ==-----------------" << std::endl;
                for(ti = worki->mTriList.begin(); ti != tend; ++ti)
                {
                        ofdump << "Triangle " << (unsigned int)ti->index << " norm: " << ti->normal << " removed: " << ti->removed << std::endl;
                        ofdump << "    Vertex 0: " << (unsigned int)ti->vertex[0]->realIndex << std::endl;
                        ofdump << "    Vertex 1: " << (unsigned int)ti->vertex[1]->realIndex << std::endl;
                        ofdump << "    Vertex 2: " << (unsigned int)ti->vertex[2]->realIndex << std::endl;
                }

                ofdump << "-------== COLLAPSE COST LIST ==-----------------" << std::endl;
                for (size_t ci = 0; ci < mNumCommonVertices; ++ci)
                {
                        ofdump << "Vertex " << (unsigned int)ci << ": " << mWorstCosts[ci] << std::endl;
                }

                ofdump.close();
        }


}