// NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
// Copyright (C) 2010  Winch Gate Property Limited
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "std3d.h"

#include "nel/3d/mrm_builder.h"
#include "nel/3d/mrm_parameters.h"
using namespace NLMISC;
using namespace std;


namespace NL3D
{


// ***************************************************************************
// ***************************************************************************
// Tools Methods.
// ***************************************************************************
// ***************************************************************************


// ***************************************************************************
static bool	findElement(vector<sint>	&array, sint elt)
{
	return find(array.begin(), array.end(), elt) != array.end();
}
// ***************************************************************************
static bool	deleteElement(vector<sint>	&array, sint elt)
{
	bool	found=false;
	vector<sint>::iterator	it=array.begin();

	while(  (it=find(array.begin(), array.end(), elt)) != array.end() )
		found=true, array.erase(it);

	return found;
	// Do not use remove<> since it desn't modify size ... (???)
	// This doesn't seem to work.
	//return remove(array.begin(), array.end(), elt)!=array.end();
}


// ***************************************************************************
// ***************************************************************************
// Edge Cost methods.
// ***************************************************************************
// ***************************************************************************


// ***************************************************************************
bool	CMRMBuilder::vertexHasOneWedge(sint numvertex)
{
	CMRMVertex	&vert= TmpVertices[numvertex];
	for(sint attId=0;attId<NumAttributes;attId++)
	{
		sint	numwedge=-1;
		for(sint i=0;i<(sint)vert.SharedFaces.size();i++)
		{
			sint	w= TmpFaces[vert.SharedFaces[i]].getAssociatedWedge(attId, numvertex);
			if(numwedge>=0 && numwedge!=w)	return false;
			else	numwedge=w;
		}
	}
	return true;
}
// ***************************************************************************
bool	CMRMBuilder::vertexHasOneMaterial(sint numvertex)
{
	sint	matId=-1;
	CMRMVertex	&vert= TmpVertices[numvertex];
	for(sint i=0;i<(sint)vert.SharedFaces.size();i++)
	{
		sint	m= TmpFaces[vert.SharedFaces[i]].MaterialId;
		if(matId>=0 && matId!=m)	return false;
		else	matId=m;
	}
	return true;
}
// ***************************************************************************
bool	CMRMBuilder::vertexContinue(sint numvertex)
{
	return vertexHasOneWedge(numvertex) && vertexHasOneMaterial(numvertex);
}
// ***************************************************************************
bool	CMRMBuilder::vertexClosed(sint numvertex)
{
	CMRMVertex	&vert= TmpVertices[numvertex];
	map<CMRMEdge, sint>		EdgeShare;
	// Init to 0.
	sint i;
	for(i=0;i<(sint)vert.SharedFaces.size();i++)
	{
		CMRMFaceBuild		&f=TmpFaces[vert.SharedFaces[i]];
		EdgeShare[f.getEdge(0)]= 0;
		EdgeShare[f.getEdge(1)]= 0;
		EdgeShare[f.getEdge(2)]= 0;
	}
	// Inc count.
	for(i=0;i<(sint)vert.SharedFaces.size();i++)
	{
		CMRMFaceBuild		&f=TmpFaces[vert.SharedFaces[i]];
		EdgeShare[f.getEdge(0)]++;
		EdgeShare[f.getEdge(1)]++;
		EdgeShare[f.getEdge(2)]++;
	}
	// Test open edges.
	for(i=0;i<(sint)vert.SharedFaces.size();i++)
	{
		CMRMFaceBuild		&f=TmpFaces[vert.SharedFaces[i]];
		sint	v0= f.Corner[0].Vertex;
		sint	v1= f.Corner[1].Vertex;
		sint	v2= f.Corner[2].Vertex;
		if(EdgeShare[f.getEdge(0)]<2 && (v0==numvertex || v1==numvertex)) return false;
		if(EdgeShare[f.getEdge(1)]<2 && (v1==numvertex || v2==numvertex)) return false;
		if(EdgeShare[f.getEdge(2)]<2 && (v0==numvertex || v2==numvertex)) return false;
	}
	return true;
}
// ***************************************************************************
float	CMRMBuilder::getDeltaFaceNormals(sint numvertex)
{
	// return a positive value of Somme(|DeltaNormals|) / NNormals.
	CMRMVertex	&vert= TmpVertices[numvertex];
	float	delta=0;
	CVector	refNormal;
	sint	nfaces=(sint)vert.SharedFaces.size();
	for(sint i=0;i<nfaces;i++)
	{
		CVector	normal;
		CVector	&v0= TmpVertices[TmpFaces[i].Corner[0].Vertex].Current;
		CVector	&v1= TmpVertices[TmpFaces[i].Corner[1].Vertex].Current;
		CVector	&v2= TmpVertices[TmpFaces[i].Corner[2].Vertex].Current;
		normal= (v1-v0)^(v2-v0);
		normal.normalize();
		if(i==0)
			refNormal=normal;
		else
			delta+=(1-refNormal*normal);
	}
	if(nfaces<2)
		return 0;
	else
		return delta/(nfaces-1);
}
// ***************************************************************************
bool	CMRMBuilder::edgeContinue(const CMRMEdge &edge)
{
	sint v0= edge.v0;
	sint v1= edge.v1;
	CMRMVertex	&Vertex1=TmpVertices[v0];

	// build list sharing edge.
	vector<sint>	deletedFaces;
	sint i;
	for(i=0;i<(sint)Vertex1.SharedFaces.size();i++)
	{
		sint	numFace= Vertex1.SharedFaces[i];
		if(TmpFaces[numFace].hasVertex(v1))
			deletedFaces.push_back(numFace);
	}

	sint	matId=-1;
	// test if faces have same material.
	for(i=0;i<(sint)deletedFaces.size();i++)
	{
		sint	m;
		m= TmpFaces[deletedFaces[i]].MaterialId;
		if(matId>=0 && matId!=m)	return false;
		else	matId=m;
	}

	// test if faces have same wedge (for all att).
	for(sint attId=0;attId<NumAttributes;attId++)
	{
		sint	numwedge1=-1,numwedge2=-1;
		for(i=0;i<(sint)deletedFaces.size();i++)
		{
			sint	w;
			w= TmpFaces[deletedFaces[i]].getAssociatedWedge(attId, v0);
			if(numwedge1>=0 && numwedge1!=w)	return false;
			else	numwedge1=w;
			w= TmpFaces[deletedFaces[i]].getAssociatedWedge(attId, v1);
			if(numwedge2>=0 && numwedge2!=w)	return false;
			else	numwedge2=w;
		}
	}

	return true;
}
// ***************************************************************************
bool	CMRMBuilder::edgeNearUniqueMatFace(const CMRMEdge &edge)
{
	sint v0= edge.v0;
	sint v1= edge.v1;
	CMRMVertex	&Vertex1=TmpVertices[v0];

	// build list sharing edge.
	vector<sint>	deletedFaces;
	sint i;
	for(i=0;i<(sint)Vertex1.SharedFaces.size();i++)
	{
		sint	numFace= Vertex1.SharedFaces[i];
		if(TmpFaces[numFace].hasVertex(v1))
			deletedFaces.push_back(numFace);
	}

	// test if faces are not isolated OneMaterial faces.
	for(i=0;i<(sint)deletedFaces.size();i++)
	{
		CMRMFaceBuild	&f=TmpFaces[deletedFaces[i]];
		if( !edgeContinue(f.getEdge(0)) &&
			!edgeContinue(f.getEdge(1)) &&
			!edgeContinue(f.getEdge(2)))
			return true;
	}

	return false;
}

// ***************************************************************************
float	CMRMBuilder::computeEdgeCost(const CMRMEdge &edge)
{
	sint	v1= edge.v0;
	sint	v2= edge.v1;
	// more expensive is the edge, later it will collapse.


	// **** standard cost

	// compute size of the edge.
	float	cost=(TmpVertices[v1].Current-TmpVertices[v2].Current).norm();

	// compute "curvature" of the edge.
	float	faceCost= (getDeltaFaceNormals(v1)+getDeltaFaceNormals(v2));
	// totally plane faces (faceCost==0) must be collapsed with respect to size (and not random if cost==0).
	// else we may have Plane Mesh (like flags) that will collapse in a very ugly way.
	faceCost= max(faceCost, 0.01f);

	// modulate size with curvature.
	cost*= faceCost;

	// Like H.Hope, add a weight on discontinuities..
	if( !vertexContinue(v1) && !vertexContinue(v2) )
	{
		// Nb: don't do this on discontinuities edges, unless the unique material face will collapse (pffiou!!).
		if( edgeContinue(edge) || edgeNearUniqueMatFace(edge) )
			cost*=4;
	}

	// **** Interface Sewing cost
	if(_HasMeshInterfaces)
	{
		// if the 2 vertices come from a Sewing Interface mesh (must be a real interface id)
		sint	meshSewingId= TmpVertices[v1].InterfaceLink.InterfaceId;
		if( meshSewingId>=0 && TmpVertices[v2].InterfaceLink.InterfaceId>=0 )
		{
			// if the 2 vertices come from the same Sewing Interface mesh
			if( meshSewingId == TmpVertices[v2].InterfaceLink.InterfaceId )
			{
				// Then the edge is one of the sewing interface mesh. must do special things for it
				CMRMSewingMesh	&sewingMesh= _SewingMeshes[meshSewingId];
				uint	dummy;

				// get the sewing edge id
				CMRMEdge	sewingEdge;
				sewingEdge.v0= TmpVertices[v1].InterfaceLink.InterfaceVertexId;
				sewingEdge.v1= TmpVertices[v2].InterfaceLink.InterfaceVertexId;
				// if the current sewing lod want to collapse this edge
				sint collapseId= sewingMesh.mustCollapseEdge(_CurrentLodComputed, sewingEdge, dummy);
				if(collapseId>=0)
				{
					// Then set a negative priority (ie will collapse as soon as possible). from -N to -1.
					// NB: sort them according to collapseId
					cost= (float)(-sewingMesh.getNumCollapseEdge(_CurrentLodComputed) + collapseId);
				}
				else
				{
					// This edge must not collapse at this Lod, set an infinite priority (hope will never collapse).
					cost= FLT_MAX;
				}
			}
			else
			{
				/* The edge is between 2 interfaces but not the same. If we collide it we'll have holes!
					This problem arise if space beetween interfaces is small. eg: if we setup an interface beetween
					hair and head, and an other one beetween head and torso, then we'll have this problem in the
					back of the neck.
					The solution is to make a big big cost to hope we'll never collide them (else Holes...)!!
					Don't use FLT_MAX to still have a correct order if we don't have choice...
				*/
				cost*= 10000;
			}
		}
	}

	return cost;
}




// ***************************************************************************
// ***************************************************************************
// Collapse Methods.
// ***************************************************************************
// ***************************************************************************


// ***************************************************************************
bool	CMRMBuilder::faceShareWedges(CMRMFaceBuild *face, sint attribId, sint numVertex1, sint numVertex2)
{
	sint	numWedge1= face->getAssociatedWedge(attribId, numVertex1);
	sint	numWedge2= face->getAssociatedWedge(attribId, numVertex2);
	if(numWedge1<0) return false;
	if(numWedge2<0) return false;

	CMRMAttribute	&w1= TmpAttributes[attribId][numWedge1];
	CMRMAttribute	&w2= TmpAttributes[attribId][numWedge2];
	return w1.Shared && w2.Shared && w1.NbSharedFaces>0 && w2.NbSharedFaces>0;
}


// ***************************************************************************
void	CMRMBuilder::insertFaceIntoEdgeList(CMRMFaceBuild &f)
{
	float	len;
	if(f.ValidIt0)
	{
		len= computeEdgeCost(f.getEdge(0));
		f. It0= EdgeCollapses.insert( TEdgeMap::value_type( len, CMRMEdgeFace(f.getEdge(0),&f) ) );
	}
	if(f.ValidIt1)
	{
		len= computeEdgeCost(f.getEdge(1));
		f. It1= EdgeCollapses.insert( TEdgeMap::value_type( len, CMRMEdgeFace(f.getEdge(1),&f) ) );
	}
	if(f.ValidIt2)
	{
		len= computeEdgeCost(f.getEdge(2));
		f. It2= EdgeCollapses.insert( TEdgeMap::value_type( len, CMRMEdgeFace(f.getEdge(2),&f) ) );
	}
}
// ***************************************************************************
void	CMRMBuilder::removeFaceFromEdgeList(CMRMFaceBuild &f)
{
	if(f.ValidIt0)
		EdgeCollapses.erase(f.It0);
	if(f.ValidIt1)
		EdgeCollapses.erase(f.It1);
	if(f.ValidIt2)
		EdgeCollapses.erase(f.It2);
}



// ***************************************************************************
struct		CTmpVertexWeight
{
	uint32		MatrixId;
	float		Weight;
	// For find().
	bool	operator==(const CTmpVertexWeight &o) const
	{
		return MatrixId==o.MatrixId;
	}
	// For sort().
	bool	operator<(const CTmpVertexWeight &o) const
	{
		return Weight>o.Weight;
	}

};


// ***************************************************************************
CMesh::CSkinWeight	CMRMBuilder::collapseSkinWeight(const CMesh::CSkinWeight &sw1, const CMesh::CSkinWeight &sw2, float interValue) const
{
	// If fast interpolation.
	if(interValue==0)
		return sw1;
	if(interValue==1)
		return sw2;

	// else, must blend a skinWeight: must identify matrix which exist in the 2 sws, and add new ones.
	uint	nbMats1=0;
	uint	nbMats2=0;
	static vector<CTmpVertexWeight>		sws;
	sws.reserve(NL3D_MESH_SKINNING_MAX_MATRIX * 2);
	sws.clear();

	// For all weights of sw1.
	uint i;
	for(i=0; i<NL3D_MESH_SKINNING_MAX_MATRIX; i++)
	{
		CTmpVertexWeight	vw;
		vw.MatrixId= sw1.MatrixId[i];
		vw.Weight= sw1.Weights[i]*(1-interValue);
		// if this weight is not null.
		if(vw.Weight>0)
		{
			// add it to the list.
			sws.push_back(vw);
		}
		// For skinning reduction.
		if(sw1.Weights[i]>0)
			nbMats1++;
	}


	// For all weights of sw1.
	for(i=0; i<NL3D_MESH_SKINNING_MAX_MATRIX; i++)
	{
		CTmpVertexWeight	vw;
		vw.MatrixId= sw2.MatrixId[i];
		vw.Weight= sw2.Weights[i]*(interValue);
		// if this weight is not null.
		if(vw.Weight>0)
		{
			// add it or add influence to the matrix.
			vector<CTmpVertexWeight>::iterator		it= find(sws.begin(), sws.end(), vw);
			if(it== sws.end())
				sws.push_back(vw);
			else
				it->Weight+= vw.Weight;
		}
		// For skinning reduction.
		if(sw2.Weights[i]>0)
			nbMats2++;
	}


	// Then keep just the best.
	// sort by Weight decreasing order.
	sort(sws.begin(), sws.end());

	// clamp the result to the wanted max matrix.
	uint	nbMatsOut;
	switch(_SkinReduction)
	{
	case CMRMParameters::SkinReductionMin:
		nbMatsOut= min(nbMats1, nbMats2);
		break;
	case CMRMParameters::SkinReductionMax:
		nbMatsOut= max(nbMats1, nbMats2);
		break;
	case CMRMParameters::SkinReductionBest:
		nbMatsOut= min( (uint)sws.size(), (uint)NL3D_MESH_SKINNING_MAX_MATRIX );
		break;
	default:
		nlstop;
	};
	// For security.
	nbMatsOut= min(nbMatsOut, (uint)sws.size());
	nlassert(nbMatsOut<=NL3D_MESH_SKINNING_MAX_MATRIX);


	// Then output the result to the skinWeight, normalizing.
	float	sumWeight=0;
	for(i= 0; i<nbMatsOut; i++)
	{
		sumWeight+= sws[i].Weight;
	}

	CMesh::CSkinWeight	ret;
	// Fill only needed matrix (other are rested in CMesh::CSkinWeight ctor).
	for(i= 0; i<nbMatsOut; i++)
	{
		ret.MatrixId[i]= sws[i].MatrixId;
		ret.Weights[i]= sws[i].Weight / sumWeight;
	}

	return ret;
}

// ***************************************************************************
sint	CMRMBuilder::collapseEdge(const CMRMEdge &edge)
{
	sint	i,j;
	float	InterValue;
	sint	edgeV1=edge.v0;
	sint	edgeV2=edge.v1;


	// 0. collapse the vertices.
	//==========================

	// edge.Vertex1 kept, but morphed.
	// edge.Vertex2 deleted, and must know on which vertex it collapse.
	CMRMVertex	&Vertex1=TmpVertices[edgeV1], &Vertex2=TmpVertices[edgeV2];

	// Interpolation choice.
	// Default is to interpolate vertex 0 to the middle of the edge.
	InterValue=0.5;
	//InterValue=1;
	// **** If at least one vertex of the edge is on a mesh sewing interface, must change InterValue
	if( _HasMeshInterfaces && (Vertex1.InterfaceLink.InterfaceId>=0 || Vertex2.InterfaceLink.InterfaceId>=0) )
	{
		// If this is an edge of a mesh sewing interface
		if(Vertex1.InterfaceLink.InterfaceId==Vertex2.InterfaceLink.InterfaceId)
		{
			// Then the edge is one of the sewing interface mesh. must do special things for it
			CMRMSewingMesh	&sewingMesh= _SewingMeshes[Vertex1.InterfaceLink.InterfaceId];

			// get the sewing edge id
			CMRMEdge	sewingEdge;
			sewingEdge.v0= Vertex1.InterfaceLink.InterfaceVertexId;
			sewingEdge.v1= Vertex2.InterfaceLink.InterfaceVertexId;

			// Get the edge in the sewing mesh which is said to be collapsed
			uint	vertToCollapse;
			sint collapseId= sewingMesh.mustCollapseEdge(_CurrentLodComputed, sewingEdge, vertToCollapse);
			// if exist
			if(collapseId>=0)
			{
				// if it is v0 which must collapse, then InterValue=1
				if(vertToCollapse==(uint)sewingEdge.v0)
					InterValue= 1;
				else
					InterValue= 0;

			}
			else
			{
				// This should not happens. But it is still possible if this edge don't want to collapse but if their
				// is no more choice. Take a default value
				InterValue= 0;
			}
		}
		else
		{
			// must collapse to the vertex on the sewing interface (as if it was open)
			if(Vertex1.InterfaceLink.InterfaceId>=0)
			{
				// NB: it is possible that both vertices are on a different sewing interface... still collapse (must have to)
				InterValue= 0;
			}
			else
			{
				// Then Vertex2 is on a sewing interface, collapse to it
				InterValue= 1;
			}
		}
	}
	// **** Else, on special cases, it is much more efficient to interpolate at start or at end of edge.
	else
	{
		// If one vertex is "open", ie his shared faces do not represent a closed Fan, then interpolate to this one,
		// so the mesh has the same silhouette.
		bool	vc1= vertexClosed(edgeV1);
		bool	vc2= vertexClosed(edgeV2);
		if(!vc1 && vc2) InterValue=0;
		else if(vc1 && !vc2) InterValue=1;
		else
		{
			// Do the same test but with vertex continue: it is preferable to not move the boundaries
			// of a material, or a mapping.
			bool	vc1= vertexContinue(edgeV1);
			bool	vc2= vertexContinue(edgeV2);
			if(!vc1 && vc2) InterValue=0;
			if(vc1 && !vc2) InterValue=1;
		}
	}
	/*BENCH_TotalCollapses++;
	if(InterValue==0.5)
		BENCH_MiddleCollapses++;*/

	// Collapse the Vertex.
	//========================
	Vertex1.Current= Vertex1.Current*(1-InterValue) + Vertex2.Current*InterValue;
	for (i = 0; i < (sint)Vertex1.BSCurrent.size(); ++i)
		Vertex1.BSCurrent[i] = Vertex1.BSCurrent[i]*(1-InterValue) + Vertex2.BSCurrent[i]*InterValue;
	Vertex2.CollapsedTo= edgeV1;
	if(_Skinned)
		Vertex1.CurrentSW= collapseSkinWeight(Vertex1.CurrentSW, Vertex2.CurrentSW, InterValue);
	if( _HasMeshInterfaces )
		Vertex1.InterfaceLink= InterValue<0.5f? Vertex1.InterfaceLink : Vertex2.InterfaceLink;

	// \todo yoyo: TODO_BUG: Don't know why, but vertices may point on deleted faces.
	// Temp: we destroy here thoses face from SharedFaces...
	for(i=0;i<(sint)Vertex1.SharedFaces.size();i++)
	{
		sint	numFace= Vertex1.SharedFaces[i];
		if(TmpFaces[numFace].Deleted)
			deleteElement(Vertex1.SharedFaces, numFace), i--;
	}
	for(i=0;i<(sint)Vertex2.SharedFaces.size();i++)
	{
		sint	numFace= Vertex2.SharedFaces[i];
		if(TmpFaces[numFace].Deleted)
			deleteElement(Vertex2.SharedFaces, numFace), i--;
	}


	// Build Neighbor faces.
	vector<sint>	neighboorFaces;
	for(i=0;i<(sint)Vertex1.SharedFaces.size();i++)
	{
		sint	numFace= Vertex1.SharedFaces[i];
		if(!findElement(neighboorFaces, numFace))
			neighboorFaces.push_back(numFace);
	}
	for(i=0;i<(sint)Vertex2.SharedFaces.size();i++)
	{
		sint	numFace= Vertex2.SharedFaces[i];
		if(!findElement(neighboorFaces, numFace))
			neighboorFaces.push_back(numFace);
	}

	// Build faces which will be destroyed (may 1 or 2, maybe more for non conventionnal meshes).
	vector<sint>	deletedFaces;
	for(i=0;i<(sint)Vertex1.SharedFaces.size();i++)
	{
		sint	numFace= Vertex1.SharedFaces[i];
		nlassert(!TmpFaces[numFace].Deleted);
		if(TmpFaces[numFace].hasVertex(edgeV2))
			deletedFaces.push_back(numFace);
	}


	// 1. Collapse the wedges.
	//========================

	// For ALL Attributes.
	for(sint attId=0;attId<NumAttributes;attId++)
	{
		// a/ Stock the wedge interpolation in each destroyed face.
		//------------------------------------------------------
		for(i=0;i<(sint)deletedFaces.size();i++)
		{
			CMRMFaceBuild		&face= TmpFaces[deletedFaces[i]];

			CVectorH	&w0= TmpAttributes[attId][ face.getAssociatedWedge(attId, edgeV1) ].Current;
			CVectorH	&w1= TmpAttributes[attId][ face.getAssociatedWedge(attId, edgeV2) ].Current;

			CVectorH	&itp= face.InterpolatedAttribute;
			itp.x= w0.x*(1-InterValue) + w1.x*InterValue;
			itp.y= w0.y*(1-InterValue) + w1.y*InterValue;
			itp.z= w0.z*(1-InterValue) + w1.z*InterValue;
			itp.w= w0.w*(1-InterValue) + w1.w*InterValue;

			for (j = 0; j < (sint)face.BSInterpolated.size(); ++j)
			{
				CVectorH &w0 = TmpAttributes[attId][face.getAssociatedWedge(attId, edgeV1)].BSCurrent[j];
				CVectorH &w1 = TmpAttributes[attId][face.getAssociatedWedge(attId, edgeV2)].BSCurrent[j];
				CVectorH &itb = face.BSInterpolated[j];
				itb.x = w0.x*(1-InterValue) + w1.x*InterValue;
				itb.y = w0.y*(1-InterValue) + w1.y*InterValue;
				itb.z = w0.z*(1-InterValue) + w1.z*InterValue;
				itb.w = w0.w*(1-InterValue) + w1.w*InterValue;
			}
		}


		// b/ Build wedge list to be modify.
		//----------------------------------
		vector<sint>	wedges;

		for(i=0;i<(sint)neighboorFaces.size();i++)
		{
			CMRMFaceBuild	&face= TmpFaces[neighboorFaces[i]];
			sint	numWedge;

			numWedge= face.getAssociatedWedge(attId, edgeV1);
			if(numWedge>=0 && !findElement(wedges, numWedge))
				wedges.push_back(numWedge);

			numWedge= face.getAssociatedWedge(attId, edgeV2);
			if(numWedge>=0 && !findElement(wedges, numWedge))
				wedges.push_back(numWedge);
		}


		// c/ Count numFaces which point on those wedges. (- deleted faces).
		//------------------------------------------------------------------

		for(i=0;i<(sint)wedges.size();i++)
		{
			sint			numWedge= wedges[i];
			CMRMAttribute	&wedge= TmpAttributes[attId][numWedge];

			wedge.NbSharedFaces=0;
			wedge.Shared=false;

			// Count total ref count.
			for(j=0;j<(sint)neighboorFaces.size();j++)
			{
				if(TmpFaces[neighboorFaces[j]].hasWedge(attId, numWedge))
					wedge.NbSharedFaces++;
			}

			// Minus deleted faces.
			for(j=0;j<(sint)deletedFaces.size();j++)
			{
				if(TmpFaces[deletedFaces[j]].hasWedge(attId, numWedge))
				{
					wedge.NbSharedFaces--;
					wedge.Shared=true;
					wedge.InterpolatedFace=deletedFaces[j];
				}
			}
		}


		// d/ Collapse wedge following 3 possibles cases.
		//-----------------------------------------------


		for(i=0;i<(sint)wedges.size();i++)
		{
			sint			numWedge= wedges[i];
			CMRMAttribute	&wedge= TmpAttributes[attId][numWedge];

			// if wedge not shared...
			if(!wedge.Shared)
			{
				// We've got an "exterior wedge" which lost no corner => do not merge it nor delete it.
				// Leave it as the same value (extrapolate it may not be a good solution).
			}
			else
			{
				// if wedge dissapears, notify.
				if(wedge.NbSharedFaces==0)
				{
					wedge.CollapsedTo=-2;
					// Do not change his value. (as specified in Hope article).
				}
				else
				{
					CMRMFaceBuild	&face= TmpFaces[wedge.InterpolatedFace];

					// Must interpolate it.
					wedge.Current= face.InterpolatedAttribute;
					wedge.BSCurrent = face.BSInterpolated;

					// Must merge the wedge of the second vertex on first
					// ONLY IF 2 interpolated wedges are shared and NbSharedFaces!=0.
					if(	numWedge==face.getAssociatedWedge(attId, edgeV2) &&
						faceShareWedges(&face, attId, edgeV1, edgeV2) )
					{
						wedge.CollapsedTo= face.getAssociatedWedge(attId, edgeV1);
					}
				}
			}
		}

	}

	// 3. collapse faces.
	//===================

	// delete face shared by edge.
	for(i=0;i<(sint)deletedFaces.size();i++)
	{
		sint	numFace= deletedFaces[i];
		TmpFaces[numFace].Deleted=true;

		// release edges from list.
		removeFaceFromEdgeList(TmpFaces[numFace]);
		// invalid all it!!
		TmpFaces[numFace].invalidAllIts(EdgeCollapses);


		// delete from vertex1 and 2 the deleted faces.
		deleteElement( Vertex1.SharedFaces, numFace);
		deleteElement( Vertex2.SharedFaces, numFace);
	}


	// must ref correctly the faces.
	for(i=0;i<(sint)neighboorFaces.size();i++)
	{
		CMRMFaceBuild		&face=TmpFaces[neighboorFaces[i]];

		// good vertices
		if(face.Corner[0].Vertex ==edgeV2)	face.Corner[0].Vertex=edgeV1;
		if(face.Corner[1].Vertex ==edgeV2)	face.Corner[1].Vertex=edgeV1;
		if(face.Corner[2].Vertex ==edgeV2)	face.Corner[2].Vertex=edgeV1;
		// nb: doesn't matter if deletedFaces are modified...

		// good wedges
		for(sint attId=0;attId<NumAttributes;attId++)
		{
			sint	newWedge;
			newWedge= TmpAttributes[attId][ face.Corner[0].Attributes[attId] ].CollapsedTo;
			if(newWedge>=0)	face.Corner[0].Attributes[attId]= newWedge;
			newWedge= TmpAttributes[attId][ face.Corner[1].Attributes[attId] ].CollapsedTo;
			if(newWedge>=0)	face.Corner[1].Attributes[attId]= newWedge;
			newWedge= TmpAttributes[attId][ face.Corner[2].Attributes[attId] ].CollapsedTo;
			if(newWedge>=0)	face.Corner[2].Attributes[attId]= newWedge;
		}

		// good edges.
		/* Those ones are updated in collapseEdges(): they are removed from the edgeCollapseList,
			then they are re-inserted with good Vertex indices.
		*/
	}


	// The vertex1 has now the shared env of vertex2.
	Vertex1.SharedFaces.insert(Vertex1.SharedFaces.end(), Vertex2.SharedFaces.begin(),
		Vertex2.SharedFaces.end());


	return (sint)deletedFaces.size();
}


// ***************************************************************************
sint	CMRMBuilder::followVertex(sint i)
{
	CMRMVertex	&vert=TmpVertices[i];
	if(vert.CollapsedTo>=0)
		return followVertex(vert.CollapsedTo);
	else
		return i;
}
// ***************************************************************************
sint	CMRMBuilder::followWedge(sint attribId, sint i)
{
	CMRMAttribute	&wedge= TmpAttributes[attribId][i];
	if(wedge.CollapsedTo>=0)
		return followWedge(attribId, wedge.CollapsedTo);
	else
		return i;
}


// ***************************************************************************
// ***************************************************************************
// Mesh Level method.
// ***************************************************************************
// ***************************************************************************


// ***************************************************************************
CMRMBuilder::CMRMBuilder()
{
	NumAttributes= 0;
	_Skinned= false;
	_HasMeshInterfaces= false;
}

// ***************************************************************************
void	CMRMBuilder::init(const CMRMMesh &baseMesh)
{
	sint	i, attId;


	// First clear ALL.
	TmpVertices.clear();
	for(attId=0;attId<NL3D_MRM_MAX_ATTRIB;attId++)
	{
		TmpAttributes[attId].clear();
	}
	TmpFaces.clear();
	EdgeCollapses.clear();


	// resize.
	NumAttributes= baseMesh.NumAttributes;
	TmpVertices.resize(baseMesh.Vertices.size());
	for(attId=0;attId<NumAttributes;attId++)
	{
		TmpAttributes[attId].resize(baseMesh.Attributes[attId].size());
	}
	TmpFaces.resize(baseMesh.Faces.size());


	// Then copy.
	for(i=0;i<(sint)baseMesh.Vertices.size();i++)
	{
		TmpVertices[i].Current= TmpVertices[i].Original= baseMesh.Vertices[i];
		TmpVertices[i].BSCurrent.resize(baseMesh.BlendShapes.size());
		for(uint32 j = 0; j <baseMesh.BlendShapes.size() ;++j)
			TmpVertices[i].BSCurrent[j]= baseMesh.BlendShapes[j].Vertices[i];
		if(_Skinned)
			TmpVertices[i].CurrentSW= TmpVertices[i].OriginalSW= baseMesh.SkinWeights[i];
		if(_HasMeshInterfaces)
			TmpVertices[i].InterfaceLink= baseMesh.InterfaceLinks[i];
	}
	for(attId=0;attId<NumAttributes;attId++)
	{
		for(i=0;i<(sint)baseMesh.Attributes[attId].size();i++)
		{
			TmpAttributes[attId][i].Current= TmpAttributes[attId][i].Original=
			baseMesh.Attributes[attId][i];
			TmpAttributes[attId][i].BSCurrent.resize(baseMesh.BlendShapes.size());
			for(uint32 j = 0; j <baseMesh.BlendShapes.size() ;++j)
				TmpAttributes[attId][i].BSCurrent[j]= baseMesh.BlendShapes[j].Attributes[attId][i];
		}
	}
	for(i=0;i<(sint)baseMesh.Faces.size();i++)
	{
		TmpFaces[i]= baseMesh.Faces[i];
		TmpFaces[i].BSInterpolated.resize(baseMesh.BlendShapes.size());
	}


	// Create vertices sharedFaces.
	for(i=0;i<(sint)TmpFaces.size();i++)
	{
		CMRMFaceBuild		&face= TmpFaces[i];

		TmpVertices[face.Corner[0].Vertex].SharedFaces.push_back(i);
		TmpVertices[face.Corner[1].Vertex].SharedFaces.push_back(i);
		TmpVertices[face.Corner[2].Vertex].SharedFaces.push_back(i);
	}


	// Compute EdgeCost.
	for(i=0;i<(sint)TmpFaces.size();i++)
	{
		CMRMFaceBuild		&f= TmpFaces[i];
		// At start, valid all edges.
		f. ValidIt0= true;
		f. ValidIt1= true;
		f. ValidIt2= true;
		insertFaceIntoEdgeList(f);
	}
}
// ***************************************************************************
void	CMRMBuilder::collapseEdges(sint nWantedFaces)
{
	ItEdgeMap		EdgeIt;

	sint	nCurrentFaces=(sint)TmpFaces.size();
	sint	bug0=0,bug2=0,bug3=0;

	while(nCurrentFaces>nWantedFaces)
	{
		bug0++;
		EdgeIt= EdgeCollapses.begin();

		if(EdgeIt== EdgeCollapses.end())
			break;

		// 0. Look if edge already deleted
		//================================
		CMRMEdge	edge=(*EdgeIt).second;

		// Is it valid?? (ie his vertices exist yet??).
		if(TmpVertices[ edge.v0 ].CollapsedTo>=0
			|| TmpVertices[ edge.v1 ].CollapsedTo>=0)
		{
			// \todo yoyo: TODO_BUG: potential bug here...
			CMRMFaceBuild		&f= *(EdgeIt->second.Face);
			nlassert(f.validEdgeIt(EdgeIt->second));
			f.invalidEdgeIt(EdgeIt->second, EdgeCollapses);
			EdgeCollapses.erase(EdgeIt);
			bug2++;
			continue;
		}
		// \todo yoyo: TODO_BUG: potential bug here...
		// If a mesh is "open" it will crash if a "hole collapse"...
		if(edge.v0==edge.v1)
		{
			CMRMFaceBuild		&f= *(EdgeIt->second.Face);
			nlassert(f.validEdgeIt(EdgeIt->second));
			f.invalidEdgeIt(EdgeIt->second, EdgeCollapses);
			EdgeCollapses.erase(EdgeIt);
			bug3++;
			continue;
		}


		// 1. else, OK, collapse it!!
		//===========================
		sint	vertexCollapsed= edge.v0;
		nCurrentFaces-= collapseEdge(edge);


		// 2. Must reorder all his neighborhood.
		//======================================
		CMRMVertex	&vert=TmpVertices[vertexCollapsed];
		sint	i;
		// we delete from list modified edges, and we re-add them with their new value.
		for(i=0;i<(sint)vert.SharedFaces.size();i++)
		{
			CMRMFaceBuild		&f= TmpFaces[vert.SharedFaces[i]];
			removeFaceFromEdgeList(f);
			insertFaceIntoEdgeList(f);
		}

	}
}
// ***************************************************************************
void	CMRMBuilder::saveCoarserMesh(CMRMMesh &coarserMesh)
{
	sint	i,attId,index;
	// First clear ALL.
	coarserMesh.Vertices.clear();
	coarserMesh.SkinWeights.clear();
	coarserMesh.InterfaceLinks.clear();
	for(attId=0;attId<NL3D_MRM_MAX_ATTRIB;attId++)
	{
		coarserMesh.Attributes[attId].clear();
	}
	coarserMesh.Faces.clear();
	coarserMesh.NumAttributes= NumAttributes;

	// Vertices.
	//==========
	index=0;
	for(i=0;i<(sint)TmpVertices.size();i++)
	{
		CMRMVertex	&vert=TmpVertices[i];
		if(vert.CollapsedTo==-1)	// if exist yet.
		{
			vert.CoarserIndex=index;
			coarserMesh.Vertices.push_back(vert.Current);
			if(_Skinned)
				coarserMesh.SkinWeights.push_back(vert.CurrentSW);
			if(_HasMeshInterfaces)
				coarserMesh.InterfaceLinks.push_back(vert.InterfaceLink);

			index++;
		}
		else
			vert.CoarserIndex=-1;	// indicate that this vertex no more exist and is to be geomorphed to an other.
	}


	// Attributes.
	//============
	for(attId=0;attId<NumAttributes;attId++)
	{
		index=0;
		for(i=0;i<(sint)TmpAttributes[attId].size();i++)
		{
			CMRMAttribute	&wedge= TmpAttributes[attId][i];
			if(wedge.CollapsedTo==-1)	// if exist yet.
			{
				wedge.CoarserIndex=index;
				coarserMesh.Attributes[attId].push_back(wedge.Current);
				index++;
			}
			else if(wedge.CollapsedTo==-2)	// else if totaly destroyed.
			{
				// Insert this wedge in the coarser mesh.
				// NB: the coarser mesh faces do not use it anymore, but FinerMesh use it
				// for geomorph (LODMesh.CoarserFaces may point to it).
				// NB: look at buildFinalMRM(), it works fine for all cases.
				wedge.CoarserIndex=index;
				coarserMesh.Attributes[attId].push_back(wedge.Current);
				index++;
			}
			else
				wedge.CoarserIndex=-1;	// indicate that this wedge no more exist and is to be geomorphed to an other.
		}
	}

	// Faces.
	//=======
	for(i=0;i<(sint)TmpFaces.size();i++)
	{
		CMRMFaceBuild	&face=TmpFaces[i];
		if(!face.Deleted)
		{
			CMRMFace	newFace;
			// Material.
			newFace.MaterialId= face.MaterialId;
			for(sint j=0;j<3;j++)
			{
				// Vertex.
				newFace.Corner[j].Vertex= TmpVertices[face.Corner[j].Vertex].CoarserIndex;
				nlassert(newFace.Corner[j].Vertex>=0);
				// Attributes.
				for(attId=0;attId<NumAttributes;attId++)
				{
					sint	oldidx= face.Corner[j].Attributes[attId];
					newFace.Corner[j].Attributes[attId]= TmpAttributes[attId][oldidx].CoarserIndex;
					nlassert(newFace.Corner[j].Attributes[attId]>=0);
				}

			}

			coarserMesh.Faces.push_back(newFace);
		}
	}

}


// ***************************************************************************
void	CMRMBuilder::makeLODMesh(CMRMMeshGeom &lodMesh)
{
	sint	i,j,attId,index,coidx;

	// for all faces of this mesh, find target in the coarser mesh.
	for(i=0;i<(sint)lodMesh.CoarserFaces.size();i++)
	{
		CMRMFace	&face= lodMesh.CoarserFaces[i];

		// For 3 corners.
		for(j=0;j<3;j++)
		{
			// Vertex.
			// The index is yet the index in the finer mesh.
			index= face.Corner[j].Vertex;
			// the index in the coarser mesh is vert.CoarserIndex.
			coidx= TmpVertices[index].CoarserIndex;
			// but if this vertex is collapsed, must find the good index (yet in the finer mesh)
			if(coidx==-1)
			{
				// find to which we must collapse.
				index= followVertex(index);
				// and so we have the coarser index. this one must be valid.
				coidx= TmpVertices[index].CoarserIndex;
				nlassert(coidx>=0);
			}
			// update corner of CoarserFace.
			face.Corner[j].Vertex= coidx;


			// Do exactly same thing for all attributes.
			for(attId=0;attId<NumAttributes;attId++)
			{
				index= face.Corner[j].Attributes[attId];
				coidx= TmpAttributes[attId][index].CoarserIndex;
				if(coidx==-1)
				{
					index= followWedge(attId, index);
					coidx= TmpAttributes[attId][index].CoarserIndex;
					nlassert(coidx>=0);
				}
				face.Corner[j].Attributes[attId]= coidx;
			}
		}
	}

}

// ***************************************************************************
// Transform source blend shapes to source blend shapes modified (just calculate new vertex/attr position)
/*void	CMRMBuilder::computeBsVerticesAttributes(vector<CMRMMesh> &srcBsMeshs, vector<CMRMMesh> &bsMeshsMod)
{
	sint	i, j, k, attId;

	bsMeshsMod.resize (srcBsMeshs.size());
	for (k = 0; k < (sint)srcBsMeshs.size(); ++k)
	{
		CMRMMesh &rBsMesh = srcBsMeshs[k];
		CMRMMesh &rBsMeshMod = bsMeshsMod[k];

		// Calculate modified vertices with the linear equation back tracking help
		rBsMeshMod.Vertices.resize (rBsMesh.Vertices.size());
		for (i = 0; i < (sint)rBsMesh.Vertices.size(); ++i)
		{
			CLinearEquation &LinEq = TmpVertices[i].CurrentLinEq;
			rBsMeshMod.Vertices[i] = CVector(0.0f, 0.0f, 0.0f);
			for (j = 0; j < (sint)LinEq.Elts.size(); ++j)
			{
				rBsMeshMod.Vertices[i] += LinEq.Elts[j].factor * rBsMesh.Vertices[LinEq.Elts[j].index];
			}
		}

		// All attributes
		rBsMeshMod.NumAttributes = NumAttributes;
		for (attId = 0; attId < NumAttributes; attId++)
		{
			rBsMeshMod.Attributes[attId].resize (rBsMesh.Attributes[attId].size());
			for (i = 0; i < (sint)rBsMesh.Attributes[attId].size(); ++i)
			{
				CLinearEquation &LinEq = TmpAttributes[attId][i].CurrentLinEq;
				rBsMeshMod.Attributes[attId][i] = CVectorH(0.0f, 0.0f, 0.0f, 0.0f);
				for (j = 0; j < (sint)LinEq.Elts.size(); ++j)
				{
					rBsMeshMod.Attributes[attId][i].x += LinEq.Elts[j].factor * rBsMesh.Attributes[attId][LinEq.Elts[j].index].x;
					rBsMeshMod.Attributes[attId][i].y += LinEq.Elts[j].factor * rBsMesh.Attributes[attId][LinEq.Elts[j].index].y;
					rBsMeshMod.Attributes[attId][i].z += LinEq.Elts[j].factor * rBsMesh.Attributes[attId][LinEq.Elts[j].index].z;
					rBsMeshMod.Attributes[attId][i].w += LinEq.Elts[j].factor * rBsMesh.Attributes[attId][LinEq.Elts[j].index].w;
				}
			}
		}
	}
}*/

// ***************************************************************************
// Transform source Blend Shape Meshes Modified into coarser blend shape mesh (compact vertices)
void	CMRMBuilder::makeCoarserBS (vector<CMRMBlendShape> &csBsMeshs)
{
	uint32 i, k;
	sint32 nSizeVert, nSizeAttr, attId;

	// Calculate size of vertices array
	nSizeVert = 0;
	for (i = 0; i < TmpVertices.size(); ++i)
		if(TmpVertices[i].CoarserIndex > nSizeVert)
			nSizeVert = TmpVertices[i].CoarserIndex;
	++nSizeVert;

	for (k = 0; k < csBsMeshs.size(); ++k)
	{
		CMRMBlendShape &rBsCoarserMesh = csBsMeshs[k];

		rBsCoarserMesh.Vertices.resize (nSizeVert);
		rBsCoarserMesh.NumAttributes = NumAttributes;

		// Vertices
		for(i = 0; i < TmpVertices.size(); ++i)
		{
			CMRMVertex &vert = TmpVertices[i];
			if (vert.CoarserIndex != -1)
			{
				rBsCoarserMesh.Vertices[vert.CoarserIndex] = vert.BSCurrent[k];
			}
		}

		for (attId = 0; attId < NumAttributes; attId++)
		{
			// Calculate size of attribute attId array
			nSizeAttr = 0;
			for(i = 0; i < TmpAttributes[attId].size(); i++)
				if (TmpAttributes[attId][i].CoarserIndex > nSizeAttr)
					nSizeAttr = TmpAttributes[attId][i].CoarserIndex;
			++nSizeAttr;

			rBsCoarserMesh.Attributes[attId].resize (nSizeAttr);

			for (i = 0; i < TmpAttributes[attId].size(); i++)
			{
				CMRMAttribute &wedge = TmpAttributes[attId][i];
				if (wedge.CoarserIndex != -1)
				{
					rBsCoarserMesh.Attributes[attId][wedge.CoarserIndex] = wedge.BSCurrent[k];
				}
			}
		}
	}
}

// ***************************************************************************
void	CMRMBuilder::makeFromMesh(const CMRMMesh &baseMesh, CMRMMeshGeom &lodMesh, CMRMMesh &coarserMesh, sint nWantedFaces)
{
	// Init Tmp values in MRM builder.
	init(baseMesh);

	// compute MRM too next tgt face.
	collapseEdges(nWantedFaces);

	// save the coarser mesh.
	saveCoarserMesh(coarserMesh);
	// Build coarser BlendShapes.
	coarserMesh.BlendShapes.resize(baseMesh.BlendShapes.size());
	makeCoarserBS(coarserMesh.BlendShapes);

	// build the lodMesh (baseMesh, with vertex/Attributes collapse infos).
	lodMesh= baseMesh;
	makeLODMesh(lodMesh);

	// end for this level.
}



// ***************************************************************************
// ***************************************************************************
// Global MRM Level method.
// ***************************************************************************
// ***************************************************************************


// ***************************************************************************
void	CMRMBuilder::buildAllLods(const CMRMMesh &baseMesh, std::vector<CMRMMeshGeom> &lodMeshs,
								  uint nWantedLods, uint divisor)
{
	sint	nFaces= (sint)baseMesh.Faces.size();
	sint	nBaseFaces;
	sint	i;
	CMRMMesh srcMesh = baseMesh;

	// coarsest LOD will have those number of faces.
	nBaseFaces=nFaces/divisor;
	nBaseFaces=max(nBaseFaces,4);

	// must have at least 2 LOD to be really intersting. But the rest of the process work too with only one Lod!!
	nlassert(nWantedLods>=1);
	lodMeshs.resize(nWantedLods);

	// If only one lod asked, must init some Tmp Global values (like NumAttributes)
	if(nWantedLods==1)
	{
		_CurrentLodComputed= 0;
		init(baseMesh);
	}

	// must fill all LODs, from end to start. do not proces last lod since it will be the coarsest mesh.
	for(i=nWantedLods-1;i>0;i--)
	{
		sint	nbWantedFaces;

		// for sewing computing
		_CurrentLodComputed= i;

		// Linear.
		nbWantedFaces= nBaseFaces + (nFaces-nBaseFaces) * (i-1)/(nWantedLods-1);
		nbWantedFaces=max(nbWantedFaces,4);

		// Build this LOD.
		CMRMMesh	csMesh;
		// The mesh
		makeFromMesh(srcMesh, lodMeshs[i], csMesh, nbWantedFaces);

		// next mesh to process is csMesh.
		srcMesh = csMesh;
	}
	// the first lodMedsh gets the coarsest mesh.
	lodMeshs[0]= srcMesh;
}


// ***************************************************************************
void	CMRMBuilder::buildFinalMRM(std::vector<CMRMMeshGeom> &lodMeshs, CMRMMeshFinal &finalMRM)
{
	sint	i,j;
	sint	lodId, attId;
	sint	nLods= (sint)lodMeshs.size();

	// Init.
	// ===============
	finalMRM.reset();
	finalMRM.NumAttributes= NumAttributes;
	finalMRM.Skinned= _Skinned;
	CMRMMeshFinal::CWedge::NumAttributesToCompare= NumAttributes;
	CMRMMeshFinal::CWedge::CompareSkinning= _Skinned;
	finalMRM.Lods.resize(nLods);


	// Build Wedges, and faces index.
	// ===============
	// for all lods.
	for(lodId=0; lodId<nLods; lodId++)
	{
		CMRMMeshGeom	&lodMesh= lodMeshs[lodId];
		CMRMMeshGeom	&lodMeshPrec= lodMeshs[lodId==0?0:lodId-1];
		// for all face corner.
		for(i=0; i<(sint)lodMesh.Faces.size();i++)
		{
			// The current face.
			CMRMFace	&face= lodMesh.Faces[i];
			// the current face, but which points to the prec LOD vertices/attributes.
			CMRMFace	&faceCoarser= lodMesh.CoarserFaces[i];
			// for 3 corners.
			for(j=0;j<3;j++)
			{
				CMRMCorner	&corner= face.Corner[j];
				CMRMCorner	&cornerCoarser= faceCoarser.Corner[j];
				// start and end wedge (geomorph), maybe same.
				CMRMMeshFinal::CWedge		wedgeStart;
				CMRMMeshFinal::CWedge		wedgeEnd;

				// fill wedgeStart with values from lodMesh.
				wedgeStart.Vertex= lodMesh.Vertices[corner.Vertex];
				if(_Skinned)
					wedgeStart.VertexSkin= lodMesh.SkinWeights[corner.Vertex];
				for(attId=0; attId<NumAttributes; attId++)
				{
					wedgeStart.Attributes[attId]= lodMesh.Attributes[attId][corner.Attributes[attId]];
				}

				// if geomorph possible (ie not lod 0).
				if(lodId>0)
				{
					// fill wedgeEnd with values from coarser lodMesh.
					wedgeEnd.Vertex= lodMeshPrec.Vertices[cornerCoarser.Vertex];
					if(_Skinned)
						wedgeEnd.VertexSkin= lodMeshPrec.SkinWeights[cornerCoarser.Vertex];
					for(attId=0; attId<NumAttributes; attId++)
					{
						wedgeEnd.Attributes[attId]= lodMeshPrec.Attributes[attId][cornerCoarser.Attributes[attId]];
					}
				}
				else
				{
					// no geomorph.
					wedgeEnd= wedgeStart;
				}

				// find/insert wedge, and get Ids. NB: if start/end same, same indices.
				sint	wedgeStartId= finalMRM.findInsertWedge(wedgeStart);
				sint	wedgeEndId= finalMRM.findInsertWedge(wedgeEnd);

				// store in TmpCorner.
				corner.WedgeStartId= wedgeStartId;
				corner.WedgeEndId= wedgeEndId;
			}
		}

		// Here, the number of wedge indicate the max number of wedge this LOD needs.
		finalMRM.Lods[lodId].NWedges= (sint)finalMRM.Wedges.size();
	}


	// Count NBWedges necessary for geomorph, and compute Dest geomorph wedges ids.
	// ===============
	// the number of geomorph required for one LOD.
	sint	sglmGeom;
	// the number of geomorph required for all LOD (max of sglmGeom).
	sint	sglmGeomMax= 0;

	// Do not process lod 0, since no geomorph.
	for(lodId=1; lodId<nLods; lodId++)
	{
		CMRMMeshGeom	&lodMesh= lodMeshs[lodId];

		// reset the GeomMap, the one which indicate if we have already inserted a geomorph.
		_GeomMap.clear();
		sglmGeom= 0;

		// for all face corner.
		for(i=0; i<(sint)lodMesh.Faces.size();i++)
		{
			// The current face.
			CMRMFace	&face= lodMesh.Faces[i];
			// for 3 corners.
			for(j=0;j<3;j++)
			{
				CMRMCorner	&corner= face.Corner[j];

				// if not same wedge Ids, this is a geomorphed wedge.
				if(corner.WedgeStartId != corner.WedgeEndId)
				{
					// search if it exist yet in the set.
					CMRMWedgeGeom	geom;
					geom.Start= corner.WedgeStartId;
					geom.End= corner.WedgeEndId;
					sint	geomDest= sglmGeom;
					// if don't find this geom in the set, then it is a new one.
					TGeomMap::const_iterator	it= _GeomMap.find(geom);
					if(it == _GeomMap.end())
					{
						_GeomMap.insert( make_pair(geom, geomDest) );
						sglmGeom++;
					}
					else
						geomDest= it->second;

					// store this Geom Id in the corner.
					corner.WedgeGeomId= geomDest;
				}
			}
		}

		// take the max.
		sglmGeomMax= max(sglmGeomMax, sglmGeom);
	}


	// inform the finalMRM.
	finalMRM.NGeomSpace= sglmGeomMax;


	// decal all wedges/ face index.
	// ===============
	// insert an empty space for dest geomorph.
	finalMRM.Wedges.insert(finalMRM.Wedges.begin(), sglmGeomMax, CMRMMeshFinal::CWedge());

	// Parse all faces corner of All lods, and decal Start/End Wedge index.
	for(lodId=0; lodId<nLods; lodId++)
	{
		CMRMMeshGeom	&lodMesh= lodMeshs[lodId];

		// for all face corner.
		for(i=0; i<(sint)lodMesh.Faces.size();i++)
		{
			// The current face.
			CMRMFace	&face= lodMesh.Faces[i];
			// for 3 corners.
			for(j=0;j<3;j++)
			{
				CMRMCorner	&corner= face.Corner[j];

				// decal indices.
				corner.WedgeStartId+= sglmGeomMax;
				corner.WedgeEndId+= sglmGeomMax;
			}
		}

		// increment too the number of wedge required for this Lod.
		finalMRM.Lods[lodId].NWedges+= sglmGeomMax;
	}


	// fill faces.
	// ===============
	// Parse all faces corner of All lods, and build Faces/Geomorphs..
	for(lodId=0; lodId<nLods; lodId++)
	{
		CMRMMeshGeom			&lodMesh= lodMeshs[lodId];
		CMRMMeshFinal::CLod		&lodDest= finalMRM.Lods[lodId];

		// alloc final faces of this LOD.
		lodDest.Faces.resize(lodMesh.Faces.size());

		// reset the GeomMap, the one which indicate if we have already inserted a geomorph.
		_GeomMap.clear();

		// for all face corner.
		for(i=0; i<(sint)lodMesh.Faces.size();i++)
		{
			// The current face.
			CMRMFace	&face= lodMesh.Faces[i];
			// The dest face.
			CMRMMeshFinal::CFace		&faceDest= lodDest.Faces[i];
			// fill good material.
			faceDest.MaterialId= face.MaterialId;

			// for 3 corners.
			for(j=0;j<3;j++)
			{
				CMRMCorner	&corner= face.Corner[j];

				// if not same wedge Ids, this is a geomorphed wedge.
				if(corner.WedgeStartId != corner.WedgeEndId)
				{
					// geomorph, so point to geomorphed wedge.
					faceDest.WedgeId[j]= corner.WedgeGeomId;

					// Build the geomorph, add it to the list (if not yet inserted).
					CMRMWedgeGeom	geom;
					geom.Start= corner.WedgeStartId;
					geom.End=	corner.WedgeEndId;
					// if don't find this geom in the set, then it is a new one.
					TGeomMap::const_iterator	it= _GeomMap.find(geom);
					if(it == _GeomMap.end())
					{
						// mark it as inserted.
						_GeomMap.insert( make_pair(geom, corner.WedgeGeomId) );
						// and we must insert this geom in the array.
						nlassert( corner.WedgeGeomId==(sint)lodDest.Geomorphs.size() );
						lodDest.Geomorphs.push_back(geom);
					}
				}
				else
				{
					// no geomorph, so just point to good wedge.
					faceDest.WedgeId[j]= corner.WedgeStartId;
				}
			}
		}
	}


	// process all wedges, and compute NSkinMatUsed, skipping geomorphs.
	// ===============
	// NB: this works because weights are sorted from biggest to lowest.
	if(_Skinned)
	{
		for(i=finalMRM.NGeomSpace; i<(sint)finalMRM.Wedges.size();i++)
		{
			CMRMMeshFinal::CWedge	&wedge= finalMRM.Wedges[i];
			for(j=0; j<NL3D_MESH_SKINNING_MAX_MATRIX; j++)
			{
				if(wedge.VertexSkin.Weights[j]==0)
					break;
			}
			nlassert(j>0);
			wedge.NSkinMatUsed= j;
		}
	}

	// Blend Shape Stuff
	finalMRM.MRMBlendShapesFinals.resize (lodMeshs[0].BlendShapes.size());
	for (lodId = 0; lodId < nLods; ++lodId)
	{
		CMRMMeshGeom &lodMesh= lodMeshs[lodId];
		CMRMMeshGeom &lodMeshPrec= lodMeshs[lodId==0?0:lodId-1];

		// for all face corner.
		for (i = 0; i < (sint)lodMesh.Faces.size(); ++i)
		{
			// The current face.
			CMRMFace &face = lodMesh.Faces[i];
			// the current face, but which points to the prec LOD vertices/attributes.
			CMRMFace &faceCoarser = lodMesh.CoarserFaces[i];
			// for 3 corners.
			for (j = 0; j < 3; ++j)
			{
				CMRMCorner &corner = face.Corner[j];
				CMRMCorner &cornerCoarser = faceCoarser.Corner[j];

				sint startDestIndex = corner.WedgeStartId;

				for (sint k = 0; k < (sint)finalMRM.MRMBlendShapesFinals.size(); ++k)
				{
					CMRMMeshFinal::CMRMBlendShapeFinal &rBSFinal = finalMRM.MRMBlendShapesFinals[k];

					rBSFinal.Wedges.resize (finalMRM.Wedges.size());
					// Fill WedgeStart used by this corner.
					rBSFinal.Wedges[startDestIndex].Vertex = lodMesh.BlendShapes[k].Vertices[corner.Vertex];
					for (attId = 0; attId < NumAttributes; ++attId)
					{
						rBSFinal.Wedges[startDestIndex].Attributes[attId] = lodMesh.BlendShapes[k].Attributes[attId][corner.Attributes[attId]];
					}

					// If geomorph, must fill the end too
					if(lodId>0 && corner.WedgeStartId != corner.WedgeEndId)
					{
						sint endDestIndex = corner.WedgeEndId;

						rBSFinal.Wedges[endDestIndex].Vertex = lodMeshPrec.BlendShapes[k].Vertices[cornerCoarser.Vertex];
						for (attId = 0; attId < NumAttributes; ++attId)
						{
							rBSFinal.Wedges[endDestIndex].Attributes[attId] = lodMeshPrec.BlendShapes[k].Attributes[attId][cornerCoarser.Attributes[attId]];
						}
					}
				}

			}
		}
	}
}



// ***************************************************************************
// ***************************************************************************
// Interface to MeshBuild Part.
// ***************************************************************************
// ***************************************************************************



// ***************************************************************************
sint			CMRMBuilder::findInsertAttributeInBaseMesh(CMRMMesh &baseMesh, sint attId, sint vertexId, const CVectorH &att)
{
	// find this attribute in the map.
	CAttributeKey	key;
	key.VertexId= vertexId;
	key.Attribute= att;
	TAttributeMap::iterator		it= _AttributeMap[attId].find(key);

	// if attribute not found in the map, then insert a new one.
	if(it==_AttributeMap[attId].end())
	{
		sint	idx= (sint)baseMesh.Attributes[attId].size();
		// insert into the array.
		baseMesh.Attributes[attId].push_back(att);
		// insert into the map.
		_AttributeMap[attId].insert(make_pair(key, idx));
		return idx;
	}
	else
	{
		// return the one found.
		return it->second;
	}
}


// ***************************************************************************
sint			CMRMBuilder::findInsertNormalInBaseMesh(CMRMMesh &baseMesh, sint attId, sint vertexId, const CVector &normal)
{
	CVectorH	att;
	att= normal;
	att.w= 0;
	return findInsertAttributeInBaseMesh(baseMesh, attId, vertexId, att);
}


// ***************************************************************************
sint			CMRMBuilder::findInsertColorInBaseMesh(CMRMMesh &baseMesh, sint attId, sint vertexId, CRGBA col)
{
	CVectorH	att;
	att.x= col.R;
	att.y= col.G;
	att.z= col.B;
	att.w= col.A;
	return findInsertAttributeInBaseMesh(baseMesh, attId, vertexId, att);
}


// ***************************************************************************
sint			CMRMBuilder::findInsertUvwInBaseMesh(CMRMMesh &baseMesh, sint attId, sint vertexId, const NLMISC::CUVW &uvw)
{
	CVectorH	att;
	att.x= uvw.U;
	att.y= uvw.V;
	att.z= uvw.W;
	att.w= 0;
	return findInsertAttributeInBaseMesh(baseMesh, attId, vertexId, att);
}


// ***************************************************************************
CRGBA			CMRMBuilder::attToColor(const CVectorH &att) const
{
	CRGBA	ret;
	float	tmp;
	tmp= att.x; clamp(tmp, 0, 255);
	ret.R= (uint8)(uint)tmp;
	tmp= att.y; clamp(tmp, 0, 255);
	ret.G= (uint8)(uint)tmp;
	tmp= att.z; clamp(tmp, 0, 255);
	ret.B= (uint8)(uint)tmp;
	tmp= att.w; clamp(tmp, 0, 255);
	ret.A= (uint8)(uint)tmp;

	return ret;
}


// ***************************************************************************
NLMISC::CUVW			CMRMBuilder::attToUvw(const CVectorH &att) const
{
	return CUVW(att.x, att.y, att.z);
}


// ***************************************************************************
uint32			CMRMBuilder::buildMrmBaseMesh(const CMesh::CMeshBuild &mbuild, CMRMMesh &baseMesh)
{
	sint		i,j,k;
	sint		nFaces;
	sint		attId;
	// build the supported VertexFormat.
	uint32		retVbFlags= CVertexBuffer::PositionFlag;


	// reset the baseMesh.
	baseMesh= CMRMMesh();
	// reset Tmp.
	for(attId=0; attId<NL3D_MRM_MAX_ATTRIB;attId++)
		_AttributeMap[attId].clear();


	// Compute number of attributes used by the MeshBuild.
	// ========================
	// Compute too
	if(mbuild.VertexFlags & CVertexBuffer::NormalFlag)
	{
		baseMesh.NumAttributes++;
		retVbFlags|= CVertexBuffer::NormalFlag;
	}
	if(mbuild.VertexFlags & CVertexBuffer::PrimaryColorFlag)
	{
		baseMesh.NumAttributes++;
		retVbFlags|= CVertexBuffer::PrimaryColorFlag;
	}
	if(mbuild.VertexFlags & CVertexBuffer::SecondaryColorFlag)
	{
		baseMesh.NumAttributes++;
		retVbFlags|= CVertexBuffer::SecondaryColorFlag;
	}
	for(k=0; k<CVertexBuffer::MaxStage;k++)
	{
		uint flag=CVertexBuffer::TexCoord0Flag<<k;
		if(mbuild.VertexFlags & flag)
		{
			baseMesh.NumAttributes++;
			retVbFlags|=flag;
		}
	}
	nlassert(baseMesh.NumAttributes<=NL3D_MRM_MAX_ATTRIB);


	// Fill basics: Vertices and Faces materials / index to vertices.
	// ========================
	// Just copy vertices.
	baseMesh.Vertices= mbuild.Vertices;
	// Just copy SkinWeights.
	if(_Skinned)
		baseMesh.SkinWeights= mbuild.SkinWeights;
	// Just copy InterfaceLinks
	if(_HasMeshInterfaces)
		baseMesh.InterfaceLinks= mbuild.InterfaceLinks;
	// Resize faces.
	nFaces= (sint)mbuild.Faces.size();
	baseMesh.Faces.resize(nFaces);
	for(i=0; i<nFaces; i++)
	{
		// copy material Id.
		baseMesh.Faces[i].MaterialId= mbuild.Faces[i].MaterialId;
		// Copy Vertex index.
		for(j=0; j<3; j++)
		{
			baseMesh.Faces[i].Corner[j].Vertex= mbuild.Faces[i].Corner[j].Vertex;
		}
	}

	// Resolve attributes discontinuities and Fill attributes of the baseMesh.
	// ========================
	// For all corners.
	for(i=0; i<nFaces; i++)
	{
		for(j=0; j<3; j++)
		{
			const CMesh::CCorner	&srcCorner= mbuild.Faces[i].Corner[j];
			CMRMCorner				&destCorner= baseMesh.Faces[i].Corner[j];
			attId= 0;

			// For all activated attributes in mbuild, find/insert the attribute in the baseMesh.
			// NB: 2 attributes are said to be different if they have not the same value OR if they don't lie
			// on the same vertex. This is very important for MRM computing.
			if(mbuild.VertexFlags & CVertexBuffer::NormalFlag)
			{
				destCorner.Attributes[attId]= findInsertNormalInBaseMesh(baseMesh, attId, destCorner.Vertex, srcCorner.Normal);
				attId++;
			}
			if(mbuild.VertexFlags & CVertexBuffer::PrimaryColorFlag)
			{
				destCorner.Attributes[attId]= findInsertColorInBaseMesh(baseMesh, attId, destCorner.Vertex, srcCorner.Color);
				attId++;
			}
			if(mbuild.VertexFlags & CVertexBuffer::SecondaryColorFlag)
			{
				destCorner.Attributes[attId]= findInsertColorInBaseMesh(baseMesh, attId, destCorner.Vertex, srcCorner.Specular);
				attId++;
			}
			for(k=0; k<CVertexBuffer::MaxStage;k++)
			{
				if(mbuild.VertexFlags & (CVertexBuffer::TexCoord0Flag<<k))
				{
					destCorner.Attributes[attId]= findInsertUvwInBaseMesh(baseMesh, attId, destCorner.Vertex, srcCorner.Uvws[k]);
					attId++;
				}
			}
		}
	}



	// End. clear Tmp infos.
	// ========================
	// reset Tmp.
	for(attId=0; attId<NL3D_MRM_MAX_ATTRIB;attId++)
		_AttributeMap[attId].clear();

	return	retVbFlags;
}



// ***************************************************************************
CMesh::CSkinWeight	CMRMBuilder::normalizeSkinWeight(const CMesh::CSkinWeight &sw) const
{
	uint	nbMats= 0;
	static vector<CTmpVertexWeight>		sws;
	sws.reserve(NL3D_MESH_SKINNING_MAX_MATRIX);
	sws.clear();

	// For all weights of sw1.
	uint i;
	for(i=0; i<NL3D_MESH_SKINNING_MAX_MATRIX; i++)
	{
		CTmpVertexWeight	vw;
		vw.MatrixId= sw.MatrixId[i];
		vw.Weight= sw.Weights[i];
		// if this weight is not null.
		if(vw.Weight>0)
		{
			// add it to the list.
			sws.push_back(vw);
			nbMats++;
		}
	}

	// sort by Weight decreasing order.
	sort(sws.begin(), sws.end());


	// Then output the result to the skinWeight, normalizing.
	float	sumWeight=0;
	for(i= 0; i<nbMats; i++)
	{
		sumWeight+= sws[i].Weight;
	}

	CMesh::CSkinWeight	ret;
	// Fill only needed matrix (other are rested in CMesh::CSkinWeight ctor).
	for(i= 0; i<nbMats; i++)
	{
		ret.MatrixId[i]= sws[i].MatrixId;
		ret.Weights[i]= sws[i].Weight / sumWeight;
	}

	return ret;
}


// ***************************************************************************
void			CMRMBuilder::normalizeBaseMeshSkin(CMRMMesh &baseMesh) const
{
	nlassert(_Skinned);

	for(uint i=0; i<baseMesh.SkinWeights.size(); i++)
	{
		baseMesh.SkinWeights[i]= normalizeSkinWeight(baseMesh.SkinWeights[i]);
	}
}



// ***************************************************************************
void			CMRMBuilder::buildMeshBuildMrm(const CMRMMeshFinal &finalMRM, CMeshMRMGeom::CMeshBuildMRM &mbuild, uint32 vbFlags, uint32 nbMats, const CMesh::CMeshBuild &mb)
{
	sint	i,j,k;
	sint	attId;

	// reset the mbuild.
	mbuild= CMeshMRMGeom::CMeshBuildMRM();
	// Setup VB.

	bool useFormatExt = false;
	// Check whether there are texture coordinates with more than 2 compnents, which force us to use an extended vertex format
	for (k = 0; k < CVertexBuffer::MaxStage; ++k)
	{
		if (
			(vbFlags & (CVertexBuffer::TexCoord0Flag << k))
			&& mb.NumCoords[k] != 2)
		{
			useFormatExt = true;
			break;
		}
	}

	uint numTexCoordUsed = 0;


	for (k = 0; k < CVertexBuffer::MaxStage; ++k)
	{
		if (vbFlags & (CVertexBuffer::TexCoord0Flag << k))
		{
			numTexCoordUsed = k;
		}
	}

	if (!useFormatExt)
	{
		// setup standard format
		mbuild.VBuffer.setVertexFormat(vbFlags);
	}
	else // setup extended format
	{
		mbuild.VBuffer.clearValueEx();
		if (vbFlags & CVertexBuffer::PositionFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Position, CVertexBuffer::Float3);
		if (vbFlags & CVertexBuffer::NormalFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Normal, CVertexBuffer::Float3);
		if (vbFlags & CVertexBuffer::PrimaryColorFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::PrimaryColor, CVertexBuffer::UChar4);
		if (vbFlags & CVertexBuffer::SecondaryColorFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::SecondaryColor, CVertexBuffer::UChar4);
		if (vbFlags & CVertexBuffer::WeightFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Weight, CVertexBuffer::Float4);
		if (vbFlags & CVertexBuffer::PaletteSkinFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::PaletteSkin, CVertexBuffer::UChar4);
		if (vbFlags & CVertexBuffer::FogFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Fog, CVertexBuffer::Float1);

		for (k = 0; k < CVertexBuffer::MaxStage; ++k)
		{
			if (vbFlags & (CVertexBuffer::TexCoord0Flag << k))
			{
				switch(mb.NumCoords[k])
				{
					case 2:
						mbuild.VBuffer.addValueEx((CVertexBuffer::TValue) (CVertexBuffer::TexCoord0 + k), CVertexBuffer::Float2);
					break;
					case 3:
						mbuild.VBuffer.addValueEx((CVertexBuffer::TValue) (CVertexBuffer::TexCoord0 + k), CVertexBuffer::Float3);
					break;
					default:
						nlassert(0);
					break;
				}
			}
		}
		mbuild.VBuffer.initEx();
	}

	// Copy the UVRouting
	for (i=0; i<CVertexBuffer::MaxStage; i++)
	{
		mbuild.VBuffer.setUVRouting (i, mb.UVRouting[i]);
	}

	// Setup the VertexBuffer.
	// ========================
	// resize the VB.
	mbuild.VBuffer.setNumVertices((uint32)finalMRM.Wedges.size());
	// Setup SkinWeights.
	if(_Skinned)
		mbuild.SkinWeights.resize(finalMRM.Wedges.size());

	CVertexBufferReadWrite vba;
	mbuild.VBuffer.lock (vba);

	// fill the VB.
	for(i=0; i<(sint)finalMRM.Wedges.size(); i++)
	{
		const CMRMMeshFinal::CWedge	&wedge= finalMRM.Wedges[i];

		// setup Vertex.
		vba.setVertexCoord(i, wedge.Vertex);

		// seutp attributes.
		attId= 0;

		// For all activated attributes in mbuild, retriev the attribute from the finalMRM.
		if(vbFlags & CVertexBuffer::NormalFlag)
		{
			vba.setNormalCoord(i, wedge.Attributes[attId] );
			attId++;
		}
		if(vbFlags & CVertexBuffer::PrimaryColorFlag)
		{
			vba.setColor(i, attToColor(wedge.Attributes[attId]) );
			attId++;
		}
		if(vbFlags & CVertexBuffer::SecondaryColorFlag)
		{
			vba.setSpecular(i, attToColor(wedge.Attributes[attId]) );
			attId++;
		}
		for(k=0; k<CVertexBuffer::MaxStage;k++)
		{
			if(vbFlags & (CVertexBuffer::TexCoord0Flag<<k))
			{
				switch(mb.NumCoords[k])
				{
					case 2:
						vba.setTexCoord(i, k, (CUV) attToUvw(wedge.Attributes[attId]) );
					break;
					case 3:
					{
						CUVW uvw = attToUvw(wedge.Attributes[attId]);
						vba.setValueFloat3Ex((CVertexBuffer::TValue) (CVertexBuffer::TexCoord0 + k), i, uvw.U, uvw.V, uvw.W);
					}
					break;
					default:
						nlassert(0);
					break;
				}
				attId++;
			}
		}

		// Setup SkinWeights.
		if(_Skinned)
		{
			mbuild.SkinWeights[i]= wedge.VertexSkin;
		}
	}


	// Build Lods.
	// ========================
	// resize
	mbuild.Lods.resize(finalMRM.Lods.size());
	// fill.
	for(i=0; i<(sint)finalMRM.Lods.size(); i++)
	{
		const CMRMMeshFinal::CLod	&srcLod= finalMRM.Lods[i];
		CMeshMRMGeom::CLod			&destLod= mbuild.Lods[i];

		// Basic.
		//---------

		// Copy NWedges infos.
		destLod.NWedges= srcLod.NWedges;
		// Copy Geomorphs infos.
		destLod.Geomorphs= srcLod.Geomorphs;


		// Reorder faces by rdrpass.
		//---------

		// First count the number of faces used by this LOD for each material
		vector<sint>	matCount;
		// resize, and reset to 0.
		matCount.clear();
		matCount.resize(nbMats, 0);
		// For each face of this Lods, incr the mat face counter.
		for(j= 0; j<(sint)srcLod.Faces.size(); j++)
		{
			sint	matId= srcLod.Faces[j].MaterialId;
			nlassert(matId>=0);
			nlassert(matId<(sint)nbMats);
			// increment the refcount of this material by this LOD.
			matCount[matId]++;
		}

		// Then for each material not empty, create a rdrPass, and ref it for this material.
		vector<sint>	rdrPassIndex;	// material to rdrPass map.
		rdrPassIndex.resize(nbMats);
		for(j=0; j<(sint)nbMats; j++)
		{
			if(matCount[j]==0)
				rdrPassIndex[j]= -1;
			else
			{
				// map material to rdrPass.
				sint	idRdrPass= (sint)destLod.RdrPass.size();
				rdrPassIndex[j]= idRdrPass;
				// create a rdrPass.
				destLod.RdrPass.push_back(CMeshMRMGeom::CRdrPass());
				// assign the good materialId to this rdrPass.
				destLod.RdrPass[idRdrPass].MaterialId= j;
				// reserve the array of faces of this rdrPass.
				destLod.RdrPass[idRdrPass].PBlock.reserve(3*matCount[j]);
			}
		}

		// Then for each face, add it to the good rdrPass of this Lod.
		for(j= 0; j<(sint)srcLod.Faces.size(); j++)
		{
			sint	matId= srcLod.Faces[j].MaterialId;
			sint	idRdrPass= rdrPassIndex[matId];
			// add this face to the good rdrPass.
			sint	w0= srcLod.Faces[j].WedgeId[0];
			sint	w1= srcLod.Faces[j].WedgeId[1];
			sint	w2= srcLod.Faces[j].WedgeId[2];
			CIndexBuffer &ib = destLod.RdrPass[idRdrPass].PBlock;
			uint index = ib.getNumIndexes();
			ib.setNumIndexes(index+3);
			CIndexBufferReadWrite ibaWrite;
			ib.lock (ibaWrite);
			ibaWrite.setTri(index, w0, w1, w2);
		}


		// Build skin info for this Lod.
		//---------
		for(j=0; j<NL3D_MESH_SKINNING_MAX_MATRIX; j++)
		{
			destLod.InfluencedVertices[j].clear();
		}
		destLod.MatrixInfluences.clear();
		if(_Skinned)
		{
			// This is the set which tell what wedge has already been inserted.
			set<uint>	wedgeInfSet;

			// First, build the list of vertices influenced by this Lod.
			for(j= 0; j<(sint)srcLod.Faces.size(); j++)
			{
				for(k=0; k<3; k++)
				{
					sint	wedgeId= srcLod.Faces[j].WedgeId[k];
					// If it is a geomorph
					if(wedgeId<finalMRM.NGeomSpace)
					{
						// add the start and end to the list (if not here). NB: wedgeId is both the id
						// of the dest wedge, and the id of the geomorph.
						sint	wedgeStartId= destLod.Geomorphs[wedgeId].Start;
						sint	wedgeEndId= destLod.Geomorphs[wedgeId].End;
						uint	nMatUsedStart= finalMRM.Wedges[wedgeStartId].NSkinMatUsed;
						uint	nMatUsedEnd= finalMRM.Wedges[wedgeEndId].NSkinMatUsed;

						// if insertion in the set work, add to the good array.
						if( wedgeInfSet.insert(wedgeStartId).second )
							destLod.InfluencedVertices[nMatUsedStart-1].push_back(wedgeStartId);
						if( wedgeInfSet.insert(wedgeEndId).second )
							destLod.InfluencedVertices[nMatUsedEnd-1].push_back(wedgeEndId);
					}
					else
					{
						uint	nMatUsed= finalMRM.Wedges[wedgeId].NSkinMatUsed;

						// just add this wedge to the list (if not here).
						// if insertion in the set work, add to the array.
						if( wedgeInfSet.insert(wedgeId).second )
							destLod.InfluencedVertices[nMatUsed-1].push_back(wedgeId);
					}
				}
			}

			// Optimisation: for better cache, sort the destLod.InfluencedVertices in increasing order.
			for(j=0; j<NL3D_MESH_SKINNING_MAX_MATRIX; j++)
			{
				sort(destLod.InfluencedVertices[j].begin(), destLod.InfluencedVertices[j].end());
			}


			// Then Build the MatrixInfluences array, for all thoses Influenced Vertices only.
			// This is the map MatrixId -> MatrixInfId.
			map<uint, uint>		matrixInfMap;

			// For all influenced vertices, flags matrix they use.
			uint	iSkinMat;
			for(iSkinMat= 0; iSkinMat<NL3D_MESH_SKINNING_MAX_MATRIX; iSkinMat++)
			{
				for(j= 0; j<(sint)destLod.InfluencedVertices[iSkinMat].size(); j++)
				{
					uint	wedgeId= destLod.InfluencedVertices[iSkinMat][j];

					// take the original wedge.
					const CMRMMeshFinal::CWedge	&wedge= finalMRM.Wedges[wedgeId];
					// For all matrix with not null influence...
					for(k= 0; k<NL3D_MESH_SKINNING_MAX_MATRIX; k++)
					{
						float	matWeight= wedge.VertexSkin.Weights[k];

						// This check the validity of skin weights sort. If false, problem before in the algo.
						if((uint)k<iSkinMat+1)
						{
							nlassert( matWeight>0 );
						}
						else
						{
							nlassert( matWeight==0 );
						}
						// if not null influence.
						if(matWeight>0)
						{
							uint	matId= wedge.VertexSkin.MatrixId[k];

							// search/insert the matrixInfId.
							map<uint, uint>::iterator	it= matrixInfMap.find(matId);
							if( it==matrixInfMap.end() )
							{
								uint matInfId= (uint)destLod.MatrixInfluences.size();
								matrixInfMap.insert( make_pair(matId, matInfId) );
								// create the new MatrixInfluence.
								destLod.MatrixInfluences.push_back(matId);
							}
						}
					}
				}
			}

		}

	}

	// Indicate Skinning.
	mbuild.Skinned= _Skinned;



	bool useTgSpace = mb.MeshVertexProgram != NULL ? mb.MeshVertexProgram->needTangentSpace() : false;

	// Construct Blend Shapes
	//// mbuild <- finalMRM
	mbuild.BlendShapes.resize (finalMRM.MRMBlendShapesFinals.size());
	for (k = 0; k < (sint)mbuild.BlendShapes.size(); ++k)
	{
		CBlendShape &rBS = mbuild.BlendShapes[k];
		sint32 nNbVertVB = (sint32)finalMRM.Wedges.size();
		bool bIsDeltaPos = false;
		rBS.deltaPos.resize (nNbVertVB, CVector(0.0f,0.0f,0.0f));
		bool bIsDeltaNorm = false;
		rBS.deltaNorm.resize (nNbVertVB, CVector(0.0f,0.0f,0.0f));
		bool bIsDeltaUV = false;
		rBS.deltaUV.resize (nNbVertVB, CUV(0.0f,0.0f));
		bool bIsDeltaCol = false;
		rBS.deltaCol.resize (nNbVertVB, CRGBAF(0.0f,0.0f,0.0f,0.0f));
		bool bIsDeltaTgSpace = false;
		if (useTgSpace)
		{
			rBS.deltaTgSpace.resize(nNbVertVB, CVector::Null);
		}

		rBS.VertRefs.resize (nNbVertVB, 0xffffffff);

		for (i = 0; i < nNbVertVB; i++)
		{
			const CMRMMeshFinal::CWedge	&rWedgeRef = finalMRM.Wedges[i];
			const CMRMMeshFinal::CWedge	&rWedgeTar = finalMRM.MRMBlendShapesFinals[k].Wedges[i];

			CVector delta = rWedgeTar.Vertex - rWedgeRef.Vertex;
			CVectorH attr;

			if (delta.norm() > 0.001f)
			{
				rBS.deltaPos[i] = delta;
				rBS.VertRefs[i] = i;
				bIsDeltaPos = true;
			}

			attId = 0;
			if (vbFlags & CVertexBuffer::NormalFlag)
			{
				attr = rWedgeRef.Attributes[attId];
				CVector NormRef = CVector(attr.x, attr.y, attr.z);
				attr = rWedgeTar.Attributes[attId];
				CVector NormTar = CVector(attr.x, attr.y, attr.z);
				delta = NormTar - NormRef;
				if (delta.norm() > 0.001f)
				{
					rBS.deltaNorm[i] = delta;
					rBS.VertRefs[i] = i;
					bIsDeltaNorm = true;
				}
				attId++;
			}

			if (vbFlags & CVertexBuffer::PrimaryColorFlag)
			{
				attr = rWedgeRef.Attributes[attId];
				CRGBAF RGBARef = CRGBAF(attr.x/255.0f, attr.y/255.0f, attr.z/255.0f, attr.w/255.0f);
				attr = rWedgeTar.Attributes[attId];
				CRGBAF RGBATar = CRGBAF(attr.x/255.0f, attr.y/255.0f, attr.z/255.0f, attr.w/255.0f);
				CRGBAF deltaRGBA = RGBATar - RGBARef;
				if ((deltaRGBA.R*deltaRGBA.R + deltaRGBA.G*deltaRGBA.G +
					deltaRGBA.B*deltaRGBA.B + deltaRGBA.A*deltaRGBA.A) > 0.0001f)
				{
					rBS.deltaCol[i] = deltaRGBA;
					rBS.VertRefs[i] = i;
					bIsDeltaCol = true;
				}
				attId++;
			}

			if (vbFlags & CVertexBuffer::SecondaryColorFlag)
			{	// Nothing to do !
				attId++;
			}

			// Do that only for the UV0
			if (vbFlags & CVertexBuffer::TexCoord0Flag)
			{
				attr = rWedgeRef.Attributes[attId];
				CUV UVRef = CUV(attr.x, attr.y);
				attr = rWedgeTar.Attributes[attId];
				CUV UVTar = CUV(attr.x, attr.y);
				CUV deltaUV = UVTar - UVRef;
				if ((deltaUV.U*deltaUV.U + deltaUV.V*deltaUV.V) > 0.0001f)
				{
					rBS.deltaUV[i] = deltaUV;
					rBS.VertRefs[i] = i;
					bIsDeltaUV = true;
				}
				attId++;
			}

			if (useTgSpace)
			{
				attr = rWedgeRef.Attributes[attId];
				CVector TgSpaceRef = CVector(attr.x, attr.y, attr.z);
				attr = rWedgeTar.Attributes[attId];
				CVector TgSpaceTar = CVector(attr.x, attr.y, attr.z);
				delta = TgSpaceTar - TgSpaceRef;
				if (delta.norm() > 0.001f)
				{
					rBS.deltaTgSpace[i] = delta;
					rBS.VertRefs[i] = i;
					bIsDeltaTgSpace = true;
				}
				attId++;
			}

		} // End of all vertices added in blend shape

		// Delete unused items and calculate the number of vertex used (blended)

		sint32 nNbVertUsed = nNbVertVB;
		sint32 nDstPos = 0;
		for (j = 0; j < nNbVertVB; ++j)
		{
			if (rBS.VertRefs[j] == 0xffffffff) // Is vertex UNused
			{
				--nNbVertUsed;
			}
			else // Vertex used
			{
				if (nDstPos != j)
				{
					rBS.VertRefs[nDstPos]	= rBS.VertRefs[j];
					rBS.deltaPos[nDstPos]	= rBS.deltaPos[j];
					rBS.deltaNorm[nDstPos]	= rBS.deltaNorm[j];
					rBS.deltaUV[nDstPos]	= rBS.deltaUV[j];
					rBS.deltaCol[nDstPos]	= rBS.deltaCol[j];
					if (useTgSpace)
					{
						rBS.deltaTgSpace[nDstPos]	= rBS.deltaTgSpace[j];
					}
				}
				++nDstPos;
			}
		}

		if (bIsDeltaPos)
			rBS.deltaPos.resize (nNbVertUsed);
		else
			rBS.deltaPos.resize (0);

		if (bIsDeltaNorm)
			rBS.deltaNorm.resize (nNbVertUsed);
		else
			rBS.deltaNorm.resize (0);

		if (bIsDeltaUV)
			rBS.deltaUV.resize (nNbVertUsed);
		else
			rBS.deltaUV.resize (0);

		if (bIsDeltaCol)
			rBS.deltaCol.resize (nNbVertUsed);
		else
			rBS.deltaCol.resize (0);

		if (bIsDeltaTgSpace)
			rBS.deltaTgSpace.resize (nNbVertUsed);
		else
			rBS.deltaTgSpace.resize (0);


		rBS.VertRefs.resize (nNbVertUsed);

	}
}

// ***************************************************************************
void			CMRMBuilder::buildMeshBuildMrm(const CMRMMeshFinal &finalMRM, CMeshMRMSkinnedGeom::CMeshBuildMRM &mbuild, uint32 vbFlags, uint32 nbMats, const CMesh::CMeshBuild &mb)
{
	sint	i,j,k;
	sint	attId;

	// reset the mbuild.
	mbuild= CMeshMRMSkinnedGeom::CMeshBuildMRM();
	// Setup VB.

	bool useFormatExt = false;
	// Check whether there are texture coordinates with more than 2 compnents, which force us to use an extended vertex format
	for (k = 0; k < CVertexBuffer::MaxStage; ++k)
	{
		if (
			(vbFlags & (CVertexBuffer::TexCoord0Flag << k))
			&& mb.NumCoords[k] != 2)
		{
			useFormatExt = true;
			break;
		}
	}

	uint numTexCoordUsed = 0;


	for (k = 0; k < CVertexBuffer::MaxStage; ++k)
	{
		if (vbFlags & (CVertexBuffer::TexCoord0Flag << k))
		{
			numTexCoordUsed = k;
		}
	}

	if (!useFormatExt)
	{
		// setup standard format
		mbuild.VBuffer.setVertexFormat(vbFlags);
	}
	else // setup extended format
	{
		mbuild.VBuffer.clearValueEx();
		if (vbFlags & CVertexBuffer::PositionFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Position, CVertexBuffer::Float3);
		if (vbFlags & CVertexBuffer::NormalFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Normal, CVertexBuffer::Float3);
		if (vbFlags & CVertexBuffer::PrimaryColorFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::PrimaryColor, CVertexBuffer::UChar4);
		if (vbFlags & CVertexBuffer::SecondaryColorFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::SecondaryColor, CVertexBuffer::UChar4);
		if (vbFlags & CVertexBuffer::WeightFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Weight, CVertexBuffer::Float4);
		if (vbFlags & CVertexBuffer::PaletteSkinFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::PaletteSkin, CVertexBuffer::UChar4);
		if (vbFlags & CVertexBuffer::FogFlag) mbuild.VBuffer.addValueEx(CVertexBuffer::Fog, CVertexBuffer::Float1);

		for (k = 0; k < CVertexBuffer::MaxStage; ++k)
		{
			if (vbFlags & (CVertexBuffer::TexCoord0Flag << k))
			{
				switch(mb.NumCoords[k])
				{
					case 2:
						mbuild.VBuffer.addValueEx((CVertexBuffer::TValue) (CVertexBuffer::TexCoord0 + k), CVertexBuffer::Float2);
					break;
					case 3:
						mbuild.VBuffer.addValueEx((CVertexBuffer::TValue) (CVertexBuffer::TexCoord0 + k), CVertexBuffer::Float3);
					break;
					default:
						nlassert(0);
					break;
				}
			}
		}
		mbuild.VBuffer.initEx();
	}

	// Copy the UVRouting
	for (i=0; i<CVertexBuffer::MaxStage; i++)
	{
		mbuild.VBuffer.setUVRouting (i, mb.UVRouting[i]);
	}

	// Setup the VertexBuffer.
	// ========================
	// resize the VB.
	mbuild.VBuffer.setNumVertices((uint32)finalMRM.Wedges.size());

	CVertexBufferReadWrite vba;
	mbuild.VBuffer.lock (vba);

	// Setup SkinWeights.
	if(_Skinned)
		mbuild.SkinWeights.resize(finalMRM.Wedges.size());

	// fill the VB.
	for(i=0; i<(sint)finalMRM.Wedges.size(); i++)
	{
		const CMRMMeshFinal::CWedge	&wedge= finalMRM.Wedges[i];

		// setup Vertex.
		vba.setVertexCoord(i, wedge.Vertex);

		// seutp attributes.
		attId= 0;

		// For all activated attributes in mbuild, retrieve the attribute from the finalMRM.
		if(vbFlags & CVertexBuffer::NormalFlag)
		{
			vba.setNormalCoord(i, wedge.Attributes[attId] );
			attId++;
		}
		if(vbFlags & CVertexBuffer::PrimaryColorFlag)
		{
			vba.setColor(i, attToColor(wedge.Attributes[attId]) );
			attId++;
		}
		if(vbFlags & CVertexBuffer::SecondaryColorFlag)
		{
			vba.setSpecular(i, attToColor(wedge.Attributes[attId]) );
			attId++;
		}
		for(k=0; k<CVertexBuffer::MaxStage;k++)
		{
			if(vbFlags & (CVertexBuffer::TexCoord0Flag<<k))
			{
				switch(mb.NumCoords[k])
				{
					case 2:
						vba.setTexCoord(i, k, (CUV) attToUvw(wedge.Attributes[attId]) );
					break;
					case 3:
					{
						CUVW uvw = attToUvw(wedge.Attributes[attId]);
						vba.setValueFloat3Ex((CVertexBuffer::TValue) (CVertexBuffer::TexCoord0 + k), i, uvw.U, uvw.V, uvw.W);
					}
					break;
					default:
						nlassert(0);
					break;
				}
				attId++;
			}
		}

		// Setup SkinWeights.
		if(_Skinned)
		{
			mbuild.SkinWeights[i]= wedge.VertexSkin;
		}
	}


	// Build Lods.
	// ========================
	// resize
	mbuild.Lods.resize(finalMRM.Lods.size());
	// fill.
	for(i=0; i<(sint)finalMRM.Lods.size(); i++)
	{
		const CMRMMeshFinal::CLod	&srcLod= finalMRM.Lods[i];
		CMeshMRMSkinnedGeom::CLod			&destLod= mbuild.Lods[i];

		// Basic.
		//---------

		// Copy NWedges infos.
		destLod.NWedges= srcLod.NWedges;
		// Copy Geomorphs infos.
		destLod.Geomorphs= srcLod.Geomorphs;


		// Reorder faces by rdrpass.
		//---------

		// First count the number of faces used by this LOD for each material
		vector<sint>	matCount;
		// resize, and reset to 0.
		matCount.clear();
		matCount.resize(nbMats, 0);
		// For each face of this Lods, incr the mat face counter.
		for(j= 0; j<(sint)srcLod.Faces.size(); j++)
		{
			sint	matId= srcLod.Faces[j].MaterialId;
			nlassert(matId>=0);
			nlassert(matId<(sint)nbMats);
			// increment the refcount of this material by this LOD.
			matCount[matId]++;
		}

		// Then for each material not empty, create a rdrPass, and ref it for this material.
		vector<sint>	rdrPassIndex;	// material to rdrPass map.
		rdrPassIndex.resize(nbMats);
		for(j=0; j<(sint)nbMats; j++)
		{
			if(matCount[j]==0)
				rdrPassIndex[j]= -1;
			else
			{
				// map material to rdrPass.
				sint	idRdrPass= (sint)destLod.RdrPass.size();
				rdrPassIndex[j]= idRdrPass;
				// create a rdrPass.
				destLod.RdrPass.push_back(CMeshMRMSkinnedGeom::CRdrPass());
				// assign the good materialId to this rdrPass.
				destLod.RdrPass[idRdrPass].MaterialId= j;
				// reserve the array of faces of this rdrPass.
				destLod.RdrPass[idRdrPass].PBlock.reserve(3*matCount[j]);
			}
		}

		// Then for each face, add it to the good rdrPass of this Lod.
		for(j= 0; j<(sint)srcLod.Faces.size(); j++)
		{
			sint	matId= srcLod.Faces[j].MaterialId;
			sint	idRdrPass= rdrPassIndex[matId];
			// add this face to the good rdrPass.
			sint	w0= srcLod.Faces[j].WedgeId[0];
			sint	w1= srcLod.Faces[j].WedgeId[1];
			sint	w2= srcLod.Faces[j].WedgeId[2];
			destLod.RdrPass[idRdrPass].PBlock.push_back (w0);
			destLod.RdrPass[idRdrPass].PBlock.push_back (w1);
			destLod.RdrPass[idRdrPass].PBlock.push_back (w2);
		}


		// Build skin info for this Lod.
		//---------
		for(j=0; j<NL3D_MESH_SKINNING_MAX_MATRIX; j++)
		{
			destLod.InfluencedVertices[j].clear();
		}
		destLod.MatrixInfluences.clear();
		if(_Skinned)
		{
			// This is the set which tell what wedge has already been inserted.
			set<uint>	wedgeInfSet;

			// First, build the list of vertices influenced by this Lod.
			for(j= 0; j<(sint)srcLod.Faces.size(); j++)
			{
				for(k=0; k<3; k++)
				{
					sint	wedgeId= srcLod.Faces[j].WedgeId[k];
					// If it is a geomorph
					if(wedgeId<finalMRM.NGeomSpace)
					{
						// add the start and end to the list (if not here). NB: wedgeId is both the id
						// of the dest wedge, and the id of the geomorph.
						sint	wedgeStartId= destLod.Geomorphs[wedgeId].Start;
						sint	wedgeEndId= destLod.Geomorphs[wedgeId].End;
						uint	nMatUsedStart= finalMRM.Wedges[wedgeStartId].NSkinMatUsed;
						uint	nMatUsedEnd= finalMRM.Wedges[wedgeEndId].NSkinMatUsed;

						// if insertion in the set work, add to the good array.
						if( wedgeInfSet.insert(wedgeStartId).second )
							destLod.InfluencedVertices[nMatUsedStart-1].push_back(wedgeStartId);
						if( wedgeInfSet.insert(wedgeEndId).second )
							destLod.InfluencedVertices[nMatUsedEnd-1].push_back(wedgeEndId);
					}
					else
					{
						uint	nMatUsed= finalMRM.Wedges[wedgeId].NSkinMatUsed;

						// just add this wedge to the list (if not here).
						// if insertion in the set work, add to the array.
						if( wedgeInfSet.insert(wedgeId).second )
							destLod.InfluencedVertices[nMatUsed-1].push_back(wedgeId);
					}
				}
			}

			// Optimisation: for better cache, sort the destLod.InfluencedVertices in increasing order.
			for(j=0; j<NL3D_MESH_SKINNING_MAX_MATRIX; j++)
			{
				sort(destLod.InfluencedVertices[j].begin(), destLod.InfluencedVertices[j].end());
			}


			// Then Build the MatrixInfluences array, for all thoses Influenced Vertices only.
			// This is the map MatrixId -> MatrixInfId.
			map<uint, uint>		matrixInfMap;

			// For all influenced vertices, flags matrix they use.
			uint	iSkinMat;
			for(iSkinMat= 0; iSkinMat<NL3D_MESH_SKINNING_MAX_MATRIX; iSkinMat++)
			{
				for(j= 0; j<(sint)destLod.InfluencedVertices[iSkinMat].size(); j++)
				{
					uint	wedgeId= destLod.InfluencedVertices[iSkinMat][j];

					// take the original wedge.
					const CMRMMeshFinal::CWedge	&wedge= finalMRM.Wedges[wedgeId];
					// For all matrix with not null influence...
					for(k= 0; k<NL3D_MESH_SKINNING_MAX_MATRIX; k++)
					{
						float	matWeight= wedge.VertexSkin.Weights[k];

						// This check the validity of skin weights sort. If false, problem before in the algo.
						if((uint)k<iSkinMat+1)
						{
							nlassert( matWeight>0 );
						}
						else
						{
							nlassert( matWeight==0 );
						}
						// if not null influence.
						if(matWeight>0)
						{
							uint	matId= wedge.VertexSkin.MatrixId[k];

							// search/insert the matrixInfId.
							map<uint, uint>::iterator	it= matrixInfMap.find(matId);
							if( it==matrixInfMap.end() )
							{
								uint matInfId= (uint)destLod.MatrixInfluences.size();
								matrixInfMap.insert( make_pair(matId, matInfId) );
								// create the new MatrixInfluence.
								destLod.MatrixInfluences.push_back(matId);
							}
						}
					}
				}
			}

		}

	}

	// Indicate Skinning.
	mbuild.Skinned= _Skinned;



	bool useTgSpace = mb.MeshVertexProgram != NULL ? mb.MeshVertexProgram->needTangentSpace() : false;

	// Construct Blend Shapes
	//// mbuild <- finalMRM
	mbuild.BlendShapes.resize (finalMRM.MRMBlendShapesFinals.size());
	for (k = 0; k < (sint)mbuild.BlendShapes.size(); ++k)
	{
		CBlendShape &rBS = mbuild.BlendShapes[k];
		sint32 nNbVertVB = (sint32)finalMRM.Wedges.size();
		bool bIsDeltaPos = false;
		rBS.deltaPos.resize (nNbVertVB, CVector(0.0f,0.0f,0.0f));
		bool bIsDeltaNorm = false;
		rBS.deltaNorm.resize (nNbVertVB, CVector(0.0f,0.0f,0.0f));
		bool bIsDeltaUV = false;
		rBS.deltaUV.resize (nNbVertVB, CUV(0.0f,0.0f));
		bool bIsDeltaCol = false;
		rBS.deltaCol.resize (nNbVertVB, CRGBAF(0.0f,0.0f,0.0f,0.0f));
		bool bIsDeltaTgSpace = false;
		if (useTgSpace)
		{
			rBS.deltaTgSpace.resize(nNbVertVB, CVector::Null);
		}

		rBS.VertRefs.resize (nNbVertVB, 0xffffffff);

		for (i = 0; i < nNbVertVB; i++)
		{
			const CMRMMeshFinal::CWedge	&rWedgeRef = finalMRM.Wedges[i];
			const CMRMMeshFinal::CWedge	&rWedgeTar = finalMRM.MRMBlendShapesFinals[k].Wedges[i];

			CVector delta = rWedgeTar.Vertex - rWedgeRef.Vertex;
			CVectorH attr;

			if (delta.norm() > 0.001f)
			{
				rBS.deltaPos[i] = delta;
				rBS.VertRefs[i] = i;
				bIsDeltaPos = true;
			}

			attId = 0;
			if (vbFlags & CVertexBuffer::NormalFlag)
			{
				attr = rWedgeRef.Attributes[attId];
				CVector NormRef = CVector(attr.x, attr.y, attr.z);
				attr = rWedgeTar.Attributes[attId];
				CVector NormTar = CVector(attr.x, attr.y, attr.z);
				delta = NormTar - NormRef;
				if (delta.norm() > 0.001f)
				{
					rBS.deltaNorm[i] = delta;
					rBS.VertRefs[i] = i;
					bIsDeltaNorm = true;
				}
				attId++;
			}

			if (vbFlags & CVertexBuffer::PrimaryColorFlag)
			{
				attr = rWedgeRef.Attributes[attId];
				CRGBAF RGBARef = CRGBAF(attr.x/255.0f, attr.y/255.0f, attr.z/255.0f, attr.w/255.0f);
				attr = rWedgeTar.Attributes[attId];
				CRGBAF RGBATar = CRGBAF(attr.x/255.0f, attr.y/255.0f, attr.z/255.0f, attr.w/255.0f);
				CRGBAF deltaRGBA = RGBATar - RGBARef;
				if ((deltaRGBA.R*deltaRGBA.R + deltaRGBA.G*deltaRGBA.G +
					deltaRGBA.B*deltaRGBA.B + deltaRGBA.A*deltaRGBA.A) > 0.0001f)
				{
					rBS.deltaCol[i] = deltaRGBA;
					rBS.VertRefs[i] = i;
					bIsDeltaCol = true;
				}
				attId++;
			}

			if (vbFlags & CVertexBuffer::SecondaryColorFlag)
			{	// Nothing to do !
				attId++;
			}

			// Do that only for the UV0
			if (vbFlags & CVertexBuffer::TexCoord0Flag)
			{
				attr = rWedgeRef.Attributes[attId];
				CUV UVRef = CUV(attr.x, attr.y);
				attr = rWedgeTar.Attributes[attId];
				CUV UVTar = CUV(attr.x, attr.y);
				CUV deltaUV = UVTar - UVRef;
				if ((deltaUV.U*deltaUV.U + deltaUV.V*deltaUV.V) > 0.0001f)
				{
					rBS.deltaUV[i] = deltaUV;
					rBS.VertRefs[i] = i;
					bIsDeltaUV = true;
				}
				attId++;
			}

			if (useTgSpace)
			{
				attr = rWedgeRef.Attributes[attId];
				CVector TgSpaceRef = CVector(attr.x, attr.y, attr.z);
				attr = rWedgeTar.Attributes[attId];
				CVector TgSpaceTar = CVector(attr.x, attr.y, attr.z);
				delta = TgSpaceTar - TgSpaceRef;
				if (delta.norm() > 0.001f)
				{
					rBS.deltaTgSpace[i] = delta;
					rBS.VertRefs[i] = i;
					bIsDeltaTgSpace = true;
				}
				attId++;
			}

		} // End of all vertices added in blend shape

		// Delete unused items and calculate the number of vertex used (blended)

		sint32 nNbVertUsed = nNbVertVB;
		sint32 nDstPos = 0;
		for (j = 0; j < nNbVertVB; ++j)
		{
			if (rBS.VertRefs[j] == 0xffffffff) // Is vertex UNused
			{
				--nNbVertUsed;
			}
			else // Vertex used
			{
				if (nDstPos != j)
				{
					rBS.VertRefs[nDstPos]	= rBS.VertRefs[j];
					rBS.deltaPos[nDstPos]	= rBS.deltaPos[j];
					rBS.deltaNorm[nDstPos]	= rBS.deltaNorm[j];
					rBS.deltaUV[nDstPos]	= rBS.deltaUV[j];
					rBS.deltaCol[nDstPos]	= rBS.deltaCol[j];
					if (useTgSpace)
					{
						rBS.deltaTgSpace[nDstPos]	= rBS.deltaTgSpace[j];
					}
				}
				++nDstPos;
			}
		}

		if (bIsDeltaPos)
			rBS.deltaPos.resize (nNbVertUsed);
		else
			rBS.deltaPos.resize (0);

		if (bIsDeltaNorm)
			rBS.deltaNorm.resize (nNbVertUsed);
		else
			rBS.deltaNorm.resize (0);

		if (bIsDeltaUV)
			rBS.deltaUV.resize (nNbVertUsed);
		else
			rBS.deltaUV.resize (0);

		if (bIsDeltaCol)
			rBS.deltaCol.resize (nNbVertUsed);
		else
			rBS.deltaCol.resize (0);

		if (bIsDeltaTgSpace)
			rBS.deltaTgSpace.resize (nNbVertUsed);
		else
			rBS.deltaTgSpace.resize (0);


		rBS.VertRefs.resize (nNbVertUsed);

	}
}

// ***************************************************************************
void CMRMBuilder::buildBlendShapes (CMRMMesh& baseMesh,
									std::vector<CMesh::CMeshBuild*> &bsList, uint32 VertexFlags)
{
	uint32 i, j, k, m, destIndex;
	uint32 attId;
	CVectorH vh;
	vector<CMRMBlendShape>	&bsMeshes= baseMesh.BlendShapes;

	bsMeshes.resize (bsList.size());

	for (i = 0; i < bsList.size(); ++i)
	{
		// Construct a blend shape like a mrm mesh
		nlassert (baseMesh.Vertices.size() == bsList[i]->Vertices.size());
		bsMeshes[i].Vertices.resize (baseMesh.Vertices.size());
		bsMeshes[i].Vertices = bsList[i]->Vertices;

		bsMeshes[i].NumAttributes = baseMesh.NumAttributes;
		for (j = 0; j < (uint32)bsMeshes[i].NumAttributes; ++j)
			bsMeshes[i].Attributes[j].resize(baseMesh.Attributes[j].size());

		// For all corners parse the faces (given by the baseMesh) and construct blend shape mrm meshes
		for (j = 0; j < baseMesh.Faces.size(); ++j)
		for (k = 0; k < 3; ++k)
		{
			const CMesh::CCorner &srcCorner = bsList[i]->Faces[j].Corner[k];
			CMRMCorner	&neutralCorner = baseMesh.Faces[j].Corner[k];

			attId= 0;

			if (VertexFlags & CVertexBuffer::NormalFlag)
			{
				destIndex = neutralCorner.Attributes[attId];
				vh.x = srcCorner.Normal.x;
				vh.y = srcCorner.Normal.y;
				vh.z = srcCorner.Normal.z;
				vh.w = 0.0f;
				bsMeshes[i].Attributes[attId].operator[](destIndex) = vh;
				attId++;
			}
			if (VertexFlags & CVertexBuffer::PrimaryColorFlag)
			{
				destIndex = neutralCorner.Attributes[attId];
				vh.x = srcCorner.Color.R;
				vh.y = srcCorner.Color.G;
				vh.z = srcCorner.Color.B;
				vh.w = srcCorner.Color.A;
				bsMeshes[i].Attributes[attId].operator[](destIndex) = vh;
				attId++;
			}
			if (VertexFlags & CVertexBuffer::SecondaryColorFlag)
			{
				destIndex = neutralCorner.Attributes[attId];
				vh.x = srcCorner.Specular.R;
				vh.y = srcCorner.Specular.G;
				vh.z = srcCorner.Specular.B;
				vh.w = srcCorner.Specular.A;
				bsMeshes[i].Attributes[attId].operator[](destIndex) = vh;
				attId++;
			}
			for (m = 0; m < CVertexBuffer::MaxStage; ++m)
			{
				if (VertexFlags & (CVertexBuffer::TexCoord0Flag<<m))
				{
					destIndex = neutralCorner.Attributes[attId];
					vh.x = srcCorner.Uvws[m].U;
					vh.y = srcCorner.Uvws[m].V;
					vh.z = srcCorner.Uvws[m].W;
					vh.w = 0.0f;
					bsMeshes[i].Attributes[attId].operator[](destIndex) = vh;
					attId++;
				}
			}
		}
	}
}


// ***************************************************************************
void	CMRMBuilder::compileMRM(const CMesh::CMeshBuild &mbuild, std::vector<CMesh::CMeshBuild*> &bsList,
								const CMRMParameters &params, CMeshMRMGeom::CMeshBuildMRM &mrmMesh,
								uint numMaxMaterial)
{
	// Temp data.
	CMRMMesh						baseMesh;
	vector<CMRMMeshGeom>			lodMeshs;
	CMRMMeshFinal					finalMRM;
	vector<CMRMMeshFinal>			finalBsMRM;
	uint32	vbFlags;


	nlassert(params.DistanceFinest>=0);
	nlassert(params.DistanceMiddle > params.DistanceFinest);
	nlassert(params.DistanceCoarsest > params.DistanceMiddle);


	// Copy some parameters.
	_SkinReduction= params.SkinReduction;

	// Skinning??
	_Skinned= ((mbuild.VertexFlags & CVertexBuffer::PaletteSkinFlag)==CVertexBuffer::PaletteSkinFlag);
	// Skinning is OK only if SkinWeights are of same size as vertices.
	_Skinned= _Skinned && ( mbuild.Vertices.size()==mbuild.SkinWeights.size() );

	// MeshInterface setuped ?
	_HasMeshInterfaces= buildMRMSewingMeshes(mbuild, params.NLods, params.Divisor);

	// from mbuild, build an internal MRM mesh representation.
	// vbFlags returned is the VBuffer format supported by CMRMBuilder.
	// NB: skinning is removed because skinning is made in software in CMeshMRMGeom.
	vbFlags= buildMrmBaseMesh(mbuild, baseMesh);

	// Construct all blend shapes in the same way we have constructed the basemesh mrm
	buildBlendShapes (baseMesh, bsList, vbFlags);

	// If skinned, must ensure that skin weights have weights in ascending order.
	if(_Skinned)
	{
		normalizeBaseMeshSkin(baseMesh);
	}

	// from this baseMesh, builds all LODs of the MRM, with geomorph info. NB: vertices/wedges are duplicated.
	buildAllLods (	baseMesh, lodMeshs, params.NLods, params.Divisor );

	// From this array of LOD, build a finalMRM, by regrouping identical vertices/wedges, and compute index geomorphs.
	buildFinalMRM(lodMeshs, finalMRM);

	// From this finalMRM, build output: a CMeshBuildMRM.
	buildMeshBuildMrm(finalMRM, mrmMesh, vbFlags, numMaxMaterial, mbuild);

	// Copy degradation control params.
	mrmMesh.DistanceFinest= params.DistanceFinest;
	mrmMesh.DistanceMiddle= params.DistanceMiddle;
	mrmMesh.DistanceCoarsest= params.DistanceCoarsest;
}


// ***************************************************************************
void	CMRMBuilder::compileMRM(const CMesh::CMeshBuild &mbuild, std::vector<CMesh::CMeshBuild*> &bsList,
								const CMRMParameters &params, CMeshMRMSkinnedGeom::CMeshBuildMRM &mrmMesh,
								uint numMaxMaterial)
{
	// Temp data.
	CMRMMesh						baseMesh;
	vector<CMRMMeshGeom>			lodMeshs;
	CMRMMeshFinal					finalMRM;
	vector<CMRMMeshFinal>			finalBsMRM;
	uint32	vbFlags;


	nlassert(params.DistanceFinest>=0);
	nlassert(params.DistanceMiddle > params.DistanceFinest);
	nlassert(params.DistanceCoarsest > params.DistanceMiddle);


	// Copy some parameters.
	_SkinReduction= params.SkinReduction;

	// Skinning??
	_Skinned= ((mbuild.VertexFlags & CVertexBuffer::PaletteSkinFlag)==CVertexBuffer::PaletteSkinFlag);
	// Skinning is OK only if SkinWeights are of same size as vertices.
	_Skinned= _Skinned && ( mbuild.Vertices.size()==mbuild.SkinWeights.size() );

	// MeshInterface setuped ?
	_HasMeshInterfaces= buildMRMSewingMeshes(mbuild, params.NLods, params.Divisor);

	// from mbuild, build an internal MRM mesh representation.
	// vbFlags returned is the VBuffer format supported by CMRMBuilder.
	// NB: skinning is removed because skinning is made in software in CMeshMRMGeom.
	vbFlags= buildMrmBaseMesh(mbuild, baseMesh);

	// Construct all blend shapes in the same way we have constructed the basemesh mrm
	buildBlendShapes (baseMesh, bsList, vbFlags);

	// If skinned, must ensure that skin weights have weights in ascending order.
	if(_Skinned)
	{
		normalizeBaseMeshSkin(baseMesh);
	}

	// from this baseMesh, builds all LODs of the MRM, with geomorph info. NB: vertices/wedges are duplicated.
	buildAllLods (	baseMesh, lodMeshs, params.NLods, params.Divisor );

	// From this array of LOD, build a finalMRM, by regrouping identical vertices/wedges, and compute index geomorphs.
	buildFinalMRM(lodMeshs, finalMRM);

	// From this finalMRM, build output: a CMeshBuildMRM.
	buildMeshBuildMrm(finalMRM, mrmMesh, vbFlags, numMaxMaterial, mbuild);

	// Copy degradation control params.
	mrmMesh.DistanceFinest= params.DistanceFinest;
	mrmMesh.DistanceMiddle= params.DistanceMiddle;
	mrmMesh.DistanceCoarsest= params.DistanceCoarsest;
}


// ***************************************************************************
// ***************************************************************************
// MRM Interface system
// ***************************************************************************
// ***************************************************************************

// ***************************************************************************
bool	CMRMBuilder::buildMRMSewingMeshes(const CMesh::CMeshBuild &mbuild, uint nWantedLods, uint divisor)
{
	nlassert(nWantedLods>=1);
	nlassert(divisor>=1);
	if(mbuild.Interfaces.size()==0)
		return false;
	// must have same size
	if(mbuild.InterfaceLinks.size()!=mbuild.Vertices.size())
		return false;

	// **** For each interface, MRM-ize it and store.
	_SewingMeshes.resize(mbuild.Interfaces.size());
	for(uint i=0;i<mbuild.Interfaces.size();i++)
	{
		_SewingMeshes[i].build(mbuild.Interfaces[i], nWantedLods, divisor);
	}


	return true;
}


} // NL3D