Picking Function

tbResult DrawSelection(void){	if(m_bPicking)	{		Pick();		tbDirect3D& D3D = tbDirect3D::Instance();		// If a triangle is picked, draw it		if(m_dwNumIntersections > 0)		{			for(UINT uPass = 0; uPass < 20; ++uPass)			{				D3D.SetFVF(D3DFVF_NORMAL);				D3D->SetStreamSource(0, m_pVertexBuffer->GetVB(), 0, sizeof(tbVertex));				D3D->DrawPrimitive( D3DPT_TRIANGLELIST, 0, m_dwNumIntersections );			}			D3D.SetRS(D3DRS_FILLMODE, D3DFILL_WIREFRAME );			D3D.SetRS( D3DRS_LIGHTING, FALSE );		}		if(!tbDirect3D::Instance().GetDevice()->DrawPrimitive(D3DPT_TRIANGLELIST, 0, m_dwNumIntersections))		{			TB_WARNING("Fehler beim Zeichnen der Auswahl!");			return TB_ERROR;		}		D3D.SetRS( D3DRS_LIGHTING, TRUE);	}	return TB_OK;}

tbResult Pick(){	if(m_bPicking)	{		tbVector3 vPickRayDir;		tbVector3 vPickRayOrig;		tbDirect3D& D3D = tbDirect3D::Instance();				m_dwNumIntersections = 0L;		tbMatrix mProj = D3D.GetTransform(D3DTS_PROJECTION);		tbVector3 v;		v.x =  ( ( ( 2.0f * m_ptMousePick.x ) / m_pCurrentChain->GetWidth()) - 1 ) / mProj.m11;		v.y = -( ( ( 2.0f * m_ptMousePick.y ) / m_pCurrentChain->GetHeight()) - 1 ) / mProj.m22;		v.z =  1.0f;			const tbMatrix	matView		= D3D.GetTransform(D3DTS_VIEW);		const tbMatrix	matWorld	= D3D.GetTransform(D3DTS_WORLD);		tbMatrix		mWorldView	= matWorld * matView;		tbMatrix		m;		D3DXMatrixInverse((D3DXMATRIX*)(&m), NULL, (D3DXMATRIX*)(&mWorldView));		vPickRayDir.x  = v.x*m.m11 + v.y*m.m21 + v.z*m.m31;		vPickRayDir.y  = v.x*m.m12 + v.y*m.m22 + v.z*m.m32;		vPickRayDir.z  = v.x*m.m13 + v.y*m.m23 + v.z*m.m33;		vPickRayOrig.x = m.m41;		vPickRayOrig.y = m.m42;		vPickRayOrig.z = m.m43;		tbModel*		pModel;		pModel			= m_pModel;		tbVertexBuffer*	pVertexBuffer;		tbIndexBuffer*	pIndexBuffer;		pVertexBuffer	= pModel->GetVertexBuffer();		pIndexBuffer	= pModel->GetIndexBuffer();		if(!pVertexBuffer)		{			TB_WARNING("Der Vertex-Buffer Pointer zeigt ins Nirvana!");			return TB_ERROR;		}		else if(!pIndexBuffer)		{			TB_WARNING("Der Index-Buffer Pointer zeigt ins Nirvana!");			return TB_ERROR;		}		else		{			WORD*		pIndices;			tbVertex*	pVertices;			pIndexBuffer->GetIB()->Lock( 0, 0, (void**)&pIndices, 0 );			pVertexBuffer->GetVB()->Lock( 0, 0, (void**)&pVertices, 0 );			DWORD dwNumFaces = pModel->GetNumVertices();			float fBary1, fBary2;			float fDist;	            			for(DWORD i=0; i<dwNumFaces; i++)			{				tbVector3 v0 = pVertices[pIndices[3*i+0]].p;				tbVector3 v1 = pVertices[pIndices[3*i+1]].p;				tbVector3 v2 = pVertices[pIndices[3*i+2]].p;				if(IntersectTriangle(vPickRayOrig, vPickRayDir, v0, v1, v2, &fDist, &fBary1, &fBary2))				{					if( m_dwNumIntersections == 0 || fDist < m_IntersectionArray[0].fDist )					{	m_dwNumIntersections = 0;						m_IntersectionArray[m_dwNumIntersections].dwFace	= i;						m_IntersectionArray[m_dwNumIntersections].fBary1	= fBary1;						m_IntersectionArray[m_dwNumIntersections].fBary2	= fBary2;						m_IntersectionArray[m_dwNumIntersections].fDist		= fDist;						m_dwNumIntersections++;	                        						if(m_dwNumIntersections == MAX_INTERSECTIONS )							break;					}				}			}			if(m_dwNumIntersections > 0)			{				tbVertex*		v;				tbVertex*		vThisTri;				WORD*			wThisTri;				tbVertex		v1, v2, v3;				tbIntersection* pIntersection;				m_pVertexBuffer->GetVB()->Lock( 0, 0, (void**)&v, 0 );				for( DWORD dwIntersection = 0; dwIntersection < m_dwNumIntersections; dwIntersection++ )				{					pIntersection = &m_IntersectionArray[dwIntersection];					vThisTri = &v[dwIntersection * 3];					wThisTri = &pIndices[3*pIntersection->dwFace];					// get vertices hit					vThisTri[0] = pVertices[wThisTri[0]];					vThisTri[1] = pVertices[wThisTri[1]];					vThisTri[2] = pVertices[wThisTri[2]];					float dtu1 = vThisTri[1].tu - vThisTri[0].tu;					float dtu2 = vThisTri[2].tu - vThisTri[0].tu;					float dtv1 = vThisTri[1].tv - vThisTri[0].tv;					float dtv2 = vThisTri[2].tv - vThisTri[0].tv;					pIntersection->tu = vThisTri[0].tu + pIntersection->fBary1 * dtu1 + pIntersection->fBary2 * dtu2;					pIntersection->tv = vThisTri[0].tv + pIntersection->fBary1 * dtv1 + pIntersection->fBary2 * dtv2;				}				m_pVertexBuffer->GetVB()->Unlock();			}			pVertexBuffer->GetVB()->Unlock();			pIndexBuffer->GetIB()->Unlock();		}	}	return TB_OK;}}

tbResult IntersectTriangle( const tbVector3& orig, const tbVector3& dir, tbVector3& v0, tbVector3& v1, tbVector3& v2, float* t, float* u, float* v ){    tbVector3 edge1 = v1 - v0;    tbVector3 edge2 = v2 - v0;    tbVector3 pvec;    pvec = tbVector3Cross(dir, edge2);     float det = tbVector3Dot(edge1, pvec);    tbVector3 tvec;    	if(det > 0)        tvec	= orig - v0;    else    {        tvec	= v0 - orig;        det		= -det;    }    if( det < 0.0001f )        return TB_ERROR;    *u = tbVector3Dot(tvec, pvec);    	if( *u < 0.0f || *u > det )        return TB_ERROR;	tbVector3 qvec;	qvec = tbVector3Cross(tvec, edge1 );    *v = tbVector3Dot(dir, qvec);    if( *v < 0.0f || *u + *v > det )        return TB_ERROR;    *t = tbVector3Dot(edge2, qvec);	float fInvDet = 1.0f / det;	*t *= fInvDet;	*u *= fInvDet;	*v *= fInvDet;    return TB_OK;}

m_pVertexBuffer = new tbVertexBuffer;	if(!m_pVertexBuffer) 		TB_ERROR_OUT_OF_MEMORY(TB_ERROR);	m_pVertexBuffer->Init(3*MAX_INTERSECTIONS*sizeof(tbVertex), sizeof(tbVertex), D3DFVF_NORMAL, D3DUSAGE_WRITEONLY, D3DPOOL_MANAGED);	m_pVertexBuffer->SetFirstVertex(0);	m_pVertexBuffer->SetLastVertex(3*MAX_INTERSECTIONS - 1);				if(m_pVertexBuffer->Update()) 		TB_ERROR("Fehler beim Aktualisieren des Vertex-Buffers!", TB_ERROR);