//----------------------------------------------------------------------------
void VETable::RemoveTriangles (V3Array& rkVA, T3Array& rkTA)
{
// ear-clip the wireframe to get the triangles
Triangle3 kTri;
while ( Remove(kTri) )
{
int iV0 = (int)rkVA.size(), iV1 = iV0+1, iV2 = iV1+1;
rkTA.push_back(Triangle3(iV0,iV1,iV2));
const Vertex& rkV0 = m_akVertex[kTri.i0];
const Vertex& rkV1 = m_akVertex[kTri.i1];
const Vertex& rkV2 = m_akVertex[kTri.i2];
rkVA.push_back(Vertex3(rkV0.m_fX,rkV0.m_fY,rkV0.m_fZ));
rkVA.push_back(Vertex3(rkV1.m_fX,rkV1.m_fY,rkV1.m_fZ));
rkVA.push_back(Vertex3(rkV2.m_fX,rkV2.m_fY,rkV2.m_fZ));
}
}
void ConvexPolyhedron3<Real>::ComputeTerminator (const Vector3<Real>& rkEye,
V3Array& rkTerminator)
{
// temporary storage for signed distances from eye to triangles
int iTQuantity = m_akTriangle.GetQuantity();
vector<Real> afDistance(iTQuantity);
int i, j;
for (i = 0; i < iTQuantity; i++)
afDistance[i] = Math<Real>::MAX_REAL;
// Start a search for a front-facing triangle that has an adjacent
// back-facing triangle or for a back-facing triangle that has an
// adjacent front-facing triangle.
int iTCurrent = 0;
MTTriangle* pkTCurrent = &m_akTriangle[iTCurrent];
Real fTriDist = GetDistance(rkEye,iTCurrent,afDistance);
int iEFirst = -1;
for (i = 0; i < iTQuantity; i++)
{
// Check adjacent neighbors for edge of terminator. Such an
// edge occurs if the signed distance changes sign.
int iMinIndex = -1;
Real fMinAbsDist = Math<Real>::MAX_REAL;
Real afAdjDist[3];
for (j = 0; j < 3; j++)
{
afAdjDist[j] = GetDistance(rkEye,pkTCurrent->Adjacent(j),
afDistance);
if ( IsNegativeProduct(fTriDist,afAdjDist[j]) )
{
iEFirst = pkTCurrent->Edge(j);
break;
}
Real fAbsDist = Math<Real>::FAbs(afAdjDist[j]);
if ( fAbsDist < fMinAbsDist )
{
fMinAbsDist = fAbsDist;
iMinIndex = j;
}
}
if ( j < 3 )
break;
// First edge not found during this iteration. Move to adjacent
// triangle whose distance is smallest of all adjacent triangles.
iTCurrent = pkTCurrent->Adjacent(iMinIndex);
pkTCurrent = &m_akTriangle[iTCurrent];
fTriDist = afAdjDist[iMinIndex];
}
assert( i < iTQuantity );
MTEdge& rkEFirst = m_akEdge[iEFirst];
rkTerminator.push_back(m_akPoint[GetVLabel(rkEFirst.Vertex(0))]);
rkTerminator.push_back(m_akPoint[GetVLabel(rkEFirst.Vertex(1))]);
// walk along the terminator
int iVFirst = rkEFirst.Vertex(0);
int iV = rkEFirst.Vertex(1);
int iE = iEFirst;
int iEQuantity = m_akEdge.GetQuantity();
for (i = 0; i < iEQuantity; i++)
{
// search all edges sharing the vertex for another terminator edge
int j, jMax = m_akVertex[iV].GetEdgeQuantity();
for (j = 0; j < m_akVertex[iV].GetEdgeQuantity(); j++)
{
int iENext = m_akVertex[iV].GetEdge(j);
if ( iENext == iE )
continue;
Real fDist0 = GetDistance(rkEye,m_akEdge[iENext].GetTriangle(0),
afDistance);
Real fDist1 = GetDistance(rkEye,m_akEdge[iENext].GetTriangle(1),
afDistance);
if ( IsNegativeProduct(fDist0,fDist1) )
{
if ( m_akEdge[iENext].GetVertex(0) == iV )
{
iV = m_akEdge[iENext].GetVertex(1);
rkTerminator.push_back(m_akPoint[GetVLabel(iV)]);
if ( iV == iVFirst )
return;
}
else
{
iV = m_akEdge[iENext].GetVertex(0);
rkTerminator.push_back(m_akPoint[GetVLabel(iV)]);
if ( iV == iVFirst )
return;
}
iE = iENext;
break;
}
}
assert( j < jMax );
}
assert( i < iEQuantity );
}