Build Tangent using Lengyel’s Method but not correct - c++

Question

screen shoot:http://1drv.ms/1C9fgyl
pls note that the normal buffer is very strange. I use method in this link: http://www.terathon.com/code/tangent.html
the fabric tangent is very different between left half side and right half side.
I don't know what happen.
I test another sponza scene and put them in other guys who use same method to calc TBN and got same issue.
what's the bug in my algrithom?
bool OBJModel_Loader::BuildTangent(std::vector<OBJModel* >& Objects)
{
for (OBJModel* actor : Objects)
{
PracEngLogf("BuildTangent For Model: %s! \n", actor->Name.c_str());
int cnt = actor->VertexBuffer.size();
PEVector3* tan1 = new PEVector3[cnt * 2];
PEVector3* tan2 = tan1 + cnt;
ZeroMemory(tan1, cnt*sizeof(PEVector3) * 2);
for (size_t i = 0; i < actor->FaceInfos.size(); i+=3)
{
int Idx1 = actor->FaceInfos[i].VertexIdx;
int Idx2 = actor->FaceInfos[i + 1].VertexIdx;
int Idx3 = actor->FaceInfos[i + 2].VertexIdx;
const PEFloat3& v1 = actor->VertexBuffer[Idx1];
const PEFloat3& v2 = actor->VertexBuffer[Idx2];
const PEFloat3& v3 = actor->VertexBuffer[Idx3];
const PEFloat2& w1 = actor->UVs[actor->FaceInfos[i].UVIdx];
const PEFloat2& w2 = actor->UVs[actor->FaceInfos[i+1].UVIdx];
const PEFloat2& w3 = actor->UVs[actor->FaceInfos[i+2].UVIdx];
PEVector3 E1(v2.X - v1.X, v2.Y - v1.Y, v2.Z - v1.Z);
PEVector3 E2(v3.X - v1.X, v3.Y - v1.Y, v3.Z - v1.Z);
PEFloat2 St1 ( w2.X - w1.X, w2.Y - w1.Y );
PEFloat2 St2 ( w3.X - w1.X, w3.Y - w1.Y );
PEVector3 sDir;
PEVector3 tDir;
float r = St1.X*St2.Y - St2.X*St1.Y;
if (fabs(r) < 1e-6f)
{
sDir = PEVector3(1.0f, .0f, .0f);
tDir = PEVector3(.0f, 1.0f, .0f);
}
else
{
r = 1.0f / r;
sDir = PEVector3((St2.Y*E1.x - St1.Y*E2.x)*r, (St2.Y*E1.y - St1.Y*E2.y)*r, (St2.Y*E1.z - St1.Y*E2.z)*r);
tDir = PEVector3((St1.X*E2.x - St2.X*E1.x)*r, (St1.X*E2.y - St2.X*E1.y)*r, (St1.X*E2.z - St2.X*E1.z)*r);
}
tan1[Idx1] += sDir;
tan1[Idx2] += sDir;
tan1[Idx3] += sDir;
tan2[Idx1] += tDir;
tan2[Idx2] += tDir;
tan2[Idx3] += tDir;
}
for (size_t i = 0; i < actor->FaceInfos.size(); i++)
{
int Idx = actor->FaceInfos[i].VertexIdx;
const PEVector3& N = actor->VertexNormal[actor->FaceInfos[i].NormalIdx];
const PEVector3& T = tan1[Idx];
PEVector3 adjTangent = T - N * PEVector3::Dot(N, T);
adjTangent.Normalize();
actor->VertexTangent[Idx] = adjTangent;
actor->VertexTangent[Idx].w = PEVector3::Dot(N.Cross(T), tan2[Idx]) < .0f ? -1.0f : 1.0f;
}
delete[] tan1;
}
return true;
}