ok
// mdx byte -> vector type
ushort[] indices = mdx.indices.ToArray();
byte[] vertexs = mdx.vertexs;
Vector3[] pos = new Vector3[mesh.num_vertex];
Vector3[] nor = new Vector3[mesh.num_vertex];
Vector2[] tex = new Vector2[mesh.num_vertex];
byte[] m1 = new byte[4];
byte[] m2 = new byte[4];
byte[] m3 = new byte[4];
for( int i = 0; i < mesh.num_vertex; i++ ) {
int offset = mesh.sufrace[0].offsets+(i*32);
for( int j = 0; j < 4; j++ )
{
m1[j] = vertexs[j+offset];
m2[j] = vertexs[4+j+offset];
m3[j] = vertexs[8+j+offset];
}
pos[i].X = BitConverter.ToSingle(m1, 0);
pos[i].Y = BitConverter.ToSingle(m2, 0);
pos[i].Z = BitConverter.ToSingle(m3, 0);
offset = mesh.sufrace[1].offsets+(i*32);
for( int j = 0; j < 4; j++ )
{
m1[j] = vertexs[j+offset];
m2[j] = vertexs[4+j+offset];
m3[j] = vertexs[8+j+offset];
}
nor[i].X = BitConverter.ToSingle(m1, 0);
nor[i].Y = BitConverter.ToSingle(m2, 0);
nor[i].Z = BitConverter.ToSingle(m3, 0);
offset = mesh.sufrace[3].offsets+(i*32);
for( int j = 0; j < 4; j++ )
{
m1[j] = vertexs[j+offset];
m2[j] = vertexs[4+j+offset];
}
tex[i].X = BitConverter.ToSingle(m1, 0);
tex[i].Y = BitConverter.ToSingle(m2, 0);
}
//calculation tangent
Vector4[] tan = new Vector4[mesh.num_vertex];
Vector3[] tan1 = new Vector3[mesh.num_vertex];
Vector3[] tan2 = new Vector3[mesh.num_vertex];
for( int i = 0; i < mdx.indices.Count; i+=3 ) {
ushort i1 = indices[i];
ushort i2 = indices[ (i+1) % mdx.indices.Count];
ushort i3 = indices[ (i+2) % mdx.indices.Count];
Vector3 v1 = pos[i1];
Vector3 v2 = pos[i2];
Vector3 v3 = pos[i3];
Vector2 t1 = tex[i1];
Vector2 t2 = tex[i2];
Vector2 t3 = tex[i3];
float x1 = v2.X - v1.X;
float x2 = v3.X - v1.X;
float y1 = v2.Y - v1.Y;
float y2 = v3.Y - v1.Y;
float z1 = v2.Z - v1.Z;
float z2 = v3.Z - v1.Z;
float s1 = t2.X - t1.X;
float s2 = t3.X - t1.X;
float s3 = t2.Y - t1.Y;
float s4 = t3.Y = t1.Y;
float r = (s1*s4-s2*s3);
if( Math.Abs(r) <= 0.00001f )
r = 1.0f;
else
r = 1.0f / r;
Vector3 sdir,tdir;
sdir.X = (s4*x1-s3*x2)*r;
sdir.Y = (s4*y1-s3*y2)*r;
sdir.Z = (s4*z1-s3*z2)*r;
tdir.X = (s1*x2-s2*x1)*r;
tdir.Y = (s1*y2-s2*y1)*r;
tdir.Z = (s1*z2-s2*z1)*r;
tan1[i1] += sdir;
tan1[i2] += sdir;
tan1[i3] += sdir;
tan2[i1] += tdir;
tan2[i2] += tdir;
tan2[i3] += tdir;
}
for( int i = 0; i < mesh.num_vertex; i++ ) {
;
tan[i].Xyz = tan1[i] - nor[i] * tan1[i].Dot(nor[i]);
tan[i] = tan[i].Normalize();
tan[i].W = (nor[i].Cross(tan1[i])).Dot(tan2[i]) < 0.0f ? -1.0f : 1.0f;
}
// tangent vector -> mdx byte
mesh.vertex_formats[2] = VertexFormat.Float4;
mesh.sufrace[2].offsets = ?????????
vertexs = ???????????
...very difficult......
