A function used to determine the intersection of rays and triangles

Code
1 //-----------------------------------------------
2 // ----------- detect the intersection of triangles and rays ---------
3 bool cdirectxapp: intersect (const d3dxvector3 & v0, const d3dxvector3 & V1, const d3dxvector3 & V2,
4 const d3dxvector3 & orgin, const d3dxvector3 & VEC, float & U, float & V, float & T)
5 {
6 // determine whether the triangle is used and the direction Vector
7 assert (VEC! = D3dxvector3 (0, 0, 0 )&&
8 V0! = V1 & V1! = V2 & V0! = V2 );
9 d3dxvector3 M = V0-V2;
10 d3dxvector3 n = V1-V2;
11 d3dxvector3 negativevec =-VEC;
12 d3dxvector3 tempvec;
13 d3dxvec3cross (& tempvec, & N, & negativevec );
14 // det is the denominator of the unknown in the Klein Law
15 float det = d3dxvec3dot (& tempvec, & M );
16
17 if (det <1e-6f)
18 {
19 Return false;
20}
21
22 d3dxvector3 vtoorigin = orgin-V2;
23 float UB = d3dxvec3dot (& tempvec, & vtoorigin );
24 U = UB/det;
25 if (U <0 | u> 1)
26 {
27 return false;
28}
29
30 d3dxvec3cross (& tempvec, & vtoorigin, & negativevec );
31 float VB = d3dxvec3dot (& M, & tempvec );
32 V = Vb/det;
33 If (v <0 | u + V> 1)
34 {
35 return false;
36}
37
38 d3dxvec3cross (& tempvec, & N, & vtoorigin );
39 float TB = d3dxvec3dot (& M, & tempvec );
40 t = Tb/det;
41 return true;