TrianglesIntersect
From Solid Graphics Wiki

The TrianglesIntersect function determines whether two triangles intersects.
bool TrianglesIntersect ( const float T10[ 3 ], const float T11[ 3 ], const float T12[ 3 ], const float T20[ 3 ], const float T21[ 3 ], const float T22[ 3 ] );
bool TrianglesIntersect ( const double T10[ 3 ], const double T11[ 3 ], const double T12[ 3 ], const double T20[ 3 ], const double T21[ 3 ], const double T22[ 3 ] );
Parameters
T10  x,y,z coordinates of first point of the first triangle 
T11  x,y,z coordinates of second point of the first triangle 
T12  x,y,z coordinates of third point of the first triangle 
T20  x,y,z coordinates of first point of the second triangle 
T21  x,y,z coordinates of second point of the second triangle 
T22  x,y,z coordinates of third point of the second triangle 
Return Value
The function returns true if the triengles touch or intersect, otherwise returns false.
See Also