The bracket ("[]") operators are overloaded operators for the D3D_OVERLOADS extensions. You can use empty brackets ("[]") for access grants, "v[0]" to access the x component of a vector, "v[1]" to access the y component, and "v[2]" to access the z component. These operators are defined as follows:
const D3DVALUE&operator[](int i) const;
D3DVALUE&operator[](int i);
inline const D3DVALUE&
_D3DVECTOR::operator[](int i) const
{
return (&x)[i];
}
inline D3DVALUE&
_D3DVECTOR::operator[](int i)
{
return (&x)[i];
}