LookAt

Matrix VFunction Matrix::LookTo(const Vector& position, const Vector& direction, const Vector& up)
{
    //Vector R2 = Vector::Normalize3(direction);
    Vector R2 = direction;

    Vector R0 = Vector::Cross(up, R2);
    R0 = Vector::Normalize3(R0);

    Vector R1 = Vector::Cross(R2, R0);

    Vector NegEyePosition = _mm_sub_ps(_mm_setzero_ps(), position);

    Vector D0 = Vector::Dot3(R0, NegEyePosition);
    Vector D1 = Vector::Dot3(R1, NegEyePosition);
    Vector D2 = Vector::Dot3(R2, NegEyePosition);

    Matrix M;
    M.x = Vector::Select(D0, R0, Vector::Constant::Select1110);
    M.y = Vector::Select(D1, R1, Vector::Constant::Select1110);
    M.z = Vector::Select(D2, R2, Vector::Constant::Select1110);
    M.w = Vector::Constant::IdentityR3.v;

    M = Transpose(M);

    return M;
}

Matrix VFunction Matrix::LookAt(const Vector& position, const Vector& target, const Vector& up)
{
    return Matrix::LookTo(position, Vector::Normalize3(_mm_sub_ps(target, position)), up);
}