protected Camera(Point3D eye, Point3D lookAt, Vector3D up, float fov, float resX, float resY)
{
this.ResX = resX;
this.ResY = resY;
this.aspect = resX / resY;
this.eye = eye;
this.Fov = fov;
this.up = up;
this.LookAt = lookAt;
this.basis = OrthoNormalBasis.MakeFromWV(eye - lookAt, up);
this.au = (float)Math.Tan(fov * 0.5f);
this.av = this.au * 1.0f / this.aspect;
}