if (point_w)
	var dist_w = m_vec3.squaredDistance(point_w, cam_trans);
else
	var dist_w = 1e10;

if (point_wl)
	var dist_wl = m_vec3.squaredDistance(point_wl, cam_trans);
else
	var dist_wl = 1e10;

if (point_wr)
	var dist_wr = m_vec3.squaredDistance(point_wr, cam_trans);
else
	var dist_wr = 1e10;

var min_dist = min(dist_w, dist_wl, dist_wr);

if (min_dist == dist_w) {
	// move object to point_w
} else if (min_dist == dist_wl) {
	// move object to point_wl
} else {
	// move object to point_wr
}

// calculate corner vectors
var cam_to_A = m_vec3.subtract(A, cam_trans, _vec3_tmp);
var cam_to_B = m_vec3.subtract(B, cam_trans, _vec3_tmp2);
var cam_to_C = m_vec3.subtract(C, cam_trans, _vec3_tmp3);
var cam_to_D = m_vec3.subtract(D, cam_trans, _vec3_tmp4);

// calculate angles in polar coordinates
var angle_ray = Math.atan2(camera_ray[0], camera_ray[2]); 
var angle_A = Math.atan2(cam_to_A[0], cam_to_A[2]);
var angle_B = Math.atan2(cam_to_B[0], cam_to_B[2]);
var angle_C = Math.atan2(cam_to_C[0], cam_to_C[2]);
var angle_D = Math.atan2(cam_to_D[0], cam_to_D[2]);

// test 
if (angle_ray >= angle_B && angle_ray <= angle_A) {
    // test front wall only
}
...