Center of Projection on the negative z-axis with viewplane parallel to the x-y plane and through the origin.
xprojected = xd/(d+z) = x/(1+(z/d)) yprojected = yd/(d+z) = y/(1+(z/d))

(1 0 0 0) (x) = (x)
(0 1 0 0) (y) = (y)
(0 0 0 0) (z) = (0)
(0 0 1/d 1) (1) = (z/d + 1)