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[Ac1DF1R3]

Am currently attempting to make a software renderer and lookin into doin bumpmapping.

Dont no if this is the best technique?? but have been lukin at Alan Watts - 3D Computer Graphics and the following equations to displace a point P and then calculate its new perturbed normal:

-to displace point
P`(u,v) = P(u,v) + B(u,v) N

-to calc normal
N` = P`u + P`v
P`u = Pu + Bu N + B(u,v) Nu
P`v = Pv + Bv N + B(u,v) Nv

where Pu and Pv are partial derivatives lying in tangent plane

Understand the theory behind wats goin on but dont quite understand wat are, and how to calculate Bu, Bv ,Nu, and Nv?