Which part? For the main lighting technique, most of the magic comes from the artist providing the surface normal components. Then to produce the image under

Which part? For the main lighting technique, most of the magic comes from the artist providing the surface normal components. Then to produce the image under some specified lighting direction, you can do the normal 3D graphics thing: dot product the light vector with the normal vector and scale that by the diffuse color. http://en.wikipedia.org/wiki/Lambertian_reflectance http://en.wikipedia.org/wiki/Lambertian_reflectance In case the artist doesn't draw the X,Y, and Z surface normal components directly but instead chooses some other set of lighting profiles, you could use photometric stereo to recover the surface normals. (If this is the approach used, then applying such a technique to specially-crafted pixel art is indeed novel). Here's a factorization technique for photometric stereo that could be applied to the artist inputs: http://www.wisdom.weizmann.ac.il/mathusers/vision/courses/2010_2/papers/photometric_stereo.pdf http://www.wisdom.weizmann.ac.il/mathusers/vision/courses/20...