Inconveniently bumping an old post, but I found out some new things on normal mapping on ps2. On the pdf normal mapping on ps2 it shows the only thing the Vu1 does is tesselate the geometry using the normal mapping(tiling the geometry, meaning reapeat the per pixel code quicky for every geometry using normal maps). This means normal and bump mapping is nothing but code out of the same ol shading in a 3d game and that ps2 wasn't actually "emulating" it in software. It's just that it's simple coding(thogh they don't say if the per pixel is being done on vu1).
Vertex shaders are merely the polygon transformation and lighting tool is all, with built in already coded per-pixel things for normal and bump mapping. On ps2 the GS and Vu1 are the poly transformation and lighting tool, and with 2.9Gflops in each vu, the per pixel math is actually quite simple, as it was ony several small lines of code out of the already there shading. Also it's not quite software when they do that stuff, it's just that the polygon transformation and lighting part is on the cpu, the Vu0 or Ai and physics vector is untouched. Also there is this....
See all the way at the bottom it shows that the earlier(and hardly taxing) grayscale version of bump mapping can use a small 2 line code of checking the x and y of the gradient at the pixel to calculate vectors. Then another tiny 1 line code to incert those vectors onto the normal, where the everyday shading(as gaurod lighting can shade it too) x y cordinates and z direction of the light at that part of the shading or texture light has a new texture gradient look up based on that calculation of the position of light and the vectors calculated on every pixel from a two line code. I seen this myself on hitman:BM on ps2 and even on SCCT on my pc that that is how it works.
This all means bump mapping if developers weren't kids and knew how to code bump mapping themself then ps2 could had bump mapping on alot of the games it had out. Because actually the thing that made xbox so popular was Halo and bump maps.
If Killzone had grayscale bump mapping on all textures it would tax les hardware then it does now. Grayscale bump maps can be done in one pass and still be the same as your path of neo 2 or 4 pass normal maps. And killzone had tons of multi-pass multi-layer textures to emulate realistic quality. If it used bump maps then it would render normal non-detailed color textures, then instead of lots of passes for multiple layers on all the textures only one pass on all textures would be needed for the height map, then the small coding for the vectors and then you have a real halo killer(especually since the bump maps wont be plasticy from specular, but realisticly film like).
Sorry for bumpping when ps3 is now out. But I wanted to share as none of those developers deserve credit with the grayscale bump maps looking the same as normal maps and being so light in passes and easy to do, I just hate looking at those ports of xbox games to ps2, like the sega baseball game and how it's so small in size and looks worse then path of neo and scarfaceyet they put the xbox shots on the back.