i was reading an article a few minutes ago about DoomIII. i read that they start with an extremely high poly model to acheive their looks. then they run the model through a program that calculates all of the model''s normals. then it puts those normals into a map and applies it to a much, much lower poly model. this gives the look of a high poly model shading but with fewer polys. my question is does anybody know how to apply normal maps or map multiple normals onto a low poly model?

Would you mind linking to the article because a) I''m interested and b) It might help us answer your question.

well if you made a skin of normal maps from the low poly model you could just use a pixel shader to apply it couldn''t you?

http://pc.ign.com/articles/368/368245p1.html

Normal maps are talked about in the 3rd paragraph.

Dest: do you have any ideas on how to create normal maps? i dont have a clue. and about pixel shaders, i dont know really what they are and how they work. if you could point me to an article or tutorial i would be very happy.

"It''s the Carmack magic that allows us to take something that high quality and take it down into the lower poly count and still have the shadows and detail that you would see on the high count model,"

The words Carmack magic could serve as a subtle hint, meaning: This isn''t going to be easy

But don''t let that phase you. Look up Cg stuff from nvidia and Vertex and Fragment Shaders from ATI first so you know what we''re talking about. They''re still relatively new to the mainstream scene so I would advise using a recent card if you can.

ATI GL VX1: Ah......., Eight texture units.....

What you are talking about is poly bump and it''s not John Carmack''s Magic. Poly bump was invented by Crytek ( www.crytek.com ).

ohh...i forgot, and it only works with VERY dark scenes!!!

I was referring to the quote from the article.

Yeah, it works the best for dark scenes; this is because otherwise the lights would have to affect the bump map to get the needed effect. More lights = more calculations

Check ATI and nvidia bump mapping tutorials, they have some good ones that use vertex and fragment shaders.

I think the article 4.13 curvature simulation using normal maps in Game Programming Gems 3 talks about this. Check it out.

is there a way to map say 50 normals onto an object with say 3 polys?