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dot3 bump mapping

Started by Khaos Dragon Jul 31, 2004 at 9:47 PM 9 replies 4k views

Original Post

Jul 31, 2004 at 9:47 PM

I am having trouble finding any decent tutorials on this topic via google, and specifically how it is implemented via open gl? For example, I think the next big step in my terrain is to dot3 it. It really consists of a grid of heightmapped tiles. I am wondering what I would do to dot3 it. Would it involve taking the sun position into account and the plane of the tile to calculating the vector of the rays bouncing off each tile? Also, does there exist a fast and good looking method that will work pretty much on all recent cards, including ATI and Nvidia?

Chman_a11w

Aug 1, 2004 at 12:49 AM

Have you take a look in the NeHe's article part ? There is a good tutorial for implementing Dot3 independant from hardware (it will run under ATI/nVidia/Matrox without any problemes...

Chman

Luke Philpot

Aug 1, 2004 at 5:34 AM

Quote:
Original post by Chman_a11w
Have you take a look in the NeHe's article part ? There is a good tutorial for implementing Dot3 independant from hardware (it will run under ATI/nVidia/Matrox without any problemes...

Chman

The one on NeHe's site is emboss bumpmapping, not dot3.

Theres a tutorial on paulsprojects.net, nutty.org, and also some code on Delphi3D (although its in Delphi, its not too hard to convert over to C/C++)

mikeman

545

mikeman

Aug 1, 2004 at 5:41 AM

If all the light comes from the sun,then why don't you just use lightmapping,and calculate the lightmaps so that they take into account bumpmapping?It's not realtime(but if the light direction is constant,you don't need it),and it does not support specular lighting,but it's fast and it will run in any card.

mikeman

545

mikeman

Aug 1, 2004 at 5:50 AM

Yeah,I was just going to post that I was wrong,to achieve bumpmapping that way would need a huge resolution lightmap.AP is right.

python_regious

103

python_regious

Aug 1, 2004 at 7:30 AM

However, with a lightmap you can use any light model you like. ( hence GI ). For a terrain, the lighting doesn't have to be amazingly accurate anyway, just the low frequency data will produce good results.

undo

Aug 1, 2004 at 7:50 AM

@Luke Philpot: Chman_a11w meant the article section, not the tutorials and there is an article about dot3. Its article 20.

tok_junior

Aug 1, 2004 at 8:02 AM

Everyone has a card that supports Dot3 bumpmapping today. It's been supported since the old GeForce 256, and noone who'll use whatever you're making has an older card than that.

extralongpants

Aug 1, 2004 at 9:14 AM

I remember having a terrible time trying to find any decent dot3 bump mapping tutorials. After much searching, I came across this page: Paul's Projects. Here's the link for the bump mapping tutorial: Dot3 bump mapping tutorial. His OpenGL tutorials, are all simple, easy to follow, and include source code. I learned how to impliment dot3 bump mapping by using his tutorial. He has a few other interesting tutorials, and I urge all of you to check his page out if you haven't yet. Anyway, I hope that helps. Good luck!

python_regious

103

python_regious

Aug 1, 2004 at 7:49 PM

If you really want to learn it properly, read Mark Kilgards "A Practical and Robust BumpMapping Technique for Todays GPU's", as can be found on the nVidia developers site. It explains the mathematics behind bumpmapping thoroughly and in an easy to understand manner. Probably the best article to understand the basics.

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