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steveharper101

Dot Product Bump Mapping

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You know there is a thing on the internet called Google. It is a search engine. It is located at www.google.com.

In case you didn''t know you can search the internet by entering a query sentence as "Dot Product Bump Mapping". You would not believe how much information can be retrieved by using it.

If I were you, before trying to code the next best 3D engine, I would try harder to improve my search engine skills. You know it''s not really hard, you enter a query and press submit and you get the results within 5 seconds.

In case you did not notice, I am sarcastic.


Here''s the result from Google:

TechnicalDemos
NVIDIA.Com> Developer Relations> TechnicalDemos> Dot
Product Bump Mapping Bookmark this Document ...
partners.nvidia.com/Marketing/Developer/DevRel.nsf/pages/ 5BDA7B063EAB9399882568310064542E - 8k - Cached - Similar pages

TechnicalPresentations
... Related Documents TechnicalPresentations - Dot Product Lighting TechnicalDemos
- Dot Product Bump Mapping Whitepapers - Dot Product Texture Blending ...
partners.nvidia.com/Marketing/Developer/DevRel.nsf/pages/ FB5C250DA264105B8825682700802561 - 8k - Cached - Similar pages
[ More results from partners.nvidia.com ]

Tom''s Hardware Guide: Graphics Guide - High-Tech And Vertex ...
... Setup For Dot Product Bump Mapping (Per Pixel Bump Mapping). Since the DirectX7-spec
and the rendering hardware of GeForce256, GeForce2 and ATi''s Radeon it is ...
www.tomshardware.com/graphic/01q1/010227/geforce3-11.html - 40k - Cached - Similar pages

??? ??? - ?? ??? ?(Vertex)? ??? ...
... Dot Product Bump Mapping? ?? ?? (Per Pixel Bump Mapping). DirectX7
??? GeForcer256, GeForce2 ??? ATi? Radeon? ?? ??? ...
www.tomshardware.co.kr/graphic/01q1/010227/geforce3-11.html - 46k - Cached - Similar pages

Tom''s Hardware Guide: Grafikkarten - Vertex-Zauber: Die ... - [ Translate this page ]
... Dot Product Bump Mapping (Per Pixel Bump Mapping). Mit Bump Mapping werden wirkungsvoll
Oberflächenreliefs erzeugt. Dies können beispielsweise die Rinde auf ...
www.tomshardware.de/graphic/01q1/010302/geforce3-16.html - 36k - Cached - Similar pages

3D Concept - Bump Mapping im Detail - [ Translate this page ]
... Bump Mapping im Detail (4/9) "Es -werd e plastisc h". Dot Product Bump Mapping.
Dot Product Bump Mapping (manchmal auch Dot3- oder Pertubed Normal Bump Mapping ...
www.3dconcept.ch/artikel/bump/4.htm - 15k - Cached - Similar pages

[PDF] www.3dlabs.com/product/technology/Bump_White_Paper.pdf
... map embossing in Expendable, by Rage Software, running on PERMEDIA 3. Dot product
bump mapping The "dot produc Bump Mapping t" bump mapping technique is very ...
Text version - Similar pages

ZDNet: Bump Mapping
... read review) support EMBM. The nVidia GeForce 256 chip supports dot-product bump
mapping, as does 3D Labs in its product line (read review). The remaining chip ...
www.zdnet.com/products/stories/reviews/0,4161,2385309,00.html - 43k - Cached - Similar pages

Tom ????: ????? - ...
... ?????????Dot Product Bump Mapping, Per Pixel Bump Mapping?---Setup
For Dot Product Bump Mapping (Per Pixel Bump Mapping). ...
www.big5.tomshardware.com/graphic/01q1/010227/geforce3-10.html - 33k - Cached - Similar pages

HardwareCentral - Reports - Ironing Out the Bumps - Dot ...
... map bump mapping is too slow, too incompatible, and that their own "dot-product"
bump mapping is in fact better than both embossing AND environment-map bump ...
www.hardwarecentral.com/hardwarecentral/reports/736/5/ - 27k - Cached - Similar pages

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Guest Anonymous Poster
... or you could be slightly polite and point him towards http://www.nvidia.com/developer.nsf

:-|

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Hey thanks Anonymous.

I only wanted a simple short answer from someone who knew about bump mapping. I am not jumping in and coding straight away i'm just intrested in a brief description of how it works more for curiosity.

Thanks Anyway

~StevE

Edited by - steveharper101 on September 7, 2001 4:05:03 PM

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Also on my site (http://nitrogl.cjb.net), I have a "tutorial" for DOT3, it doesn''t explain how it works, but you could copy/paste some of the code to get you started.

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DOT3 bumpmapping is very similar to creating a landscape from a heightmap. When creating a landscape from a heightmap you treat each pixel in the heightmap as the height of a vertex in your landscape grid. This gives you a landscape with valleys where there are black pixels and hills where there are white pixels.

With DOT3 bumpmapping you take the heightmap and create a normal map from it, this is done by taking three samples from the heightmap (0,0 0,1 and 1,0 for example) and treating them as points in a triangle. A simple cross product and you have the normal for that "triangle". This normal is then range compressed (converted from [-1, 1] range to [0, 1] range as colors are unsigned in OpenGL) and stored in the normal map.

Once you have the normal map you calculate the lighting on a per-pixel level using the normal from the normal map (N) and the light vector (L). So the amount of light a given pixel gets is equal to L dot N. You can then blend this with some decal texture to give you a nice bumpmapped surface.

You can also do specular highlights by calculating the half-angle(H) vector (by adding the light and eye vector) and calculating H dot N and adding the result to bumpped surface, this gives you the "shiny" bumps.

Jason A.

---
I write code.
DelphiGL (http://delphigl.cfxweb.net)

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