Terrain Data

Todd,

I use Paint Shop and create a 256 colour grey-scale image, and save it as .raw format. It literally dumps out 1024x1024 (or width x height) bytes, nothing more nothing less.

Bye

My terrain is 64 by 64 with all vertex normals pre-generated and stored - generating them takes a long time - how do commercial terrained games do it for huge terrains like flight sims etc. they can''t possibly calculate vertex normals realtime can they?
Chris

You can find some info''s about this topic on www.vterrain.org.
This is definitely the source for terrain rendering.

Yoshi

I''m using a 256x256 heightmap at the moment for my terrain engine. It could easily be converted using a 1024x1024, and this would be fine if you''d ask me
If you''re calculating all values for all vertices - you''re right - it would use up too much memory. But why should you?
I''m using a 256x256x8bit height-map and a 256x256x8bit light-map. It works perfect. I''m NOT depending on OGL to do the lighting, but I''m pre-calculating it myself.
So the lightmap values are not a normals, but a simple light-intensity (0=black, 255=white).

Its not dynamic lighting though...

quote:

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Original post by Anonymous Poster

Terrain is pretty much static, so it doesn''t change. If you have enough memory,
you might as well use it.

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I agree, but using all the memory for precalculated normals for every triangle is overdoing it - I think.

quote:

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However, games that use huge terrain heightmaps like 1024x1024 must obviously
calculate their vertices in real-time directly from the heightmap data. Then
everything else that relies on these vertices, like normals and planes, must
be calculated every frame as well.

For simple terrain rendering purposes, you probably just need to calculate
vertices. But if you need collision detection, like objects moving around on
the terrain, you''re going to need the normals and probably the plane equations
of those vertices.

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I''m doing collision detection in my game engine I''m currently writing. Pre-calculating plane data for all your terrain triangles might be overdoing it! Unless you have >1000 objects moving around. But if you did - using plane collision for terrain-object collision would not be fast enough.

The CPU cycles that go into calculating the plane-equation realtime, would not even be close to the cycles needed for calculating the exact collision. Let alone collision reaction and animation of the object.

It can never be wrong of course to do as much pre-calculation as possible, but it might blow your cache. This could be harmfull in some situations. (Sorry I brought this up - going into these details are not important in this thread - please dont post about cache)

Do you also pre-calculate texture coords per vertex?


(ps: this is only out of personal experience - but please prove me wrong )

Thanks for all of the great info. I''m going to use a 64x64 RAW height map for my first run. What is a standard distance X/Z if the height values represented the Y component (Y being in the range of 0-255)? Thanks.

Todd

My terrain has vertex normals for smooth shaded polygons so the terrain doesn''t look like it is made up of triangles - just smooth ground - and my vertex normals are generated by taking the average of all the face normals that use a particular vertex and normalize that - then use that normal as the normal for that vertex.

This takes ages to generate - on my celeron 400 w/ 64 megs RAM it takes about 36 seconds. I am using linked lists of vertices and faces for easy extension - is this a good way to calculate them - could it be done much faster - I need to have dynamic lighting (sun moving across sky - changing shadows) so the normals are needed.

Chris

has anyone got a link for articles on Procedural Texturing?

If you are interrested - I've just released the full source-code of my little landscape demo. You can download it from my site: baskuenen.cfxweb.net

I also included 3 textures (256x256x24bit TGA).
I used this landscape in my 3D game engine, that you can also download from this site.



Edited by - baskuenen on November 6, 2000 9:51:48 PM

Baskuenen,
Thanks for the code man - been waiting to see it ever since you first showed that screenshot on the forum - its a really impressive looking demo - I''m really interested in how you made it run so fast. Also - did you make the textures - they''re amazing.

Chris