Good morning all you game coders, What a wonderful morning here in South Africa. Up so bright and early. Well let''s start. Where can I begin. I hope this will be an inspirational thread for most Terrain Engine Coders. I hope we can discuss full blown techniques here and help out beginners such as myself. http://www.lachdannan.za.net/images/terrain_texture.jpg This is a screenshot of my very new terrain engine. This is the topics I would like to discuss here. 1) Post some links to some very explanitory Terrain Texturing Tutorials 2) Post some links of very in depth and easy to follow LOD and ROAM Tutorials 3) Where and how do you guys get your Textures? 4) LAST BUT NOT LEAST. POST your screenshots of your terrain engines. Thanks guys. Gamedev is a very good resource for everyone starting out and a very good inspirational place to come. GAMEDEV the future of GAMEDEVELOPMENT ---DirectXSA--- Lachdannan Corp. www.lachdannan.za.net

Screenshot 1 - The terrain as it stands.

Wireframe shots of the LOD when it was using the bintree algorithm that ROAM uses. I switched to using D3D PMesh simplification (it''s less restricted and I didn''t have to write my own!)
Screenshot 2a - Lowest detail
Screenshot 2b - Not-quite-lowest detail
Screenshot 2c - Little-higher-than-not detail
Screenshot 2d - High-as-a-kite detail

Screenshot 3 - Single texture, looking into sun.

These are an old screenshots. I''m working on a totally different way (non-heightfield based) of doing terrain than that, though, so it''s not very representative of what my terrain will end up as. But it''s a semi-decent screenshot.

I hated the texturing in it, though (hence the name of the first URL).

A quick rundown of what''s in that shot:

1. Geo-mip mapping (or geomorphing or Chunked LOD, I don''t remember which technique it is -- the one with the quadtree of levels). However, I used a different breakdown of LOD detail (I didn''t break it down regularly, instead I used the Progressive Meshing algorithm to remove the least-different points).

2. Sky generation - it actually looks pretty good, though not necessarily in that screenshot. No clouds yet, though. Done according to the Preetham paper, though I had to do tons upon tons of tweaking to get it right.

3. Huge draw distance - I''m going for 2 km (1.2 miles) draw distance.

The only problem with the terrain (Besides the heightfield limitation) is the sheer size of it. It''s HUGE on-disk. But it DOES take a full 5 minutes to get to the far side of it.

That''s all. Enjoy


---

Actually, to answer the questions you asked:

1. Terrain Texturing Tutorials (say it 5 times fast!) - Uh. Well, There are a few on the Gamedev.net resource page. Try there.

2. There are som LOD tutorials at that site as well. Here''s a ROAM tutorial for you. You have to register with Gamasutra, but it''s free. And there are tons of articles on terrain there too.

3. Uh, I do google searches for "free terrain textures" and look through page after page until I find some. But eventually I''m going to wander around the greater Indianapolis area with a digital camera and take pictures of the surface types I need, and make them tileable in Photoshop.

4. Done already


Okay. This time, that''s really all.


I think.

Screenshot

That''s a shot from my old terrain engine. It was loosely based on the Gamasutra tutorial that somebody already linked to.

The texture is one large 4096^2 texture. It was created by blending 4 basic textures ( water, grass, mountain, snowy mountain ) into a single texture based on designer specificed height ranges. This was done offline.

Clicky
Clicky #2

Another old terrain engine. Covers 66x66km2 with per-meter detail using controlled noise (takes 6 MB in storage space ). It takes about 44 mins to go from one side of the map to the other with a car going at cruising speed. The terrain in the screenshot has a viewing-distance of 2 km I think. Uses a quad-tree with geomorphing and run-time generated chunks. Textured by having one grass texture, one rocky texture and one detail texture. The color textures are interpolated based on terrain slope only.

EDIT: As for other terrain resources, check vterrain's game-terrains page and search in the GDnet forums.

EDIT2: My hands are trippy...

[edited by - coelurus on May 31, 2004 5:24:52 AM]

[edited by - coelurus on May 31, 2004 5:25:39 AM]

to drillian:

how big is that landscape? You said it takes 5 minutes to cross it.

I am doing an airplane simulator for fun and I was impressed with your screenshots. What technique do you use? I am using ROAM at this point but I got alot of problems with popping and huge cpu usage. Any suggestions?

And last but not least, how did you generate that sky? my sky it''s just a blue color and yours looks pretty nice. Any tutorials or code on that one?

Joaquin

quote:Original post by creative1
I am doing an airplane simulator for fun and I was impressed with your screenshots. What technique do you use? I am using ROAM at this point but I got alot of problems with popping and huge cpu usage. Any suggestions?

I strongly recommend against using the typical ROAM error metric of checking the height of ''wedgies'' in screen space. The screen space projection costs way too much for reasonable sized terrains. What I am currently doing is determining likely error level in object space. If you take the ratio of distanceOfPlayerToNode-:-deltaHeightFromApexOfNodeToBaseOfNode in object space you can get a very decent looking LOD that requires ''much'' less CPU work.

I also recommend against using split/merge lists. I have had much better results using an exclusively split/based implementation.

As far as popping goes I tend to tweak the above object-space formula until popping is not really noticable. You could also simply smoothly interpolate the splits rather than immediately splitting.