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Submitted by Francis Woodhouse, posted on April 05, 2002

Image Description, by Francis Woodhouse

The two images show some screenshots from the early stages of my terrain engine (yes, another one!) that I've been working on since Christmas Eve of 2001. I've rewritten the LOD system 3 times, first using a 9x9 vertex tile system, then an adaptive quadtree algorithm, then back to the tile system but with each tile having 17x17 vertices. The tiles can be rendered at 8 different levels of detail, using the vertex error as the factor to decide which LOD to use for that particular tile. Frustum culling is done on each tile's bounding sphere, but a quadtree is yet to be implemeneted. It gets around 130 FPS at the moment, and goes down to 100 FPS with a particle system being used (not shown in these screenshots - that's what I'm working on at the moment).

There are lots of things that are still to do - finishing the particle engine, quadtrees, level editor, models, moving sky, lighting, and more. However, I am designing the engine with dynamically alterable terrain in mind, so you'll be able to have rockets dig holes in the ground.

Cheers, and I look forward to your feedback!

Image of the Day Gallery


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Archive Notice: This thread is old and no longer active. It is here for reference purposes. This thread was created on an older version of the flipcode forums, before the site closed in 2005. Please keep that in mind as you view this thread, as many of the topics and opinions may be outdated.
Lars Birkemose

April 05, 2002, 02:16 PM

Nice shots.... but isnt it time to make some new approaches on terrain rendering ?


Division By Zero

April 05, 2002, 02:37 PM




Yes it is ... cuz its terrain engine ! :P

Love terrains


April 05, 2002, 02:42 PM

Why not wait and publish this when there's more to see? You can't really judge anything based on those two shots.

*** I don't think it's worth a comment! *** :-)


April 05, 2002, 02:46 PM

re: larsB

I hope so. Every single bloody terrain engine I have seen (bar Ken Silverman's cool Voxel one, which doesn't count) has only enabled terrain which can be represented by a 2d image. I haven't seen any engine which can display caves, overhangs and not even very steep inclines effectively. Most people today are simply concentrating on level of detail algorithms :(


April 05, 2002, 02:50 PM

Whoa, green hills plus orange sky & fog?
That orange just seems out of place. Now if the hills in that bottom pic were brown/red then it might look more like mars.

Some detail texture in there too I see. Definately needed it. There isn't any other form of detail in the picture.

OGL? DX? Software?


April 05, 2002, 02:54 PM

Yeah true. We should stop creating special algorithms for all kinds of objects. Make it generic. Just like JohnC mentioned. Hardware is getting fast enough. You optimize the generic algo and everything speeds up :o)...

just my humble opinion..

Wim Libaers

April 05, 2002, 02:58 PM

Actually, such terrain engines have been made. For example, Enemy Engaged: RAH-66 Comanche vs KA-52 Hokum has this system. No caves, but it does have very steep valleys and the terrain in general is not the usual square grid but allows irregular shapes. The lighting model isn't as advanced as in some other games, however.

zed zeek

April 05, 2002, 02:58 PM



April 05, 2002, 02:58 PM

Do people use the word 'engine' just to confuse me or has someone defined where that words should be used now? Is this an application, engine, visualization, simulation, library, tool, game, ????


April 05, 2002, 03:00 PM

Let me get this straight, what someone else mentioned is now your opinion?!

zed zeek

April 05, 2002, 03:01 PM

this is one of my 2 main rules that i follow
A/ treat everything is equal (make no exceptions)
B/ think ahead
as well as the other bollux about premature optimization etc


April 05, 2002, 04:53 PM

Very good point postalrat... what is an engine now? :P

I mean, I wrote a simple terrain engine, but I didn't really consider it an engine cuz it lacked way too much. It was more a flythrough demo than an engine, but hey, that's just me...

In an age of catchphrases and diet soda, I guess we can't be too surprised.

Clint Brewer

April 05, 2002, 05:29 PM

Hey, congrats on your terrain engine. I know how much work it can be to get these things going, and it's a good accomplishment despite what other would say.

I certainly wouldn't complain if I saw a non heightfield terrain though, that iotd with the green swiss cheese voxel terrain was really nice!


April 05, 2002, 05:50 PM

my stuff as well. Heightmaps = EVIL!

-=[ Megahertz ]=-


April 05, 2002, 05:50 PM

We have a lot of terrain engine on flipcode.. Most of us wish to see more new and original things. However, good work.



April 05, 2002, 05:57 PM

Congrats on your posting . . .got a demo or a website?

Clint, thanks for the complement about the "green swiss cheese" voxel terrain, I wrote that! :) I have a much improved demo coming out soon, hope to post on flipcode soon.

Anyway, good work Francis, it took me over two years before I had anything worth looking at.. Keep at it!


April 05, 2002, 06:18 PM

There was a demo up not too long ago called Cubes which was literally a terrain engine being used for a indoor rendering. So there you go. Don't remember the link, off the top of my head, but if you interested in looking at it I will look it up.


April 05, 2002, 06:31 PM

The Drakan (Riot) Engine approach, how could you forget? With layered heightmaps, making really cool cavelike environmants, I must say that I havent seen a terrain engine/implementation of that quality in any of the recent hey_im_making_my_own_3d_game_engine craze of comunity projects. That was truly a unique approach to things...

Clint Brewer

April 05, 2002, 06:39 PM

very welcome, I look forward to your new demo :)
I just found it again last night because someone was asking about volume terrain on the VTP list.

we need an image search though. I had to go through every page to find it :) maybe there is an image search on flipcode that I didn't see?

Clint Brewer

April 05, 2002, 06:51 PM

yeah that was a nice terrain setup. do you have any links to a technical description of their terrain?

was it a sandwiched

right side up terrain
upside down terrain
right side up terrain

maybe divided into tiles, so yuo don't waste a lot of invisible terrain stuff?


April 05, 2002, 08:10 PM

Looks nice. It would be great to be able to download a demo though, since these two images leave a lot to be imagined :)

One question though... if you've rewritten your LOD system 3 times, why have you not considered VIPM or something a little more modern? Not to say there is anything wrong with your implementation. I would just really like to see a IOTD of a VIPM algorithm (with downloadable demo and source) one day :)

Keep up the good work.


April 05, 2002, 10:45 PM

sadly, there aren't any good tech links about the riot engine, since they decided to remake the surreal home into an artsy-type site it lost any useful info it contained I actually dont know why the hell they even have a site anymore without any informational content. In fact is now a porn site. Go Fig :o So you can imagine that any game info is long dead, but probably still lurking somewhere on the net.

But what I got from attempting to make levels using their editor, was that it was basically a sandwich of heightmaps. with per-vert editing so the shapes could be better tweaked.

The rendering from what I gather was done with a visible square grid of tiles, simply took the cam view matrix, transposed it half the grid's size forward, then took the y,x coords and that was the center of the render grid. I believe one of the programmers explained that in a forum a long time ago, or maybe someone posing as one of the game's programmers. Either was it sounds good.


April 05, 2002, 10:49 PM

oh poop, forgot to give you the link to the surreal site about the riot engine if you want to look for yourself


April 05, 2002, 11:01 PM

I would think software that managed displaying something like this iotd, static terrain, be called a scene-graph. Now it would be a "terrain engine" if it handled interactive terrain, a situation where terrain must be redefined because of non-premeditated action.

At least that is what I define as a software engine, something that handles rules for a self-propagating virtual situation, am I wrong?


April 05, 2002, 11:52 PM

You should make a game based entirely around sniping... with massive outdoor environnements. That would rock. :)

Although it's hard to say just from the screens, your engine at least sounds very cool ;) Good luck with your particle system!


April 06, 2002, 03:36 AM

That would depend on if you want to research some new approach, or just get something to work in your engine that is fast enough :)

Let me know if you do find some ground breaking new way of doing it though :)

Wim Libaers

April 06, 2002, 04:32 AM

Never played that one. Similar to Magic Carpet 2 cave levels?


April 06, 2002, 05:28 AM

i took a look at a few terrain engines back here and one thing they have in common: bald hills with some triangle tree here and there. it all looks like Island scenery. Isn't it a right time to undergo some 'research' on topics like forests, bushes and grass?

Arne Rosenfeldt

April 06, 2002, 07:17 AM

bald hills are described by a smooth function:
you can differentiate it
and an approxiamtion with a polygons converges fast with increase in number of polys

trees and bushes are fractals
you cannot differentiate it, lightnig is difficult
and an approxiamtion with a polygons converges slowly

therefore people use particles, imposters, voxels,
but this representation still converge slowly

I think the representation don't have to be so exact,
since our brain also has problems dealing with fractals


April 06, 2002, 08:09 AM

You can get away with a lot when something is zipping by quickly rather than sitting still on the screen. Like that shoe in place of a ship in Star Wars.

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