RE: [GP] Large map virtual 3D world

[Jason Clark <jclark@ccpu.com>]

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One trick I use is to break the world down into grids, and only load the
current grid and the ones immediately around it, so they can travel without
interruption and it appears seamless without taking up all of their memory.

i.e.,

here's the world, x is the grid the player is in and L is loaded:

 - - - - -
| |L|L|L| |
 - - - - -
| |L|x|L| |
 - - - - -
| |L|L|L| |
 - - - - -

Then as they travel you can load the surrounding grids and unload the ones
out of range. If they are flying and traveling quickly, you may need to load
more at a time.

Just an idea,
Jason


-----Original Message-----
From: Famechon Ludovic [mailto:ludovic.famechon@aloatec.com]
Sent: Tuesday, March 30, 2004 7:09 AM
To: gameprogrammer@topica.com
Subject: [GP] Large map virtual 3D world


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I give you more details.

I want the players be able to walk on the map for hours.
So the map must be very large.
On the map, they will find moutain, grass, wood, river or lake. There will
be cities.

In future, perhaps, walkers will be able to become flyers, so they would be
able to see at a long distance.

I think the best representation for the terrain is a height map but I can be
wrong.
I don't already set the resolution of the map, it will depend of the
capacity of the chosen rendering algorithm.

I don't think that BSP tree is a good solution for a such engine. Or the map
must be cut in several little parts. What is your opinion?

I have seen an article describing a rendering algorithm using isosphere
("Terrain Rendering at High Levels of Detail" by Jonathan Blow) but I
haven't found any implementation detail (preprocessing or rendering).

Is this a good choice and, if so, where can I find more information, samples
or open source engine?

For the ATLAS protocol, I am not documented on high level of this protocol.
I am interested by the communication layer and the possibility to exchange
object information but I can write my own or use another one.
Sure that the map and characters will be stocked on client side.

Thanks for any comments.

Ludovic Famechon

----- Message d'origine -----
De : "Bob Pendleton" <bob@pendleton.com>
À : "Gameprogrammer Mailing List" <gameprogrammer@topica.com>
Envoyé : jeudi 25 mars 2004 17:35
Objet : Re: [GP]


>> Hi,
>>
>> I want to develop a client-server application where several players could
>> walk in a large virtual 3D world (~65kmx65km).
>>
>> I am in the technical choice phase of this project and I have some
>> questions.
>>
>> To render the map, I have seen the ROAM et VDPM algorithms but it seems
to
>> me they are good for fly simulator but not when the player is very near
the
>> floor.

>What a great question! I found this paper that discusses the differences
>between to the two algorithms http://www.cs.umu.se/~tdv94aog/ROAM.pdf
>The author seems to prefer ROAM.

>Both of those algorithms were developed for flight simulators. Walking
>around is a different problem. Except when you are at the top of a hill
>or have a long line of sight. Then you are dealing with the same level
>of detail problem that flight simulators have to deal with.

>>
>> Am I wrong? If no, what algorithm could I use? Do you know an open source
>> engine?

>Depends on where the walker can go. If you always have a short line of
>site you might be able to get by with good old BSP trees, but I don't
>know what you restrictions are.

>>
>> For the communication protocol, I have seen the ATLAS protocol. Is there
a
>> best choice?

>I just skimmed the atlas protocol doc. It seems fine at a first glance.
>But, do you really need something that complex? Also, how big is the map
>(in bytes)? It may be best to just copy it to each client.

>Tell us more about the project. It will help us answer the questions.

>Bob Pendleton

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