[Opensim-dev] terrain texture blend weight painting

[Toni Alatalo]

Hi,

we've had a first implementation of terrain texture blend weight  
painting in Naali for some weeks now. Am posting to ask for insight  
about how to go about integrating it to Opensim, or at least to give a  
little heads-up of what is going on with rex dev, also related to the  
generic scene entity-component work.

An ugly but hopefully informative screenshot:  
http://wiki.realxtend.org/images/2/27/Terraintexturepaint2_scaled.png  
(from the public sandbox on world.realxtend.org:9000 -- that has auth  
off).

What you see there is two terrains: 1) below a Linden style terrain  
received from Opensim with the lludp terrain messages, using the  
height-based texture mapping. The brick tile is used underwater, and  
the dirt above the water level. 2) above there is another terrain,  
using the same textures, but so that a weigtmap is used to specify  
where each texture is used, instead of determining it from the height.  
So with this you can e.g. paint where roads go for traffic sims or  
racing games. This works using the previous Naali (0.3.3) release and  
any version of opensim+modrex, for example the previous Taiga release.  
It currently just uses a local file to save the weights though, so  
doesn't work for real use now, but works for testing how it looks etc.  
currently.

Now the question is: are there people out there interested in using  
this? Perhaps to help with integrating it to Opensim? Or at least with  
insight to how it should be integrated?

Currently in that test Opensim doesn't know anything about that  
terrain. For Opensim it is just a prim, and the generic  
entity-component storage mechanism in ModRex is used to store and  
replicate it to clients. So Opensim doesn't do any collisions with it  
or anything.

There are two ways to go about integrating:

a) Add something to the Linden terrain protocol to communicate what  
technique is used to define the texture usage on a terrain. I.e. keep  
using the single hardcoded terrain otherwise as is, but just add the  
option to paint the texture blend weights. This I suppose would be  
quite simple to hack somehow?

b) Work towards having a generic entity-component mechanism, and  
implement terrain as a component that can support different features  
depending on the type of the terrain, but integrate with the physics  
etc. elsewhere in Opensim.

We are currently using the b) approach in the so-called Tundra  
experiment, where use Naali itself as a server (we've added a simple  
server module to Naali for that, but the scene code etc. is the same  
as when using as a client). This has been the simplest way to get to  
test how using the generic EC-model works for making features ..  
there's nothing hardcoded about the world, it starts as completely  
empty by default, but you can then add an Environment entity with a  
WaterPlane component, and any number of scene entities with the  
Terrain component etc. if you want. And the terrain component feeds  
the physics info for the physics module (we've also added physics with  
bullet to Naali). So far it still seems like this would be the good  
way for Opensim too. Tundra is very much w.i.p. yet and there is no  
release of it, is in a branch of Naali on github, but we'll make some  
sort of preview release soon (in 1-2 weeks I think) for those who want  
to test.

But to get this feature to work properly with Opensim quickly I  
suppose some simple hack to do a) would be it. We'll be using this now  
with Tundra at least 'cause need it in some projects already now, but  
if there's interest in devving / using this with Opensim as well I  
think that'd be cool (and also the folks using it with Tundra now may  
need it some day in a project where need Opensim feats).

~Toni