New Terrain Commands

Some time ago, I reworked the terrain engine into a new shiny module. This module is now nearing completion as far as core features go – from here on in, new features will be towards things like v2.0 goals. Since it is now working correctly for most things, I have reworked the console commands back in – with some improvements. Many of you noticed in the last two-three weeks the old commands were ‘depreciated’ – these should now be working again as of r4039/4040.

So, a little guide.

First – I’ve created a new ‘command manager’ which also handles console commands, the goal of here is to enable LSL/Scripting functions for every console command, as well as allowing proper syntax-checked console input plus help. The short of this is you can now type “<module> <command> help” for help about a particular command, or “<module> help” for a list of valid commands. At the moment only “terrain” is supported for modules.

Region# :
terrain help
17:48:06 - ===Terrain===
17:48:06 - * load - Loads a terrain from a specified file.
17:48:06 - * load-tile - Loads a terrain from a section of a larger file.
17:48:06 - * save - Saves the current heightmap to a specified file.
17:48:06 - * fill - Fills the current heightmap with a specified value.
17:48:06 - * newbrushes - Enables experimental brushes which replace the standar
d terrain brushes. WARNING: This is a debug setting and may be removed at any ti
Region# :

You can see the list of commands there, with a brief description of what they do. You can see more detailed help, IE.

Region# :
terrain load-tile help
17:50:26 - == load-tile ==
17:50:26 - Loads a terrain from a section of a larger file.
17:50:26 - = Parameters =
17:50:26 - * filename (String)
17:50:26 -      The file you wish to load from, the file extension determines th
e loader to be used. Supported extensions include:  .r32 (RAW32) .f32 (RAW32) .t
er (Terragen) .raw (LL/SL RAW) .jpg (JPEG) .jpeg (JPEG)
17:50:26 - * file width (Integer)
17:50:26 -      The width of the file in tiles
17:50:26 - * file height (Integer)
17:50:26 -      The height of the file in tiles
17:50:26 - * minimum X tile (Integer)
17:50:26 -      The X region coordinate of the first section on the file
17:50:26 - * minimum Y tile (Integer)
17:50:26 -      The Y region coordinate of the first section on the file
Region# :

You will notice some of the commands have subtly changed since the previous version, load-tile now takes a slightly different input format, measured in tiles rather than pixels. Tiles are assumed to be equal to Constants.RegionSize (256) squared. So, the old format of ‘load-tile file.raw 512 512 1999 1999’ now takes the syntax ‘load-tile file.raw 2 2 1999 1999’.

The help in this new version should be more comprehensive and user-friendly for end users (or I at least hope so), I’m keen to see what users think. Also, if there are any features the previous version had that are not supported now and you were using, please let me know and I will add them to my TODO, but all other things being equal – I’m now going to move on to redesigning the console input for the rest of OpenSim.



OpenSim Weekly News – Week ending 29th March 2008


So, since I’ve encountered a few situations where people haven’t been aware of certain new features or fixes (since us developers are in the habit of sometimes only writing this in the subversion logs), I thought I’d start writing a weekly summary of the technical activity. Most of this is culled from svn updates, so I might not actually know all that much about the change in question. As these changes are hot off the keyboard, there are also no guarantees that they actually work yet ๐Ÿ™‚ These entries are just the highlights – not all changes and fixes are included.

I’ve no idea how long I’m going to keep this up, but I’m going to try ๐Ÿ™‚

Anyway, on with the show! This week in OpenSim…

  • I implemented code to limit incoming texture requests. For some time now we’ve had an issue (which shows up on osgrid) where memory leaks away when many clients are logged on until the simulator crashes. I believe this is primarily due to the fact that on a heavily loaded sim, we don’t respond to client texture requests within the client’s timeout and retry period. When the client retries the request, we add another load of texture packets on to the output queue. As a temporary solution, we now limit the number of requests that can be made for the same texture, dropping extra requests after a predetermined number. This is crude, but appears to work for now and can be improved later.
  • Alondria implemented the lsl functions llLoopSound(), llStopSound(), llAdjustSoundVolume(), llRemoveFromLandBanList, llRemoveFromLandPassList, llAddToLandBanList, llAddToLandPassList, llResetLandPassList, llResetLandBanList, llGetParcelPrimOwners(), llGetInventoryNumber(), llGetInventoryType(), llGetInventoryCreator(), llGetInventoryPermMask(), llGetInventoryNumber(). Go Alondria!
  • Teravus fixed up llApplyImpulse()
  • Teravus added partial support for llMoveToTarget() and llStopMoveToTarget() to the ODE physics engine.
  • Michael Osias submitted a patch to fix multiple llListens and implemented llMessageLinked()
  • Teravus implemented Oriented Bounding Box raytracing. Now you can rez one prim on top of another!
  • I implemented proper CAPS seed hand off on region crossings. Essentially, this means CAPS functions (which includes script and notecard saving) should be available on non-home regions on a grid.
  • I fixed initial inventory skeleton passing and some async inventory issues. Essentially, this means that folders deeper than the first level should now work better. Also, the texture picker in the edit prim dialog should now work (again).

Phew, that was more stuff than I thought.

— justincc (Justin Clark-Casey)

Proof of Concept – Advanced Terrain Brushes

In my previous post, I mentioned that I would be working on some new features this weekend, I’ve now finished the first of those – the new terrain brushes. As a proof of concept, I have developed a set of terraforming brushes simulating three different erosion techniques. Read on to learn about the brushes, and how to enable them.

To test these brushes, run the following command on your simulator console – please note that this is permanent until you disable it or restart the simulator.

script terrain newbrushes true

This will swap your default brushes, with the following new and exciting brushes.

  1. Thermal Erosion Brush (Replaces ‘REVERT’ tool) – my favourite. This acts as a sort of a cross between a smooth tool and a flatten tool, it creates very natural looking results if you drag it around a little. The effects of it are sort of similar to what would happen if you blew on a pile of very fine sand from directly above. Spikes and pinnacles get flattened out and their ‘mass’ gets transfered to neighbouring sections, creating a sort of plateau.
  2. Olsen Erosion (Replaces ‘FLATTEN’ tool) – this is a implementation of the oddlabs optimised hybrid erosion routine, described in the paper “Procedural Terrain Generation“. It will flatten flat areas, and sharpen sharp areas – think of it as a light touch you can apply over the top of a terrain to give it more contrast.
  3. Hydraulic Erosion (Replaces ‘SMOOTH’ tool) – this is a fairly powerful brush that needs a little more tweaking. The intended effect of this brush should be like pouring a bottle of water on a sandcastle, in that it will create a river system and drag sediment along with it as it flows.

I’m now going to look at implementing terrain effect filters that apply to an entire sim. Tom Coulthard, author of the GPL’d CAESAR package has been kind enough to give me permission to take a look over his code, and reimplement some of the high-end algorithms inside it for the purpose of developing OpenSim. (Thanks!)

Continuing with Terrain

So, the majority of the internal work of Terrain Module is now done – it works for all the standard operations you expect in SL. We now have the standard array of Raise, Lower, Smooth, Flatten, Noise and Revert brushes, both Paint and Area. The Noise brush still needs a little work as it uses random noise, rather than perlin noise for modifying the terrain, but the rest should behave normally. Parcel support is pending a rewrite of the parcel engine coming soonish, but is on the agenda.

This weekend, I am to knock out at least one, hopefully more of the following features.

  1. Erosion Brushes to complement the raise/lower/smooth/flatten/noise/revert brushes. Thermal erosion I should be able to do in under an hour. Hydraulic erosion is a bit more complex and might probably take longer. My own personal Aerobic erosion routine will probably make a return visit too once I clean it up a little.
  2. Effect Brushes. Part of the original libTerrain I wrote for OpenSim was a very rich and diverse set of routines for doing special effects to a terrain. The original erosion routines sat here, as did a mountain of procedural generators, and things to that effect. I’d like to bring these back, but make them more accessible to end users, I may see if I can instead of hiding them on the console, expose them to the inworld scripting language, I’ll try hunt Tedd to find out how we can do that if we can.
  3. Finish file saving and loading for a variety of file formats. One of the new features I brought into the new Terrain Module was the ability to write File Loaders as plugins to the Terrain Module itself. I also implemented a terragen loader which we didn’t have before. Presently we support loading from RAW32, LLRAW, Terragen, and saving to RAW32, LLRAW and JPEG. The full set I’d like to support is full read/write from the following formats: RAW32, LLRAW, TER, JPEG, BMP, PNG (16-bit ideal), BT, CSV and DEM. We’ll see how I go.
  4. Implement loading/saving for partial heightmaps (the old ‘load-tile’ method) properly.

That’s my TODO for Terrain at the moment. If anyone has any ideas or suggestions for TerrainModule – now is the time to let me know. Comments on here will do just fine.


Introducing … TerrainModule

Sounds boring, doesnt it?

Well, it probably is. But that doesn’t mean I can’t get excited about it, because it’s replacing our old and trusty warhorse of a terrain engine with something that’s less likely to turn your computer into radioactive slag every time someone decides to smooth an area of your sim.

There’s some important changes to how Terrain is handled internally in OpenSim – or to be more correct, how it isnt. Previous versions of OpenSim have relied on the internal terrain engine – this has been a problem because you could not replace it easily, and it was tied pretty heavily into the core of OpenSim. The new engine promises to be more flexible, as you can still operate the sim without it, it’s also closer to the OpenSim spirit of being modular — you can swap individual brushes and rewrite them without major effort.

Over the next few weeks, I aim to write a few more interesting terraforming brushes (my ultimate goal will be to write a series of erosion simulating brushes) and also rebuild part of how the console commands operated.

What the effect on you today will be

  • The terrain console commands will not work. You can still load and save terrain, but you need to use the new ‘script terrain save <filename>’ and ‘script terrain load <filename>’ operations. The other commands have not been implemented just yet.
  • Terrain operations should be faster. Particularly things which apply ‘Area of Effects’ such as select-drag-apply functions.
  • Smoothing and Flattening should no longer freeze the sim when using a debug build.
  • We will be able to support terraforming individual parcels, by the parcel, using the cutout bitmap in the next few days.

So, for developers – if you want to write your own brushes, it’s pretty simple. Take a look in the “Environment/Modules/Terrain” folder to see the directories “FloodBrushes” and “PaintBrushes” — flood brushes are ones that apply to an area (such as smoothing a selection), paint brushes are ones that you can drag across the terrain (such as raising or lowering normally). Brushes are passed a copy of the sim’s ITerrainChannel, and are expected to modify that channel. Please dont create temporary channels if you can avoid it, as creating and destroying channels is computationally very expensive.

Moving on – console commands. Part of the problem with the old Terrain Engine console commands were, they weren’t exactly the best things to document as they were heavily oriented towards how the engine speaks with the old Channel classes, and not how a user should speak to the engine. When I recreate these, I am thinking more along the lines of a rigid programming API interface, which can be self-documenting (ie min vals, max vals, etc) plus also be programmatically accessible, say for the purpose of remote admin. This is going to take a bit more thinking – but it is on the agenda.

Adam out!