Updated OpenSimulator BulletSim with fixes for Windows crashes (mantis 7371) and building physical linkset problems (mantis 7191). The former took a while as I managed to mangle by Visual Studio C++ build environment. The fix for that was just upgrading everything (after power cycling, of course).

Tweaking mega-regions

Adding the varregion feature to OpenSimulator caused me to bump into the mega-region code. The most recent commits to OpenSimulator are a rewrite of some of that code to make it easier to understand and eliminate some complexities (like creation and testing of complex border classes).

There have been some Mantis entries saying how mega-regions were broken but now that should be better. This is, previous mega-region configurations should now properly test for border crossings within the mega-region.

One side effect of the changes is to allow combining varregions into mega-regions. Although not completely tested (I figure there are some problems with maps and TPing with maps), you can mega-region’ize adjacent, same-sized large regions. Not for the faint-of-heart, but a configuration possibility.

I have been working on several Mantis entries for varregion and mega-regions and getting those problems resolved. If you find something that doesn’t work, Mantis away.

— mb


varregion gets adjacent regions, maptiles and better viewer support

The ‘varregion’ source branch in the OpenSimulator source repository has been updated this last week to fix a lot of the existing varregion problems. Some things that now work:

Teleporting to and from large regions using Singularity does not crash any more. There are still some problems with using the map to select teleport locations greater than 256 but that is being worked on.

Adjacent large regions now works. For instance, you can create adjacent 512×512 regions to reduce the number of border crossings. Remember that the region coordinates are specified in 256m region count so a group of four 512×512 regions would be specified at 8000/8000, 8000/8002, 8002/8000, and 8002/8002, for instance.

Another feature of adjacent large regions is, if you set your draw distance, you can see into the other regions.

Large regions show up in the map correctly. In fact, a lot of work was done on the Warp3D maptile rendered to make it faster, more functional (it now does meshes and prim textures[1]) and to not crash.

These changes are in the ‘varregion’ source branch which is in-sync with the master branch. More testing will make it get into the master branch quicker so test and file those manti.

[1] Check out the new parameters under the “[Map]” section in Opensim.ini.example.


Features for OAR files

I wanted to make the creation of varregions easier so I added some parameters to the ‘load oar’ simulator command. But, while I was in the area, I got a little carried away.

For varregions, ‘load oar’ now has a ‘–displacement “<x,y,z>”‘ parameter. This displaces all of the objects and the terrain from the oar file when loading them into the new region. For instance, say you have four OAR files from four adjacent 256×256 regions (oar00.oar, oar01.oar, oar10.oar, and oar11.oar). You create a new 512×512 varregion named ‘bigregion’.
The following commands place the four regions of objects, terrains and parcels into the new larger region:

change region bigregion
load oar oar00.oar
load oar --displacement "<0,256,0>" --merge --forceterrain --forceparcel oar01.oar
load oar --displacement "<256,0,0>" --merge --forceterrain --forceparcel oar10.oar
load oar --displacement "<256,256,0>" --merge --forceterrain --forceparcel oar11.oar

Note the new “–forceterrain” and “–forceparcel” parameters. “–merge”, used by itself, is for merging together the objects from multiple OARs. Merging also suppresses the loading of terrain and parcel data which is just what you want when merging objects. But, if loading multiple OARs to create a new, larger region, the terrain and parcel information must be loaded. Thus the new parameters.

While I was in the neighborhood, I also added ‘–rotation degrees’ and ‘–rotationcenter “<x,y,z>”‘. These apply a rotation to all the objects in the OAR file before they are displaced and placed in the new region. The rotation center is relative to the original OAR and defaults to “<128,128,0>”. At the moment, the rotation is applied only to objects and not the terrain or parcels.

Say you have a 512×512 region named ‘bigregion2′ and an oar file with buildings named ‘buildings.oar’ which is from a 256×256 region. The following places the buildings big region rotated 30 degrees without modifying the terrain:

change region bigregion2
load oar --merge --displacement "<128,128,0>" --rotation 30 buildings.oar

The caveat to all this is that it is only in the ‘varregion’ source branch. More testing will make it get into the master branch quicker so test and file those manti.

And have fun with those OAR files.

Varregion and the grid

After a brief hiatus recovering from a crashed disk and installing and becoming accustomed with Windows 8.1 (question to MS: what the heck were you thinking???), I’ve spent more time on the OpenSimulator varregion code.

The code is still on the ‘varregion’ branch of the source repository and it has been kept pretty close to the ‘master’ branch. I’ve added the size information to a bunch of the teleport messages trying to get teleport to a large region working. Sadly, it crashes Singularity whenever you log into or teleport to a non-legacy sized region in grid mode. Works in standalone mode. I haven’t tested it yet, but I’m hoping adjacent standalone large regions (like four 512×512) now border cross. It is an iffy thing, though, since there is ‘find my neighbor’ logic in Scene, GridService, EntityTransferModule, and a few other places. That logic does need some cleaning up.

I found that the Singularity crash when running in grid mode has to do with the fact that the grids out there are not running the ‘varregion’ code. In particular, OSGrid’s grid service is not storing and returning the region size. This means that Singularity gets told the destination region is zero by zero which is assumes means that region is legacy sized (256×256). The simulator, though, thinks the region is larger and sends terrain patches to Singularity for the larger region. Singularity doesn’t like that and it crashes complaining about bad terrain patches.

The fix is to get the grid services updated. To that end, I added a new commit to ‘master’ that adds the size accounting to RegionInfo, RegionData, and GridRegion classes. Since the database code already knows about storing the region sizes, this makes for a downward compatible update to the ‘master’ branch that does not change any APIs or change any functionality except for passing around and storing the region size along with its location.

Once that patch is distributed or cherry-picked (commit 6869633d76b2a6664743a608e4284b8dd7df85a6), testing will continue.


varregion: maximum region size

Seems that 8192 is a good maximum for region size. Both the viewer and the simulator agree.

To that end, I added Constants.MaximumRegionSize and have RegionInfo enforcing same.

Having a maximum region size is also good for searching for neighbor regions as this limits the search area. This constant is thus used in the ‘find neighboring region’ logic as well as the ‘find region containing point’ logic.

For the moment, this is in the varregion branch of the OpenSimulator source repository.

Varregion: crossing region boundries

Most of the ‘move to new region’ code is based on checking boundaries. There is much code related to computing if an object or avatar has crossed a region boundary and then computing the address of the next region from same. Introducing variable sized regions messes a lot of this computation up. That is, the code doing the arithmetic usually assumes it knows the address of the next region based on a known region size and them can compute the location of the next region based on that. With varregions those assumptions no longer hold. Varregion implementation means that the computation of region base locations and border locations moves to the GridService who is the entity who really knows the size of all the regions and what is adjacent to what.

The realization that location to region computation is really a GridService operation lead me to totally rip apart the grid boundary checking code and replace it with two functions: Scene.PositionIsInCurrentRegion(Vector3 pos) and then IGridService.GetRegionContainingWorldLocation(double X, double Y). The former function tests to see if the object/avatar has moved out of the current region and the latter gets the region moved into.

A side note is the computation of positions. A region has a base X,Y that is measured in meters and in “region units” (the number of 256 regions to this point). For instance, the region location of (1000,1000) is in ‘region units’ which is the number of 256 meter regions to the location. The “world coordinate” of the region is (256000, 256000) — the meters from zero. These meter measurements are usually passed around at ‘int’s or ‘uint’s. An object/avatar within a region has a relative position — relative to the base of the region. This relative location is usually a ‘float’. So an object would be at (23.234, 44.768) withing a region. An object’s world location, though, must be a ‘double’ since a C# float has only 6 or 7 significant digits. An object’s relative location (float) plus a region’s base (uint) are combined into a world coordinate (double) that can be used to find the region that includes  that point.

VarRegion: adding TerrainData and HeightmapTerrainData classes

One major problem is passing the terrain data from the region to the protocol stack. The existing implementation passed an array of floats that were presumed to be a 256×256 array of region terrain heights. The TerrainChannelclass is an attempt to hide the terrain implementation from TerrainModuleTerrainChannel can’t be passed into the protocol
stack (LLClientView) because TerrainChannel is defined as part of OpenSim.Region.Framework which is not visible to the protocol code.

My solution is to create the TerrainData class in OpenSim.Framework. TerrainData just wraps the data structure for the terrain and additionally has the attributes giving X and Y size.

I didn’t want to change the signature of IClientAPI since so many external modules rely on it. It should be  changed to pass TerrainData rather than a float[]. I decided to not change IClientAPI but rather have LLClientView ignore the passed array and instead reach back into the associated scene and fetch the TerrainData instance.

At the moment, all of these changes are in the varregion branch of the OpenSimulator repository.

Doing VarRegion for OpenSimulator

I’ve taken on the task of porting Aurora‘s variable region feature into OpenSimulator.

This port will use Aurora’s protocol extensions so the existing Firestorm and Singularity Aurora support will now work for OpenSimulator. The larger regions size will be restricted to multiples of 256 meters and adjacent regions (the ability to have other regions spacially next to larger regions) will not be implemented and will not work. Additionally, the larger regions must be square. This latter restriction is because the viewers currently (20131101) only use the X size dimension for both X and Y size. These restrictions are enforced by code in RegionInfo.cs which truncates and rounds values and output warning log messages.

The size is be specified in the Region.ini file:

RegionUUID = 95ec77ec-58c5-4ce2-9ff3-b6d1900d78a2
Location = 1000,1000
SizeX = 1024
SizeY = 1024
InternalAddress =
InternalPort = 9200
AllowAlternatePorts = False
ExternalHostName = SYSTEMIP

If size is not specified, it will, of course, default to the legacy size of 256.

Since this will be a major change to OpenSimulator that touches a lot of different parts, subsequent posts, will discuss the changes I’m making.

3D Worlds on the web

I’ve been working on LookingGlass which is a stand-alone, you-have-to-download-it viewer for the OpenSimulator virtual worlds. I really wish one didn’t have to download the viewer. Viewing should just happen as part of the web.

I’ve looked at this several times and it looks like the infrastructure is maturing. WebGL is appearing or will soon appear in most browsers. This provides the basis for getting accelerated, 3D graphics on the screen. Additionally, it is standard in the browsers (IE is a problem, Microsoft being who they are, but Google has a plugin to fix that).

Recently, Google has decided to move their O3D project to being a scene graph wrapper for WebGL. This makes JavaScript connect to the 3D world reasonably while keeping all the 3D technology in the standard browser.

The new O3D is early in its development but it is coming. 3D on the web is just around the corner.

Late phase education

I have some ideas for data coding (more on that in a later post) but it required me to do some heavy weight math. It has been a long time since I did math so I needed some refreshers. One amazing resource is the online MIT classes at MIT Open Course Ware. They have video lectures, class notes and exercises for freshman to graduate.

I’m making my way through freshman calculus. Have to begin somewhere and I’ve forgotten a lot. It’s like a foreign language — if you don’t use it, you loose it.

LookingGlass is over there

The updates for LookingGlass have been happening over at the official web site.

Camera and avatar movement is MUCH smoother because of finding bugs and adding position and rotation animation code. That also means that movement of animated objects is now smooth. LG works great in OSGrid/Lbsa Plaza but larger sims like OSGrid/Wright Plaza stretch the bounds of memory. SkyX now works with OpenGL although the shaders aren’t all together for the sun and moon lighting. Avatars are still stuck in T-pose and attachments are at the feet. Sitting avatars now are near the sit location and not at the sim’s 0,0. Also upgraded to the latest libomv. A new Windows 32-bit installation package is in the download section.

Under the hood LookingGlass progress

I broke a lot of stuff getting to a better place. The loading and reloading experience was poor (slow and jerky) so I moved a bunch of the update code from C# to C++. That has necessitated (after a while finding that this was the problem) building and including [http://boost.org Boost] for data structure access locking. I also wanted to have the Radegast window navigatable via the keyboard. This meant reorganizing the input code to extract common routines. Adding avatars meant rethinking and redoing the organization of Entities to allow for extensions for attachements, etc. Avatars are not first class items but merely a specialization of an entity which the viewer has to figure out how to display. The short of all this is I ripped a lot of things apart and they are not all together yet. Hopefully only another week. Fingers crossed.

Keeping up with LookingGlass

To make for  open discussions and transparency in my design directions, I will be added design comments to my blog here as well as in the LookingGlass forum on the Forge. Join in the discussions on the forge.

Integrating Avatars and Attachments and generalizing entities

I had been fretting about whether avatars and their attachements are first class objects or subclasses of entities. I am now thinking the latter. That is, World just deals with Regions that contain Entities and the Entities have sub-classes that are created by Comm and sensed by the Viewer.

The pattern I’m working with at the moment is (using an Avatar as an example) for there to be a World.IEntityAvatar which defines the operations beyond the base entity. For LLLP, there is a World.LL.LLEntityAvatar that implements the IEntityAvatar and IEntity for an LLLP avatar. Additionally, LLEntityAvatar does a


to add the interface to the IEntity. Later, the Viewer will do a

TryGet<IEntityAvatar>(out anAV)

to see if the underlying entity is an avatar or not. If it is, it will call the avatar specific methods to view the avatar.

Over time, methods will be added to IEntityAvatar and LLEntityAvatar to try and hide the implementation details of an avatar and create an abstract interface for a boned mesh with animations. I figure that the specific positioning logic that is now in RendererOgreLL will move into LLEntityPhysical with a generalized interface for RendererOgreLL to call into the entity to compute the location and parent.

The goal would be to extend Viewer to handler IEntityPhysical (a regular object in the view), IEntityFoliage, IEntityAvatar and IEntityAttachment and all the protocol and item type specific logic will move into protocol specific implementation of classes with those interfaces.

LookingGlass progress 20090730

I am about to make a video of logging into Wright Plaza and flying around but I wanted to get shadows working first. I introduced an oddity whereby the brightness of a prim is tied to it’s x or y rotation. I just can’t find the problem but, since it makes most buildings have large black sections, I have to find the bug before I show LG off. Other than that, LG allows logging into and navigating most sims.

LookingGlass Progress 20090722

I’ve wanted to advance a version but the main thing keeping LookingGlass from being usable was the unbelievable memory footprint. Ogre vertices took up all the memory until it crashed. So, I’ve spent the last two weeks adding a dynamic loading and unloading system. Now I can log into Wright Plaza and walk an fly around. Woot!! I’ll add a video and some updates this weekend.

LookingGlass progress 20090706

I’ve completed sculpties and added many texture processing improvements. Normal LLLP textures are JPEG2000 but I had to figure out how to store sculptie textures as PNGs so I could read them into the .NET/Mono graphics functions. Once I was more familiar with textures, I put in checks for transparency and put in the code to pass that info down into the renderer. There are some problems around PrimMesher but I don’t know if it’s a bug or me using it wrong. You’ll see the problems with box prims having the wrong textures on the bottom (most notable if someone rotated the box to use the hollow for a hole) and that textures are placed on scuplties upside down.

But it’s getting more stable and can pretty much do a sim. Walking around is not very easy but that will take prioritization of the work queues.

More Ogre Dynamic Loading

I updated my page on dynamically loading meshes, materials and textures in Ogre with information for textures. Turns out that the requests for the textures works out but that, again, the containing mesh has to be reloaded to get the texture to pop up in the scene. The code for finding which meshes need reloading is included.

LookingGlass progress 20090619

I reduced the detail of Meshermizer from High to Low. The effect is not visible (at least so far) but the number of vertices generated per mesh is much less. After setting ‘MultipleSims’ to one, I was able to login and render the whole of OSGrid/Wright Plaza. Woot!!

Performance is no where near good enough yet. The callback for materials is taking forever since there are > 30k materials in Wright Plaza. Ogre also freezes up now and then. I added/completed statistics gathering and RESTing to try and find it. At the moment, it looks like Ogre hangs up doing the JPEG2000 decompression for the mipmaps. Might have to convert the textures on reception.

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