BulletSim: fix race condition when creating very large mega-regions.

The symptom was exceptions while creating physical terrain.
Reduce default terrain mesh magnification to 2 from 3 because the
higher resolution uses a lot of memory and doesn't solve the terrain
smoothness for vehicles.
Added comments here and there and improved some debugging log messages.

OpenSim/Region/Physics/BulletSPlugin/BSMaterials.cs

@@ -180,11 +180,14 @@ public static class BSMaterials
     // Use reflection to set the value in the attribute structure.
     private static void SetAttributeValue(int matType, string attribName, float val)
     {
+        // Get the current attribute values for this material
         MaterialAttributes thisAttrib = Attributes[matType];
+        // Find the field for the passed attribute name (eg, find field named 'friction')
         FieldInfo fieldInfo = thisAttrib.GetType().GetField(attribName.ToLower());
         if (fieldInfo != null)
         {
             fieldInfo.SetValue(thisAttrib, val);
+            // Copy new attributes back to array -- since MaterialAttributes is 'struct', passed by value, not reference.
             Attributes[matType] = thisAttrib;
         }
     }

OpenSim/Region/Physics/BulletSPlugin/BSParam.cs

@@ -482,7 +482,7 @@ public static class BSParam
             (s) => { return TerrainImplementation; },
             (s,v) => { TerrainImplementation = v; } ),
         new ParameterDefn<int>("TerrainMeshMagnification", "Number of times the 256x256 heightmap is multiplied to create the terrain mesh" ,
-            3,
+            2,
             (s) => { return TerrainMeshMagnification; },
             (s,v) => { TerrainMeshMagnification = v; } ),
         new ParameterDefn<float>("TerrainFriction", "Factor to reduce movement against terrain surface" ,

OpenSim/Region/Physics/BulletSPlugin/BSTerrainManager.cs

@@ -132,6 +132,7 @@ public sealed class BSTerrainManager : IDisposable
     //    safe to call Bullet in real time. We hope no one is moving prims around yet.
     public void CreateInitialGroundPlaneAndTerrain()
     {
+        DetailLog("{0},BSTerrainManager.CreateInitialGroundPlaneAndTerrain,region={1}", BSScene.DetailLogZero, PhysicsScene.RegionName);
         // The ground plane is here to catch things that are trying to drop to negative infinity
         BulletShape groundPlaneShape = PhysicsScene.PE.CreateGroundPlaneShape(BSScene.GROUNDPLANE_ID, 1f, BSParam.TerrainCollisionMargin);
         m_groundPlane = PhysicsScene.PE.CreateBodyWithDefaultMotionState(groundPlaneShape, 
@@ -145,14 +146,18 @@ public sealed class BSTerrainManager : IDisposable
         m_groundPlane.collisionType = CollisionType.Groundplane;
         m_groundPlane.ApplyCollisionMask(PhysicsScene);
 
-        // Build an initial terrain and put it in the world. This quickly gets replaced by the real region terrain.
         BSTerrainPhys initialTerrain = new BSTerrainHeightmap(PhysicsScene, Vector3.Zero, BSScene.TERRAIN_ID, DefaultRegionSize);
-        m_terrains.Add(Vector3.Zero, initialTerrain);
+        lock (m_terrains)
+        {
+            // Build an initial terrain and put it in the world. This quickly gets replaced by the real region terrain.
+            m_terrains.Add(Vector3.Zero, initialTerrain);
+        }
     }
 
     // Release all the terrain structures we might have allocated
     public void ReleaseGroundPlaneAndTerrain()
     {
+        DetailLog("{0},BSTerrainManager.ReleaseGroundPlaneAndTerrain,region={1}", BSScene.DetailLogZero, PhysicsScene.RegionName);
         if (m_groundPlane.HasPhysicalBody)
         {
             if (PhysicsScene.PE.RemoveObjectFromWorld(PhysicsScene.World, m_groundPlane))
@@ -193,11 +198,16 @@ public sealed class BSTerrainManager : IDisposable
                 //    the terrain is added to our parent
                 if (MegaRegionParentPhysicsScene is BSScene)
                 {
-                    DetailLog("{0},SetTerrain.ToParent,offset={1},worldMax={2}",
+                    DetailLog("{0},SetTerrain.ToParent,offset={1},worldMax={2}", BSScene.DetailLogZero, m_worldOffset, m_worldMax);
-                                    BSScene.DetailLogZero, m_worldOffset, m_worldMax);
+                    // This looks really odd but this region is passing its terrain to its mega-region root region
-                    ((BSScene)MegaRegionParentPhysicsScene).TerrainManager.UpdateTerrain(
+                    //    and the creation of the terrain must happen on the root region's taint thread and not
-                                    BSScene.CHILDTERRAIN_ID, localHeightMap, 
+                    //    my taint thread.
-                                    m_worldOffset, m_worldOffset + DefaultRegionSize, true);
+                    ((BSScene)MegaRegionParentPhysicsScene).PostTaintObject("TerrainManager.SetTerrain.Mega-" + m_worldOffset.ToString(), 0, delegate()
+                    {
+                        ((BSScene)MegaRegionParentPhysicsScene).TerrainManager.UpdateTerrain(
+                                        BSScene.CHILDTERRAIN_ID, localHeightMap,
+                                        m_worldOffset, m_worldOffset + DefaultRegionSize, true /* inTaintTime */);
+                    });
                 }
             }
             else
@@ -206,16 +216,16 @@ public sealed class BSTerrainManager : IDisposable
                 DetailLog("{0},SetTerrain.Existing", BSScene.DetailLogZero);
 
                 UpdateTerrain(BSScene.TERRAIN_ID, localHeightMap,
-                                    m_worldOffset, m_worldOffset + DefaultRegionSize, true);
+                                    m_worldOffset, m_worldOffset + DefaultRegionSize, true /* inTaintTime */);
             }
         });
     }
 
-    // If called with no mapInfo for the terrain, this will create a new mapInfo and terrain
+    // If called for terrain has has not been previously allocated, a new terrain will be built
     //     based on the passed information. The 'id' should be either the terrain id or
     //     BSScene.CHILDTERRAIN_ID. If the latter, a new child terrain ID will be allocated and used.
     //     The latter feature is for creating child terrains for mega-regions.
-    // If called with a mapInfo in m_heightMaps and there is an existing terrain body, a new
+    // If there is an existing terrain body, a new
     //     terrain shape is created and added to the body.
     //     This call is most often used to update the heightMap and parameters of the terrain.
     // (The above does suggest that some simplification/refactoring is in order.)
@@ -223,8 +233,8 @@ public sealed class BSTerrainManager : IDisposable
     private void UpdateTerrain(uint id, float[] heightMap, 
                             Vector3 minCoords, Vector3 maxCoords, bool inTaintTime)
     {
-        DetailLog("{0},BSTerrainManager.UpdateTerrain,call,minC={1},maxC={2},inTaintTime={3}",
+        DetailLog("{0},BSTerrainManager.UpdateTerrain,call,id={1},minC={2},maxC={3},inTaintTime={4}",
-                            BSScene.DetailLogZero, minCoords, maxCoords, inTaintTime);
+                            BSScene.DetailLogZero, id, minCoords, maxCoords, inTaintTime);
 
         // Find high and low points of passed heightmap.
         // The min and max passed in is usually the area objects can be in (maximum
@@ -253,7 +263,7 @@ public sealed class BSTerrainManager : IDisposable
             if (m_terrains.TryGetValue(terrainRegionBase, out terrainPhys))
             {
                 // There is already a terrain in this spot. Free the old and build the new.
-                DetailLog("{0},UpdateTerrain:UpdateExisting,call,id={1},base={2},minC={3},maxC={4}",
+                DetailLog("{0},BSTErrainManager.UpdateTerrain:UpdateExisting,call,id={1},base={2},minC={3},maxC={4}",
                                 BSScene.DetailLogZero, id, terrainRegionBase, minCoords, minCoords);
 
                 // Remove old terrain from the collection
@@ -292,7 +302,7 @@ public sealed class BSTerrainManager : IDisposable
                 if (newTerrainID >= BSScene.CHILDTERRAIN_ID)
                     newTerrainID = ++m_terrainCount;
 
-                DetailLog("{0},UpdateTerrain:NewTerrain,taint,newID={1},minCoord={2},maxCoord={3}",
+                DetailLog("{0},BSTerrainManager.UpdateTerrain:NewTerrain,taint,newID={1},minCoord={2},maxCoord={3}",
                                             BSScene.DetailLogZero, newTerrainID, minCoords, minCoords);
                 BSTerrainPhys newTerrainPhys = BuildPhysicalTerrain(terrainRegionBase, id, heightMap, minCoords, maxCoords);
                 m_terrains.Add(terrainRegionBase, newTerrainPhys);

OpenSim/Region/Physics/BulletSPlugin/BSTerrainMesh.cs

@@ -98,20 +98,20 @@ public sealed class BSTerrainMesh : BSTerrainPhys
         if (!meshCreationSuccess)
         {
             // DISASTER!!
-            PhysicsScene.DetailLog("{0},BSTerrainMesh.create,failedConversionOfHeightmap", ID);
+            PhysicsScene.DetailLog("{0},BSTerrainMesh.create,failedConversionOfHeightmap,id={1}", BSScene.DetailLogZero, ID);
             PhysicsScene.Logger.ErrorFormat("{0} Failed conversion of heightmap to mesh! base={1}", LogHeader, TerrainBase);
             // Something is very messed up and a crash is in our future.
             return;
         }
 
-        PhysicsScene.DetailLog("{0},BSTerrainMesh.create,meshed,indices={1},indSz={2},vertices={3},vertSz={4}", 
+        PhysicsScene.DetailLog("{0},BSTerrainMesh.create,meshed,id={1},indices={2},indSz={3},vertices={4},vertSz={5}", 
-                                ID, indicesCount, indices.Length, verticesCount, vertices.Length);
+                                BSScene.DetailLogZero, ID, indicesCount, indices.Length, verticesCount, vertices.Length);
 
         m_terrainShape = PhysicsScene.PE.CreateMeshShape(PhysicsScene.World, indicesCount, indices, verticesCount, vertices);
         if (!m_terrainShape.HasPhysicalShape)
         {
             // DISASTER!!
-            PhysicsScene.DetailLog("{0},BSTerrainMesh.create,failedCreationOfShape", ID);
+            PhysicsScene.DetailLog("{0},BSTerrainMesh.create,failedCreationOfShape,id={1}", BSScene.DetailLogZero, ID);
             PhysicsScene.Logger.ErrorFormat("{0} Failed creation of terrain mesh! base={1}", LogHeader, TerrainBase);
             // Something is very messed up and a crash is in our future.
             return;
@@ -151,7 +151,7 @@ public sealed class BSTerrainMesh : BSTerrainPhys
 
         if (BSParam.UseSingleSidedMeshes)
         {
-            PhysicsScene.DetailLog("{0},BSTerrainMesh.settingCustomMaterial", id);
+            PhysicsScene.DetailLog("{0},BSTerrainMesh.settingCustomMaterial,id={1}", BSScene.DetailLogZero, id);
             PhysicsScene.PE.AddToCollisionFlags(m_terrainBody, CollisionFlags.CF_CUSTOM_MATERIAL_CALLBACK);
         }