BulletSim: fix exceptions while rebuilding linksets with mesh children.

This should get around the exception reported in Mantis 7191 and 7204
by checking for the unbuilt child and rebuilding the linkset the next tick.
A warning message is output when this rebuild happens and this message is
clamped to 10 times in case there is a problem with a loop.

1 files changed, 30 insertions, 3 deletions

diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs b/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs
index 6f4f686..67cb2f6 100755
--- a/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs
+++ b/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs
@@ -305,6 +305,10 @@ public sealed class BSLinksetCompound : BSLinkset
     // Note that this works for rebuilding just the root after a linkset is taken apart.
     // Called at taint time!!
     private bool UseBulletSimRootOffsetHack = false;    // Attempt to have Bullet track the coords of root compound shape
+    // Number of times to perform rebuilds on broken linkset children. This should only happen when
+    //    a linkset is initially being created and should happen only one or two times at the most.
+    //    This exists to cause a looping problem to be reported while not rebuilding a linkset forever.
+    private static int LinksetRebuildFailureLoopPrevention = 10;
     private void RecomputeLinksetCompound()
     {
         try
@@ -376,9 +380,32 @@ public sealed class BSLinksetCompound : BSLinkset
                 OMV.Quaternion offsetRot = OMV.Quaternion.Normalize(cPrim.RawOrientation) * invRootOrientation;
 
                 // Add the child shape to the compound shape being built
-                m_physicsScene.PE.AddChildShapeToCompoundShape(linksetShape.physShapeInfo, childShape.physShapeInfo, offsetPos, offsetRot);
-                DetailLog("{0},BSLinksetCompound.RecomputeLinksetCompound,addChild,indx={1},cShape={2},offPos={3},offRot={4}",
-                                    LinksetRoot.LocalID, cPrim.LinksetChildIndex, childShape, offsetPos, offsetRot);
+                if (childShape.physShapeInfo.HasPhysicalShape)
+                {
+                    m_physicsScene.PE.AddChildShapeToCompoundShape(linksetShape.physShapeInfo, childShape.physShapeInfo, offsetPos, offsetRot);
+                    DetailLog("{0},BSLinksetCompound.RecomputeLinksetCompound,addChild,indx={1},cShape={2},offPos={3},offRot={4}",
+                                LinksetRoot.LocalID, cPrim.LinksetChildIndex, childShape, offsetPos, offsetRot);
+                }
+                else
+                {
+                    // The linkset must be in an intermediate state where all the children have not yet
+                    //    been constructed. This sometimes happens on startup when everything is getting
+                    //    built and some shapes have to wait for assets to be read in.
+                    // Just skip this child for the moment and cause the shape to be rebuilt next tick.
+                    // One problem might be that the shape is broken somehow and it never becomes completely
+                    //    available. This might cause the rebuild to happen over and over.
+                    if (LinksetRebuildFailureLoopPrevention-- > 0)
+                    {
+                        LinksetRoot.ForceBodyShapeRebuild(false);
+                        DetailLog("{0},BSLinksetCompound.RecomputeLinksetCompound,addChildWithNoShape,indx={1},cShape={2},offPos={3},offRot={4}",
+                                        LinksetRoot.LocalID, cPrim.LinksetChildIndex, childShape, offsetPos, offsetRot);
+                        // Output an annoying warning. It should only happen once but if it keeps coming out,
+                        //    the user knows there is something wrong and will report it.
+                        m_physicsScene.Logger.WarnFormat("{0} Linkset rebuild warning. If this happens more than one or two times, please report in Mantis 7191", LogHeader);
+                        m_physicsScene.Logger.WarnFormat("{0} pName={1}, childIdx={2}, shape={3}",
+                                        LogHeader, LinksetRoot.Name, cPrim.LinksetChildIndex, childShape);
+                    }
+                }
 
                 // Since we are borrowing the shape of the child, disable the origional child body
                 if (!IsRoot(cPrim))