* Initial commit of BulletSimN (BulletSNPlugin). Purely C# implementation of BulletSim. This is designed to be /as close as possible/ to the BulletSim plugin while still being entirely in the managed space to make keeping it up to date easy as possible (no thinking work). This implementation is /slower/ then the c++ version just because it's fully managed, so it's not appropriate for huge sims, but it will run small ones OK. At the moment, it supports all known features of BulletSim. Think of it like.. POS but everything works. To use this plugin, set the physics plugin to BulletSimN.

1 files changed, 314 insertions, 0 deletions

diff --git a/OpenSim/Region/Physics/BulletSNPlugin/BSLinksetConstraints.cs b/OpenSim/Region/Physics/BulletSNPlugin/BSLinksetConstraints.cs
new file mode 100644
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--- /dev/null
+++ b/OpenSim/Region/Physics/BulletSNPlugin/BSLinksetConstraints.cs
@@ -0,0 +1,314 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyrightD
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+using OMV = OpenMetaverse;
+
+namespace OpenSim.Region.Physics.BulletSNPlugin
+{
+public sealed class BSLinksetConstraints : BSLinkset
+{
+    // private static string LogHeader = "[BULLETSIM LINKSET CONSTRAINTS]";
+
+    public BSLinksetConstraints(BSScene scene, BSPhysObject parent) : base(scene, parent)
+    {
+    }
+
+    // When physical properties are changed the linkset needs to recalculate
+    //   its internal properties.
+    // This is queued in the 'post taint' queue so the
+    //   refresh will happen once after all the other taints are applied.
+    public override void Refresh(BSPhysObject requestor)
+    {
+        // Queue to happen after all the other taint processing
+        PhysicsScene.PostTaintObject("BSLinksetContraints.Refresh", requestor.LocalID, delegate()
+            {
+                if (HasAnyChildren && IsRoot(requestor))
+                    RecomputeLinksetConstraints();
+            });
+    }
+
+    // The object is going dynamic (physical). Do any setup necessary
+    //     for a dynamic linkset.
+    // Only the state of the passed object can be modified. The rest of the linkset
+    //     has not yet been fully constructed.
+    // Return 'true' if any properties updated on the passed object.
+    // Called at taint-time!
+    public override bool MakeDynamic(BSPhysObject child)
+    {
+        // What is done for each object in BSPrim is what we want.
+        return false;
+    }
+
+    // The object is going static (non-physical). Do any setup necessary for a static linkset.
+    // Return 'true' if any properties updated on the passed object.
+    // This doesn't normally happen -- OpenSim removes the objects from the physical
+    //     world if it is a static linkset.
+    // Called at taint-time!
+    public override bool MakeStatic(BSPhysObject child)
+    {
+        // What is done for each object in BSPrim is what we want.
+        return false;
+    }
+
+    // Called at taint-time!!
+    public override void UpdateProperties(BSPhysObject updated, bool inTaintTime)
+    {
+        // Nothing to do for constraints on property updates
+    }
+
+    // Routine called when rebuilding the body of some member of the linkset.
+    // Destroy all the constraints have have been made to root and set
+    //     up to rebuild the constraints before the next simulation step.
+    // Returns 'true' of something was actually removed and would need restoring
+    // Called at taint-time!!
+    public override bool RemoveBodyDependencies(BSPrim child)
+    {
+        bool ret = false;
+
+        DetailLog("{0},BSLinksetConstraint.RemoveBodyDependencies,removeChildrenForRoot,rID={1},rBody={2}",
+                                    child.LocalID, LinksetRoot.LocalID, LinksetRoot.PhysBody.ptr.ToString());
+
+        lock (m_linksetActivityLock)
+        {
+            // Just undo all the constraints for this linkset. Rebuild at the end of the step.
+            ret = PhysicallyUnlinkAllChildrenFromRoot(LinksetRoot);
+            // Cause the constraints, et al to be rebuilt before the next simulation step.
+            Refresh(LinksetRoot);
+        }
+        return ret;
+    }
+
+    // Companion to RemoveBodyDependencies(). If RemoveBodyDependencies() returns 'true',
+    // this routine will restore the removed constraints.
+    // Called at taint-time!!
+    public override void RestoreBodyDependencies(BSPrim child)
+    {
+        // The Refresh operation queued by RemoveBodyDependencies() will build any missing constraints.
+    }
+
+    // ================================================================
+
+    // Add a new child to the linkset.
+    // Called while LinkActivity is locked.
+    protected override void AddChildToLinkset(BSPhysObject child)
+    {
+        if (!HasChild(child))
+        {
+            m_children.Add(child);
+
+            DetailLog("{0},BSLinksetConstraints.AddChildToLinkset,call,child={1}", LinksetRoot.LocalID, child.LocalID);
+
+            // Cause constraints and assorted properties to be recomputed before the next simulation step.
+            Refresh(LinksetRoot);
+        }
+        return;
+    }
+
+    // Remove the specified child from the linkset.
+    // Safe to call even if the child is not really in my linkset.
+    protected override void RemoveChildFromLinkset(BSPhysObject child)
+    {
+        if (m_children.Remove(child))
+        {
+            BSPhysObject rootx = LinksetRoot; // capture the root and body as of now
+            BSPhysObject childx = child;
+
+            DetailLog("{0},BSLinksetConstraints.RemoveChildFromLinkset,call,rID={1},rBody={2},cID={3},cBody={4}",
+                            childx.LocalID,
+                            rootx.LocalID, rootx.PhysBody.ptr.ToString(),
+                            childx.LocalID, childx.PhysBody.ptr.ToString());
+
+            PhysicsScene.TaintedObject("BSLinksetConstraints.RemoveChildFromLinkset", delegate()
+            {
+                PhysicallyUnlinkAChildFromRoot(rootx, childx);
+            });
+            // See that the linkset parameters are recomputed at the end of the taint time.
+            Refresh(LinksetRoot);
+        }
+        else
+        {
+            // Non-fatal occurance.
+            // PhysicsScene.Logger.ErrorFormat("{0}: Asked to remove child from linkset that was not in linkset", LogHeader);
+        }
+        return;
+    }
+
+    // Create a constraint between me (root of linkset) and the passed prim (the child).
+    // Called at taint time!
+    private void PhysicallyLinkAChildToRoot(BSPhysObject rootPrim, BSPhysObject childPrim)
+    {
+        // Don't build the constraint when asked. Put it off until just before the simulation step.
+        Refresh(rootPrim);
+    }
+
+    private BSConstraint BuildConstraint(BSPhysObject rootPrim, BSPhysObject childPrim)
+    {
+        // Zero motion for children so they don't interpolate
+        childPrim.ZeroMotion(true);
+
+        // Relative position normalized to the root prim
+        // Essentually a vector pointing from center of rootPrim to center of childPrim
+        OMV.Vector3 childRelativePosition = childPrim.Position - rootPrim.Position;
+
+        // real world coordinate of midpoint between the two objects
+        OMV.Vector3 midPoint = rootPrim.Position + (childRelativePosition / 2);
+
+        DetailLog("{0},BSLinksetConstraint.BuildConstraint,taint,root={1},rBody={2},child={3},cBody={4},rLoc={5},cLoc={6},midLoc={7}",
+                                        rootPrim.LocalID,
+                                        rootPrim.LocalID, rootPrim.PhysBody.ptr.ToString(),
+                                        childPrim.LocalID, childPrim.PhysBody.ptr.ToString(),
+                                        rootPrim.Position, childPrim.Position, midPoint);
+
+        // create a constraint that allows no freedom of movement between the two objects
+        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
+
+        BSConstraint6Dof constrain = new BSConstraint6Dof(
+                            PhysicsScene.World, rootPrim.PhysBody, childPrim.PhysBody, midPoint, true, true );
+                            // PhysicsScene.World, childPrim.BSBody, rootPrim.BSBody, midPoint, true, true );
+
+        /* NOTE: below is an attempt to build constraint with full frame computation, etc.
+         *     Using the midpoint is easier since it lets the Bullet code manipulate the transforms
+         *     of the objects.
+         * Code left for future programmers.
+        // ==================================================================================
+        // relative position normalized to the root prim
+        OMV.Quaternion invThisOrientation = OMV.Quaternion.Inverse(rootPrim.Orientation);
+        OMV.Vector3 childRelativePosition = (childPrim.Position - rootPrim.Position) * invThisOrientation;
+
+        // relative rotation of the child to the parent
+        OMV.Quaternion childRelativeRotation = invThisOrientation * childPrim.Orientation;
+        OMV.Quaternion inverseChildRelativeRotation = OMV.Quaternion.Inverse(childRelativeRotation);
+
+        DetailLog("{0},BSLinksetConstraint.PhysicallyLinkAChildToRoot,taint,root={1},child={2}", rootPrim.LocalID, rootPrim.LocalID, childPrim.LocalID);
+        BS6DofConstraint constrain = new BS6DofConstraint(
+                        PhysicsScene.World, rootPrim.Body, childPrim.Body,
+                        OMV.Vector3.Zero,
+                        OMV.Quaternion.Inverse(rootPrim.Orientation),
+                        OMV.Vector3.Zero,
+                        OMV.Quaternion.Inverse(childPrim.Orientation),
+                        true,
+                        true
+                        );
+        // ==================================================================================
+        */
+
+        PhysicsScene.Constraints.AddConstraint(constrain);
+
+        // zero linear and angular limits makes the objects unable to move in relation to each other
+        constrain.SetLinearLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
+        constrain.SetAngularLimits(OMV.Vector3.Zero, OMV.Vector3.Zero);
+
+        // tweek the constraint to increase stability
+        constrain.UseFrameOffset(BSParam.BoolNumeric(BSParam.LinkConstraintUseFrameOffset));
+        constrain.TranslationalLimitMotor(BSParam.BoolNumeric(BSParam.LinkConstraintEnableTransMotor),
+                        BSParam.LinkConstraintTransMotorMaxVel,
+                        BSParam.LinkConstraintTransMotorMaxForce);
+        constrain.SetCFMAndERP(BSParam.LinkConstraintCFM, BSParam.LinkConstraintERP);
+        if (BSParam.LinkConstraintSolverIterations != 0f)
+        {
+            constrain.SetSolverIterations(BSParam.LinkConstraintSolverIterations);
+        }
+        return constrain;
+    }
+
+    // Remove linkage between the linkset root and a particular child
+    // The root and child bodies are passed in because we need to remove the constraint between
+    //      the bodies that were present at unlink time.
+    // Called at taint time!
+    private bool PhysicallyUnlinkAChildFromRoot(BSPhysObject rootPrim, BSPhysObject childPrim)
+    {
+        bool ret = false;
+        DetailLog("{0},BSLinksetConstraint.PhysicallyUnlinkAChildFromRoot,taint,root={1},rBody={2},child={3},cBody={4}",
+                            rootPrim.LocalID,
+                            rootPrim.LocalID, rootPrim.PhysBody.ptr.ToString(),
+                            childPrim.LocalID, childPrim.PhysBody.ptr.ToString());
+
+        // Find the constraint for this link and get rid of it from the overall collection and from my list
+        if (PhysicsScene.Constraints.RemoveAndDestroyConstraint(rootPrim.PhysBody, childPrim.PhysBody))
+        {
+            // Make the child refresh its location
+            BulletSimAPI.PushUpdate2(childPrim.PhysBody.ptr);
+            ret = true;
+        }
+
+        return ret;
+    }
+
+    // Remove linkage between myself and any possible children I might have.
+    // Returns 'true' of any constraints were destroyed.
+    // Called at taint time!
+    private bool PhysicallyUnlinkAllChildrenFromRoot(BSPhysObject rootPrim)
+    {
+        DetailLog("{0},BSLinksetConstraint.PhysicallyUnlinkAllChildren,taint", rootPrim.LocalID);
+
+        return PhysicsScene.Constraints.RemoveAndDestroyConstraint(rootPrim.PhysBody);
+    }
+
+    // Call each of the constraints that make up this linkset and recompute the
+    //    various transforms and variables. Create constraints of not created yet.
+    // Called before the simulation step to make sure the constraint based linkset
+    //    is all initialized.
+    // Called at taint time!!
+    private void RecomputeLinksetConstraints()
+    {
+        float linksetMass = LinksetMass;
+        LinksetRoot.UpdatePhysicalMassProperties(linksetMass);
+
+        // DEBUG: see of inter-linkset collisions are causing problems
+        // BulletSimAPI.SetCollisionFilterMask2(LinksetRoot.BSBody.ptr, 
+        //                     (uint)CollisionFilterGroups.LinksetFilter, (uint)CollisionFilterGroups.LinksetMask);
+        DetailLog("{0},BSLinksetConstraint.RecomputeLinksetConstraints,set,rBody={1},linksetMass={2}",
+                            LinksetRoot.LocalID, LinksetRoot.PhysBody.ptr.ToString(), linksetMass);
+
+        foreach (BSPhysObject child in m_children)
+        {
+            // A child in the linkset physically shows the mass of the whole linkset.
+            // This allows Bullet to apply enough force on the child to move the whole linkset.
+            // (Also do the mass stuff before recomputing the constraint so mass is not zero.)
+            child.UpdatePhysicalMassProperties(linksetMass);
+
+            BSConstraint constrain;
+            if (!PhysicsScene.Constraints.TryGetConstraint(LinksetRoot.PhysBody, child.PhysBody, out constrain))
+            {
+                // If constraint doesn't exist yet, create it.
+                constrain = BuildConstraint(LinksetRoot, child);
+            }
+            constrain.RecomputeConstraintVariables(linksetMass);
+
+            // DEBUG: see of inter-linkset collisions are causing problems
+            // BulletSimAPI.SetCollisionFilterMask2(child.BSBody.ptr, 
+            //                 (uint)CollisionFilterGroups.LinksetFilter, (uint)CollisionFilterGroups.LinksetMask);
+
+            // BulletSimAPI.DumpConstraint2(PhysicsScene.World.ptr, constrain.Constraint.ptr);    // DEBUG DEBUG
+        }
+
+    }
+}
+}