/* * 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.BulletSPlugin { public sealed class BSLinksetConstraints : BSLinkset { // private static string LogHeader = "[BULLETSIM LINKSET CONSTRAINTS]"; public BSLinksetConstraints(BSScene scene, BSPrimLinkable 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(BSPrimLinkable requestor) { base.Refresh(requestor); if (HasAnyChildren && IsRoot(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(BSPrimLinkable 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(BSPrimLinkable child) { // What is done for each object in BSPrim is what we want. return false; } // Called at taint-time!! public override void UpdateProperties(UpdatedProperties whichUpdated, BSPrimLinkable pObj) { // 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 RemoveDependencies(BSPrimLinkable child) { bool ret = false; DetailLog("{0},BSLinksetConstraint.RemoveDependencies,removeChildrenForRoot,rID={1},rBody={2}", child.LocalID, LinksetRoot.LocalID, LinksetRoot.PhysBody.AddrString); 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; } // ================================================================ // Add a new child to the linkset. // Called while LinkActivity is locked. protected override void AddChildToLinkset(BSPrimLinkable 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(BSPrimLinkable child) { if (m_children.Remove(child)) { BSPrimLinkable rootx = LinksetRoot; // capture the root and body as of now BSPrimLinkable childx = child; DetailLog("{0},BSLinksetConstraints.RemoveChildFromLinkset,call,rID={1},rBody={2},cID={3},cBody={4}", childx.LocalID, rootx.LocalID, rootx.PhysBody.AddrString, childx.LocalID, childx.PhysBody.AddrString); 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(BSPrimLinkable rootPrim, BSPrimLinkable childPrim) { // Don't build the constraint when asked. Put it off until just before the simulation step. Refresh(rootPrim); } private BSConstraint BuildConstraint(BSPrimLinkable rootPrim, BSPrimLinkable 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.AddrString, childPrim.LocalID, childPrim.PhysBody.AddrString, 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.LinkConstraintUseFrameOffset); constrain.TranslationalLimitMotor(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(BSPrimLinkable rootPrim, BSPrimLinkable childPrim) { bool ret = false; DetailLog("{0},BSLinksetConstraint.PhysicallyUnlinkAChildFromRoot,taint,root={1},rBody={2},child={3},cBody={4}", rootPrim.LocalID, rootPrim.LocalID, rootPrim.PhysBody.AddrString, childPrim.LocalID, childPrim.PhysBody.AddrString); // 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 PhysicsScene.PE.PushUpdate(childPrim.PhysBody); 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(BSPrimLinkable 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, true); DetailLog("{0},BSLinksetConstraint.RecomputeLinksetConstraints,set,rBody={1},linksetMass={2}", LinksetRoot.LocalID, LinksetRoot.PhysBody.AddrString, linksetMass); foreach (BSPrimLinkable 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, true); 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); // PhysicsScene.PE.DumpConstraint(PhysicsScene.World, constrain.Constraint); // DEBUG DEBUG } } } }