C# BSPhysObject.ZeroMotion方法代碼示例

    // Create a constraint between me (root of linkset) and the passed prim (the child).
    // Called at taint time!
    private void PhysicallyLinkAChildToRoot(BSPhysObject rootPrim, BulletBody rootBody,
                                    BSPhysObject childPrim, BulletBody childBody)
    {
        // Zero motion for children so they don't interpolate
        childPrim.ZeroMotion();

        // 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},PhysicallyLinkAChildToRoot,taint,root={1},rBody={2},child={3},cBody={4},rLoc={5},cLoc={6},midLoc={7}",
                                        rootPrim.LocalID,
                                        rootPrim.LocalID, rootBody.ptr.ToString("X"),
                                        childPrim.LocalID, childBody.ptr.ToString("X"),
                                        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

        // There is great subtlty in these paramters. Notice the check for a ptr of zero.
        // We pass the BulletBody structure into the taint in order to capture the pointer
        //     of the body at the time of constraint creation. This doesn't work for the very first
        //     construction because there is no body yet. The body
        //     is constructed later at taint time. Thus we use the body address at time of the
        //     taint creation but, if it is zero, use what's in the prim at the moment.
        //     There is a possible race condition since shape can change without a taint call
        //     (like changing to a mesh that is already constructed). The fix for that would be
        //     to only change BSShape at taint time thus syncronizing these operations at
        //     the cost of efficiency and lag.
        BS6DofConstraint constrain = new BS6DofConstraint(
                        PhysicsScene.World,
                        rootBody.ptr == IntPtr.Zero ? rootPrim.BSBody : rootBody,
                        childBody.ptr == IntPtr.Zero ? childPrim.BSBody : childBody,
                        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 as a warning to 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);

        // create a constraint that allows no freedom of movement between the two objects
        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
        DetailLog("{0},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),
                        // A point half way between the parent and child
                        // childRelativePosition/2,
                        // childRelativeRotation,
                        // childRelativePosition/2,
                        // inverseChildRelativeRotation,
                        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(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintUseFrameOffset));
        constrain.TranslationalLimitMotor(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintEnableTransMotor),
                        PhysicsScene.Params.linkConstraintTransMotorMaxVel,
                        PhysicsScene.Params.linkConstraintTransMotorMaxForce);
        constrain.SetCFMAndERP(PhysicsScene.Params.linkConstraintCFM, PhysicsScene.Params.linkConstraintERP);
        if (PhysicsScene.Params.linkConstraintSolverIterations != 0f)
        {
            constrain.SetSolverIterations(PhysicsScene.Params.linkConstraintSolverIterations);
        }

        RecomputeLinksetConstraintVariables();
    }

    // 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)
    {
        // Zero motion for children so they don't interpolate
        childPrim.ZeroMotion();

        // 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},BSLinkset.PhysicallyLinkAChildToRoot,taint,root={1},rBody={2},child={3},cBody={4},rLoc={5},cLoc={6},midLoc={7}",
                                        rootPrim.LocalID,
                                        rootPrim.LocalID, rootPrim.BSBody.ptr.ToString("X"),
                                        childPrim.LocalID, childPrim.BSBody.ptr.ToString("X"),
                                        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

        BS6DofConstraint constrain = new BS6DofConstraint(
                            PhysicsScene.World, rootPrim.BSBody, childPrim.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 as a warning to 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);

        // create a constraint that allows no freedom of movement between the two objects
        // http://bulletphysics.org/Bullet/phpBB3/viewtopic.php?t=4818
        DetailLog("{0},BSLinkset.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),
                        // A point half way between the parent and child
                        // childRelativePosition/2,
                        // childRelativeRotation,
                        // childRelativePosition/2,
                        // inverseChildRelativeRotation,
                        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(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintUseFrameOffset));
        constrain.TranslationalLimitMotor(PhysicsScene.BoolNumeric(PhysicsScene.Params.linkConstraintEnableTransMotor),
                        PhysicsScene.Params.linkConstraintTransMotorMaxVel,
                        PhysicsScene.Params.linkConstraintTransMotorMaxForce);
        constrain.SetCFMAndERP(PhysicsScene.Params.linkConstraintCFM, PhysicsScene.Params.linkConstraintERP);
        if (PhysicsScene.Params.linkConstraintSolverIterations != 0f)
        {
            constrain.SetSolverIterations(PhysicsScene.Params.linkConstraintSolverIterations);
        }
    }