aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/OpenSim/Region/Physics/BulletSPlugin/BSLinkset.cs
blob: 569d2e71f9a91a85bbbceb6c30bafda7c523323c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
/*
 * 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 abstract class BSLinkset
{
    // private static string LogHeader = "[BULLETSIM LINKSET]";

    // Create the correct type of linkset for this child
    public static BSLinkset Factory(BSScene physScene, BSPhysObject parent)
    {
        BSLinkset ret = null;
        /*
        if (parent.IsPhysical)
            ret = new BSLinksetConstraints(physScene, parent);
        else
            ret = new BSLinksetManual(physScene, parent);
         */

        // at the moment, there is only one
        ret = new BSLinksetConstraints(physScene, parent);

        return ret;
    }

    public BSPhysObject LinksetRoot { get; protected set; }

    public BSScene PhysicsScene { get; private set; }

    static int m_nextLinksetID = 1;
    public int LinksetID { get; private set; }

    // The children under the root in this linkset.
    // There are two lists of children: the current children at runtime
    //    and the children at taint-time. For instance, if you delink a
    //    child from the linkset, the child is removed from m_children
    //    but the constraint won't be removed until taint time.
    //    Two lists lets this track the 'current' children and
    //    the physical 'taint' children separately.
    // After taint processing and before the simulation step, these
    //    two lists must be the same.
    protected HashSet<BSPhysObject> m_children;
    protected HashSet<BSPhysObject> m_taintChildren;

    // We lock the diddling of linkset classes to prevent any badness.
    // This locks the modification of the instances of this class. Changes
    //    to the physical representation is done via the tainting mechenism.
    protected object m_linksetActivityLock = new Object();

    // We keep the prim's mass in the linkset structure since it could be dependent on other prims
    protected float m_mass;
    public float LinksetMass
    {
        get
        {
            m_mass = ComputeLinksetMass();
            return m_mass;
        }
    }

    public virtual bool LinksetIsColliding { get { return false; } }

    public OMV.Vector3 CenterOfMass
    {
        get { return ComputeLinksetCenterOfMass(); }
    }

    public OMV.Vector3 GeometricCenter
    {
        get { return ComputeLinksetGeometricCenter(); }
    }

    protected void Initialize(BSScene scene, BSPhysObject parent)
    {
        // A simple linkset of one (no children)
        LinksetID = m_nextLinksetID++;
        // We create LOTS of linksets.
        if (m_nextLinksetID <= 0)
            m_nextLinksetID = 1;
        PhysicsScene = scene;
        LinksetRoot = parent;
        m_children = new HashSet<BSPhysObject>();
        m_taintChildren = new HashSet<BSPhysObject>();
        m_mass = parent.MassRaw;
    }

    // Link to a linkset where the child knows the parent.
    // Parent changing should not happen so do some sanity checking.
    // We return the parent's linkset so the child can track its membership.
    // Called at runtime.
    public BSLinkset AddMeToLinkset(BSPhysObject child)
    {
        lock (m_linksetActivityLock)
        {
            // Don't add the root to its own linkset
            if (!IsRoot(child))
                AddChildToLinkset(child);
        }
        return this;
    }

    // Remove a child from a linkset.
    // Returns a new linkset for the child which is a linkset of one (just the
    //    orphened child).
    // Called at runtime.
    public BSLinkset RemoveMeFromLinkset(BSPhysObject child)
    {
        lock (m_linksetActivityLock)
        {
            if (IsRoot(child))
            {
                // Cannot remove the root from a linkset.
                return this;
            }

            RemoveChildFromLinkset(child);
        }

        // The child is down to a linkset of just itself
        return BSLinkset.Factory(PhysicsScene, child);
    }

    // Return 'true' if the passed object is the root object of this linkset
    public bool IsRoot(BSPhysObject requestor)
    {
        return (requestor.LocalID == LinksetRoot.LocalID);
    }

    public int NumberOfChildren { get { return m_children.Count; } }

    // Return 'true' if this linkset has any children (more than the root member)
    public bool HasAnyChildren { get { return (m_children.Count > 0); } }

    // Return 'true' if this child is in this linkset
    public bool HasChild(BSPhysObject child)
    {
        bool ret = false;
        lock (m_linksetActivityLock)
        {
            ret = m_children.Contains(child);
            /* Safer version but the above should work
            foreach (BSPhysObject bp in m_children)
            {
                if (child.LocalID == bp.LocalID)
                {
                    ret = true;
                    break;
                }
            }
             */
        }
        return ret;
    }

    // Perform an action on each member of the linkset including root prim.
    // The action is performed only on the objects that are physically in the linkset.
    // Depends on the action on whether this should be done at taint time.
    public delegate bool ForEachMemberAction(BSPhysObject obj);
    public virtual bool ForEachMember(ForEachMemberAction action)
    {
        bool ret = false;
        lock (m_linksetActivityLock)
        {
            action(LinksetRoot);
            foreach (BSPhysObject po in m_taintChildren)
            {
                if (action(po))
                    break;
            }
        }
        return ret;
    }

    // When physical properties are changed the linkset needs to recalculate
    //   its internal properties.
    // May be called at runtime or taint-time (just pass the appropriate flag).
    public abstract void Refresh(BSPhysObject requestor);

    // 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 abstract bool MakeDynamic(BSPhysObject child);

    // 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.
    // Called at taint-time!
    public abstract bool MakeStatic(BSPhysObject child);

    // Called when a parameter update comes from the physics engine for any object
    //      of the linkset is received.
    // Called at taint-time!!
    public abstract void UpdateProperties(BSPhysObject physObject);

    // Routine used when rebuilding the body of the root of the linkset
    // Destroy all the constraints have have been made to root.
    // This is called when the root body is changing.
    // Returns 'true' of something was actually removed and would need restoring
    // Called at taint-time!!
    public abstract bool RemoveBodyDependencies(BSPrim child);

    // Companion to RemoveBodyDependencies(). If RemoveBodyDependencies() returns 'true',
    //     this routine will restore the removed constraints.
    // Called at taint-time!!
    public abstract void RestoreBodyDependencies(BSPrim child);

    // ================================================================
    // Below this point is internal magic

    protected virtual float ComputeLinksetMass()
    {
        float mass = LinksetRoot.MassRaw;
        if (HasAnyChildren)
        {
            lock (m_linksetActivityLock)
            {
                foreach (BSPhysObject bp in m_children)
                {
                    mass += bp.MassRaw;
                }
            }
        }
        return mass;
    }

    protected virtual OMV.Vector3 ComputeLinksetCenterOfMass()
    {
        OMV.Vector3 com;
        lock (m_linksetActivityLock)
        {
            com = LinksetRoot.Position * LinksetRoot.MassRaw;
            float totalMass = LinksetRoot.MassRaw;

            foreach (BSPhysObject bp in m_taintChildren)
            {
                com += bp.Position * bp.MassRaw;
                totalMass += bp.MassRaw;
            }
            if (totalMass != 0f)
                com /= totalMass;
        }

        return com;
    }

    protected virtual OMV.Vector3 ComputeLinksetGeometricCenter()
    {
        OMV.Vector3 com;
        lock (m_linksetActivityLock)
        {
            com = LinksetRoot.Position;

            foreach (BSPhysObject bp in m_taintChildren)
            {
                com += bp.Position * bp.MassRaw;
            }
            com /= (m_taintChildren.Count + 1);
        }

        return com;
    }

    // I am the root of a linkset and a new child is being added
    // Called while LinkActivity is locked.
    protected abstract void AddChildToLinkset(BSPhysObject child);

    // Forcefully removing a child from a linkset.
    // This is not being called by the child so we have to make sure the child doesn't think
    //    it's still connected to the linkset.
    // Normal OpenSimulator operation will never do this because other SceneObjectPart information
    //    also has to be updated (like pointer to prim's parent).
    protected abstract void RemoveChildFromOtherLinkset(BSPhysObject pchild);

    // I am the root of a linkset and one of my children is being removed.
    // Safe to call even if the child is not really in my linkset.
    protected abstract void RemoveChildFromLinkset(BSPhysObject child);

    // Invoke the detailed logger and output something if it's enabled.
    protected void DetailLog(string msg, params Object[] args)
    {
        if (PhysicsScene.PhysicsLogging.Enabled)
            PhysicsScene.DetailLog(msg, args);
    }

}
}