* 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, 267 insertions, 0 deletions

diff --git a/OpenSim/Region/Physics/BulletSNPlugin/BSTerrainMesh.cs b/OpenSim/Region/Physics/BulletSNPlugin/BSTerrainMesh.cs
new file mode 100644
index 0000000..6083dd4
--- /dev/null
+++ b/OpenSim/Region/Physics/BulletSNPlugin/BSTerrainMesh.cs
@@ -0,0 +1,267 @@
+/*
+ * 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 OpenSim.Framework;
+using OpenSim.Region.Framework;
+using OpenSim.Region.CoreModules;
+using OpenSim.Region.Physics.Manager;
+
+using Nini.Config;
+using log4net;
+
+using OpenMetaverse;
+
+namespace OpenSim.Region.Physics.BulletSNPlugin
+{
+public sealed class BSTerrainMesh : BSTerrainPhys
+{
+    static string LogHeader = "[BULLETSIM TERRAIN MESH]";
+
+    private float[] m_savedHeightMap;
+    int m_sizeX;
+    int m_sizeY;
+
+    BulletShape m_terrainShape;
+    BulletBody m_terrainBody;
+
+    public BSTerrainMesh(BSScene physicsScene, Vector3 regionBase, uint id, Vector3 regionSize) 
+        : base(physicsScene, regionBase, id)
+    {
+    }
+
+    public BSTerrainMesh(BSScene physicsScene, Vector3 regionBase, uint id /* parameters for making mesh */)
+        : base(physicsScene, regionBase, id)
+    {
+    }
+
+    // Create terrain mesh from a heightmap.
+    public BSTerrainMesh(BSScene physicsScene, Vector3 regionBase, uint id, float[] initialMap, 
+                                                    Vector3 minCoords, Vector3 maxCoords)
+        : base(physicsScene, regionBase, id)
+    {
+        int indicesCount;
+        int[] indices;
+        int verticesCount;
+        float[] vertices;
+
+        m_savedHeightMap = initialMap;
+
+        m_sizeX = (int)(maxCoords.X - minCoords.X);
+        m_sizeY = (int)(maxCoords.Y - minCoords.Y);
+
+        if (!BSTerrainMesh.ConvertHeightmapToMesh(PhysicsScene, initialMap,
+                            m_sizeX, m_sizeY,
+                            (float)m_sizeX, (float)m_sizeY,
+                            Vector3.Zero, 1.0f,
+                            out indicesCount, out indices, out verticesCount, out vertices))
+        {
+            // DISASTER!!
+            PhysicsScene.DetailLog("{0},BSTerrainMesh.create,failedConversionOfHeightmap", ID);
+            PhysicsScene.Logger.ErrorFormat("{0} Failed conversion of heightmap to mesh! base={1}", LogHeader, TerrainBase);
+            // Something is very messed up and a crash is in our future.
+            return;
+        }
+        PhysicsScene.DetailLog("{0},BSTerrainMesh.create,meshed,indices={1},indSz={2},vertices={3},vertSz={4}", 
+                                ID, indicesCount, indices.Length, verticesCount, vertices.Length);
+
+        m_terrainShape = new BulletShape(BulletSimAPI.CreateMeshShape2(PhysicsScene.World.ptr,
+                                                    indicesCount, indices, verticesCount, vertices),
+                                        BSPhysicsShapeType.SHAPE_MESH);
+        if (!m_terrainShape.HasPhysicalShape)
+        {
+            // DISASTER!!
+            PhysicsScene.DetailLog("{0},BSTerrainMesh.create,failedCreationOfShape", ID);
+            physicsScene.Logger.ErrorFormat("{0} Failed creation of terrain mesh! base={1}", LogHeader, TerrainBase);
+            // Something is very messed up and a crash is in our future.
+            return;
+        }
+
+        Vector3 pos = regionBase;
+        Quaternion rot = Quaternion.Identity;
+
+        m_terrainBody = new BulletBody(id, BulletSimAPI.CreateBodyWithDefaultMotionState2( m_terrainShape.ptr, ID, pos, rot));
+        if (!m_terrainBody.HasPhysicalBody)
+        {
+            // DISASTER!!
+            physicsScene.Logger.ErrorFormat("{0} Failed creation of terrain body! base={1}", LogHeader, TerrainBase);
+            // Something is very messed up and a crash is in our future.
+            return;
+        }
+
+        // Set current terrain attributes
+        BulletSimAPI.SetFriction2(m_terrainBody.ptr, BSParam.TerrainFriction);
+        BulletSimAPI.SetHitFraction2(m_terrainBody.ptr, BSParam.TerrainHitFraction);
+        BulletSimAPI.SetRestitution2(m_terrainBody.ptr, BSParam.TerrainRestitution);
+        BulletSimAPI.SetCollisionFlags2(m_terrainBody.ptr, CollisionFlags.CF_STATIC_OBJECT);
+
+        // Static objects are not very massive.
+        BulletSimAPI.SetMassProps2(m_terrainBody.ptr, 0f, Vector3.Zero);
+
+        // Put the new terrain to the world of physical objects
+        BulletSimAPI.AddObjectToWorld2(PhysicsScene.World.ptr, m_terrainBody.ptr, pos, rot);
+
+        // Redo its bounding box now that it is in the world
+        BulletSimAPI.UpdateSingleAabb2(PhysicsScene.World.ptr, m_terrainBody.ptr);
+
+        m_terrainBody.collisionType = CollisionType.Terrain;
+        m_terrainBody.ApplyCollisionMask();
+
+        // Make it so the terrain will not move or be considered for movement.
+        BulletSimAPI.ForceActivationState2(m_terrainBody.ptr, ActivationState.DISABLE_SIMULATION);
+    }
+
+    public override void Dispose()
+    {
+        if (m_terrainBody.HasPhysicalBody)
+        {
+            BulletSimAPI.RemoveObjectFromWorld2(PhysicsScene.World.ptr, m_terrainBody.ptr);
+            // Frees both the body and the shape.
+            BulletSimAPI.DestroyObject2(PhysicsScene.World.ptr, m_terrainBody.ptr);
+        }
+    }
+
+    public override float GetTerrainHeightAtXYZ(Vector3 pos)
+    {
+        // For the moment use the saved heightmap to get the terrain height.
+        // TODO: raycast downward to find the true terrain below the position.
+        float ret = BSTerrainManager.HEIGHT_GETHEIGHT_RET;
+
+        int mapIndex = (int)pos.Y * m_sizeY + (int)pos.X;
+        try
+        {
+            ret = m_savedHeightMap[mapIndex];
+        }
+        catch
+        {
+            // Sometimes they give us wonky values of X and Y. Give a warning and return something.
+            PhysicsScene.Logger.WarnFormat("{0} Bad request for terrain height. terrainBase={1}, pos={2}",
+                                                LogHeader, TerrainBase, pos);
+            ret = BSTerrainManager.HEIGHT_GETHEIGHT_RET;
+        }
+        return ret;
+    }
+
+    // The passed position is relative to the base of the region.
+    public override float GetWaterLevelAtXYZ(Vector3 pos)
+    {
+        return PhysicsScene.SimpleWaterLevel;
+    }
+
+    // Convert the passed heightmap to mesh information suitable for CreateMeshShape2().
+    // Return 'true' if successfully created.
+    public static bool ConvertHeightmapToMesh(
+                                BSScene physicsScene,
+                                float[] heightMap, int sizeX, int sizeY,    // parameters of incoming heightmap
+                                float extentX, float extentY,               // zero based range for output vertices
+                                Vector3 extentBase,                         // base to be added to all vertices
+                                float magnification,                        // number of vertices to create between heightMap coords
+                                out int indicesCountO, out int[] indicesO,
+                                out int verticesCountO, out float[] verticesO)
+    {
+        bool ret = false;
+
+        int indicesCount = 0;
+        int verticesCount = 0;
+        int[] indices = new int[0];
+        float[] vertices = new float[0];
+
+        // Simple mesh creation which assumes magnification == 1.
+        // TODO: do a more general solution that scales, adds new vertices and smoothes the result.
+
+        // Create an array of vertices that is sizeX+1 by sizeY+1 (note the loop
+        //    from zero to <= sizeX). The triangle indices are then generated as two triangles
+        //    per heightmap point. There are sizeX by sizeY of these squares. The extra row and
+        //    column of vertices are used to complete the triangles of the last row and column
+        //    of the heightmap.
+        try
+        {
+            // One vertice per heightmap value plus the vertices off the top and bottom edge.
+            int totalVertices = (sizeX + 1) * (sizeY + 1);
+            vertices = new float[totalVertices * 3];
+            int totalIndices = sizeX * sizeY * 6;
+            indices = new int[totalIndices];
+
+            float magX = (float)sizeX / extentX;
+            float magY = (float)sizeY / extentY;
+            physicsScene.DetailLog("{0},BSTerrainMesh.ConvertHeightMapToMesh,totVert={1},totInd={2},extentBase={3},magX={4},magY={5}",
+                                    BSScene.DetailLogZero, totalVertices, totalIndices, extentBase, magX, magY);
+            float minHeight = float.MaxValue;
+            // Note that sizeX+1 vertices are created since there is land between this and the next region.
+            for (int yy = 0; yy <= sizeY; yy++)
+            {
+                for (int xx = 0; xx <= sizeX; xx++)     // Hint: the "<=" means we go around sizeX + 1 times
+                {
+                    int offset = yy * sizeX + xx;
+                    // Extend the height with the height from the last row or column
+                    if (yy == sizeY) offset -= sizeX;
+                    if (xx == sizeX) offset -= 1;
+                    float height = heightMap[offset];
+                    minHeight = Math.Min(minHeight, height);
+                    vertices[verticesCount + 0] = (float)xx * magX + extentBase.X;
+                    vertices[verticesCount + 1] = (float)yy * magY + extentBase.Y;
+                    vertices[verticesCount + 2] = height + extentBase.Z;
+                    verticesCount += 3;
+                }
+            }
+            verticesCount = verticesCount / 3;
+
+            for (int yy = 0; yy < sizeY; yy++)
+            {
+                for (int xx = 0; xx < sizeX; xx++)
+                {
+                    int offset = yy * (sizeX + 1) + xx;
+                    // Each vertices is presumed to be the upper left corner of a box of two triangles
+                    indices[indicesCount + 0] = offset;
+                    indices[indicesCount + 1] = offset + 1;
+                    indices[indicesCount + 2] = offset + sizeX + 1; // accounting for the extra column
+                    indices[indicesCount + 3] = offset + 1;
+                    indices[indicesCount + 4] = offset + sizeX + 2;
+                    indices[indicesCount + 5] = offset + sizeX + 1;
+                    indicesCount += 6;
+                }
+            }
+
+            ret = true;
+        }
+        catch (Exception e)
+        {
+            physicsScene.Logger.ErrorFormat("{0} Failed conversion of heightmap to mesh. For={1}/{2}, e={3}",
+                                                LogHeader, physicsScene.RegionName, extentBase, e);
+        }
+
+        indicesCountO = indicesCount;
+        indicesO = indices;
+        verticesCountO = verticesCount;
+        verticesO = vertices;
+
+        return ret;
+    }
+}
+}