C# EntityIntersection类代码示例

        public EntityIntersection TestIntersectionOBB(Ray iray, Quaternion parentrot, bool frontFacesOnly, bool faceCenters)
        {
            // In this case we're using a rectangular prism, which has 6 faces and therefore 6 planes
            // This breaks down into the ray---> plane equation.
            // TODO: Change to take shape into account
            Vector3[] vertexes = new Vector3[8];

            // float[] distance = new float[6];
            Vector3[] FaceA = new Vector3[6]; // vertex A for Facei
            Vector3[] FaceB = new Vector3[6]; // vertex B for Facei
            Vector3[] FaceC = new Vector3[6]; // vertex C for Facei
            Vector3[] FaceD = new Vector3[6]; // vertex D for Facei

            Vector3[] normals = new Vector3[6]; // Normal for Facei
            Vector3[] AAfacenormals = new Vector3[6]; // Axis Aligned face normals

            AAfacenormals[0] = new Vector3(1, 0, 0);
            AAfacenormals[1] = new Vector3(0, 1, 0);
            AAfacenormals[2] = new Vector3(-1, 0, 0);
            AAfacenormals[3] = new Vector3(0, -1, 0);
            AAfacenormals[4] = new Vector3(0, 0, 1);
            AAfacenormals[5] = new Vector3(0, 0, -1);

            Vector3 AmBa = new Vector3(0, 0, 0); // Vertex A - Vertex B
            Vector3 AmBb = new Vector3(0, 0, 0); // Vertex B - Vertex C
            Vector3 cross = new Vector3();

            Vector3 pos = GetWorldPosition();
            Quaternion rot = GetWorldRotation();

            // Variables prefixed with AX are Axiom.Math copies of the LL variety.

            Quaternion AXrot = rot;
            AXrot.Normalize();

            Vector3 AXpos = pos;

            // tScale is the offset to derive the vertex based on the scale.
            // it's different for each vertex because we've got to rotate it
            // to get the world position of the vertex to produce the Oriented Bounding Box

            Vector3 tScale = Vector3.Zero;

            Vector3 AXscale = new Vector3(m_shape.Scale.X * 0.5f, m_shape.Scale.Y * 0.5f, m_shape.Scale.Z * 0.5f);

            //Vector3 pScale = (AXscale) - (AXrot.Inverse() * (AXscale));
            //Vector3 nScale = (AXscale * -1) - (AXrot.Inverse() * (AXscale * -1));

            // rScale is the rotated offset to find a vertex based on the scale and the world rotation.
            Vector3 rScale = new Vector3();

            // Get Vertexes for Faces Stick them into ABCD for each Face
            // Form: Face<vertex>[face] that corresponds to the below diagram
            #region ABCD Face Vertex Map Comment Diagram
            //                   A _________ B
            //                    |         |
            //                    |  4 top  |
            //                    |_________|
            //                   C           D

            //                   A _________ B
            //                    |  Back   |
            //                    |    3    |
            //                    |_________|
            //                   C           D

            //   A _________ B                     B _________ A
            //    |  Left   |                       |  Right  |
            //    |    0    |                       |    2    |
            //    |_________|                       |_________|
            //   C           D                     D           C

            //                   A _________ B
            //                    |  Front  |
            //                    |    1    |
            //                    |_________|
            //                   C           D

            //                   C _________ D
            //                    |         |
            //                    |  5 bot  |
            //                    |_________|
            //                   A           B
            #endregion

            #region Plane Decomposition of Oriented Bounding Box
            tScale = new Vector3(AXscale.X, -AXscale.Y, AXscale.Z);
            rScale = tScale * AXrot;
            vertexes[0] = (new Vector3((pos.X + rScale.X), (pos.Y + rScale.Y), (pos.Z + rScale.Z)));
               // vertexes[0].X = pos.X + vertexes[0].X;
            //vertexes[0].Y = pos.Y + vertexes[0].Y;
            //vertexes[0].Z = pos.Z + vertexes[0].Z;

            FaceA[0] = vertexes[0];
            FaceB[3] = vertexes[0];
            FaceA[4] = vertexes[0];

            tScale = AXscale;
            rScale = tScale * AXrot;
            vertexes[1] = (new Vector3((pos.X + rScale.X), (pos.Y + rScale.Y), (pos.Z + rScale.Z)));
//.........这里部分代码省略.........

        public EntityIntersection TestIntersection(Ray hRay, bool frontFacesOnly, bool faceCenters)
        {
            // We got a request from the inner_scene to raytrace along the Ray hRay
            // We're going to check all of the prim in this group for intersection with the ray
            // If we get a result, we're going to find the closest result to the origin of the ray
            // and send back the intersection information back to the innerscene.

            EntityIntersection result = new EntityIntersection();

            foreach (SceneObjectPart part in m_partsList)
            {
                // Temporary commented to stop compiler warning
                //Vector3 partPosition =
                //    new Vector3(part.AbsolutePosition.X, part.AbsolutePosition.Y, part.AbsolutePosition.Z);
                Quaternion parentrotation = GroupRotation;
                // Telling the prim to raytrace.
                //EntityIntersection inter = part.TestIntersection(hRay, parentrotation);
                EntityIntersection inter = part.TestIntersectionOBB(hRay, parentrotation, frontFacesOnly, faceCenters);

                // This may need to be updated to the maximum draw distance possible..
                // We might (and probably will) be checking for prim creation from other sims
                // when the camera crosses the border.
                float idist = Constants.RegionSize;
                if (inter.HitTF)
                {
                    // We need to find the closest prim to return to the testcaller along the ray
                    if (inter.distance < idist)
                    {
                        result.HitTF = true;
                        result.ipoint = inter.ipoint;
                        result.obj = part;
                        result.normal = inter.normal;
                        result.distance = inter.distance;
                    }
                }
            }

            return result;
        }

        /// <summary>
        ///     Gets a list of scene object group that intersect with the given ray
        /// </summary>
        public List<EntityIntersection> GetIntersectingPrims(Ray hray, float length, int count,
                                                             bool frontFacesOnly, bool faceCenters, bool getAvatars,
                                                             bool getLand, bool getPrims)
        {
            // Primitive Ray Tracing
            List<EntityIntersection> result = new List<EntityIntersection>(count);
            if (getPrims)
            {
                ISceneEntity[] EntityList = Entities.GetEntities(hray.Origin, length);

                result.AddRange(
                    EntityList.OfType<SceneObjectGroup>()
                              .Select(reportingG => reportingG.TestIntersection(hray, frontFacesOnly, faceCenters))
                              .Where(inter => inter.HitTF));
            }
            if (getAvatars)
            {
                List<IScenePresence> presenceList = Entities.GetPresences();
                foreach (IScenePresence ent in presenceList)
                {
                    //Do rough approximation and keep the # of loops down
                    Vector3 newPos = hray.Origin;
                    for (int i = 0; i < 100; i++)
                    {
                        newPos += ((Vector3.One*(length*(i/100)))*hray.Direction);
                        if (ent.AbsolutePosition.ApproxEquals(newPos, ent.PhysicsActor.Size.X*2))
                        {
                            EntityIntersection intersection = new EntityIntersection();
                            intersection.distance = length*(i/100);
                            intersection.face = 0;
                            intersection.HitTF = true;
                            intersection.obj = ent;
                            intersection.ipoint = newPos;
                            intersection.normal = newPos;
                            result.Add(intersection);
                            break;
                        }
                    }
                }
            }
            if (getLand)
            {
                //TODO
            }

            result.Sort((a, b) => a.distance.CompareTo(b.distance));

            if (result.Count > count)
                result.RemoveRange(count, result.Count - count);
            return result;
        }

        public EntityIntersection TestIntersection(Ray iray, Quaternion parentrot)
        {
            // In this case we're using a sphere with a radius of the largest dimension of the prim
            // TODO: Change to take shape into account

            EntityIntersection result = new EntityIntersection();
            Vector3 vAbsolutePosition = AbsolutePosition;
            Vector3 vScale = Scale;
            Vector3 rOrigin = iray.Origin;
            Vector3 rDirection = iray.Direction;

            //rDirection = rDirection.Normalize();
            // Buidling the first part of the Quadratic equation
            Vector3 r2ndDirection = rDirection*rDirection;
            float itestPart1 = r2ndDirection.X + r2ndDirection.Y + r2ndDirection.Z;

            // Buidling the second part of the Quadratic equation
            Vector3 tmVal2 = rOrigin - vAbsolutePosition;
            Vector3 r2Direction = rDirection*2.0f;
            Vector3 tmVal3 = r2Direction*tmVal2;

            float itestPart2 = tmVal3.X + tmVal3.Y + tmVal3.Z;

            // Buidling the third part of the Quadratic equation
            Vector3 tmVal4 = rOrigin*rOrigin;
            Vector3 tmVal5 = vAbsolutePosition*vAbsolutePosition;

            Vector3 tmVal6 = vAbsolutePosition*rOrigin;

            // Set Radius to the largest dimension of the prim
            float radius = 0f;
            if (vScale.X > radius)
                radius = vScale.X;
            if (vScale.Y > radius)
                radius = vScale.Y;
            if (vScale.Z > radius)
                radius = vScale.Z;

            // the second part of this is the default prim size
            // once we factor in the aabb of the prim we're adding we can
            // change this to;
            // radius = (radius / 2) - 0.01f;
            //
            radius = (radius / 2) + (0.5f / 2) - 0.1f;

            //radius = radius;

            float itestPart3 = tmVal4.X + tmVal4.Y + tmVal4.Z + tmVal5.X + tmVal5.Y + tmVal5.Z -
                               (2.0f*(tmVal6.X + tmVal6.Y + tmVal6.Z + (radius*radius)));

            // Yuk Quadradrics..    Solve first
            float rootsqr = (itestPart2*itestPart2) - (4.0f*itestPart1*itestPart3);
            if (rootsqr < 0.0f)
            {
                // No intersection
                return result;
            }
            float root = ((-itestPart2) - (float) Math.Sqrt((double) rootsqr))/(itestPart1*2.0f);

            if (root < 0.0f)
            {
                // perform second quadratic root solution
                root = ((-itestPart2) + (float) Math.Sqrt((double) rootsqr))/(itestPart1*2.0f);

                // is there any intersection?
                if (root < 0.0f)
                {
                    // nope, no intersection
                    return result;
                }
            }

            // We got an intersection.  putting together an EntityIntersection object with the
            // intersection information
            Vector3 ipoint =
                new Vector3(iray.Origin.X + (iray.Direction.X*root), iray.Origin.Y + (iray.Direction.Y*root),
                            iray.Origin.Z + (iray.Direction.Z*root));

            result.HitTF = true;
            result.ipoint = ipoint;

            // Normal is calculated by the difference and then normalizing the result
            Vector3 normalpart = ipoint - vAbsolutePosition;
            result.normal = normalpart / normalpart.Length();

            // It's funny how the Vector3 object has a Distance function, but the Axiom.Math object doesn't.
            // I can write a function to do it..    but I like the fact that this one is Static.

            Vector3 distanceConvert1 = new Vector3(iray.Origin.X, iray.Origin.Y, iray.Origin.Z);
            Vector3 distanceConvert2 = new Vector3(ipoint.X, ipoint.Y, ipoint.Z);
            float distance = (float) Util.GetDistanceTo(distanceConvert1, distanceConvert2);

            result.distance = distance;

            return result;
        }

 /// <summary>
 ///     Get a scene object group that contains the prim with the given uuid
 /// </summary>
 /// <param name="hray"></param>
 /// <param name="frontFacesOnly"></param>
 /// <param name="faceCenters"></param>
 /// <returns>null if no scene object group containing that prim is found</returns>
 protected internal EntityIntersection GetClosestIntersectingPrim(Ray hray, bool frontFacesOnly, bool faceCenters)
 {
     // Primitive Ray Tracing
     float closestDistance = 280f;
     EntityIntersection result = new EntityIntersection();
     ISceneEntity[] EntityList = Entities.GetEntities(hray.Origin, closestDistance);
     foreach (ISceneEntity ent in EntityList)
     {
         if (ent is SceneObjectGroup)
         {
             SceneObjectGroup reportingG = (SceneObjectGroup) ent;
             EntityIntersection inter = reportingG.TestIntersection(hray, frontFacesOnly, faceCenters);
             if (inter.HitTF && inter.distance < closestDistance)
             {
                 closestDistance = inter.distance;
                 result = inter;
             }
         }
     }
     return result;
 }

        public EntityIntersection TestIntersection(Ray hRay, bool frontFacesOnly, bool faceCenters)
        {
            // We got a request from the inner_scene to raytrace along the Ray hRay
            // We're going to check all of the prim in this group for intersection with the ray
            // If we get a result, we're going to find the closest result to the origin of the ray
            // and send back the intersection information back to the innerscene.

            EntityIntersection result = new EntityIntersection();

            SceneObjectPart[] parts = m_parts.GetArray();

            // Find closest hit here
            float idist = float.MaxValue;

            for (int i = 0; i < parts.Length; i++)
            {
                SceneObjectPart part = parts[i];

                // Temporary commented to stop compiler warning
                //Vector3 partPosition =
                //    new Vector3(part.AbsolutePosition.X, part.AbsolutePosition.Y, part.AbsolutePosition.Z);
                Quaternion parentrotation = GroupRotation;

                // Telling the prim to raytrace.
                //EntityIntersection inter = part.TestIntersection(hRay, parentrotation);

                EntityIntersection inter = part.TestIntersectionOBB(hRay, parentrotation, frontFacesOnly, faceCenters);

                if (inter.HitTF)
                {
                    // We need to find the closest prim to return to the testcaller along the ray
                    if (inter.distance < idist)
                    {
                        result.HitTF = true;
                        result.ipoint = inter.ipoint;
                        result.obj = part;
                        result.normal = inter.normal;
                        result.distance = inter.distance;

                        idist = inter.distance;
                    }
                }
            }
            return result;
        }

 protected internal EntityIntersection GetClosestIntersectingPrim(Ray hray, bool frontFacesOnly, bool faceCenters)
 {
     // Primitive Ray Tracing
     float closestDistance = 280f;
     EntityIntersection returnResult = new EntityIntersection();
     List<EntityBase> EntityList = GetEntities();
     foreach (EntityBase ent in EntityList)
     {
         if (ent is SceneObjectGroup)
         {
             SceneObjectGroup reportingG = (SceneObjectGroup)ent;
             EntityIntersection result = reportingG.TestIntersection(hray, frontFacesOnly, faceCenters);
             if (result.HitTF)
             {
                 if (result.distance < closestDistance)
                 {
                     closestDistance = result.distance;
                     returnResult = result;
                 }
             }
         }
     }
     return returnResult;
 }

        /// <summary>
        /// A method which find the first object the ray hit. This is done by comparing distances. 
        /// The smallest distance is the distance between the intersection point and the ray start point. 
        /// </summary>
        /// <param name="ray">The ray which will be used to test the intersection against each part in the scene</param>
        /// <param name="source">An object which the ray start from. We need this to make sure that the shortest
        /// distance isn't zero (from itself to itself)</param>
        /// <returns>Intersection point with True if this ray intersect something, or false if nothing at all</returns>
        public EntityIntersectionWithPart findNextHit(Ray ray, SceneObjectPart source)
        {
            float smallestDistance = 1000000f;
            EntityIntersection closestIntersection = new EntityIntersection();
            SceneObjectPart closestPart = new SceneObjectPart();
            foreach (SceneObjectPart part in worldObjects)
            {
                if (!part.Equals(source)) //Cannot intersect itself (i.e. ignore/do nothing when it is itself)
                {
                    //Test if the ray intersect this part. 
                    EntityIntersection intersection;
                    if (part.GetPrimType() == OpenSim.Region.Framework.Scenes.PrimType.SPHERE)
                    {
                        intersection = part.TestIntersection(ray, part.ParentGroup.GroupRotation);
                    }
                    else
                    {
                        intersection = part.TestIntersectionOBB(ray, part.ParentGroup.GroupRotation, true, false);
                    }

                    //If it intersects, then check again with another method checkPointIntersectPrim().
                    if (intersection.HitTF && checkPointIntersectPrim(intersection.ipoint, part, 0.1f))
                    {
                        //If yes, then remember this distance and this intersection as the current 'return' candidate
                        if (intersection.distance < smallestDistance)
                        {
                            smallestDistance = intersection.distance;
                            closestIntersection = intersection;
                            closestPart = part;
                        }//if
                    }//if
                }//if
            }//foreach
            return new EntityIntersectionWithPart(closestIntersection, closestPart);
        }

 public EntityIntersectionWithPart(EntityIntersection _intersection, SceneObjectPart part)
 {
     intersection = _intersection;
     intersectPart = part;
 }//constructor