path: root/OpenSim/Region/Physics/Meshing/Meshmerizer.cs

/*
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 *
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 * modification, are permitted provided that the following conditions are met:
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 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */

using System;
using System.Collections.Generic;
using OpenSim.Framework;
using OpenSim.Framework.Console;
using OpenSim.Region.Physics.Manager;

namespace OpenSim.Region.Physics.Meshing
{
    public class MeshmerizerPlugin : IMeshingPlugin
    {
        public MeshmerizerPlugin()
        {
        }

        public string GetName()
        {
            return "Meshmerizer";
        }

        public IMesher GetMesher()
        {
            return new Meshmerizer();
        }
    }

    public class Meshmerizer : IMesher
    {
        //private static readonly log4net.ILog m_log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

        // Setting baseDir to a path will enable the dumping of raw files
        // raw files can be imported by blender so a visual inspection of the results can be done
        //        const string baseDir = "rawFiles";
        private const string baseDir = null; //"rawFiles";

// TODO: unused
//         private static void IntersectionParameterPD(PhysicsVector p1, PhysicsVector r1, PhysicsVector p2,
//                                                     PhysicsVector r2, ref float lambda, ref float mu)
//         {
//             // p1, p2, points on the straight
//             // r1, r2, directional vectors of the straight. Not necessarily of length 1!
//             // note, that l, m can be scaled such, that the range 0..1 is mapped to the area between two points,
//             // thus allowing to decide whether an intersection is between two points

//             float r1x = r1.X;
//             float r1y = r1.Y;
//             float r2x = r2.X;
//             float r2y = r2.Y;

//             float denom = r1y*r2x - r1x*r2y;

//             if (denom == 0.0)
//             {
//                 lambda = Single.NaN;
//                 mu = Single.NaN;
//                 return;
//             }

//             float p1x = p1.X;
//             float p1y = p1.Y;
//             float p2x = p2.X;
//             float p2y = p2.Y;
//             lambda = (-p2x*r2y + p1x*r2y + (p2y - p1y)*r2x)/denom;
//             mu = (-p2x*r1y + p1x*r1y + (p2y - p1y)*r1x)/denom;
//         }

        private static List<Triangle> FindInfluencedTriangles(List<Triangle> triangles, Vertex v)
        {
            List<Triangle> influenced = new List<Triangle>();
            foreach (Triangle t in triangles)
            {
                if (t.isInCircle(v.X, v.Y))
                {
                    influenced.Add(t);
                }
            }
            return influenced;
        }

        private static void InsertVertices(List<Vertex> vertices, int usedForSeed, List<Triangle> triangles)
        {
            // This is a variant of the delaunay algorithm
            // each time a new vertex is inserted, all triangles that are influenced by it are deleted
            // and replaced by new ones including the new vertex
            // It is not very time efficient but easy to implement.

            int iCurrentVertex;
            int iMaxVertex = vertices.Count;
            for (iCurrentVertex = usedForSeed; iCurrentVertex < iMaxVertex; iCurrentVertex++)
            {
                // Background: A triangle mesh fulfills the delaunay condition if (iff!)
                // each circumlocutory circle (i.e. the circle that touches all three corners) 
                // of each triangle is empty of other vertices.
                // Obviously a single (seeding) triangle fulfills this condition.
                // If we now add one vertex, we need to reconstruct all triangles, that
                // do not fulfill this condition with respect to the new triangle

                // Find the triangles that are influenced by the new vertex
                Vertex v = vertices[iCurrentVertex];
                if (v == null)
                    continue; // Null is polygon stop marker. Ignore it
                List<Triangle> influencedTriangles = FindInfluencedTriangles(triangles, v);

                List<Simplex> simplices = new List<Simplex>();

                // Reconstruction phase. First step, dissolve each triangle into it's simplices,
                // i.e. it's "border lines"
                // Goal is to find "inner" borders and delete them, while the hull gets conserved.
                // Inner borders are special in the way that they always come twice, which is how we detect them 
                foreach (Triangle t in influencedTriangles)
                {
                    List<Simplex> newSimplices = t.GetSimplices();
                    simplices.AddRange(newSimplices);
                    triangles.Remove(t);
                }
                // Now sort the simplices. That will make identical ones reside side by side in the list
                simplices.Sort();

                // Look for duplicate simplices here. 
                // Remember, they are directly side by side in the list right now, 
                // So we only check directly neighbours
                int iSimplex;
                List<Simplex> innerSimplices = new List<Simplex>();
                for (iSimplex = 1; iSimplex < simplices.Count; iSimplex++) // Startindex=1, so we can refer backwards
                {
                    if (simplices[iSimplex - 1].CompareTo(simplices[iSimplex]) == 0)
                    {
                        innerSimplices.Add(simplices[iSimplex - 1]);
                        innerSimplices.Add(simplices[iSimplex]);
                    }
                }

                foreach (Simplex s in innerSimplices)
                {
                    simplices.Remove(s);
                }

                // each simplex still in the list belongs to the hull of the region in question
                // The new vertex (yes, we still deal with verices here :-) ) forms a triangle 
                // with each of these simplices. Build the new triangles and add them to the list
                foreach (Simplex s in simplices)
                {
                    Triangle t = new Triangle(s.v1, s.v2, vertices[iCurrentVertex]);
                    if (!t.isDegraded())
                    {
                        triangles.Add(t);
                    }
                }
            }
        }

        private static SimpleHull BuildHoleHull(PrimitiveBaseShape pbs, ProfileShape pshape, HollowShape hshape, UInt16 hollowFactor)
        {
            // Tackle HollowShape.Same
            float fhollowFactor = (float)hollowFactor;

            switch (pshape)
            {
                case ProfileShape.Square:
                    if (hshape == HollowShape.Same)
                        hshape= HollowShape.Square;
                    break;
                case ProfileShape.EquilateralTriangle:
                    fhollowFactor = ((float)hollowFactor / 1.9f);
                    if (hshape == HollowShape.Same)
                    {
                        hshape = HollowShape.Triangle;
                    }

                    break;

                case ProfileShape.Circle:
                    if (pbs.PathCurve == (byte)Extrusion.Straight)
                    {
                        if (hshape == HollowShape.Same)
                        {
                            hshape = HollowShape.Circle;
                        }
                    }
                    break;

                
                default:
                    if (hshape == HollowShape.Same)
                        hshape= HollowShape.Square;
                    break;
            }

            
            SimpleHull holeHull = null;

            if (hshape == HollowShape.Square)
            {
                float hollowFactorF = (float)fhollowFactor / (float)50000;
                Vertex IMM = new Vertex(-0.5f * hollowFactorF, -0.5f * hollowFactorF, 0.0f);
                Vertex IPM = new Vertex(+0.5f * hollowFactorF, -0.5f * hollowFactorF, 0.0f);
                Vertex IPP = new Vertex(+0.5f * hollowFactorF, +0.5f * hollowFactorF, 0.0f);
                Vertex IMP = new Vertex(-0.5f * hollowFactorF, +0.5f * hollowFactorF, 0.0f);


                holeHull = new SimpleHull();

                holeHull.AddVertex(IMM);
                holeHull.AddVertex(IMP);
                holeHull.AddVertex(IPP);
                holeHull.AddVertex(IPM);
            }
            if (hshape == HollowShape.Circle && pbs.PathCurve == (byte)Extrusion.Straight)
            {
                float hollowFactorF = (float)fhollowFactor / (float)50000;

                Vertex IQ1Q15 = new Vertex(-0.35f * hollowFactorF, -0.35f * hollowFactorF, 0.0f);
                Vertex IQ1Q16 = new Vertex(-0.30f * hollowFactorF, -0.40f * hollowFactorF, 0.0f);
                Vertex IQ1Q17 = new Vertex(-0.24f * hollowFactorF, -0.43f * hollowFactorF, 0.0f);
                Vertex IQ1Q18 = new Vertex(-0.18f * hollowFactorF, -0.46f * hollowFactorF, 0.0f);
                Vertex IQ1Q19 = new Vertex(-0.11f * hollowFactorF, -0.48f * hollowFactorF, 0.0f);

                Vertex IQ2Q10 = new Vertex(+0.0f * hollowFactorF, -0.50f * hollowFactorF, 0.0f);
                Vertex IQ2Q11 = new Vertex(+0.11f * hollowFactorF, -0.48f * hollowFactorF, 0.0f);
                Vertex IQ2Q12 = new Vertex(+0.18f * hollowFactorF, -0.46f * hollowFactorF, 0.0f);
                Vertex IQ2Q13 = new Vertex(+0.24f * hollowFactorF, -0.43f * hollowFactorF, 0.0f);
                Vertex IQ2Q14 = new Vertex(+0.30f * hollowFactorF, -0.40f * hollowFactorF, 0.0f);
                Vertex IQ2Q15 = new Vertex(+0.35f * hollowFactorF, -0.35f * hollowFactorF, 0.0f);
                Vertex IQ2Q16 = new Vertex(+0.40f * hollowFactorF, -0.30f * hollowFactorF, 0.0f);
                Vertex IQ2Q17 = new Vertex(+0.43f * hollowFactorF, -0.24f * hollowFactorF, 0.0f);
                Vertex IQ2Q18 = new Vertex(+0.46f * hollowFactorF, -0.18f * hollowFactorF, 0.0f);
                Vertex IQ2Q19 = new Vertex(+0.48f * hollowFactorF, -0.11f * hollowFactorF, 0.0f);

                Vertex IQ2Q20 = new Vertex(+0.50f * hollowFactorF, +0.0f * hollowFactorF, 0.0f);
                Vertex IQ2Q21 = new Vertex(+0.48f * hollowFactorF, +0.11f * hollowFactorF, 0.0f);
                Vertex IQ2Q22 = new Vertex(+0.46f * hollowFactorF, +0.18f * hollowFactorF, 0.0f);
                Vertex IQ2Q23 = new Vertex(+0.43f * hollowFactorF, +0.24f * hollowFactorF, 0.0f);
                Vertex IQ2Q24 = new Vertex(+0.40f * hollowFactorF, +0.30f * hollowFactorF, 0.0f);
                Vertex IQ2Q25 = new Vertex(+0.35f * hollowFactorF, +0.35f * hollowFactorF, 0.0f);
                Vertex IQ2Q26 = new Vertex(+0.30f * hollowFactorF, +0.40f * hollowFactorF, 0.0f);
                Vertex IQ2Q27 = new Vertex(+0.24f * hollowFactorF, +0.43f * hollowFactorF, 0.0f);
                Vertex IQ2Q28 = new Vertex(+0.18f * hollowFactorF, +0.46f * hollowFactorF, 0.0f);
                Vertex IQ2Q29 = new Vertex(+0.11f * hollowFactorF, +0.48f * hollowFactorF, 0.0f);

                Vertex IQ1Q20 = new Vertex(+0.0f * hollowFactorF, +0.50f * hollowFactorF, 0.0f);
                Vertex IQ1Q21 = new Vertex(-0.11f * hollowFactorF, +0.48f * hollowFactorF, 0.0f);
                Vertex IQ1Q22 = new Vertex(-0.18f * hollowFactorF, +0.46f * hollowFactorF, 0.0f);
                Vertex IQ1Q23 = new Vertex(-0.24f * hollowFactorF, +0.43f * hollowFactorF, 0.0f);
                Vertex IQ1Q24 = new Vertex(-0.30f * hollowFactorF, +0.40f * hollowFactorF, 0.0f);
                Vertex IQ1Q25 = new Vertex(-0.35f * hollowFactorF, +0.35f * hollowFactorF, 0.0f);
                Vertex IQ1Q26 = new Vertex(-0.40f * hollowFactorF, +0.30f * hollowFactorF, 0.0f);
                Vertex IQ1Q27 = new Vertex(-0.43f * hollowFactorF, +0.24f * hollowFactorF, 0.0f);
                Vertex IQ1Q28 = new Vertex(-0.46f * hollowFactorF, +0.18f * hollowFactorF, 0.0f);
                Vertex IQ1Q29 = new Vertex(-0.48f * hollowFactorF, +0.11f * hollowFactorF, 0.0f);

                Vertex IQ1Q10 = new Vertex(-0.50f * hollowFactorF, +0.0f * hollowFactorF, 0.0f);
                Vertex IQ1Q11 = new Vertex(-0.48f * hollowFactorF, -0.11f * hollowFactorF, 0.0f);
                Vertex IQ1Q12 = new Vertex(-0.46f * hollowFactorF, -0.18f * hollowFactorF, 0.0f);
                Vertex IQ1Q13 = new Vertex(-0.43f * hollowFactorF, -0.24f * hollowFactorF, 0.0f);
                Vertex IQ1Q14 = new Vertex(-0.40f * hollowFactorF, -0.30f * hollowFactorF, 0.0f);

                //Counter clockwise around the quadrants
                holeHull = new SimpleHull();
                holeHull.AddVertex(IQ1Q15);
                holeHull.AddVertex(IQ1Q14);
                holeHull.AddVertex(IQ1Q13);
                holeHull.AddVertex(IQ1Q12);
                holeHull.AddVertex(IQ1Q11);
                holeHull.AddVertex(IQ1Q10);

                holeHull.AddVertex(IQ1Q29);
                holeHull.AddVertex(IQ1Q28);
                holeHull.AddVertex(IQ1Q27);
                holeHull.AddVertex(IQ1Q26);
                holeHull.AddVertex(IQ1Q25);
                holeHull.AddVertex(IQ1Q24);
                holeHull.AddVertex(IQ1Q23);
                holeHull.AddVertex(IQ1Q22);
                holeHull.AddVertex(IQ1Q21);
                holeHull.AddVertex(IQ1Q20);

                holeHull.AddVertex(IQ2Q29);
                holeHull.AddVertex(IQ2Q28);
                holeHull.AddVertex(IQ2Q27);
                holeHull.AddVertex(IQ2Q26);
                holeHull.AddVertex(IQ2Q25);
                holeHull.AddVertex(IQ2Q24);
                holeHull.AddVertex(IQ2Q23);
                holeHull.AddVertex(IQ2Q22);
                holeHull.AddVertex(IQ2Q21);
                holeHull.AddVertex(IQ2Q20);

                holeHull.AddVertex(IQ2Q19);
                holeHull.AddVertex(IQ2Q18);
                holeHull.AddVertex(IQ2Q17);
                holeHull.AddVertex(IQ2Q16);
                holeHull.AddVertex(IQ2Q15);
                holeHull.AddVertex(IQ2Q14);
                holeHull.AddVertex(IQ2Q13);
                holeHull.AddVertex(IQ2Q12);
                holeHull.AddVertex(IQ2Q11);
                holeHull.AddVertex(IQ2Q10);

                holeHull.AddVertex(IQ1Q19);
                holeHull.AddVertex(IQ1Q18);
                holeHull.AddVertex(IQ1Q17);
                holeHull.AddVertex(IQ1Q16);
            }
            if (hshape == HollowShape.Triangle)
            {
                float hollowFactorF = (float)fhollowFactor / (float)50000;
                Vertex IMM = new Vertex(-0.25f * hollowFactorF, -0.45f * hollowFactorF, 0.0f);
                Vertex IPM = new Vertex(+0.5f * hollowFactorF, +0f * hollowFactorF, 0.0f);
                Vertex IPP = new Vertex(-0.25f * hollowFactorF, +0.45f * hollowFactorF, 0.0f);



                holeHull = new SimpleHull();

                holeHull.AddVertex(IMM);
                holeHull.AddVertex(IPP);
                holeHull.AddVertex(IPM);

            }

            return holeHull;


        }

        private static Mesh CreateBoxMesh(String primName, PrimitiveBaseShape primShape, PhysicsVector size)
            // Builds the z (+ and -) surfaces of a box shaped prim
        {
            UInt16 hollowFactor = primShape.ProfileHollow;
            UInt16 profileBegin = primShape.ProfileBegin;
            UInt16 profileEnd = primShape.ProfileEnd;
            UInt16 taperX = primShape.PathScaleX;
            UInt16 taperY = primShape.PathScaleY;
            UInt16 pathShearX = primShape.PathShearX;
            UInt16 pathShearY = primShape.PathShearY;
            

            //m_log.Error("pathShear:" + primShape.PathShearX.ToString() + "," + primShape.PathShearY.ToString());
            //m_log.Error("pathTaper:" + primShape.PathTaperX.ToString() + "," + primShape.PathTaperY.ToString());
            //m_log.Error("ProfileBegin:" + primShape.ProfileBegin.ToString() + "," + primShape.ProfileBegin.ToString());
            //m_log.Error("PathScale:" + primShape.PathScaleX.ToString() + "," + primShape.PathScaleY.ToString());
            
            // Procedure: This is based on the fact that the upper (plus) and lower (minus) Z-surface
            // of a block are basically the same
            // They may be warped differently but the shape is identical
            // So we only create one surface as a model and derive both plus and minus surface of the block from it
            // This is done in a model space where the block spans from -.5 to +.5 in X and Y
            // The mapping to Scene space is done later during the "extrusion" phase

            // Base
            Vertex MM = new Vertex(-0.5f, -0.5f, 0.0f);
            Vertex PM = new Vertex(+0.5f, -0.5f, 0.0f);
            Vertex PP = new Vertex(+0.5f, +0.5f, 0.0f);
            Vertex MP = new Vertex(-0.5f, +0.5f, 0.0f);

            SimpleHull outerHull = new SimpleHull();
            outerHull.AddVertex(MM);
            outerHull.AddVertex(PM);
            outerHull.AddVertex(PP);
            outerHull.AddVertex(MP);

            // Deal with cuts now
            if ((profileBegin != 0) || (profileEnd != 0))
            {
                double fProfileBeginAngle = profileBegin/50000.0*360.0;
                    // In degree, for easier debugging and understanding
                fProfileBeginAngle -= (90.0 + 45.0); // for some reasons, the SL client counts from the corner -X/-Y
                double fProfileEndAngle = 360.0 - profileEnd/50000.0*360.0; // Pathend comes as complement to 1.0
                fProfileEndAngle -= (90.0 + 45.0);
                if (fProfileBeginAngle < fProfileEndAngle)
                    fProfileEndAngle -= 360.0;

                // Note, that we don't want to cut out a triangle, even if this is a 
                // good approximation for small cuts. Indeed we want to cut out an arc
                // and we approximate this arc by a polygon chain
                // Also note, that these vectors are of length 1.0 and thus their endpoints lay outside the model space
                // So it can easily be subtracted from the outer hull
                int iSteps = (int) (((fProfileBeginAngle - fProfileEndAngle)/45.0) + .5);
                    // how many steps do we need with approximately 45 degree
                double dStepWidth = (fProfileBeginAngle - fProfileEndAngle)/iSteps;

                Vertex origin = new Vertex(0.0f, 0.0f, 0.0f);

                // Note the sequence of vertices here. It's important to have the other rotational sense than in outerHull
                SimpleHull cutHull = new SimpleHull();
                cutHull.AddVertex(origin);
                for (int i = 0; i < iSteps; i++)
                {
                    double angle = fProfileBeginAngle - i*dStepWidth; // we count against the angle orientation!!!!
                    Vertex v = Vertex.FromAngle(angle*Math.PI/180.0);
                    cutHull.AddVertex(v);
                }
                Vertex legEnd = Vertex.FromAngle(fProfileEndAngle*Math.PI/180.0);
                    // Calculated separately to avoid errors
                cutHull.AddVertex(legEnd);

                //m_log.DebugFormat("Starting cutting of the hollow shape from the prim {1}", 0, primName);
                SimpleHull cuttedHull = SimpleHull.SubtractHull(outerHull, cutHull);

                outerHull = cuttedHull;
            }

            // Deal with the hole here
            if (hollowFactor > 0)
            {

                SimpleHull holeHull = BuildHoleHull(primShape, primShape.ProfileShape, primShape.HollowShape, hollowFactor);
                if (holeHull != null)
                {
                    SimpleHull hollowedHull = SimpleHull.SubtractHull(outerHull, holeHull);

                    outerHull = hollowedHull;
                }
            }

            Mesh m = new Mesh();

            Vertex Seed1 = new Vertex(0.0f, -10.0f, 0.0f);
            Vertex Seed2 = new Vertex(-10.0f, 10.0f, 0.0f);
            Vertex Seed3 = new Vertex(10.0f, 10.0f, 0.0f);

            m.Add(Seed1);
            m.Add(Seed2);
            m.Add(Seed3);

            m.Add(new Triangle(Seed1, Seed2, Seed3));
            m.Add(outerHull.getVertices());

            InsertVertices(m.vertices, 3, m.triangles);
            m.DumpRaw(baseDir, primName, "Proto first Mesh");

            m.Remove(Seed1);
            m.Remove(Seed2);
            m.Remove(Seed3);
            m.DumpRaw(baseDir, primName, "Proto seeds removed");

            m.RemoveTrianglesOutside(outerHull);
            m.DumpRaw(baseDir, primName, "Proto outsides removed");

            foreach (Triangle t in m.triangles)
            {
                PhysicsVector n = t.getNormal();
                if (n.Z < 0.0)
                    t.invertNormal();
            }

            Extruder extr = new Extruder();

            extr.size = size;

            if (taperX != 100)
            {
                if (taperX > 100)
                {
                    extr.taperTopFactorX = 1.0f - ((float)taperX / 200);
                    //m_log.Warn("taperTopFactorX: " + extr.taperTopFactorX.ToString());
                }
                else
                {
                    extr.taperBotFactorX = 1.0f - ((100 - (float)taperX) / 100);
                    //m_log.Warn("taperBotFactorX: " + extr.taperBotFactorX.ToString());
                }
                
            }

            if (taperY != 100)
            {
                if (taperY > 100)
                {
                    extr.taperTopFactorY = 1.0f - ((float)taperY / 200);
                    //m_log.Warn("taperTopFactorY: " + extr.taperTopFactorY.ToString());
                }
                else
                {
                    extr.taperBotFactorY = 1.0f - ((100 - (float)taperY) / 100);
                    //m_log.Warn("taperBotFactorY: " + extr.taperBotFactorY.ToString());
                }
            }
            
            
            if (pathShearX != 0)
            {
                if (pathShearX > 50) {
                    // Complimentary byte.  Negative values wrap around the byte.  Positive values go up to 50
                    extr.pushX = (((float)(256 - pathShearX) / 100) * -1f);
                   // m_log.Warn("pushX: " + extr.pushX);
                }
                else 
                {
                    extr.pushX = (float)pathShearX / 100;
                   // m_log.Warn("pushX: " + extr.pushX);
                }
            }

            if (pathShearY != 0)
            {
                if (pathShearY > 50) {
                    // Complimentary byte.  Negative values wrap around the byte.  Positive values go up to 50
                    extr.pushY = (((float)(256 - pathShearY) / 100) * -1f);
                    //m_log.Warn("pushY: " + extr.pushY);
                }
                else 
                {
                    extr.pushY = (float)pathShearY / 100;
                    //m_log.Warn("pushY: " + extr.pushY);
                }
            }
            
            Mesh result = extr.Extrude(m);
            result.DumpRaw(baseDir, primName, "Z extruded");
            return result;
        }

        private static Mesh CreateCyllinderMesh(String primName, PrimitiveBaseShape primShape, PhysicsVector size)
        // Builds the z (+ and -) surfaces of a box shaped prim
        {
            UInt16 hollowFactor = primShape.ProfileHollow;
            UInt16 profileBegin = primShape.ProfileBegin;
            UInt16 profileEnd = primShape.ProfileEnd;
            UInt16 taperX = primShape.PathScaleX;
            UInt16 taperY = primShape.PathScaleY;
            UInt16 pathShearX = primShape.PathShearX;
            UInt16 pathShearY = primShape.PathShearY;

            // Procedure: This is based on the fact that the upper (plus) and lower (minus) Z-surface
            // of a block are basically the same
            // They may be warped differently but the shape is identical
            // So we only create one surface as a model and derive both plus and minus surface of the block from it
            // This is done in a model space where the block spans from -.5 to +.5 in X and Y
            // The mapping to Scene space is done later during the "extrusion" phase

            // Base
            // Q1Q15 = Quadrant 1, Quadrant1, Vertex 5
            Vertex Q1Q15 = new Vertex(-0.35f, -0.35f, 0.0f);
            Vertex Q1Q16 = new Vertex(-0.30f, -0.40f, 0.0f);
            Vertex Q1Q17 = new Vertex(-0.24f, -0.43f, 0.0f);
            Vertex Q1Q18 = new Vertex(-0.18f, -0.46f, 0.0f);
            Vertex Q1Q19 = new Vertex(-0.11f, -0.48f, 0.0f);

            Vertex Q2Q10 = new Vertex(+0.0f, -0.50f, 0.0f);
            Vertex Q2Q11 = new Vertex(+0.11f, -0.48f, 0.0f);
            Vertex Q2Q12 = new Vertex(+0.18f, -0.46f, 0.0f);
            Vertex Q2Q13 = new Vertex(+0.24f, -0.43f, 0.0f);
            Vertex Q2Q14 = new Vertex(+0.30f, -0.40f, 0.0f);
            Vertex Q2Q15 = new Vertex(+0.35f, -0.35f, 0.0f);
            Vertex Q2Q16 = new Vertex(+0.40f, -0.30f, 0.0f);
            Vertex Q2Q17 = new Vertex(+0.43f, -0.24f, 0.0f);
            Vertex Q2Q18 = new Vertex(+0.46f, -0.18f, 0.0f);
            Vertex Q2Q19 = new Vertex(+0.48f, -0.11f, 0.0f);

            Vertex Q2Q20 = new Vertex(+0.50f, +0.0f, 0.0f);
            Vertex Q2Q21 = new Vertex(+0.48f, +0.11f, 0.0f);
            Vertex Q2Q22 = new Vertex(+0.46f, +0.18f, 0.0f);
            Vertex Q2Q23 = new Vertex(+0.43f, +0.24f, 0.0f);
            Vertex Q2Q24 = new Vertex(+0.40f, +0.30f, 0.0f);
            Vertex Q2Q25 = new Vertex(+0.35f, +0.35f, 0.0f);
            Vertex Q2Q26 = new Vertex(+0.30f, +0.40f, 0.0f);
            Vertex Q2Q27 = new Vertex(+0.24f, +0.43f, 0.0f);
            Vertex Q2Q28 = new Vertex(+0.18f, +0.46f, 0.0f);
            Vertex Q2Q29 = new Vertex(+0.11f, +0.48f, 0.0f);

            Vertex Q1Q20 = new Vertex(+0.0f, +0.50f, 0.0f);
            Vertex Q1Q21 = new Vertex(-0.11f, +0.48f, 0.0f);
            Vertex Q1Q22 = new Vertex(-0.18f, +0.46f, 0.0f);
            Vertex Q1Q23 = new Vertex(-0.24f, +0.43f, 0.0f);
            Vertex Q1Q24 = new Vertex(-0.30f, +0.40f, 0.0f);
            Vertex Q1Q25 = new Vertex(-0.35f, +0.35f, 0.0f);
            Vertex Q1Q26 = new Vertex(-0.40f, +0.30f, 0.0f);
            Vertex Q1Q27 = new Vertex(-0.43f, +0.24f, 0.0f);
            Vertex Q1Q28 = new Vertex(-0.46f, +0.18f, 0.0f);
            Vertex Q1Q29 = new Vertex(-0.48f, +0.11f, 0.0f);

            Vertex Q1Q10 = new Vertex(-0.50f, +0.0f, 0.0f);
            Vertex Q1Q11 = new Vertex(-0.48f, -0.11f, 0.0f);
            Vertex Q1Q12 = new Vertex(-0.46f, -0.18f, 0.0f);
            Vertex Q1Q13 = new Vertex(-0.43f, -0.24f, 0.0f);
            Vertex Q1Q14 = new Vertex(-0.40f, -0.30f, 0.0f);
            
            SimpleHull outerHull = new SimpleHull();
            //Clockwise around the quadrants
            outerHull.AddVertex(Q1Q15);
            outerHull.AddVertex(Q1Q16);
            outerHull.AddVertex(Q1Q17);
            outerHull.AddVertex(Q1Q18);
            outerHull.AddVertex(Q1Q19);

            outerHull.AddVertex(Q2Q10);
            outerHull.AddVertex(Q2Q11);
            outerHull.AddVertex(Q2Q12);
            outerHull.AddVertex(Q2Q13);
            outerHull.AddVertex(Q2Q14);
            outerHull.AddVertex(Q2Q15);
            outerHull.AddVertex(Q2Q16);
            outerHull.AddVertex(Q2Q17);
            outerHull.AddVertex(Q2Q18);
            outerHull.AddVertex(Q2Q19);

            outerHull.AddVertex(Q2Q20);
            outerHull.AddVertex(Q2Q21);
            outerHull.AddVertex(Q2Q22);
            outerHull.AddVertex(Q2Q23);
            outerHull.AddVertex(Q2Q24);
            outerHull.AddVertex(Q2Q25);
            outerHull.AddVertex(Q2Q26);
            outerHull.AddVertex(Q2Q27);
            outerHull.AddVertex(Q2Q28);
            outerHull.AddVertex(Q2Q29);

            outerHull.AddVertex(Q1Q20);
            outerHull.AddVertex(Q1Q21);
            outerHull.AddVertex(Q1Q22);
            outerHull.AddVertex(Q1Q23);
            outerHull.AddVertex(Q1Q24);
            outerHull.AddVertex(Q1Q25);
            outerHull.AddVertex(Q1Q26);
            outerHull.AddVertex(Q1Q27);
            outerHull.AddVertex(Q1Q28);
            outerHull.AddVertex(Q1Q29);

            outerHull.AddVertex(Q1Q10);
            outerHull.AddVertex(Q1Q11);
            outerHull.AddVertex(Q1Q12);
            outerHull.AddVertex(Q1Q13);
            outerHull.AddVertex(Q1Q14);

            // Deal with cuts now
            if ((profileBegin != 0) || (profileEnd != 0))
            {
                double fProfileBeginAngle = profileBegin / 50000.0 * 360.0;
                // In degree, for easier debugging and understanding
                //fProfileBeginAngle -= (90.0 + 45.0); // for some reasons, the SL client counts from the corner -X/-Y
                double fProfileEndAngle = 360.0 - profileEnd / 50000.0 * 360.0; // Pathend comes as complement to 1.0
                //fProfileEndAngle -= (90.0 + 45.0);
                if (fProfileBeginAngle < fProfileEndAngle)
                    fProfileEndAngle -= 360.0;

                // Note, that we don't want to cut out a triangle, even if this is a 
                // good approximation for small cuts. Indeed we want to cut out an arc
                // and we approximate this arc by a polygon chain
                // Also note, that these vectors are of length 1.0 and thus their endpoints lay outside the model space
                // So it can easily be subtracted from the outer hull
                int iSteps = (int)(((fProfileBeginAngle - fProfileEndAngle) / 45.0) + .5);
                // how many steps do we need with approximately 45 degree
                double dStepWidth = (fProfileBeginAngle - fProfileEndAngle) / iSteps;

                Vertex origin = new Vertex(0.0f, 0.0f, 0.0f);

                // Note the sequence of vertices here. It's important to have the other rotational sense than in outerHull
                SimpleHull cutHull = new SimpleHull();
                cutHull.AddVertex(origin);
                for (int i = 0; i < iSteps; i++)
                {
                    double angle = fProfileBeginAngle - i * dStepWidth; // we count against the angle orientation!!!!
                    Vertex v = Vertex.FromAngle(angle * Math.PI / 180.0);
                    cutHull.AddVertex(v);
                }
                Vertex legEnd = Vertex.FromAngle(fProfileEndAngle * Math.PI / 180.0);
                // Calculated separately to avoid errors
                cutHull.AddVertex(legEnd);

                // m_log.DebugFormat("Starting cutting of the hollow shape from the prim {1}", 0, primName);
                SimpleHull cuttedHull = SimpleHull.SubtractHull(outerHull, cutHull);

                outerHull = cuttedHull;
            }

            // Deal with the hole here
            if (hollowFactor > 0)
            {
                SimpleHull holeHull = BuildHoleHull(primShape, primShape.ProfileShape, primShape.HollowShape, hollowFactor);
                if (holeHull != null)
                {
                    SimpleHull hollowedHull = SimpleHull.SubtractHull(outerHull, holeHull);

                    outerHull = hollowedHull;
                }
            }

            Mesh m = new Mesh();

            Vertex Seed1 = new Vertex(0.0f, -10.0f, 0.0f);
            Vertex Seed2 = new Vertex(-10.0f, 10.0f, 0.0f);
            Vertex Seed3 = new Vertex(10.0f, 10.0f, 0.0f);

            m.Add(Seed1);
            m.Add(Seed2);
            m.Add(Seed3);

            m.Add(new Triangle(Seed1, Seed2, Seed3));
            m.Add(outerHull.getVertices());

            InsertVertices(m.vertices, 3, m.triangles);
            m.DumpRaw(baseDir, primName, "Proto first Mesh");

            m.Remove(Seed1);
            m.Remove(Seed2);
            m.Remove(Seed3);
            m.DumpRaw(baseDir, primName, "Proto seeds removed");

            m.RemoveTrianglesOutside(outerHull);
            m.DumpRaw(baseDir, primName, "Proto outsides removed");

            foreach (Triangle t in m.triangles)
            {
                PhysicsVector n = t.getNormal();
                if (n.Z < 0.0)
                    t.invertNormal();
            }

            Extruder extr = new Extruder();

            extr.size = size;

            //System.Console.WriteLine("taperFactorX: " + taperX.ToString());
            //System.Console.WriteLine("taperFactorY: " + taperY.ToString());

            if (taperX != 100)
            {
                if (taperX > 100)
                {
                    extr.taperTopFactorX = 1.0f - ((float)(taperX - 100) / 100);
                    //System.Console.WriteLine("taperTopFactorX: " + extr.taperTopFactorX.ToString());
                }
                else
                {
                    extr.taperBotFactorX = 1.0f - ((100 - (float)taperX) / 100);
                    //System.Console.WriteLine("taperBotFactorX: " + extr.taperBotFactorX.ToString());
                }

            }

            if (taperY != 100)
            {
                if (taperY > 100)
                {
                    extr.taperTopFactorY = 1.0f - ((float)(taperY - 100) / 200);
                   // System.Console.WriteLine("taperTopFactorY: " + extr.taperTopFactorY.ToString());
                }
                else
                {
                    extr.taperBotFactorY = 1.0f - ((100 - (float)taperY) / 100);
                    //System.Console.WriteLine("taperBotFactorY: " + extr.taperBotFactorY.ToString());
                }
            }

            if (pathShearX != 0)
            {
                if (pathShearX > 50)
                {
                    // Complimentary byte.  Negative values wrap around the byte.  Positive values go up to 50
                    extr.pushX = (((float)(256 - pathShearX) / 100) * -1f);
                    //m_log.Warn("pushX: " + extr.pushX);
                }
                else
                {
                    extr.pushX = (float)pathShearX / 100;
                    //m_log.Warn("pushX: " + extr.pushX);
                }
            }

            if (pathShearY != 0)
            {
                if (pathShearY > 50)
                {
                    // Complimentary byte.  Negative values wrap around the byte.  Positive values go up to 50
                    extr.pushY = (((float)(256 - pathShearY) / 100) * -1f);
                    //m_log.Warn("pushY: " + extr.pushY);
                }
                else
                {
                    extr.pushY = (float)pathShearY / 100;
                    //m_log.Warn("pushY: " + extr.pushY);
                }
            }

            Mesh result = extr.Extrude(m);
            result.DumpRaw(baseDir, primName, "Z extruded");
            return result;
        }

        private static Mesh CreatePrismMesh(String primName, PrimitiveBaseShape primShape, PhysicsVector size)
        // Builds the z (+ and -) surfaces of a box shaped prim
        {
            UInt16 hollowFactor = primShape.ProfileHollow;
            UInt16 profileBegin = primShape.ProfileBegin;
            UInt16 profileEnd = primShape.ProfileEnd;
            UInt16 taperX = primShape.PathScaleX;
            UInt16 taperY = primShape.PathScaleY;
            UInt16 pathShearX = primShape.PathShearX;
            UInt16 pathShearY = primShape.PathShearY;

            //m_log.Error("pathShear:" + primShape.PathShearX.ToString() + "," + primShape.PathShearY.ToString());
            //m_log.Error("pathTaper:" + primShape.PathTaperX.ToString() + "," + primShape.PathTaperY.ToString());
            //m_log.Error("ProfileBegin:" + primShape.ProfileBegin.ToString() + "," + primShape.ProfileBegin.ToString());
            //m_log.Error("PathScale:" + primShape.PathScaleX.ToString() + "," + primShape.PathScaleY.ToString());

            // Procedure: This is based on the fact that the upper (plus) and lower (minus) Z-surface
            // of a block are basically the same
            // They may be warped differently but the shape is identical
            // So we only create one surface as a model and derive both plus and minus surface of the block from it
            // This is done in a model space where the block spans from -.5 to +.5 in X and Y
            // The mapping to Scene space is done later during the "extrusion" phase

            // Base
            Vertex MM = new Vertex(-0.25f, -0.45f, 0.0f);
            Vertex PM = new Vertex(+0.5f, 0f, 0.0f);
            Vertex PP = new Vertex(-0.25f, +0.45f, 0.0f);
            

            SimpleHull outerHull = new SimpleHull();
            outerHull.AddVertex(MM);
            outerHull.AddVertex(PM);
            outerHull.AddVertex(PP);
            
            // Deal with cuts now
            if ((profileBegin != 0) || (profileEnd != 0))
            {
                double fProfileBeginAngle = profileBegin / 50000.0 * 360.0;
                // In degree, for easier debugging and understanding
                //fProfileBeginAngle -= (90.0 + 45.0); // for some reasons, the SL client counts from the corner -X/-Y
                double fProfileEndAngle = 360.0 - profileEnd / 50000.0 * 360.0; // Pathend comes as complement to 1.0
                //fProfileEndAngle -= (90.0 + 45.0);
                if (fProfileBeginAngle < fProfileEndAngle)
                    fProfileEndAngle -= 360.0;

                // Note, that we don't want to cut out a triangle, even if this is a 
                // good approximation for small cuts. Indeed we want to cut out an arc
                // and we approximate this arc by a polygon chain
                // Also note, that these vectors are of length 1.0 and thus their endpoints lay outside the model space
                // So it can easily be subtracted from the outer hull
                int iSteps = (int)(((fProfileBeginAngle - fProfileEndAngle) / 45.0) + .5);
                // how many steps do we need with approximately 45 degree
                double dStepWidth = (fProfileBeginAngle - fProfileEndAngle) / iSteps;

                Vertex origin = new Vertex(0.0f, 0.0f, 0.0f);

                // Note the sequence of vertices here. It's important to have the other rotational sense than in outerHull
                SimpleHull cutHull = new SimpleHull();
                cutHull.AddVertex(origin);
                for (int i = 0; i < iSteps; i++)
                {
                    double angle = fProfileBeginAngle - i * dStepWidth; // we count against the angle orientation!!!!
                    Vertex v = Vertex.FromAngle(angle * Math.PI / 180.0);
                    cutHull.AddVertex(v);
                }
                Vertex legEnd = Vertex.FromAngle(fProfileEndAngle * Math.PI / 180.0);
                // Calculated separately to avoid errors
                cutHull.AddVertex(legEnd);

                //m_log.DebugFormat("Starting cutting of the hollow shape from the prim {1}", 0, primName);
                SimpleHull cuttedHull = SimpleHull.SubtractHull(outerHull, cutHull);

                outerHull = cuttedHull;
            }

            // Deal with the hole here
            if (hollowFactor > 0)
            {
                SimpleHull holeHull = BuildHoleHull(primShape, primShape.ProfileShape, primShape.HollowShape, hollowFactor);
                if (holeHull != null)
                {
                    SimpleHull hollowedHull = SimpleHull.SubtractHull(outerHull, holeHull);

                    outerHull = hollowedHull;
                }
            }

            Mesh m = new Mesh();

            Vertex Seed1 = new Vertex(0.0f, -10.0f, 0.0f);
            Vertex Seed2 = new Vertex(-10.0f, 10.0f, 0.0f);
            Vertex Seed3 = new Vertex(10.0f, 10.0f, 0.0f);

            m.Add(Seed1);
            m.Add(Seed2);
            m.Add(Seed3);

            m.Add(new Triangle(Seed1, Seed2, Seed3));
            m.Add(outerHull.getVertices());

            InsertVertices(m.vertices, 3, m.triangles);
            m.DumpRaw(baseDir, primName, "Proto first Mesh");

            m.Remove(Seed1);
            m.Remove(Seed2);
            m.Remove(Seed3);
            m.DumpRaw(baseDir, primName, "Proto seeds removed");

            m.RemoveTrianglesOutside(outerHull);
            m.DumpRaw(baseDir, primName, "Proto outsides removed");

            foreach (Triangle t in m.triangles)
            {
                PhysicsVector n = t.getNormal();
                if (n.Z < 0.0)
                    t.invertNormal();
            }

            Extruder extr = new Extruder();

            extr.size = size;

            if (taperX != 100)
            {
                if (taperX > 100)
                {
                    extr.taperTopFactorX = 1.0f - ((float)taperX / 200);
                    //System.Console.WriteLine("taperTopFactorX: " + extr.taperTopFactorX.ToString());
                }
                else
                {
                    extr.taperBotFactorX = 1.0f - ((100 - (float)taperX) / 100);
                    //System.Console.WriteLine("taperBotFactorX: " + extr.taperBotFactorX.ToString());
                }
            }

            if (taperY != 100)
            {
                if (taperY > 100)
                {
                    extr.taperTopFactorY = 1.0f - ((float)taperY / 200);
                    //System.Console.WriteLine("taperTopFactorY: " + extr.taperTopFactorY.ToString());
                }
                else
                {
                    extr.taperBotFactorY = 1.0f - ((100 - (float)taperY) / 100);
                    //System.Console.WriteLine("taperBotFactorY: " + extr.taperBotFactorY.ToString());
                }
            }

            if (pathShearX != 0)
            {
                if (pathShearX > 50)
                {
                    // Complimentary byte.  Negative values wrap around the byte.  Positive values go up to 50
                    extr.pushX = (((float)(256 - pathShearX) / 100) * -1f);
                    // m_log.Warn("pushX: " + extr.pushX);
                }
                else
                {
                    extr.pushX = (float)pathShearX / 100;
                    // m_log.Warn("pushX: " + extr.pushX);
                }
            }

            if (pathShearY != 0)
            {
                if (pathShearY > 50)
                {
                    // Complimentary byte.  Negative values wrap around the byte.  Positive values go up to 50
                    extr.pushY = (((float)(256 - pathShearY) / 100) * -1f);
                    //m_log.Warn("pushY: " + extr.pushY);
                }
                else
                {
                    extr.pushY = (float)pathShearY / 100;
                    //m_log.Warn("pushY: " + extr.pushY);
                }
            }

            Mesh result = extr.Extrude(m);
            result.DumpRaw(baseDir, primName, "Z extruded");
            return result;
        }
        private static Mesh CreateSphereMesh(String primName, PrimitiveBaseShape primShape, PhysicsVector size)
        {
            // Builds an icosahedral geodesic sphere
            // based on an article by Paul Bourke
            // http://local.wasp.uwa.edu.au/~pbourke/
            // articles:
            // http://local.wasp.uwa.edu.au/~pbourke/geometry/polygonmesh/
            // and
            // http://local.wasp.uwa.edu.au/~pbourke/geometry/polyhedra/index.html

            // Still have more to do here.

            UInt16 hollowFactor = primShape.ProfileHollow;
            UInt16 profileBegin = primShape.ProfileBegin;
            UInt16 profileEnd = primShape.ProfileEnd;
            UInt16 taperX = primShape.PathScaleX;
            UInt16 taperY = primShape.PathScaleY;
            UInt16 pathShearX = primShape.PathShearX;
            UInt16 pathShearY = primShape.PathShearY;
            Mesh m = new Mesh();

            float LOD = 0.2f;
            float diameter = 0.5f;// Our object will result in -0.5 to 0.5
            float sq5 = (float) Math.Sqrt(5.0);
            float phi = (1 + sq5) * 0.5f;
            float rat = (float) Math.Sqrt(10f + (2f * sq5)) / (4f * phi);
            float a = (diameter / rat) * 0.5f;
            float b = (diameter / rat) / (2.0f * phi);


            // 12 Icosahedron vertexes
            Vertex v1 = new Vertex(0f, b, -a);
            Vertex v2 = new Vertex(b, a, 0f);
            Vertex v3 = new Vertex(-b, a, 0f);
            Vertex v4 = new Vertex(0f, b, a);
            Vertex v5 = new Vertex(0f, -b, a);
            Vertex v6 = new Vertex(-a, 0f, b);
            Vertex v7 = new Vertex(0f, -b, -a);
            Vertex v8 = new Vertex(a, 0f, -b);
            Vertex v9 = new Vertex(a, 0f, b);
            Vertex v10 = new Vertex(-a, 0f, -b);
            Vertex v11 = new Vertex(b, -a, 0);
            Vertex v12 = new Vertex(-b, -a, 0);



            // Base Faces of the Icosahedron (20)
            SphereLODTriangle(v1, v2, v3, diameter, LOD, m); 
            SphereLODTriangle(v4, v3, v2, diameter, LOD, m);
            SphereLODTriangle(v4, v5, v6, diameter, LOD, m);
            SphereLODTriangle(v4, v9, v5, diameter, LOD, m);
            SphereLODTriangle(v1, v7, v8, diameter, LOD, m);
            SphereLODTriangle(v1, v10, v7, diameter, LOD, m);
            SphereLODTriangle(v5, v11, v12, diameter, LOD, m);
            SphereLODTriangle(v7, v12, v11, diameter, LOD, m);
            SphereLODTriangle(v3, v6, v10, diameter, LOD, m);
            SphereLODTriangle(v12, v10, v6, diameter, LOD, m);
            SphereLODTriangle(v2, v8, v9, diameter, LOD, m);
            SphereLODTriangle(v11, v9, v8, diameter, LOD, m);
            SphereLODTriangle(v4, v6, v3, diameter, LOD, m);
            SphereLODTriangle(v4, v2, v9, diameter, LOD, m);
            SphereLODTriangle(v1, v3, v10, diameter, LOD, m);
            SphereLODTriangle(v1, v8, v2, diameter, LOD, m);
            SphereLODTriangle(v7, v10, v12, diameter, LOD, m);
            SphereLODTriangle(v7, v11, v8, diameter, LOD, m);
            SphereLODTriangle(v5, v12, v6, diameter, LOD, m);
            SphereLODTriangle(v5, v9, v11, diameter, LOD, m);

            // Scale the mesh based on our prim scale
            foreach (Vertex v in m.vertices)
            {
                v.X *= size.X;
                v.Y *= size.Y;
                v.Z *= size.Z;
            }

            // This was built with the normals pointing inside.. 
            // therefore we have to invert the normals
            foreach (Triangle t in m.triangles)
            {
                t.invertNormal();
            }
            // Dump the faces for visualization in blender.
            m.DumpRaw(baseDir, primName, "Icosahedron");

            return m;
        }

        public static void CalcNormals(Mesh mesh)
        {
            int iTriangles = mesh.triangles.Count;

            mesh.normals = new float[iTriangles*3];

            int i = 0;
            foreach (Triangle t in mesh.triangles)
            {
                float ux, uy, uz;
                float vx, vy, vz;
                float wx, wy, wz;

                ux = t.v1.X;
                uy = t.v1.Y;
                uz = t.v1.Z;

                vx = t.v2.X;
                vy = t.v2.Y;
                vz = t.v2.Z;

                wx = t.v3.X;
                wy = t.v3.Y;
                wz = t.v3.Z;


                // Vectors for edges
                float e1x, e1y, e1z;
                float e2x, e2y, e2z;

                e1x = ux - vx;
                e1y = uy - vy;
                e1z = uz - vz;

                e2x = ux - wx;
                e2y = uy - wy;
                e2z = uz - wz;


                // Cross product for normal
                float nx, ny, nz;
                nx = e1y*e2z - e1z*e2y;
                ny = e1z*e2x - e1x*e2z;
                nz = e1x*e2y - e1y*e2x;

                // Length
                float l = (float) Math.Sqrt(nx*nx + ny*ny + nz*nz);

                // Normalized "normal"
                nx /= l;
                ny /= l;
                nz /= l;

                mesh.normals[i] = nx;
                mesh.normals[i + 1] = ny;
                mesh.normals[i + 2] = nz;

                i += 3;
            }
        }

        public static Vertex midUnitRadialPoint(Vertex a, Vertex b, float radius)
        {
            Vertex midpoint = new Vertex(a + b) * 0.5f;
            return  (midpoint.normalize() * radius);
        }

        public static void SphereLODTriangle(Vertex a, Vertex b, Vertex c, float diameter, float LOD, Mesh m)
        {
            Vertex aa = a - b;
            Vertex ba = b - c;
            Vertex da = c - a;

            if (((aa.length() < LOD) && (ba.length() < LOD) && (da.length() < LOD)))
            {
                // We don't want duplicate verticies.  Duplicates cause the scale algorithm to produce a spikeball
                // spikes are novel, but we want ellipsoids.

                if (!m.vertices.Contains(a))
                    m.Add(a);
                if (!m.vertices.Contains(b))
                    m.Add(b);
                if (!m.vertices.Contains(c))
                    m.Add(c);

                // Add the triangle to the mesh
                Triangle t = new Triangle(a, b, c);
                m.Add(t);
            }
            else
            {
                Vertex ab = midUnitRadialPoint(a, b, diameter);
                Vertex bc = midUnitRadialPoint(b, c, diameter);
                Vertex ca = midUnitRadialPoint(c, a, diameter);

                // Recursive!  Splits the triangle up into 4 smaller triangles
                SphereLODTriangle(a, ab, ca, diameter, LOD, m);
                SphereLODTriangle(ab, b, bc, diameter, LOD, m);
                SphereLODTriangle(ca, bc, c, diameter, LOD, m);
                SphereLODTriangle(ab, bc, ca, diameter, LOD, m);

            }
        }

        public IMesh CreateMesh(String primName, PrimitiveBaseShape primShape, PhysicsVector size)
        {
            Mesh mesh = null;

            switch (primShape.ProfileShape)
            {
                case ProfileShape.Square:
                    mesh = CreateBoxMesh(primName, primShape, size);
                    CalcNormals(mesh);
                    break;
                case ProfileShape.Circle:
                    if (primShape.PathCurve == (byte)Extrusion.Straight)
                    {
                        mesh = CreateCyllinderMesh(primName, primShape, size);
                        CalcNormals(mesh);
                    }
                    break;
                case ProfileShape.HalfCircle:
                    if (primShape.PathCurve == (byte)Extrusion.Curve1)
                    {
                        mesh = CreateSphereMesh(primName, primShape, size);
                        CalcNormals(mesh);
                    }
                    break;

                case ProfileShape.EquilateralTriangle:
                    mesh = CreatePrismMesh(primName, primShape, size);
                    CalcNormals(mesh);
                    break;

                default:
                    mesh = CreateBoxMesh(primName, primShape, size);
                    CalcNormals(mesh);
                    //Set default mesh to cube otherwise it'll return 
                    // null and crash on the 'setMesh' method in the physics plugins.
                    //mesh = null;
                    break;
            }

            return mesh;
        }
    }
}