opensim/trunk/OpenSim/Region/Physics/Meshing/Extruder.cs

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using OpenSim.Region.Physics.Manager;

namespace OpenSim.Region.Physics.Meshing
{
    internal class Extruder
    {
        public float startParameter;
        public float stopParameter;
        public PhysicsVector size;

        public float taperTopFactorX = 1f;
        public float taperTopFactorY = 1f;
        public float taperBotFactorX = 1f;
        public float taperBotFactorY = 1f;
        public float pushX = 0f;
        public float pushY = 0f;

        public Mesh Extrude(Mesh m)
        {
            // Currently only works for iSteps=1;
            Mesh result = new Mesh();

            Mesh workingPlus = m.Clone();
            Mesh workingMinus = m.Clone();

            foreach (Vertex v in workingPlus.vertices)
            {
                if (v == null)
                    continue;

                // This is the top
                // Set the Z + .5 to match the rest of the scale of the mesh
                // Scale it by Size, and Taper the scaling
                v.Z = +.5f;
                v.X *= (size.X * taperTopFactorX);
                v.Y *= (size.Y * taperTopFactorY);
                v.Z *= size.Z;
                
                //Push the top of the object over by the Top Shear amount
                v.X += pushX * size.X;
                v.Y += pushY * size.X;
            }

            foreach (Vertex v in workingMinus.vertices)
            {
                if (v == null)
                    continue;

                // This is the bottom
                v.Z = -.5f;
                v.X *= (size.X * taperBotFactorX);
                v.Y *= (size.Y * taperBotFactorY);
                v.Z *= size.Z;
            }

            foreach (Triangle t in workingMinus.triangles)
            {
                t.invertNormal();
            }

            result.Append(workingMinus);
            result.Append(workingPlus);

            int iLastNull = 0;
            for (int i = 0; i < workingPlus.vertices.Count; i++)
            {
                int iNext = (i + 1);

                if (workingPlus.vertices[i] == null) // Can't make a simplex here
                {
                    iLastNull = i + 1;
                    continue;
                }

                if (i == workingPlus.vertices.Count - 1) // End of list
                {
                    iNext = iLastNull;
                }

                if (workingPlus.vertices[iNext] == null) // Null means wrap to begin of last segment
                {
                    iNext = iLastNull;
                }

                Triangle tSide;
                tSide = new Triangle(workingPlus.vertices[i], workingMinus.vertices[i], workingPlus.vertices[iNext]);
                result.Add(tSide);

                tSide =
                    new Triangle(workingPlus.vertices[iNext], workingMinus.vertices[i], workingMinus.vertices[iNext]);
                result.Add(tSide);
            }

            return result;
        }
    }
}