public QuadPatch( Terrain terrain, QuadPatchVertices vertices, Color patchColour, float x, float z, float w, float d )
        {
            m_Rs.FaceRenderMode = PolygonRenderMode.Lines;
            m_Rs.Colour = patchColour;

            m_Terrain = terrain;
            m_Vertices = vertices;
            m_X = x;
            m_Z = z;
            m_Width = w;
            m_Depth = d;

            m_IncreaseDetailDistance = float.MaxValue;
            m_VbIndex = vertices.Allocate( );

            m_BuildVertices = true;
            m_BuildIndices = true;
        }