C# Otri.Sym方法代码示例

        /// <summary>
        /// Create a new subsegment and inserts it between two triangles. Its 
        /// vertices are properly initialized.
        /// </summary>
        /// <param name="tri">The new subsegment is inserted at the edge 
        /// described by this handle.</param>
        /// <param name="subsegmark">The marker 'subsegmark' is applied to the 
        /// subsegment and, if appropriate, its vertices.</param>
        internal void InsertSubseg(ref Otri tri, int subsegmark)
        {
            Otri oppotri = default(Otri);
            Osub newsubseg = default(Osub);
            Vertex triorg, tridest;

            triorg = tri.Org();
            tridest = tri.Dest();
            // Mark vertices if possible.
            if (triorg.mark == 0)
            {
                triorg.mark = subsegmark;
            }
            if (tridest.mark == 0)
            {
                tridest.mark = subsegmark;
            }
            // Check if there's already a subsegment here.
            tri.SegPivot(ref newsubseg);
            if (newsubseg.seg == dummysub)
            {
                // Make new subsegment and initialize its vertices.
                MakeSegment(ref newsubseg);
                newsubseg.SetOrg(tridest);
                newsubseg.SetDest(triorg);
                newsubseg.SetSegOrg(tridest);
                newsubseg.SetSegDest(triorg);
                // Bond new subsegment to the two triangles it is sandwiched between.
                // Note that the facing triangle 'oppotri' might be equal to 'dummytri'
                // (outer space), but the new subsegment is bonded to it all the same.
                tri.SegBond(ref newsubseg);
                tri.Sym(ref oppotri);
                newsubseg.SymSelf();
                oppotri.SegBond(ref newsubseg);
                newsubseg.seg.boundary = subsegmark;
            }
            else
            {
                if (newsubseg.seg.boundary == 0)
                {
                    newsubseg.seg.boundary = subsegmark;
                }
            }
        }

        /// <summary>
        /// Transform two triangles to two different triangles by flipping an edge 
        /// counterclockwise within a quadrilateral.
        /// </summary>
        /// <param name="flipedge">Handle to the edge that will be flipped.</param>
        /// <remarks>Imagine the original triangles, abc and bad, oriented so that the
        /// shared edge ab lies in a horizontal plane, with the vertex b on the left
        /// and the vertex a on the right. The vertex c lies below the edge, and
        /// the vertex d lies above the edge. The 'flipedge' handle holds the edge
        /// ab of triangle abc, and is directed left, from vertex a to vertex b.
        ///
        /// The triangles abc and bad are deleted and replaced by the triangles cdb
        /// and dca.  The triangles that represent abc and bad are NOT deallocated;
        /// they are reused for dca and cdb, respectively.  Hence, any handles that
        /// may have held the original triangles are still valid, although not
        /// directed as they were before.
        ///
        /// Upon completion of this routine, the 'flipedge' handle holds the edge
        /// dc of triangle dca, and is directed down, from vertex d to vertex c.
        /// (Hence, the two triangles have rotated counterclockwise.)
        ///
        /// WARNING:  This transformation is geometrically valid only if the
        /// quadrilateral adbc is convex.  Furthermore, this transformation is
        /// valid only if there is not a subsegment between the triangles abc and
        /// bad.  This routine does not check either of these preconditions, and
        /// it is the responsibility of the calling routine to ensure that they are
        /// met.  If they are not, the streets shall be filled with wailing and
        /// gnashing of teeth.
        /// 
        /// Terminology
        ///
        /// A "local transformation" replaces a small set of triangles with another
        /// set of triangles.  This may or may not involve inserting or deleting a
        /// vertex.
        ///
        /// The term "casing" is used to describe the set of triangles that are
        /// attached to the triangles being transformed, but are not transformed
        /// themselves.  Think of the casing as a fixed hollow structure inside
        /// which all the action happens.  A "casing" is only defined relative to
        /// a single transformation; each occurrence of a transformation will
        /// involve a different casing.
        /// </remarks>
        internal void Flip(ref Otri flipedge)
        {
            Otri botleft = default(Otri), botright = default(Otri);
            Otri topleft = default(Otri), topright = default(Otri);
            Otri top = default(Otri);
            Otri botlcasing = default(Otri), botrcasing = default(Otri);
            Otri toplcasing = default(Otri), toprcasing = default(Otri);
            Osub botlsubseg = default(Osub), botrsubseg = default(Osub);
            Osub toplsubseg = default(Osub), toprsubseg = default(Osub);
            Vertex leftvertex, rightvertex, botvertex;
            Vertex farvertex;

            // Identify the vertices of the quadrilateral.
            rightvertex = flipedge.Org();
            leftvertex = flipedge.Dest();
            botvertex = flipedge.Apex();
            flipedge.Sym(ref top);

            // SELF CHECK

            //if (top.triangle == dummytri)
            //{
            //    logger.Error("Attempt to flip on boundary.", "Mesh.Flip()");
            //    flipedge.LnextSelf();
            //    return;
            //}

            //if (checksegments)
            //{
            //    flipedge.SegPivot(ref toplsubseg);
            //    if (toplsubseg.ss != dummysub)
            //    {
            //        logger.Error("Attempt to flip a segment.", "Mesh.Flip()");
            //        flipedge.LnextSelf();
            //        return;
            //    }
            //}

            farvertex = top.Apex();

            // Identify the casing of the quadrilateral.
            top.Lprev(ref topleft);
            topleft.Sym(ref toplcasing);
            top.Lnext(ref topright);
            topright.Sym(ref toprcasing);
            flipedge.Lnext(ref botleft);
            botleft.Sym(ref botlcasing);
            flipedge.Lprev(ref botright);
            botright.Sym(ref botrcasing);
            // Rotate the quadrilateral one-quarter turn counterclockwise.
            topleft.Bond(ref botlcasing);
            botleft.Bond(ref botrcasing);
            botright.Bond(ref toprcasing);
            topright.Bond(ref toplcasing);

            if (checksegments)
            {
                // Check for subsegments and rebond them to the quadrilateral.
//.........这里部分代码省略.........

        /// <summary>
        /// Gets a neighbours vertex.
        /// </summary>
        /// <param name="badotri"></param>
        /// <param name="first_x"></param>
        /// <param name="first_y"></param>
        /// <param name="second_x"></param>
        /// <param name="second_y"></param>
        /// <param name="thirdpoint">Neighbor's third vertex incident to given edge.</param>
        /// <param name="neighotri">Pointer for the neighbor triangle.</param>
        /// <returns>Returns true if vertex was found.</returns>
        private bool GetNeighborsVertex(Otri badotri,
                        double first_x, double first_y,
                        double second_x, double second_y,
                        ref double[] thirdpoint, ref Otri neighotri)
        {

            Otri neighbor = default(Otri); // keeps the neighbor triangles
            bool notFound = false;	// boolean variable if we can find that neighbor or not

            // for keeping the vertices of the neighbor triangle
            Vertex neighborvertex_1 = null;
            Vertex neighborvertex_2 = null;
            Vertex neighborvertex_3 = null;

            // used for finding neighbor triangle
            int firstVertexMatched = 0, secondVertexMatched = 0;	// to find the correct neighbor
            //triangle ptr;             // Temporary variable used by sym()
            //int i;	// index variable	
            // find neighbors
            // Check each of the triangle's three neighbors to find the correct one
            for (badotri.orient = 0; badotri.orient < 3; badotri.orient++)
            {
                // Find the neighbor.
                badotri.Sym(ref neighbor);
                // check if it is the one we are looking for by checking the corners			
                // first check if the neighbor is nonexistent, since it can be on the border
                if ((neighbor.triangle != Mesh.dummytri))
                {
                    // then check if two wanted corners are also in this triangle
                    // take the vertices of the candidate neighbor		
                    neighborvertex_1 = neighbor.Org();
                    neighborvertex_2 = neighbor.Dest();
                    neighborvertex_3 = neighbor.Apex();

                    // check if it is really a triangle
                    if ((neighborvertex_1.x == neighborvertex_2.x && neighborvertex_1.y == neighborvertex_2.y)
                     || (neighborvertex_2.x == neighborvertex_3.x && neighborvertex_2.y == neighborvertex_3.y)
                     || (neighborvertex_1.x == neighborvertex_3.x && neighborvertex_1.y == neighborvertex_3.y))
                    {
                        //printf("Two vertices are the same!!!!!!!\n");
                    }
                    else
                    {
                        // begin searching for the correct neighbor triangle
                        firstVertexMatched = 0;
                        if ((Math.Abs(first_x - neighborvertex_1.x) < EPS) &&
                             (Math.Abs(first_y - neighborvertex_1.y) < EPS))
                        {
                            firstVertexMatched = 11; // neighbor's 1st vertex is matched to first vertex

                        }
                        else if ((Math.Abs(first_x - neighborvertex_2.x) < EPS) &&
                               (Math.Abs(first_y - neighborvertex_2.y) < EPS))
                        {
                            firstVertexMatched = 12; // neighbor's 2nd vertex is matched to first vertex

                        }
                        else if ((Math.Abs(first_x - neighborvertex_3.x) < EPS) &&
                                   (Math.Abs(first_y - neighborvertex_3.y) < EPS))
                        {
                            firstVertexMatched = 13; // neighbor's 3rd vertex is matched to first vertex

                        }/*else{	
                     // none of them matched
                } // end of first vertex matching */

                        secondVertexMatched = 0;
                        if ((Math.Abs(second_x - neighborvertex_1.x) < EPS) &&
                            (Math.Abs(second_y - neighborvertex_1.y) < EPS))
                        {
                            secondVertexMatched = 21; // neighbor's 1st vertex is matched to second vertex
                        }
                        else if ((Math.Abs(second_x - neighborvertex_2.x) < EPS) &&
                           (Math.Abs(second_y - neighborvertex_2.y) < EPS))
                        {
                            secondVertexMatched = 22; // neighbor's 2nd vertex is matched to second vertex
                        }
                        else if ((Math.Abs(second_x - neighborvertex_3.x) < EPS) &&
                               (Math.Abs(second_y - neighborvertex_3.y) < EPS))
                        {
                            secondVertexMatched = 23; // neighbor's 3rd vertex is matched to second vertex
                        }/*else{	
                    // none of them matched
                } // end of second vertex matching*/

                    }

                }// if neighbor exists or not

//.........这里部分代码省略.........

        /// <summary>
        /// Transform two triangles to two different triangles by flipping an edge 
        /// clockwise within a quadrilateral. Reverses the flip() operation so that 
        /// the data structures representing the triangles are back where they were 
        /// before the flip().
        /// </summary>
        /// <param name="flipedge"></param>
        /// <remarks>
        /// See above Flip() remarks for more information.
        ///
        /// Upon completion of this routine, the 'flipedge' handle holds the edge
        /// cd of triangle cdb, and is directed up, from vertex c to vertex d.
        /// (Hence, the two triangles have rotated clockwise.)
        /// </remarks>
        internal void Unflip(ref Otri flipedge)
        {
            Otri botleft = default(Otri), botright = default(Otri);
            Otri topleft = default(Otri), topright = default(Otri);
            Otri top = default(Otri);
            Otri botlcasing = default(Otri), botrcasing = default(Otri);
            Otri toplcasing = default(Otri), toprcasing = default(Otri);
            Osub botlsubseg = default(Osub), botrsubseg = default(Osub);
            Osub toplsubseg = default(Osub), toprsubseg = default(Osub);
            Vertex leftvertex, rightvertex, botvertex;
            Vertex farvertex;

            // Identify the vertices of the quadrilateral.
            rightvertex = flipedge.Org();
            leftvertex = flipedge.Dest();
            botvertex = flipedge.Apex();
            flipedge.Sym(ref top);

            farvertex = top.Apex();

            // Identify the casing of the quadrilateral.
            top.Lprev(ref topleft);
            topleft.Sym(ref toplcasing);
            top.Lnext(ref topright);
            topright.Sym(ref toprcasing);
            flipedge.Lnext(ref botleft);
            botleft.Sym(ref botlcasing);
            flipedge.Lprev(ref botright);
            botright.Sym(ref botrcasing);
            // Rotate the quadrilateral one-quarter turn clockwise.
            topleft.Bond(ref toprcasing);
            botleft.Bond(ref toplcasing);
            botright.Bond(ref botlcasing);
            topright.Bond(ref botrcasing);

            if (checksegments)
            {
                // Check for subsegments and rebond them to the quadrilateral.
                topleft.SegPivot(ref toplsubseg);
                botleft.SegPivot(ref botlsubseg);
                botright.SegPivot(ref botrsubseg);
                topright.SegPivot(ref toprsubseg);
                if (toplsubseg.seg == Mesh.dummysub)
                {
                    botleft.SegDissolve();
                }
                else
                {
                    botleft.SegBond(ref toplsubseg);
                }
                if (botlsubseg.seg == Mesh.dummysub)
                {
                    botright.SegDissolve();
                }
                else
                {
                    botright.SegBond(ref botlsubseg);
                }
                if (botrsubseg.seg == Mesh.dummysub)
                {
                    topright.SegDissolve();
                }
                else
                {
                    topright.SegBond(ref botrsubseg);
                }
                if (toprsubseg.seg == Mesh.dummysub)
                {
                    topleft.SegDissolve();
                }
                else
                {
                    topleft.SegBond(ref toprsubseg);
                }
            }

            // New vertex assignments for the rotated quadrilateral.
            flipedge.SetOrg(botvertex);
            flipedge.SetDest(farvertex);
            flipedge.SetApex(leftvertex);
            top.SetOrg(farvertex);
            top.SetDest(botvertex);
            top.SetApex(rightvertex);
        }

        /// <summary>
        /// Merge two adjacent Delaunay triangulations into a single Delaunay triangulation.
        /// </summary>
        /// <param name="farleft">Bounding triangles of the left triangulation.</param>
        /// <param name="innerleft">Bounding triangles of the left triangulation.</param>
        /// <param name="innerright">Bounding triangles of the right triangulation.</param>
        /// <param name="farright">Bounding triangles of the right triangulation.</param>
        /// <param name="axis"></param>
        /// <remarks>
        /// This is similar to the algorithm given by Guibas and Stolfi, but uses
        /// a triangle-based, rather than edge-based, data structure.
        ///
        /// The algorithm walks up the gap between the two triangulations, knitting
        /// them together.  As they are merged, some of their bounding triangles
        /// are converted into real triangles of the triangulation.  The procedure
        /// pulls each hull's bounding triangles apart, then knits them together
        /// like the teeth of two gears.  The Delaunay property determines, at each
        /// step, whether the next "tooth" is a bounding triangle of the left hull
        /// or the right.  When a bounding triangle becomes real, its apex is
        /// changed from NULL to a real vertex.
        ///
        /// Only two new triangles need to be allocated.  These become new bounding
        /// triangles at the top and bottom of the seam.  They are used to connect
        /// the remaining bounding triangles (those that have not been converted
        /// into real triangles) into a single fan.
        ///
        /// On entry, 'farleft' and 'innerleft' are bounding triangles of the left
        /// triangulation.  The origin of 'farleft' is the leftmost vertex, and
        /// the destination of 'innerleft' is the rightmost vertex of the
        /// triangulation.  Similarly, 'innerright' and 'farright' are bounding
        /// triangles of the right triangulation.  The origin of 'innerright' and
        /// destination of 'farright' are the leftmost and rightmost vertices.
        ///
        /// On completion, the origin of 'farleft' is the leftmost vertex of the
        /// merged triangulation, and the destination of 'farright' is the rightmost
        /// vertex.
        /// </remarks>
        void MergeHulls(ref Otri farleft, ref Otri innerleft, ref Otri innerright,
                        ref Otri farright, int axis)
        {
            Otri leftcand = default(Otri), rightcand = default(Otri);
            Otri nextedge = default(Otri);
            Otri sidecasing = default(Otri), topcasing = default(Otri), outercasing = default(Otri);
            Otri checkedge = default(Otri);
            Otri baseedge = default(Otri);
            Vertex innerleftdest;
            Vertex innerrightorg;
            Vertex innerleftapex, innerrightapex;
            Vertex farleftpt, farrightpt;
            Vertex farleftapex, farrightapex;
            Vertex lowerleft, lowerright;
            Vertex upperleft, upperright;
            Vertex nextapex;
            Vertex checkvertex;
            bool changemade;
            bool badedge;
            bool leftfinished, rightfinished;

            innerleftdest = innerleft.Dest();
            innerleftapex = innerleft.Apex();
            innerrightorg = innerright.Org();
            innerrightapex = innerright.Apex();
            // Special treatment for horizontal cuts.
            if (useDwyer && (axis == 1))
            {
                farleftpt = farleft.Org();
                farleftapex = farleft.Apex();
                farrightpt = farright.Dest();
                farrightapex = farright.Apex();
                // The pointers to the extremal vertices are shifted to point to the
                // topmost and bottommost vertex of each hull, rather than the
                // leftmost and rightmost vertices.
                while (farleftapex.y < farleftpt.y)
                {
                    farleft.LnextSelf();
                    farleft.SymSelf();
                    farleftpt = farleftapex;
                    farleftapex = farleft.Apex();
                }
                innerleft.Sym(ref checkedge);
                checkvertex = checkedge.Apex();
                while (checkvertex.y > innerleftdest.y)
                {
                    checkedge.Lnext(ref innerleft);
                    innerleftapex = innerleftdest;
                    innerleftdest = checkvertex;
                    innerleft.Sym(ref checkedge);
                    checkvertex = checkedge.Apex();
                }
                while (innerrightapex.y < innerrightorg.y)
                {
                    innerright.LnextSelf();
                    innerright.SymSelf();
                    innerrightorg = innerrightapex;
                    innerrightapex = innerright.Apex();
                }
                farright.Sym(ref checkedge);
                checkvertex = checkedge.Apex();
                while (checkvertex.y > farrightpt.y)
                {
//.........这里部分代码省略.........