C# Otri.OnextSelf方法代码示例

//.........这里部分代码省略.........
        /// </remarks>
        private void SegmentIntersection(ref Otri splittri, ref Osub splitsubseg, Vertex endpoint2)
        {
            Osub opposubseg = default(Osub);
            Vertex endpoint1;
            Vertex torg, tdest;
            Vertex leftvertex, rightvertex;
            Vertex newvertex;
            InsertVertexResult success;

            double ex, ey;
            double tx, ty;
            double etx, ety;
            double split, denom;

            // Find the other three segment endpoints.
            endpoint1 = splittri.Apex();
            torg = splittri.Org();
            tdest = splittri.Dest();
            // Segment intersection formulae; see the Antonio reference.
            tx = tdest.x - torg.x;
            ty = tdest.y - torg.y;
            ex = endpoint2.x - endpoint1.x;
            ey = endpoint2.y - endpoint1.y;
            etx = torg.x - endpoint2.x;
            ety = torg.y - endpoint2.y;
            denom = ty * ex - tx * ey;
            if (denom == 0.0)
            {
                logger.Error("Attempt to find intersection of parallel segments.",
                    "Mesh.SegmentIntersection()");
                throw new Exception("Attempt to find intersection of parallel segments.");
            }
            split = (ey * etx - ex * ety) / denom;

            // Create the new vertex.
            newvertex = new Vertex(
                torg.x + split * (tdest.x - torg.x),
                torg.y + split * (tdest.y - torg.y),
                splitsubseg.seg.boundary,
                this.nextras);

            newvertex.hash = this.hash_vtx++;
            newvertex.id = newvertex.hash;

            // Interpolate its attributes.
            for (int i = 0; i < nextras; i++)
            {
                newvertex.attributes[i] = torg.attributes[i] + split * (tdest.attributes[i] - torg.attributes[i]);
            }

            vertices.Add(newvertex.hash, newvertex);

            // Insert the intersection vertex.  This should always succeed.
            success = InsertVertex(newvertex, ref splittri, ref splitsubseg, false, false);
            if (success != InsertVertexResult.Successful)
            {
                logger.Error("Failure to split a segment.", "Mesh.SegmentIntersection()");
                throw new Exception("Failure to split a segment.");
            }
            // Record a triangle whose origin is the new vertex.
            newvertex.tri = splittri;
            if (steinerleft > 0)
            {
                steinerleft--;
            }

            // Divide the segment into two, and correct the segment endpoints.
            splitsubseg.SymSelf();
            splitsubseg.Pivot(ref opposubseg);
            splitsubseg.Dissolve();
            opposubseg.Dissolve();
            do
            {
                splitsubseg.SetSegOrg(newvertex);
                splitsubseg.NextSelf();
            } while (splitsubseg.seg != Mesh.dummysub);
            do
            {
                opposubseg.SetSegOrg(newvertex);
                opposubseg.NextSelf();
            } while (opposubseg.seg != Mesh.dummysub);

            // Inserting the vertex may have caused edge flips.  We wish to rediscover
            // the edge connecting endpoint1 to the new intersection vertex.
            FindDirection(ref splittri, endpoint1);

            rightvertex = splittri.Dest();
            leftvertex = splittri.Apex();
            if ((leftvertex.x == endpoint1.x) && (leftvertex.y == endpoint1.y))
            {
                splittri.OnextSelf();
            }
            else if ((rightvertex.x != endpoint1.x) || (rightvertex.y != endpoint1.y))
            {
                logger.Error("Topological inconsistency after splitting a segment.", "Mesh.SegmentIntersection()");
                throw new Exception("Topological inconsistency after splitting a segment.");
            }
            // 'splittri' should have destination endpoint1.
        }

        SplayNode FrontLocate(SplayNode splayroot, Otri bottommost, Vertex searchvertex,
                              ref Otri searchtri, ref bool farright)
        {
            bool farrightflag;

            bottommost.Copy(ref searchtri);
            splayroot = Splay(splayroot, searchvertex, ref searchtri);

            farrightflag = false;
            while (!farrightflag && RightOfHyperbola(ref searchtri, searchvertex))
            {
                searchtri.OnextSelf();
                farrightflag = searchtri.Equal(bottommost);
            }
            farright = farrightflag;
            return splayroot;
        }

        /// <summary>
        /// Find the first triangle on the path from one point to another.
        /// </summary>
        /// <param name="searchtri"></param>
        /// <param name="searchpoint"></param>
        /// <returns>
        /// The return value notes whether the destination or apex of the found
        /// triangle is collinear with the two points in question.</returns>
        /// <remarks>
        /// Finds the triangle that intersects a line segment drawn from the
        /// origin of 'searchtri' to the point 'searchpoint', and returns the result
        /// in 'searchtri'. The origin of 'searchtri' does not change, even though
        /// the triangle returned may differ from the one passed in. This routine
        /// is used to find the direction to move in to get from one point to
        /// another.
        /// </remarks>
        private FindDirectionResult FindDirection(ref Otri searchtri, Vertex searchpoint)
        {
            Otri checktri = default(Otri);
            Vertex startvertex;
            Vertex leftvertex, rightvertex;
            double leftccw, rightccw;
            bool leftflag, rightflag;

            startvertex = searchtri.Org();
            rightvertex = searchtri.Dest();
            leftvertex = searchtri.Apex();
            // Is 'searchpoint' to the left?
            leftccw = Primitives.CounterClockwise(searchpoint, startvertex, leftvertex);
            leftflag = leftccw > 0.0;
            // Is 'searchpoint' to the right?
            rightccw = Primitives.CounterClockwise(startvertex, searchpoint, rightvertex);
            rightflag = rightccw > 0.0;
            if (leftflag && rightflag)
            {
                // 'searchtri' faces directly away from 'searchpoint'. We could go left
                // or right. Ask whether it's a triangle or a boundary on the left.
                searchtri.Onext(ref checktri);
                if (checktri.triangle == Mesh.dummytri)
                {
                    leftflag = false;
                }
                else
                {
                    rightflag = false;
                }
            }
            while (leftflag)
            {
                // Turn left until satisfied.
                searchtri.OnextSelf();
                if (searchtri.triangle == Mesh.dummytri)
                {
                    logger.Error("Unable to find a triangle on path.", "Mesh.FindDirection().1");
                    throw new Exception("Unable to find a triangle on path.");
                }
                leftvertex = searchtri.Apex();
                rightccw = leftccw;
                leftccw = Primitives.CounterClockwise(searchpoint, startvertex, leftvertex);
                leftflag = leftccw > 0.0;
            }
            while (rightflag)
            {
                // Turn right until satisfied.
                searchtri.OprevSelf();
                if (searchtri.triangle == Mesh.dummytri)
                {
                    logger.Error("Unable to find a triangle on path.", "Mesh.FindDirection().2");
                    throw new Exception("Unable to find a triangle on path.");
                }
                rightvertex = searchtri.Dest();
                leftccw = rightccw;
                rightccw = Primitives.CounterClockwise(startvertex, searchpoint, rightvertex);
                rightflag = rightccw > 0.0;
            }
            if (leftccw == 0.0)
            {
                return FindDirectionResult.Leftcollinear;
            }
            else if (rightccw == 0.0)
            {
                return FindDirectionResult.Rightcollinear;
            }
            else
            {
                return FindDirectionResult.Within;
            }
        }