ComputerGraphics/20210129/doc/zxq/NwGeoExporter/NwGeoExporter/Models/Mesh.cs

using Autodesk.Navisworks.Api.Interop.ComApi;
using Newtonsoft.Json;
using NwGeoExporter.NwEx;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace NwGeoExporter.Models
{
    public class Mesh
    {
        /// <summary>
        /// 顶点数组-序列化数据
        /// </summary>
        public double[] vertices { get => VerticeList.SelectMany(x => new List<double> { x.X.Feet2Mm(), x.Y.Feet2Mm(), x.Z.Feet2Mm() }).ToArray(); }

        /// <summary>
        /// 顶点索引-序列化数据
        /// </summary>
        public int[] indices { get => IndiceList.ToArray(); }

        /// <summary>
        /// 顶点法向-序列化数据
        /// </summary>
        public double[] normals { get => NormalList.SelectMany(x => new List<double> { x.X, x.Y, x.Z }).ToArray(); }

        /// <summary>
        /// 顶点集合
        /// </summary>
        [JsonIgnore]
        public List<PointM> VerticeList { get; set; }

        /// <summary>
        /// 顶点法线
        /// </summary>
        [JsonIgnore]
        public List<VectorM> NormalList { get; set; }

        /// <summary>
        /// 顶点索引
        /// </summary>
        [JsonIgnore]
        public List<int> IndiceList { get; set; }

        /// <summary>
        /// 材质索引
        /// </summary>
        public int material { get; set; }

        public Mesh(int materialIndex)
        {
            VerticeList = new List<PointM>();
            NormalList = new List<VectorM>();
            IndiceList = new List<int>();
            material = materialIndex;
        }

        public Mesh(IEnumerable<Triangle> triangles, int materialIndex) : this(materialIndex)
        {
            this.AddTriangles(triangles);

        }
        public Mesh(Triangle triangle, int materialIndex) : this(materialIndex)
        {
            this.AddTriangle(triangle);
        }

        public void AddTriangle(Triangle triangle)
        {
            for (int i = 0; i < triangle.Vertices.Length; i++)
            {
                bool isHandle = false;
                //相同的顶点位置的索引
                List<int> indexList = VerticeList.FindIndexs(x => x == triangle.Vertices[i]);
                //当前三角面片顶点法向
                VectorM currentVector = triangle.Normals[i];
                //最后一次合并的索引
                int lastMergeIndex = 0;
                while (indexList.Count != 0)
                {
                    //判断索引内是否需要合并的顶点
                    var index = indexList.FindIndex(x => NormalList[x].AngelTo(currentVector).ToAngle() - 90 > 0.1);
                    if (index == -1)
                    {
                        break;
                    }
                    else if (!isHandle)//第一次
                    {
                        NormalList[indexList[index]] = (currentVector + NormalList[indexList[index]]).Normalize();
                        currentVector = NormalList[indexList[index]];
                        lastMergeIndex = indexList[index];
                        indexList.RemoveAt(index);
                        isHandle = true;
                    }
                    else//原来顶点位置一致的与合并后的顶点进行比较
                    {
                        int removeIndex = Math.Max(lastMergeIndex, indexList[index]);
                        lastMergeIndex = Math.Min(lastMergeIndex, indexList[index]);

                        //重置索引
                        for (int k = 0; k < IndiceList.Count; k++)
                        {
                            if (IndiceList[k] > removeIndex)
                            {
                                IndiceList[k]--;
                            }
                            else if (IndiceList[k] == removeIndex)
                            {
                                IndiceList[k] = lastMergeIndex;
                            }
                        }

                        //删除不需要的顶点和法向
                        NormalList.RemoveAt(removeIndex);
                        VerticeList.RemoveAt(removeIndex);
                    }
                }
                if (!isHandle)
                {
                    //添加顶点以及顶点法向以及对应的索引
                    VerticeList.Add(triangle.Vertices[i]);
                    NormalList.Add(triangle.Normals[i]);
                    IndiceList.Add(VerticeList.Count - 1);
                }else
                {
                    IndiceList.Add(lastMergeIndex);
                }
            }
        }

        public void AddTriangles(IEnumerable<Triangle> triangles)
        {
            foreach (var triangle in triangles)
            {
                this.AddTriangle(triangle);
            }
        }

    }
}