Unity網格編程(一)

using System.Collections;
using System.Collections.Generic;
using UnityEngine;


//網格創建差不多分這幾步: 1,確認頂點 2,確認頂點順序 3,確認法線,uv...
public class MeshStudy : MonoBehaviour
{
    public float sideLength = 2;
    public float angleDegree = 100;
    private static readonly int ANGLE_DEGREE_PRECISION = 1000;
    private static readonly int SIDE_LENGTH_PRECISION = 1000;

    private MeshFilter _meshFilter;

    private TriangleMeshCreator creator = new TriangleMeshCreator();


    //在編輯器中執行
    [ExecuteInEditMode]
    private void Awake()
    {
        _meshFilter = GetComponent<MeshFilter>();

    }

    private void Update() {
        _meshFilter.mesh = creator.CreateMesh(sideLength,angleDegree);
    }

    //在沒選中的時候 畫出的網格設置為灰色
    void OnDrawGizmos() {
        Gizmos.color = Color.gray;
        DrawMesh();
    }

    void OnDrawGizmosSelected() {
        Gizmos.color = Color.green;
        DrawMesh();
    }

    void DrawMesh() {
        Mesh mesh = creator.CreateMesh(sideLength,angleDegree);
        int[] tris = mesh.triangles;
        //繪制三角形  網格信息是從本地坐標獲取的 若在正確的世界位置顯示需求轉換到世界坐標系
        Gizmos.DrawLine(Transform2World(mesh.vertices[0]), Transform2World(mesh.vertices[1]));
        Gizmos.DrawLine(Transform2World(mesh.vertices[1]), Transform2World(mesh.vertices[2]));
        Gizmos.DrawLine(Transform2World(mesh.vertices[2]), Transform2World(mesh.vertices[0]));
    }

    private Vector3 Transform2World(Vector3 src) {
        return transform.TransformPoint(src);
    }

    private class TriangleMeshCreator
    {
        private float _sideLength;
        private float _angleDegree;

        private Mesh _cacheMesh;
       

        public Mesh CreateMesh(float sideLength, float angleDegree)
        {
            if (checkDiff(sideLength, angleDegree)) {
                Mesh newMesh = Create(sideLength,angleDegree);
                if (newMesh != null) {
                    _cacheMesh = newMesh;
                    this._sideLength = sideLength;
                    this._angleDegree = angleDegree;
                }
            }
            return _cacheMesh;
        }
        //三角形邊長和弧長                        
        private Mesh Create(float sideLength, float angleDegree)
        {
            Mesh mesh = new Mesh();
            Vector3[] verticles = new Vector3[3];

            //圓的周長為2ΠR 所以弧長 = (n°/360)*2ΠR (簡化后: L = n°ΠR/180) 
            //從弧度轉化到角度
            float angle = Mathf.Deg2Rad * angleDegree;
            float halfAngle = angle / 2;

            float cosA = Mathf.Cos(halfAngle);
            float sinA = Mathf.Sin(halfAngle);

            //隨便畫一個三角形
            verticles[0] = Vector3.zero;
            verticles[1] = new Vector3(cosA * sideLength, 0, sinA * sideLength);
            verticles[2] = new Vector3(cosA * sideLength, 0, -sinA * sideLength);


            //輸入網格的頂點和頂點順序
            int[] triangles = new int[3] { 0, 1, 2 };
            mesh.vertices = verticles;
            mesh.triangles = triangles;

            //設置uv頂點信息
            Vector2[] uvs = new Vector2[verticles.Length];

            //設置如下貼圖中就避開了數字 說明uv的對角線坐標分別對應 (0,0) 和 (1,1)
            uvs[0] = new Vector2(0, 0.5f);
            uvs[1] = new Vector2(0.5f, 0.5f);
            uvs[2] = new Vector2(0.6f, 0);
            //uvs[0] = new Vector2(0, 0.5f);
            //uvs[1] = Vector2.one;
            //uvs[2] = Vector2.right;



            mesh.uv = uvs;

            return mesh;


        }
        //檢測是否滿足構成條件
        private bool checkDiff(float sideLength, float angleDegree)
        {
            return (int)((sideLength - this._sideLength) * SIDE_LENGTH_PRECISION) != 0 ||
                (int)((angleDegree - this._angleDegree) * ANGLE_DEGREE_PRECISION) != 0;
        }
    }



}

 

 原創地址:https://www.cnblogs.com/JLZT1223/p/6085339.html