(3) plana y circular

descripción general

Dado que el artículo básico ya está relativamente detallado, solo se publica el código en este artículo.

código de círculo plano

Un círculo también se compone de triángulos, y cuantos más triángulos haya, más círculo será.

clase base

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

[RequireComponent(typeof(MeshFilter),typeof(MeshRenderer))]
public class CreateMeshBase : MonoBehaviour
{
    MeshFilter meshFilter;

    protected Mesh mesh;

    protected virtual Vector3[] Vertices { get; }
    protected virtual int[] Triangles { get; }
    protected virtual Vector3[] Normals { get; }
    protected virtual Vector2[] Uvs { get; }
    protected virtual string MeshName { get; }

    protected virtual void Start()
    {
        GetMeshFilter();
    }

    protected virtual void Reset()
    {
        GetMeshFilter();
    }

    protected virtual void OnValidate()
    {
        GetMeshFilter();
    }

    void GetMeshFilter()
    {
        if (meshFilter == null)
        {
            meshFilter = GetComponent<MeshFilter>();
            mesh = new Mesh();            
        }

        mesh.triangles = null;
        mesh.uv = null;
        mesh.vertices = null;

        mesh.name = MeshName;
        mesh.vertices = Vertices;
        mesh.triangles = Triangles;
        mesh.uv = Uvs;

        meshFilter.mesh = mesh;
    }

    private void OnDrawGizmos()
    {
        if (Vertices == null) return;

        Gizmos.color = Color.red;
        Gizmos.DrawSphere(Vector3.zero, 0.5f);

        Gizmos.color = Color.blue;

        for (int i = 0; i < Vertices.Length; i++)
        {
            Gizmos.DrawSphere(Vertices[i], 0.3f);
        }
    }
}

rejilla circular

Entre ellos, triCount controla el número de triángulos y el radio controla el tamaño del círculo.

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

public class CreateCircle : CreateMeshBase
{
    [Range(3,100)]
    public int triCount = 6;
    public float radius = 5;
    public bool showHalf = false;

    protected override string MeshName
    {
        get
        {
            return "Circle Mesh";
        }
    }

    protected override Vector3[] Vertices
    {
        get
        {
            Vector3[] vertices = new Vector3[triCount + 1];
            vertices[0] = Vector3.zero;
            float angleDelta = 2 * Mathf.PI / triCount;

            for (int i = 0; i < triCount; i++)
            {
                float angle = angleDelta * i;
                float x = radius * Mathf.Cos(angle);
                float y = radius * Mathf.Sin(angle);

                vertices[i + 1] = new Vector3(x, y, 0);
            }

            return vertices;
        }
    }

    protected override int[] Triangles
    {
        get
        {
            int[] triangles = new int[triCount * 3];

            for (int i = 0; i < triCount; i++)
            {
                if (showHalf)
                {
                    if (i % 2 == 0) continue;
                }

                triangles[i * 3] = 0;
                triangles[i * 3 + 2] = i + 1;

                if (i + 2 > triCount)
                {
                    triangles[i * 3 + 1] = 1;
                }else
                {
                    triangles[i * 3 + 1] = i + 2;
                }
            }
            return triangles;
        }
    }

    protected override Vector2[] Uvs
    {
        get
        {
            Vector2[] uvs = new Vector2[triCount + 1];
            uvs[0] = new Vector2(0.5f,0.5f);
            float angleDelta = 2 * Mathf.PI / triCount;

            for (int i = 0; i < triCount; i++)
            {
                float angle = angleDelta * i;
                float x = Mathf.Cos(angle) * 0.5f + 0.5f;
                float y = Mathf.Sin(angle) * 0.5f + 0.5f;

                uvs[i + 1] = new Vector2(x, y);
            }
            return uvs;
        }
    }
}