Mesh Generation으로 다각형 만들기

 

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

public class CreatePoly : MonoBehaviour
{
    Mesh mesh;
    public Vector3[] polygonPoints;
    public int[] polygonTriangles;

    public bool isFilled;
    public int polygonSides;
    public float polygonRadius;
    public float centerRadius;

    private void Start()
    {
        mesh = new Mesh();
        this.GetComponent<MeshFilter>().mesh = mesh;
    }

    private void Update()
    {
        if (isFilled)
        {
            DrawFilled(polygonSides, polygonRadius);
        }
        else
        {
            DrawHollow(polygonSides, polygonRadius, centerRadius);
        }
    }

    private void DrawFilled(int sides, float radius)
    {
        polygonPoints = GetCircumferencePoints(sides, radius).ToArray();
        polygonTriangles = DrawFilledTriangles(polygonPoints);
        mesh.Clear();
        mesh.vertices = polygonPoints;
        mesh.triangles = polygonTriangles;
    }

    private void DrawHollow(int sides, float outerRadius, float inneRadius)
    {
        List<Vector3> pointsList =  new List<Vector3>();
        List<Vector3> outerPoints = GetCircumferencePoints(sides, outerRadius);
        pointsList.AddRange(outerPoints);
        List<Vector3> innerPoints = GetCircumferencePoints(sides, inneRadius);
        pointsList.AddRange(innerPoints);

        polygonPoints = pointsList.ToArray();

        polygonTriangles = DrawHollowTriangles(polygonPoints);
        mesh.Clear();
        mesh.vertices = polygonPoints;
        mesh.triangles = polygonTriangles;
    }

    private int[] DrawHollowTriangles(Vector3[] points)
    {
        int sides = points.Length / 2;
        int triangleAmount = sides * 2;

        List<int> newTriangles = new List<int>();
        for(int i = 0; i < sides; i++)
        {
            int outerIndex = i;
            int innerIndex = i + sides;

            newTriangles.Add(outerIndex);
            newTriangles.Add(innerIndex);
            newTriangles.Add((i + 1) % sides);

            newTriangles.Add(outerIndex);
            newTriangles.Add(sides + ((sides + i - 1) % sides));
            newTriangles.Add(outerIndex + sides);
        }
        return newTriangles.ToArray();
    }

    private List<Vector3> GetCircumferencePoints(int sides, float radius)
    {
        List<Vector3> points = new List<Vector3>();
        float circumferenceProgressPerStep = (float)1 / sides;
        float TAU = 2 * Mathf.PI;
        float radianProgressPerStep = circumferenceProgressPerStep * TAU;

        for (int i = 0; i < sides; i++)
        {
            float currentRadian = radianProgressPerStep * i;
            points.Add(new Vector3(Mathf.Cos(currentRadian) * radius, Mathf.Sin(currentRadian) * radius, 0));
        }
        return points;
    }

    private int[] DrawFilledTriangles(Vector3[] points)
    {
        int triangleAmount = points.Length - 2;
        List<int> newTriangles = new List<int>();
        for (int i = 0; i < triangleAmount; i++)
        {
            newTriangles.Add(0);
            newTriangles.Add(i + 2);
            newTriangles.Add(i + 1);
        }
        return newTriangles.ToArray();
    }
}

 

 

 

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