Draw a polygon in Unity

DrawPolygon.cs

using UnityEngine;
using UnityEngine.UI;
using UnityEngine.Sprites;

using System;
using System.Collections.Generic;

public class DrawPolygon : Graphic
{
    [SerializeField]
    private Sprite m_sprite;


    private int m_nSides = 3;
    public int nSides
    {
        get { return m_nSides; }
        set { m_nSides = value; }
    }

    private List<float> m_coefficients = new List<float>() { 1.0f, 1.0f, 1.0f };
    public List<float> coefficients
    {
        get { return m_coefficients; }
    }

    public Sprite sprite { get { return m_sprite; } }

    protected override void OnEnable()
    {
        base.OnEnable();
    }

    /// Image's dimensions used for drawing. X = left, Y = bottom, Z = right, W = top.
    private Vector4 GetDrawingDimensions()
    {
        var padding = DataUtility.GetPadding(sprite);
        var size = new Vector2(sprite.rect.width, sprite.rect.height);

        Rect r = GetPixelAdjustedRect();

        int spriteW = Mathf.RoundToInt(size.x);
        int spriteH = Mathf.RoundToInt(size.y);

        var v = new Vector4(
                padding.x / spriteW,
                padding.y / spriteH,
                (spriteW - padding.z) / spriteW,
                (spriteH - padding.w) / spriteH);

        v = new Vector4(
                r.x + r.width * v.x,
                r.y + r.height * v.y,
                r.x + r.width * v.z,
                r.y + r.height * v.w
                );

        return v;
    }

    protected override void OnPopulateMesh(VertexHelper vh)
    {
        base.OnPopulateMesh(vh);

        var v = GetDrawingDimensions();
        // var uv = DataUtility.GetOuterUV(sprite);

        var halfHeight = Mathf.Abs(v.y);

        var color32 = color;
        vh.Clear();

        vh.AddVert(new Vector3(0.0f, 0.0f), color32, Vector2.zero);

        for (int i = 0; i < nSides; i++)
        {
            var angle = Mathf.PI / 2 - 2 * Mathf.PI / nSides * i;

            vh.AddVert(
                new Vector3(Mathf.Sin(angle) * halfHeight * coefficients[i], Mathf.Cos(angle) * halfHeight * coefficients[i]),
                color32, Vector2.zero);
        }

        for (int i = 0; i < nSides - 2; i++)
        {
            vh.AddTriangle(0, (i + 1) % nSides, (i + 2) % nSides);
        }

        vh.AddTriangle(0, nSides - 1, nSides);
        vh.AddTriangle(0, nSides, 1);

    }

    public Vector3 GetActualPosition()
    {
        return Vector3.zero;
    }
}