不同半径的游戏道具扇形或者弧形摆放实现

先上效果图

 

实现思路直接上代码，加了详细注释：

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

public class Inventory : MonoBehaviour
{
    //道具半径
    //支持每个道具半径不同
    public float[] itemRadii = new float[3] { 0.05f, 0.05f, 0.05f };
    //弧长
    public float arcRadius = 0.5f;
    //角度转为向量方法，默认圆心在（0,0）处，这里默认半径是1，也就是单位圆
    static Vector2 AngToDir(float angRad)
    {
        return new Vector2(Mathf.Cos(angRad), Mathf.Sin(angRad));
    }
    private void OnDrawGizmos()
    {
        using (new Handles.DrawingScope(transform.localToWorldMatrix))
        {
            //画一个90度的弧
            Handles.DrawWireArc(default, Vector3.forward, Vector3.right, 45, arcRadius);
            Handles.DrawWireArc(default, Vector3.forward, Vector3.right, -45, arcRadius);
            int itemCount = itemRadii.Length;
            //道具之间的夹角，N-1个夹角
            //这里的夹角只是两个道具中心到圆弧中心（0,0）连线（长度也就是圆弧半径）
            //形成的夹角
            float[] angleBetween = new float[itemCount - 1];
            for(int i = 0; i < angleBetween.Length; i++)
            {
                //道具半径
                float a = itemRadii[i];
                //相邻的道具半径
                float b = itemRadii[i + 1];
                //利用三角形三边和夹角的关系计算夹角（余弦定理）
                float ang = Mathf.Acos(1f - ((a+b) * (a+ b)) / (2 * arcRadius * arcRadius));
                angleBetween[i] = ang;
            }
            float angRad = 0f;
            for (int i = 0; i < itemCount; i++)
            {
                float radius = itemRadii[i];
                //计算每个道具在圆弧上的圆心
                Vector3 itemCenter = AngToDir(angRad) * arcRadius;
                //从圆弧中心画一个直线，到道具中心便于理解
                Handles.DrawLine(Vector3.zero, itemCenter);
                //再画出每个道具的原点
                Gizmos.DrawSphere(itemCenter, 0.03f);
                //根据道具半径，画出道具代表的圆圈
                Handles.DrawWireDisc(itemCenter, Vector3.forward, radius);
                //根据两个道具之间的夹角计算下一个道具偏移角度
                if (i < itemCount - 1)
                 angRad += angleBetween[i];
            }


        }
    }

    /*这里注释的是物品半径都一样功能逻辑
    public float itemRadius = 0.05f;
    public float arcRadius = 0.5f;
    public int itemCount = 3;
    static Vector2 AngToDir(float angRad)
    {
        return new Vector2(Mathf.Cos(angRad), Mathf.Sin(angRad));
    }
    private void OnDrawGizmos()
    {
        using(new Handles.DrawingScope(transform.localToWorldMatrix))
        {
            //draw arc
            Handles.DrawWireArc(default, Vector3.forward, Vector3.right, 45, arcRadius);
            Handles.DrawWireArc(default, Vector3.forward, Vector3.right, -45, arcRadius);
            float itemSeparationAngleRad = Mathf.Asin(itemRadius / arcRadius) * 2;
            //从第一个到第itemCount 个跨越了几个itemsepatationAngleRad
            float angOffset = itemSeparationAngleRad * (itemCount - 1) * 0.5f;
            for(int i = 0; i <itemCount; i++)
            {
                float angRad = itemSeparationAngleRad * i - angOffset;
                Vector3 itemCenter = AngToDir(angRad) * arcRadius;
                Handles.DrawLine(default, itemCenter);
                Handles.DrawWireDisc(itemCenter, Vector3.forward, itemRadius);
            }
            
           
        }
    }*/
}