Unity中通过Gizmos绘制OverlapBox

小咪咪 2024-03-30 10:04 43阅读 0赞

#### OverlapBox的绘制问题 ####

我们发现Gizmos没有直接绘制OverlapBox的API，所以只能借助DrawLine来间接绘制OverlapBox，所以首先我们需要计算出Box四个顶点的坐标公式。

转换为如下问题：

**已知有一个矩形ABCD，A为矩形的左上顶点，C为矩形的右下顶点，宽为w，高为h，矩形中心点O坐标为(a,b)，∠α是OA与X轴负方向的夹角，矩形有一个外接圆，现使得矩形按中心进行顺时针或逆时针旋转θ角度，规定-π <= θ <= π，求旋转过后矩形四个顶点A1,B1,C1,D1的坐标分别是多少？**

求解过程如下：

![fe988a10def74e2b9b5dbc07e4c6dc1a.png][]

![ad5cef150f6149e5af2c4bd1960516ed.jpeg][]

![b7e4d0722191499da7f27eb05f455c03.png][]

![03c3abd9b97149c89e45d593b446658d.png][]

![09ff09e1625847098470dd2a4593516d.png][]

![b8ec7317ac40415884e08c00123c8a84.jpeg][]

![a5371bed324944abb8520946da4f4feb.png][]

#### 代码示例（C\#） ####

using System.Collections;
    using System.Collections.Generic;
    using UnityEngine;
    
    public class BoxTrigger : MonoBehaviour
    {
        [Header("必要组件")]
        [Tooltip("触发器检测层")]
        [SerializeField] private LayerMask cTriggerLayer;
        public LayerMask triggerLayer { get => cTriggerLayer; set => cTriggerLayer = value; }
        [Tooltip("触发器检测区域的中心坐标组件")]
        [SerializeField] private Transform cTriggerArea;
        public Transform triggerArea { get => cTriggerArea; set => cTriggerArea = value; }
    
        [Header("必要属性")]
        [Tooltip("触发器的宽度和高度")]
        [SerializeField] private Vector2 mSize;
        [Tooltip("触发器的角度")]
        [Range(-180f, 180f)]
        [SerializeField] private float mAngle;
        [Tooltip("触发器绘制颜色")]
        [SerializeField] private DrawColor mColor;
    
        public Vector2 center { get => cTriggerArea.position; }
        public Vector2 size { get => mSize; set => mSize = value; }
        public float angle { get => mAngle; set { if (value >= -180f && value <= 180f) mAngle = value; } }
    
        //Trigger_check用于检测主角是否进入触发区域
        private bool trigger_check { get; set; }
        private Vector2 mLU;
        private Vector2 mRU;
        private Vector2 mRD;
        private Vector2 mLD;
        private Color currentColor;
        private float mSin;
        private float mCos;
        private float mWidth;
        private float mHeight;
        private const float mC = 1f / 2;
        
        void Start()
        {
            if (!cTriggerArea) cTriggerArea = transform;
        }
    
        void Update()
        {
    
        }
    
        //触发检测
        public bool TriggerCheck()
        {
            //检测是否进入了触发区域
            if (!Physics2D.OverlapBox(center, mSize, mAngle, cTriggerLayer))
                trigger_check = false;
            else
                trigger_check = true;
            return trigger_check;
        }
    
        //角度转换为弧度
        private void AngleConversion()
        {
            float v_angle = mAngle * Mathf.PI / 180;
            mSin = Mathf.Sin(v_angle);
            mCos = Mathf.Cos(v_angle);
        }
    
        //坐标更新
        private void UpdatePosition()
        {
            mWidth = mSize.x;
            mHeight = mSize.y;
            float x_Lu = (-mC * (mWidth * mCos + mHeight * mSin)) + center.x;
            float y_Lu = (mC * (mHeight * mCos - mWidth * mSin)) + center.y;
            float x_Ru = (mC * (mWidth * mCos - mHeight * mSin)) + center.x;
            float y_Ru = (mC * (mWidth * mSin + mHeight * mCos)) + center.y;
            float x_Rd = (mC * (mWidth * mCos + mHeight * mSin)) + center.x;
            float y_Rd = (mC * (mWidth * mSin - mHeight * mCos)) + center.y;
            float x_Ld = (mC * (mHeight * mSin - mWidth * mCos)) + center.x;
            float y_Ld = (-mC * (mHeight * mCos + mWidth * mSin)) + center.y;
            mLU = new Vector2(x_Lu, y_Lu);
            mRU = new Vector2(x_Ru, y_Ru);
            mRD = new Vector2(x_Rd, y_Rd);
            mLD = new Vector2(x_Ld, y_Ld);
        }
    
        //颜色替换
        private void UpdateColor()
        {
            switch (mColor)
            {
                case DrawColor.Red:
                    currentColor = Color.red;
                    break;
                case DrawColor.Blue:
                    currentColor = Color.blue;
                    break;
                case DrawColor.Green:
                    currentColor = Color.green;
                    break;
                case DrawColor.White:
                    currentColor = Color.white;
                    break;
                case DrawColor.Yellow:
                    currentColor = Color.yellow;
                    break;
                case DrawColor.Cyan:
                    currentColor = Color.cyan;
                    break;
                case DrawColor.Gray:
                    currentColor = Color.gray;
                    break;
                case DrawColor.Grey:
                    currentColor = Color.grey;
                    break;
                case DrawColor.Magenta:
                    currentColor = Color.magenta;
                    break;
                default:
                    currentColor = Color.red;
                    break;
            }
        }
    
        //Gizmos绘制
        private void OnDrawGizmos()
        {
            AngleConversion();
            UpdatePosition();
            UpdateColor();
            Gizmos.color = currentColor;
            Gizmos.DrawLine(mLU, mRU);
            Gizmos.DrawLine(mRU, mRD);
            Gizmos.DrawLine(mRD, mLD);
            Gizmos.DrawLine(mLD, mLU);
        }
    }

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[fe988a10def74e2b9b5dbc07e4c6dc1a.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/d81e06ea4ad34206b726e56129e5ce91.png
[ad5cef150f6149e5af2c4bd1960516ed.jpeg]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/01a8c4b290da42dc8d84322f9cdb0734.jpeg
[b7e4d0722191499da7f27eb05f455c03.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/eecefbdaf71f477e962c8a1bb813057d.png
[03c3abd9b97149c89e45d593b446658d.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/b959d379b582470aa95e080ec6f71dc2.png
[09ff09e1625847098470dd2a4593516d.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/11f2050650d147cc9e4a26ae722207e5.png
[b8ec7317ac40415884e08c00123c8a84.jpeg]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/1830fed21740432eb698591784d2841f.jpeg
[a5371bed324944abb8520946da4f4feb.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/30/4f2511b614b34673be70a0b2e715c00a.png