屏幕可视范围跟随目标物体移动，可修改可视范围大小，边缘渐变大小、以及遮罩颜色，支持最高物体数量可在Shader中修改，当前版本支持最多9个物体。

效果图如下：

控制面板如下：

Shader代码如下：

Shader "Peter/DarkEffect"{ Properties { _MainTex ("Texture", 2D) = "white" {} } SubShader { // No culling or depth Cull Off ZWrite Off ZTest Always Pass { CGPROGRAM #pragma vertex vert #pragma fragment frag #include "UnityCG.cginc" //追踪物体最多个数 #define ItemSize 9 struct appdata { float4 vertex : POSITION; float2 uv : TEXCOORD0; }; struct v2f { float2 uv : TEXCOORD0; float4 vertex : SV_POSITION; }; sampler2D _MainTex; fixed4 _DarkColor; float _SmoothLength; fixed _ItemCnt; float4 _Item[ItemSize]; v2f vert (appdata v) { v2f o; o.vertex = UnityObjectToClipPos(v.vertex); o.uv = v.uv; return o; } fixed CalcAlpha(float4 vt, float4 pt) { if(pt.z < 0) { return 1; } float distPow2 = pow(vt.x - pt.x, 2) + pow(vt.y - pt.y, 2); float dist = (distPow2 > 0) ? sqrt(distPow2) : 0; float smoothLength = _SmoothLength; if(smoothLength < 0) { smoothLength = 0; } float maxValue = pt.z; float minValue = pt.z - smoothLength; if(minValue < 0) { minValue = 0; smoothLength = pt.z; } if(dist <= minValue) { return 0; } else if (dist > maxValue) { return 1; } fixed retVal = (dist - minValue) / smoothLength; return retVal; } fixed4 frag (v2f i) : SV_Target { fixed alphaVal = 1; fixed tmpVal = 1; for(fixed index = 0; index < _ItemCnt; ++index) { tmpVal = CalcAlpha(i.vertex, _Item[index]); if(tmpVal < alphaVal) { alphaVal = tmpVal; } } alphaVal *= _DarkColor.a; return tex2D(_MainTex, i.uv) * ( 1 - alphaVal) + _DarkColor * alphaVal; } ENDCG } }}

C#调用代码如下：

using System.Collections;using System.Collections.Generic;using UnityEngine;[ExecuteInEditMode][RequireComponent(typeof(Camera))]public class DarkEffect : MonoBehaviour{ [System.Serializable] public class Item { [SerializeField] public Transform target; [SerializeField] public int radius; public Vector3 GetScreenPosition(Camera cam) { return cam.WorldToScreenPoint(target.position); } } //渐变像素数量 public int _smoothLength = 20; //遮罩混合颜色 public Color _darkColor = Color.black; //目标物体 public List<Item> _items = new List<Item>(); protected Material _mainMaterial; protected Camera _mainCamera; Vector4[] _itemDatas; Item _tmpItem; Vector4 _tmpVt; Vector3 _tmpPos; int _tmpScreenHeight; private void OnEnable() { _mainMaterial = new Material(Shader.Find("Peter/DarkEffect")); _mainCamera = GetComponent<Camera>(); } private void OnRenderImage(RenderTexture source, RenderTexture destination) { if (_itemDatas == null || _itemDatas.Length != _items.Count) { _itemDatas = new Vector4[_items.Count]; } _tmpScreenHeight = Screen.height; for (int i = 0; i < _items.Count; i++) { _tmpItem = _items[i]; _tmpPos = _tmpItem.GetScreenPosition(_mainCamera); _tmpVt.x = _tmpPos.x; _tmpVt.y = _tmpScreenHeight - _tmpPos.y; _tmpVt.z = _tmpItem.radius; _tmpVt.w = 0; _itemDatas[i] = _tmpVt; } _mainMaterial.SetInt("_SmoothLength", _smoothLength); _mainMaterial.SetColor("_DarkColor", _darkColor); _mainMaterial.SetInt("_ItemCnt", _itemDatas.Length); _mainMaterial.SetVectorArray("_Item", _itemDatas); Graphics.Blit(source, destination, _mainMaterial); }}

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