螢幕可視範圍跟随目标物體移動,可修改可視範圍大小,邊緣漸變大小、以及遮罩顔色,支援最高物體數量可在Shader中修改,目前版本支援最多9個物體。
效果圖如下:
控制台如下:
Shader代碼如下:
Shader "Peter/DarkEffect"
{
Properties
{
_MainTex ("Texture", D) = "white" {}
}
SubShader
{
// No culling or depth
Cull Off ZWrite Off ZTest Always
Pass
{
CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#include "UnityCG.cginc"
//追蹤物體最多個數
#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 < )
{
return ;
}
float distPow2 = pow(vt.x - pt.x, ) + pow(vt.y - pt.y, );
float dist = (distPow2 > ) ? sqrt(distPow2) : ;
float smoothLength = _SmoothLength;
if(smoothLength < )
{
smoothLength = ;
}
float maxValue = pt.z;
float minValue = pt.z - smoothLength;
if(minValue < )
{
minValue = ;
smoothLength = pt.z;
}
if(dist <= minValue)
{
return ;
}
else if (dist > maxValue)
{
return ;
}
fixed retVal = (dist - minValue) / smoothLength;
return retVal;
}
fixed4 frag (v2f i) : SV_Target
{
fixed alphaVal = ;
fixed tmpVal = ;
for(fixed index = ; index < _ItemCnt; ++index)
{
tmpVal = CalcAlpha(i.vertex, _Item[index]);
if(tmpVal < alphaVal)
{
alphaVal = tmpVal;
}
}
alphaVal *= _DarkColor.a;
return tex2D(_MainTex, i.uv) * ( - alphaVal) + _DarkColor * alphaVal;
}
ENDCG
}
}
}
C#調用代碼如下:
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);
}
}
//漸變像素數量
public int _smoothLength = ;
//遮罩混合顔色
public Color _darkColor = Color.black;
//目标物體
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 = ; 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 = ;
_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);
}
}