扭曲效果

用GrabPass抓屏，法线图扰动UV，最好是自己用脚本抓屏，应该会省点,主要是好进行后续控制

Shader "Artist/Effect/Distort" 
{
    Properties
    {
        _DistortStrength("DistortStrength", Range(0,1)) = 0.2
        _DistortTimeFactor("DistortTimeFactor", Range(0,1)) = 1
        _NoiseTex("NoiseTexture", 2D) = "white" {}
    }
    SubShader
    {
        ZWrite Off
        Cull Off
        
        GrabPass
        {
            
            "_GrabTex"
        }
 
        Pass
        {
            Tags
            { 
                "RenderType" = "Transparent"
                "Queue" = "Transparent + 100"
            }
 
            CGPROGRAM
            sampler2D _GrabTex;
            float4 _GrabTex_ST;
            sampler2D _NoiseTex;
            float4 _NoiseTex_ST;
            float _DistortStrength;
            float _DistortTimeFactor;
            #include "UnityCG.cginc"
            struct v2f
            {
                float4 pos : SV_POSITION;
                float2 uv : TEXCOORD0;
                float4 grabPos : TEXCOORD1;
            };
 
            v2f vert(appdata_base v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                o.grabPos = ComputeGrabScreenPos(o.pos);
                o.uv = TRANSFORM_TEX(v.texcoord, _NoiseTex);
                return o;
            }
 
            fixed4 frag(v2f i) : SV_Target
            {
                
                float4 offset = tex2D(_NoiseTex, i.uv - _Time.xy * _DistortTimeFactor);
                
                i.grabPos.xy -= offset.xy * _DistortStrength;
                
                fixed4 color = tex2Dproj(_GrabTex, i.grabPos);
                return color;
            }
 
            #pragma vertex vert
            #pragma fragment frag
            ENDCG
        }
    }
}

据说会有安卓机上GrabPass读帧缓存卡死的问题，那么我转载了另一篇方法也很不错

先做全屏后处理，然后渲染一张黑白mask作为遮罩的Texture，代码如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
 
public class DistortEffect : PostEffectBase {
 
  
    [Range(0.0f, 1.0f)]
    public float DistortTimeFactor = 0.15f;
  
    [Range(0.0f, 0.2f)]
    public float DistortStrength = 0.01f;

    public Texture NoiseTexture = null;
 
    public Shader maskObjShader = null;
 
    public int downSample = 4;
 
    private Camera mainCam = null;
    private Camera additionalCam = null;
    private RenderTexture renderTexture = null;
 
    public void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        if (_Material)
        {
            _Material.SetTexture("_NoiseTex", NoiseTexture);
            _Material.SetFloat("_DistortTimeFactor", DistortTimeFactor);
            _Material.SetFloat("_DistortStrength", DistortStrength);
            _Material.SetTexture("_MaskTex", renderTexture);
            Graphics.Blit(source, destination, _Material);
        }
        else
        {
            Graphics.Blit(source, destination);
        }
    }
 
    void Awake()
    {
      
        InitAdditionalCam();
    }
 
    private void InitAdditionalCam()
    {
        mainCam = GetComponent<Camera>();
        if (mainCam == null)
            return;
 
        Transform addCamTransform = transform.FindChild("additionalDistortCam");
        if (addCamTransform != null)
            DestroyImmediate(addCamTransform.gameObject);
 
        GameObject additionalCamObj = new GameObject("additionalDistortCam");
        additionalCam = additionalCamObj.AddComponent<Camera>();
 
        SetAdditionalCam();
    }
 
    private void SetAdditionalCam()
    {
        if (additionalCam)
        {
            additionalCam.transform.parent = mainCam.transform;
            additionalCam.transform.localPosition = Vector3.zero;
            additionalCam.transform.localRotation = Quaternion.identity;
            additionalCam.transform.localScale = Vector3.one;
            additionalCam.farClipPlane = mainCam.farClipPlane;
            additionalCam.nearClipPlane = mainCam.nearClipPlane;
            additionalCam.fieldOfView = mainCam.fieldOfView;
            additionalCam.backgroundColor = Color.clear;
            additionalCam.clearFlags = CameraClearFlags.Color;
            additionalCam.cullingMask = 1 << LayerMask.NameToLayer("Distort");
            additionalCam.depth = -999;
            
            if (renderTexture == null)
                renderTexture = RenderTexture.GetTemporary(Screen.width >> downSample, Screen.height >> downSample, 0);
        }
    }
 
    void OnEnable()
    {
        SetAdditionalCam();
        additionalCam.enabled = true;
    }
 
    void OnDisable()
    {
        additionalCam.enabled = false;
    }
 
    void OnDestroy()
    {
        if (renderTexture)
        {
            RenderTexture.ReleaseTemporary(renderTexture);
        }
        DestroyImmediate(additionalCam.gameObject);
    }
 
   
    void OnPreRender()
    {
       
        if (additionalCam.enabled)
        {
            additionalCam.targetTexture = renderTexture;
            additionalCam.RenderWithShader(maskObjShader, "");
        }
    }
}

以下shader挂在模型上，对全屏图片处理并使用mask做遮罩

Shader "Custom/DistortPostEffect"
{
    Properties
    {
        _MainTex("Base (RGB)", 2D) = "white" {}
        _NoiseTex("Noise", 2D) = "black" {}
        _MaskTex("Mask", 2D) = "black" {}
    }
 
    CGINCLUDE
    #include "UnityCG.cginc"
    uniform sampler2D _MainTex;
    uniform sampler2D _NoiseTex;
    uniform sampler2D _MaskTex;
    uniform float _DistortTimeFactor;
    uniform float _DistortStrength;
 
    fixed4 frag(v2f_img i) : SV_Target
    {
    
        
        float4 noise = tex2D(_NoiseTex, i.uv - _Time.xy * _DistortTimeFactor);
        
        float2 offset = noise.xy * _DistortStrength;
        
        fixed4 factor = tex2D(_MaskTex, i.uv);
        
        float2 uv = offset * factor.r + i.uv;
        return tex2D(_MainTex, uv);
    }
 
    ENDCG
 
    SubShader
    {
        Pass
        {
            ZTest Always
            Cull Off
            ZWrite Off
            Fog{ Mode off }
 
            CGPROGRAM
            #pragma vertex vert_img
            #pragma fragment frag
            #pragma fragmentoption ARB_precision_hint_fastest 
            ENDCG
        }
    }
    Fallback off
}

mask专用shader

Shader "ApcShader/MaskObjPrepass"
{
    //子着色器  
    SubShader
    {
        Pass
        {   
            Cull Off
            CGPROGRAM
            #include "UnityCG.cginc"
            
            struct v2f
            {
                float4 pos : SV_POSITION;
            };
            
            v2f vert(appdata_full v)
            {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                return o;
            }
            
            fixed4 frag(v2f i) : SV_Target
            {
                //这个Pass直接输出颜色
                return fixed4(1,1,1,1);
            }
            
            //使用vert函数和frag函数
            #pragma vertex vert
            #pragma fragment frag
            ENDCG
        }
    }
}