实现Unity shader扭曲效果

实现思路

1、扭曲材质赋于面片

2、抓取当前一帧的图片内容

3、获取屏幕坐标

4、利用屏幕坐标对抓取的图片采样

5、再采样张扰动贴图做扭曲

Shader "Unlit/NewUnlitShader"
{Properties {_DistortTex ("扰动贴图 (RGB)", 2D) = "bump" {}_DistortPower ("扭曲强度", Range(0, 0.1)) = 0.05_Speed ("扰动速度", Range(0, 5)) = 1}SubShader {Tags { "Queue"="Transparent" }// 抓取屏幕内容GrabPass { "_GrabTexture" }Pass {CGPROGRAM#pragma vertex vert#pragma fragment frag#include "UnityCG.cginc"struct appdata {float4 vertex : POSITION;float2 uv : TEXCOORD0;};struct v2f {float4 pos : SV_POSITION;float4 grabPos : TEXCOORD0;float2 uv : TEXCOORD1;};sampler2D _GrabTexture;sampler2D _DistortTex;float _DistortPower;float _Speed;v2f vert (appdata v) {v2f o;// 顶点位置变换o.pos = UnityObjectToClipPos(v.vertex);// 计算抓取纹理坐标o.grabPos = ComputeGrabScreenPos(o.pos);// 扰动贴图UV动画（随时间滚动）o.uv = v.uv + frac(float2(0, _Time.y * _Speed));return o;}fixed4 frag (v2f i) : SV_Target {// 采样扰动贴图half2 distort = UnpackNormal(tex2D(_DistortTex, i.uv)).rg;// 计算偏移量float2 offset = distort * _DistortPower;// 应用偏移到抓取纹理坐标i.grabPos.xy += offset;// 采样抓取纹理fixed4 col = tex2Dproj(_GrabTexture, i.grabPos);return col;}ENDCG}}
}