Distortion Blit in Universal Render Pipeline

Blit.cs

using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.Universal;

public class Blit : ScriptableRendererFeature {
	public Settings settings = new Settings();

	private Pass pass;

	public override void Create() =>
		pass = new Pass(settings.@event, settings.material, name);

	public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData) {
		if (settings.material != null) {
			pass.source = renderer.cameraColorTarget;
			renderer.EnqueuePass(pass);
		}
	}

	[System.Serializable]
	public class Settings {
		public RenderPassEvent @event = RenderPassEvent.AfterRenderingOpaques;
		public Material material = null;
	}

	public class Pass : ScriptableRenderPass {
		public Material material;
		public RenderTargetIdentifier source;

		private string name;
		private RenderTargetHandle texture;
		
		public Pass(RenderPassEvent @event, Material material, string name) {
			this.renderPassEvent = @event;
			this.material = material;
			this.name = name;
			texture.Init("_TemporaryColorTexture");
		}

		public override void Configure(CommandBuffer buffer, RenderTextureDescriptor descriptor) =>
			buffer.GetTemporaryRT(texture.id, descriptor);

		public override void Execute(ScriptableRenderContext context, ref RenderingData data) {
			var buffer = CommandBufferPool.Get(name);
			buffer.Clear();
			data.cameraData.cameraTargetDescriptor.depthBufferBits = 0;
			Blit(buffer, source, destination: texture.Identifier(), material, passIndex: -1);
			Blit(buffer, source: texture.Identifier(), destination: source);
			context.ExecuteCommandBuffer(buffer);
			CommandBufferPool.Release(buffer);
		}

		public override void FrameCleanup(CommandBuffer buffer) =>
			buffer.ReleaseTemporaryRT(texture.id);
	}
}

Distortion.shader

Shader "Features/Distortion" {
	Properties {
		[HideInInspector] _MainTex ("Texture", 2D) = "white" {}
		_DistortionTex ("Distortion (Normalmap)", 2D) = "white" {}
		_Properties ("Intensity (XY), Stretch (ZW)", Vector) = (0.5, 0.5, 0.5, 0.5)
		_TimeFactor ("Time factor", Float) = 0.5
	}
	SubShader {
		Cull Off ZWrite Off ZTest Always

		Pass {
			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag

			#include "UnityCG.cginc"

			struct appdata {
				float4 vertex : POSITION;
				float2 uv : TEXCOORD0;
			};

			struct v2f {
				float2 uv : TEXCOORD0;
				float4 vertex : SV_POSITION;
			};

			v2f vert(appdata v) {
				v2f o;
				o.vertex = UnityObjectToClipPos(v.vertex);
				o.uv = v.uv;
				return o;
			}

			sampler2D _MainTex;
			sampler2D _DistortionTex;
			float4 _Properties;
			float _TimeFactor;

			float4 frag(v2f i) : SV_Target {
				float2 offset = (i.uv + _Time.xx * _TimeFactor) * _Properties.wz;
				float2 distortion = tex2D(_DistortionTex, offset).xy - 0.5;
				float4 color = tex2D(_MainTex, i.uv + distortion * _Properties.xy);
				return color;
			}
			ENDCG
		}
	}
}