Pixelate Image Effect For Unity

PixelateImageEffect.cs

using UnityEngine;

[ExecuteInEditMode, RequireComponent(typeof(Camera))]
public class PixelateImageEffect : MonoBehaviour
{
    public Material material;
    public int pixelDensity = 64;

    private void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        Vector2 aspectRatioData;
        if (Screen.height > Screen.width)
            aspectRatioData = new Vector2((float)Screen.width / Screen.height, 1);
        else
            aspectRatioData = new Vector2(1, (float)Screen.height / Screen.width);
        material.SetVector("_AspectRatioMultiplier", aspectRatioData);
        material.SetInt("_PixelDensity", pixelDensity);
        Graphics.Blit(source, destination, material);
    }
}

Pixelation.shader

Shader "Hidden/Pixelation"
{
	Properties
	{
		_MainTex ("Texture", 2D) = "white" {}
	}
	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;
			int _PixelDensity;
			float2 _AspectRatioMultiplier;

			fixed4 frag (v2f i) : SV_Target
			{
				float2 pixelScaling = _PixelDensity * _AspectRatioMultiplier;
				i.uv = round(i.uv * pixelScaling)/ pixelScaling;
				return tex2D(_MainTex, i.uv);
			}
			ENDCG
		}
	}
}