[Unity] Post Process Scan Effect

DepthScan.cs

using UnityEngine;

public class DepthScan : MonoBehaviour
{
    [SerializeField] private Camera cam;
    [SerializeField] private Material mat;
    [SerializeField] private float scanSpeed = 80f;

    private float scanDistance;

    private void Start()
    {
        cam.depthTextureMode = cam.depthTextureMode | DepthTextureMode.Depth;
    }

    private void Update()
    {
        if (Input.GetKeyDown(KeyCode.S)) scanDistance = 0.0f;
        scanDistance = scanDistance + scanSpeed * Time.deltaTime;
    }

    private void OnRenderImage(RenderTexture source, RenderTexture destination)
    {
        mat.SetFloat("_ScanDistance", scanDistance);
        Graphics.Blit(source, destination, mat);
    }
}

DepthScan.shader

Shader "DepthScan"
{
    Properties
    {
        [HideInspector] _MainTex ("Texture", 2D) = "white" {}
        _ScanDistance ("Distance", float) = 10
        _ScanTrail ("Trail", float) = 4
        _ScanColor ("Color", Color) = (0,1,1,1)
    }
    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;
            }

            float _ScanDistance;
            float _ScanTrail;
            float4 _ScanColor;

            sampler2D _MainTex;
            sampler2D _CameraDepthTexture;

            fixed4 frag (v2f i) : SV_Target
            {
                float depth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, i.uv);
                depth = LinearEyeDepth(depth);

                fixed4 mainColor = tex2D(_MainTex, i.uv);
                if (depth > _ScanDistance) return mainColor;
                float ScanColorIntensity = clamp((depth - _ScanDistance + _ScanTrail) / _ScanTrail, 0, 1);
                fixed4 col = lerp(mainColor, _ScanColor, ScanColorIntensity);
                return col;
            }
            ENDCG
        }
    }
}

参考元
https://www.ronja-tutorials.com/2018/07/01/postprocessing-depth.html