[游戏开发]Shader 巡逻体扫描探照灯效果

视频链接
Shader：

Shader "LSQ/EffectAchievement/GlobalConeOfSight"
{
    Properties 
	{
		_SightColor("SightColor",Color) = (1,1,1,1)
		_SightAngle("SightAngle",Range(0, 360)) = 60
		_SightRadius("SightRadius",Range(0, 0.5)) = 0.5
	}

	SubShader
	{
	 	Tags 
		{ 
	 		"Queue"="Transparent"
	 		"RenderType"="Transparent" 
	 	} 
	 	Blend SrcAlpha OneMinusSrcAlpha

		Pass
		{
			ZWrite Off
			CGPROGRAM

			#pragma vertex vert
			#pragma fragment frag

			#include "UnityCG.cginc"

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

			struct v2f
			{
				float4 vertex : SV_POSITION;
				float2 uv : TEXCOORD0;
				float4 worldPos : TEXCOORD1;
			};

			fixed4 _SightColor;
			float _SightAngle;
			float _SightRadius;

			sampler2D _SightDepthTexture;
			float4x4 _ViewProjectMatrix;

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

			float GetObstacle(float4 worldPos)
			{
				float4 posViewSpace = mul(_ViewProjectMatrix, worldPos);
				float3 projCoords = posViewSpace.xyz / posViewSpace.w;	// ndc : -1 to 1
				projCoords = projCoords * 0.5 + 0.5; // 0 to 1
				float sampledDepth = 1 - SAMPLE_DEPTH_TEXTURE(_SightDepthTexture, projCoords.xy);
				return projCoords.z < sampledDepth;
			}

			fixed4 frag(v2f i) : SV_Target
			{
				float obstacle = GetObstacle(i.worldPos);

				const float PI = 3.14159;
				float2 uv = i.uv - 0.5f;
				float len = length(uv);
				float radius = _SightRadius > len;
				float angle = atan2(uv.y, uv.x) / PI * 180;
				float sightRange = smoothstep(_SightAngle, 0, angle) - smoothstep(0, -_SightAngle, angle);
				float sight = sightRange * radius * obstacle;

				return _SightColor * saturate(sight);
			}

			ENDCG
		}
	}
}

C# ：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GlobalConeOfSight : MonoBehaviour
{
    public Color sightColor = Color.red;
    public float sightAngle = 60;
    public float sightRadius = 5;
    public float scanSpeed = 60;

    public Transform headTF;
    public GameObject sightGO;
    public Camera sightCamera;
    private Material sightMaterial;

    private void Awake()
    {
        Initialize();

        RenderTexture depthTexture = new RenderTexture(sightCamera.pixelWidth, sightCamera.pixelHeight, 24, RenderTextureFormat.Depth);
        sightCamera.targetTexture = depthTexture;
        sightMaterial.SetTexture("_SightDepthTexture", sightCamera.targetTexture);
    }

    private void Update()
    {
        if (headTF != null)
        {
            headTF.Rotate(Vector3.up, Time.deltaTime * scanSpeed * -1, Space.Self);
        }

        if (sightCamera != null) 
        {
            sightCamera.Render();
            sightMaterial.SetMatrix("_ViewProjectMatrix", sightCamera.projectionMatrix * sightCamera.worldToCameraMatrix);
        }
    }

    private void OnValidate()
    {
        Initialize();
    }

    private void Initialize()
    {
        if (sightGO != null)
        {
            if (sightMaterial == null)
            {
                sightMaterial = sightGO.GetComponent<Renderer>().sharedMaterial;
            }
            else
            {
                sightGO.transform.localScale = Vector3.one * sightRadius * 2;
                sightMaterial.SetColor("_SightColor", sightColor);
                sightMaterial.SetFloat("_SightAngle", sightAngle);
                sightMaterial.SetFloat("_ScanSpeed", scanSpeed);
            }
        }

        if (sightCamera != null)
        {
            sightCamera.fieldOfView = sightAngle;
            sightCamera.farClipPlane = sightRadius;
        }
    }

    private void OnDrawGizmos()
    {
        Gizmos.matrix = Matrix4x4.TRS(transform.position, Quaternion.identity, new Vector3(1f, 0f, 1f));
        Gizmos.DrawWireSphere(Vector3.zero, sightRadius);
        Gizmos.matrix = Matrix4x4.identity;
    }
}