CommandBufferで全画面にメッシュを表示するやつ (URP 10.8.1)

DrawMeshFeature.cs

using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Rendering.Universal;


public class DrawMeshFeature : ScriptableRendererFeature
{
    [SerializeField] private Material materialAsset;
    [System.NonSerialized] private Mesh _mesh;
    
    DrawMeshPass drawMeshPass;

    /// <inheritdoc/>
    public override void Create()
    {
        drawMeshPass = new DrawMeshPass();
        drawMeshPass.renderPassEvent = RenderPassEvent.AfterRenderingOpaques;
    }

    public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData)
    {
        if (_mesh == null)
        {
            Debug.Log("Create Mesh");
            _mesh = CreateMesh();
        }
        
        drawMeshPass.Setup(_mesh, materialAsset);
        renderer.EnqueuePass(drawMeshPass);
    }
    
    // 正規化デバイス座標系で画面の４隅に張り付くメッシュを作る
    Mesh CreateMesh () {
        var mesh = new Mesh ();
        mesh.name = "TestMesh";

        // NOTE: z = 0 だと表示されなくなるので、大きい値を入れておく
        float z = 0.5f;
        var uv = new List<Vector2>
        {
            new Vector2(1, 1),
            new Vector2(0, 1),
            new Vector2(1, 0),
            new Vector2(0, 0),
        };
        
        var vertices = new List<Vector3> {
            new Vector3 (1f, 1f, z),
            new Vector3 (-1f, 1f, z),
            new Vector3 (1f, -1f, z),
            new Vector3 (-1f, -1f, z),
        };
        var triangles = new List<int> {
            1, 0, 2, 
            1, 2, 3
        };
        
        mesh.SetVertices (vertices);
        mesh.SetUVs(0, uv);
        mesh.SetTriangles (triangles, 0);
        return mesh;
    }
}

DrawMeshPass.cs

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

public class DrawMeshPass : ScriptableRenderPass
{
    private Mesh _mesh;
    private Material _material;

    public void Setup(Mesh mesh, Material material)
    {
        _mesh = mesh;
        _material = material;
    }

    public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData)
    {
        var cmd = CommandBufferPool.Get("DrawMeshPass");

        if (!_mesh) return;

        cmd.DrawMesh(_mesh, Matrix4x4.identity, _material);
        context.ExecuteCommandBuffer(cmd);
        cmd.Clear();
        
        CommandBufferPool.Release(cmd);
    }
}

ScreenSpaceUnlit.shader

Shader "Unlit/ScreenSpaceUnlit"
{
    SubShader
    {
        Tags { "RenderType"="Opaque" }
        LOD 100
        Cull Off // 裏表を無視

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

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

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

            v2f vert (appdata v)
            {
                v2f o;

                // 頂点には、正規化デバイス座標系の物が入っているので、ここでは特に座標変換を行わない
                o.vertex = float4(v.vertex.xyz, 1);
                o.uv = v.uv;
                return o;
            }

            half4 frag (v2f i) : SV_Target
            {
                return half4(i.uv, 0, 1);
            }
            ENDCG
        }
    }
}