Question CommandBuffer.Draw* insteadof Graphics.Draw* URP way?

How to replace Graphics.DrawProceduralNow in (OnRenderObject) calls with a CommandBuffer to get access to the correct render order in URP?

Code (CSharp):

1. using System.Collections.Generic;
2. using Unity.Mathematics;
3. using UnityEngine;
4. using UnityEngine.Rendering;
5.  
6. public sealed class CommandBufferRenderInOrder : MonoBehaviour {
7.  
8.     public Mesh mesh;
9.     public Material material;
10.  
11.     struct Data {
12.         public float3 pos;
13.     }
14.  
15.     [SerializeField]  Shader shader;
16.  
17.     [SerializeField] float Size = 0.25f;
18.  
19.     public enum Type {
20.         GraphicsWay,
21.         CommandBufferWay
22.     }
23.  
24.     [SerializeField] Type way = Type.GraphicsWay;
25.  
26.     Material pointsMaterial;
27.  
28.     ComputeBuffer outputBuffer;
29.  
30.     private readonly Dictionary<Camera, CommandBuffer> cameras = new();
31.  
32.     private void OnEnable() {
33.         //RenderPipelineManager.beginCameraRendering += WriteLogMessage;
34.  
35.         var points = new List<float4>();
36.  
37.         for (int i = 0; i < 1000; i++) {
38.             points.Add(new float4(
39.                 i * 0.1f,
40.                 UnityEngine.Random.Range(-2, 2f),
41.                 0f,
42.                 i));
43.         }
44.  
45.         outputBuffer = new ComputeBuffer(points.Count, sizeof(float) * 4);
46.         outputBuffer.SetData(points.ToArray());
47.  
48.         pointsMaterial = new Material(shader);
49.         pointsMaterial.SetBuffer("_Points", outputBuffer);
50.     }
51.  
52.     private void OnDisable() {
53.  
54.         foreach (var kvp in cameras) {
55.  
56.             if (kvp.Key) {
57.  
58.                 kvp.Key.RemoveCommandBuffer(CameraEvent.AfterForwardOpaque, kvp.Value);
59.             }
60.         }
61.  
62.         cameras.Clear();
63.  
64.         //RenderPipelineManager.beginCameraRendering -= WriteLogMessage;
65.     }
66.  
67.     void OnWillRenderObject() {
68.         if (way != Type.CommandBufferWay)
69.             return;
70.  
71.         var active = enabled && gameObject.activeInHierarchy;
72.  
73.         if (!active) {
74.  
75.             OnDisable();
76.             return;
77.         }
78.  
79.         var camera = Camera.current;
80.  
81.         if (!camera || !material || !mesh) {
82.             return;
83.         }
84.  
85.         var matrix = Matrix4x4.identity;
86.  
87.         pointsMaterial.SetFloat("_Size", Size);
88.         pointsMaterial.SetMatrix("_LocalToWorldMatrix", transform.localToWorldMatrix);
89.  
90.         if (!cameras.TryGetValue(camera, out CommandBuffer buffer)) {
91.             buffer = new CommandBuffer {
92.                 name = "Command Buffer"
93.             };
94.  
95.             camera.AddCommandBuffer(CameraEvent.AfterForwardOpaque, buffer);
96.             cameras.Add(camera, buffer);
97.         } else {
98.             foreach (var cb in cameras.Values) {
99.                 cb.Clear();
100.                 cb.DrawMesh(mesh, matrix, material, 0, 0);
101.  
102.                 cb.DrawProcedural(matrix, pointsMaterial, 0, MeshTopology.Points, outputBuffer.count);
103.             }
104.         }
105.     }
106.  
107.     public void OnRenderObject() {
108.         if (way != Type.GraphicsWay)
109.             return;
110.  
111.         pointsMaterial.SetPass(0);
112.  
113.         pointsMaterial.SetFloat("_Size", Size);
114.         pointsMaterial.SetMatrix("_LocalToWorldMatrix", transform.localToWorldMatrix);
115.  
116.         Graphics.DrawProceduralNow(MeshTopology.Lines, outputBuffer.count);
117.     }
118.  
119.     void WriteLogMessage(ScriptableRenderContext context, Camera camera) {
120.         //Debug.Log($"Beginning rendering the camera: {camera.name}");
121.     }
122. }

Thanks

 

Solution found

Code (CSharp):

1. using System.Collections.Generic;
2. using Unity.Mathematics;
3. using UnityEngine;
4. using UnityEngine.Rendering;
5. using UnityEngine.Rendering.Universal;
6.  
7. public sealed class CommandBufferRenderInOrder : MonoBehaviour {
8.  
9.     [SerializeField] Shader shader;
10.  
11.     [SerializeField] float size = 0.25f;
12.  
13.     Pass pass;
14.  
15.     Material material;
16.  
17.     struct Data {
18.         public float3 pos;
19.     }
20.  
21.     ComputeBuffer buffer;
22.  
23.     private void OnEnable() {
24.         var points = new List<float4>();
25.  
26.         for (int i = 0; i < 1000; i++) {
27.             points.Add(new float4(
28.                 i * 0.1f,
29.                 UnityEngine.Random.Range(-2, 2f),
30.                 0f,
31.                 i));
32.         }
33.  
34.         buffer = new ComputeBuffer(points.Count, sizeof(float) * 4);
35.         buffer.SetData(points.ToArray());
36.  
37.         material = new Material(shader);
38.         material.SetBuffer("_Points", buffer);
39.  
40.         pass = new Pass {
41.             renderPassEvent = RenderPassEvent.BeforeRenderingOpaques,
42.             Material = material,
43.             Count = buffer.count
44.         };
45.  
46.         RenderPipelineManager.beginCameraRendering += Draw;
47.     }
48.  
49.     private void OnDisable() {
50.         RenderPipelineManager.beginCameraRendering -= Draw;
51.     }
52.  
53.     void Draw(ScriptableRenderContext context, Camera camera) {
54.         material.SetFloat("_Size", size);
55.         material.SetMatrix("_LocalToWorldMatrix", transform.localToWorldMatrix);
56.  
57.  
58.         var renderer = camera.GetComponent<UniversalAdditionalCameraData>().scriptableRenderer;
59.         if (renderer != null) {
60.             pass.Matrix = transform.localToWorldMatrix;
61.             renderer.EnqueuePass(pass);
62.         }
63.     }
64. }
65.  
66. class Pass : ScriptableRenderPass {
67.  
68.     public Matrix4x4 Matrix { get; set; }
69.  
70.     public Material Material { get; set; }
71.  
72.     public int Count { get; set; }
73.  
74.     public override void Execute(ScriptableRenderContext context, ref RenderingData renderingData) {
75.         CommandBuffer cb = CommandBufferPool.Get("DrawMesh");
76.         cb.DrawProcedural(Matrix, Material, 0, MeshTopology.Lines, Count);
77.         context.ExecuteCommandBuffer(cb);
78.         context.Submit();
79.         CommandBufferPool.Release(cb);
80.     }
81. }

 

I was just looking for something like this. Thank you so much for coming back and posting the solution.