Resolved DrawMeshInstanced allocating like mad?

see those big GC spikes?
i'm not allocating anything, i think but i might have missed something
if the code's not wrong then DrawMeshInstanced allocates like crazy
iznogood

Code (CSharp):

1. using System;
2. using System.Collections;
3. using System.Collections.Generic;
4. using TreeEditor;
5. using UnityEngine;
6. using UnityEngine.Rendering;
7. using UnityEngine.Serialization;
8. using Random = UnityEngine.Random;
9.  
10. public class ImmediateInstantiator : MonoBehaviour
11. {
12.     public Mesh mesh;
13.     public Material material;
14.     Vector3[] positions;
15.     Matrix4x4[] matrices;
16.     const int MAX = 1022;
17.     public int howManyMatrices = 10000;
18.     public Vector2 randomness = Vector2.one * 50;
19.     MaterialPropertyBlock block;
20.  
21.     void OnEnable()
22.     {
23.         MakeRandomMatrices();
24.     }
25.  
26.     void MakeLightProbesPropertyBlock()
27.     {
28.         // Calculate probes at these positions
29.         var lightprobes = new UnityEngine.Rendering.SphericalHarmonicsL2[howManyMatrices];
30.         var occlusionprobes = new Vector4[howManyMatrices];
31.         LightProbes.CalculateInterpolatedLightAndOcclusionProbes(positions, lightprobes, occlusionprobes);
32.         // Put them into the MPB
33.         block = new MaterialPropertyBlock();
34.         block.CopySHCoefficientArraysFrom(lightprobes);
35.         block.CopyProbeOcclusionArrayFrom(occlusionprobes);
36.     }
37.  
38.     void MakeRandomMatrices()
39.     {
40.         matrices = new Matrix4x4[howManyMatrices];
41.         positions = new Vector3[howManyMatrices];
42.         for (int i = 0; i < howManyMatrices; i++)
43.         {
44.             positions[i] = Random.insideUnitSphere * randomness.y;
45.             positions[i].y = 0;
46.             matrices[i] = Matrix4x4.TRS(positions[i], Quaternion.AngleAxis(positions[i].x, Vector3.up), Vector3.one);
47.         }
48.         block = new MaterialPropertyBlock();
49.         MakeLightProbesPropertyBlock();
50.     }
51.  
52.     void WobbleScale()
53.     {
54.         for (int i = 0; i < howManyMatrices; i++)
55.             matrices[i] = Matrix4x4.TRS(positions[i], Quaternion.AngleAxis(positions[i].x, Vector3.up), (float)(Math.Sin(Time.time + positions[i].x)+2)*Vector3.one);
56.     }
57.  
58.     void Update()
59.     {
60.         // if (matrices == null || howManyMatrices != matrices.Length)
61.         //     MakeRandomMatrices();
62.         //WobbleScale();
63.         for (int i = 0; i < howManyMatrices; i += MAX)
64.         {
65.             Graphics.DrawMeshInstanced(mesh, 0, material, matrices.SubArray(i, Mathf.Min(matrices.Length - i, MAX)), Mathf.Min(matrices.Length - i, MAX), block, ShadowCastingMode.On, true, 1, Camera.current, LightProbeUsage.CustomProvided); // UseProxyVolume, lppv);
66.         }
67.     }
68. }
69.  
70. public static class Extension
71. {
72.     public static T[] SubArray<T>(this T[] data, int index, int length)
73.     {
74.         T[] result = new T[length];
75.         System.Array.Copy(data, index, result, 0, length);
76.         return result;
77.     }
78. }

 

duh
the array copy