Instance Rendering Helper

InstancedRenderer.cs

public class InstancedRenderer : System.IDisposable
{
    const int BATCH_MAX = 1023;

    public NativeArray<Matrix4x4> matrices;
    public readonly int count, allocated;
    public readonly Mesh mesh;
    public readonly Material material;

    Matrix4x4[] batchedMatrices = new Matrix4x4[BATCH_MAX];

    public void Dispose()
    {
        matrices.Dispose();
    }

    public InstancedRenderer(int count, Mesh mesh, Material material)
    {
        this.count = count;
        this.mesh = mesh;
        this.material = material;

        var remainder = count % BATCH_MAX;
        allocated = remainder == 0 ? count : count + BATCH_MAX - remainder;
        matrices = new NativeArray<Matrix4x4>(allocated, Allocator.Persistent);
        for (int i = 0; i < count; ++i)
            matrices[i] = Matrix4x4.identity;
    }

    public void Render(int submeshIndex = 0)
    {
        int batches = Mathf.CeilToInt(count / BATCH_MAX);
        for (int i = 0; i < batches; ++i)
        {
            int batchCount = Mathf.Min(1023, count - (BATCH_MAX * i));
            int start = Mathf.Max(0, (i - 1) * BATCH_MAX);
            matrices.Slice(start, batchCount).CopyTo(batchedMatrices);
            Graphics.DrawMeshInstanced(mesh, submeshIndex, material, batchedMatrices, batchCount);
        }
    }
}