DrawInstancedCustomCB

DrawInstancedCustomCB.cs

class DrawInstancedCustomCB : MonoBehaviour
{
    [SerializeField] private Mesh mesh;
    [SerializeField] private Material mat;

    private MaterialPropertyBlock propBlock;
    private GraphicsBuffer objectToWorlds;

    void Start()
    {
        Random.InitState(123);

        objectToWorlds = new GraphicsBuffer(GraphicsBuffer.Target.Constant, GraphicsBuffer.UsageFlags.LockBufferForWrite, 1023, UnsafeUtility.SizeOf<Matrix4x4>());
        var buffer = objectToWorlds.LockBufferForWrite<Matrix4x4>(0, objectToWorlds.count);

        for (int i = 0; i < objectToWorlds.count; i++)

            buffer[i] = Matrix4x4.TRS(new Vector3(Random.Range(-100, 100), Random.Range(-20, 20), Random.Range(-100, 100)), Quaternion.identity, Vector3.one);

        objectToWorlds.UnlockBufferAfterWrite<Matrix4x4>(1023);

        propBlock = new MaterialPropertyBlock();
        propBlock.SetConstantBuffer("UnityInstancing_PerDraw0", objectToWorlds, 0, objectToWorlds.count * objectToWorlds.stride);
    }

    void Update()
    {
        mat.enabledKeywords = new UnityEngine.Rendering.LocalKeyword[] { new UnityEngine.Rendering.LocalKeyword(mat.shader, "INSTANCING_ON") };
        Graphics.RenderMeshPrimitives(new RenderParams(mat) { matProps = propBlock }, mesh, 0, objectToWorlds.count);
    }
}