godot/modules/multiplayer/scene_replication_interface...

537 lines
21 KiB
C++

/*************************************************************************/
/* scene_replication_interface.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2022 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2022 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#include "scene_replication_interface.h"
#include "core/io/marshalls.h"
#include "scene/main/node.h"
#include "multiplayer_spawner.h"
#include "multiplayer_synchronizer.h"
#include "scene_multiplayer.h"
#define MAKE_ROOM(m_amount) \
if (packet_cache.size() < m_amount) \
packet_cache.resize(m_amount);
void SceneReplicationInterface::_free_remotes(int p_id) {
const HashMap<uint32_t, ObjectID> remotes = rep_state->peer_get_remotes(p_id);
for (const KeyValue<uint32_t, ObjectID> &E : remotes) {
Node *node = rep_state->get_node(E.value);
ERR_CONTINUE(!node);
node->queue_delete();
}
}
void SceneReplicationInterface::on_peer_change(int p_id, bool p_connected) {
if (p_connected) {
rep_state->on_peer_change(p_id, p_connected);
for (const ObjectID &oid : rep_state->get_spawned_nodes()) {
_update_spawn_visibility(p_id, oid);
}
for (const ObjectID &oid : rep_state->get_synced_nodes()) {
MultiplayerSynchronizer *sync = rep_state->get_synchronizer(oid);
ERR_CONTINUE(!sync); // ERR_BUG
if (sync->is_multiplayer_authority()) {
_update_sync_visibility(p_id, oid);
}
}
} else {
_free_remotes(p_id);
rep_state->on_peer_change(p_id, p_connected);
}
}
void SceneReplicationInterface::on_reset() {
for (int pid : rep_state->get_peers()) {
_free_remotes(pid);
}
rep_state->reset();
}
void SceneReplicationInterface::on_network_process() {
uint64_t msec = OS::get_singleton()->get_ticks_msec();
for (int peer : rep_state->get_peers()) {
_send_sync(peer, msec);
}
}
Error SceneReplicationInterface::on_spawn(Object *p_obj, Variant p_config) {
Node *node = Object::cast_to<Node>(p_obj);
ERR_FAIL_COND_V(!node || p_config.get_type() != Variant::OBJECT, ERR_INVALID_PARAMETER);
MultiplayerSpawner *spawner = Object::cast_to<MultiplayerSpawner>(p_config.get_validated_object());
ERR_FAIL_COND_V(!spawner, ERR_INVALID_PARAMETER);
Error err = rep_state->config_add_spawn(node, spawner);
ERR_FAIL_COND_V(err != OK, err);
const ObjectID oid = node->get_instance_id();
if (multiplayer->has_multiplayer_peer() && spawner->is_multiplayer_authority()) {
rep_state->ensure_net_id(oid);
_update_spawn_visibility(0, oid);
}
ERR_FAIL_COND_V(err != OK, err);
return OK;
}
Error SceneReplicationInterface::on_despawn(Object *p_obj, Variant p_config) {
Node *node = Object::cast_to<Node>(p_obj);
ERR_FAIL_COND_V(!node || p_config.get_type() != Variant::OBJECT, ERR_INVALID_PARAMETER);
MultiplayerSpawner *spawner = Object::cast_to<MultiplayerSpawner>(p_config.get_validated_object());
ERR_FAIL_COND_V(!p_obj || !spawner, ERR_INVALID_PARAMETER);
// Forcibly despawn to all peers that knowns me.
int len = 0;
Error err = _make_despawn_packet(node, len);
ERR_FAIL_COND_V(err != OK, ERR_BUG);
const ObjectID oid = p_obj->get_instance_id();
for (int pid : rep_state->get_peers()) {
if (!rep_state->is_peer_spawn(pid, oid)) {
continue;
}
_send_raw(packet_cache.ptr(), len, pid, true);
}
// Also remove spawner tracking from the replication state.
return rep_state->config_del_spawn(node, spawner);
}
Error SceneReplicationInterface::on_replication_start(Object *p_obj, Variant p_config) {
Node *node = Object::cast_to<Node>(p_obj);
ERR_FAIL_COND_V(!node || p_config.get_type() != Variant::OBJECT, ERR_INVALID_PARAMETER);
MultiplayerSynchronizer *sync = Object::cast_to<MultiplayerSynchronizer>(p_config.get_validated_object());
ERR_FAIL_COND_V(!sync, ERR_INVALID_PARAMETER);
// Add to synchronizer list and setup visibility.
rep_state->config_add_sync(node, sync);
const ObjectID oid = node->get_instance_id();
sync->connect("visibility_changed", callable_mp(this, &SceneReplicationInterface::_visibility_changed).bind(oid));
if (multiplayer->has_multiplayer_peer() && sync->is_multiplayer_authority()) {
_update_sync_visibility(0, oid);
}
// Try to apply initial state if spawning (hack to apply if before ready).
if (pending_spawn == p_obj->get_instance_id()) {
pending_spawn = ObjectID(); // Make sure this only happens once.
const List<NodePath> props = sync->get_replication_config()->get_spawn_properties();
Vector<Variant> vars;
vars.resize(props.size());
int consumed;
Error err = MultiplayerAPI::decode_and_decompress_variants(vars, pending_buffer, pending_buffer_size, consumed);
ERR_FAIL_COND_V(err, err);
err = MultiplayerSynchronizer::set_state(props, node, vars);
ERR_FAIL_COND_V(err, err);
}
return OK;
}
Error SceneReplicationInterface::on_replication_stop(Object *p_obj, Variant p_config) {
Node *node = Object::cast_to<Node>(p_obj);
ERR_FAIL_COND_V(!node || p_config.get_type() != Variant::OBJECT, ERR_INVALID_PARAMETER);
MultiplayerSynchronizer *sync = Object::cast_to<MultiplayerSynchronizer>(p_config.get_validated_object());
ERR_FAIL_COND_V(!sync, ERR_INVALID_PARAMETER);
sync->disconnect("visibility_changed", callable_mp(this, &SceneReplicationInterface::_visibility_changed));
return rep_state->config_del_sync(node, sync);
}
void SceneReplicationInterface::_visibility_changed(int p_peer, ObjectID p_oid) {
if (rep_state->is_spawned_node(p_oid)) {
_update_spawn_visibility(p_peer, p_oid);
}
if (rep_state->is_synced_node(p_oid)) {
_update_sync_visibility(p_peer, p_oid);
}
}
Error SceneReplicationInterface::_update_sync_visibility(int p_peer, const ObjectID &p_oid) {
MultiplayerSynchronizer *sync = rep_state->get_synchronizer(p_oid);
ERR_FAIL_COND_V(!sync || !sync->is_multiplayer_authority(), ERR_BUG);
bool is_visible = sync->is_visible_to(p_peer);
if (p_peer == 0) {
for (int pid : rep_state->get_peers()) {
// Might be visible to this specific peer.
is_visible = is_visible || sync->is_visible_to(pid);
if (rep_state->is_peer_sync(pid, p_oid) == is_visible) {
continue;
}
if (is_visible) {
rep_state->peer_add_sync(pid, p_oid);
} else {
rep_state->peer_del_sync(pid, p_oid);
}
}
return OK;
} else {
if (is_visible == rep_state->is_peer_sync(p_peer, p_oid)) {
return OK;
}
if (is_visible) {
return rep_state->peer_add_sync(p_peer, p_oid);
} else {
return rep_state->peer_del_sync(p_peer, p_oid);
}
}
}
Error SceneReplicationInterface::_update_spawn_visibility(int p_peer, const ObjectID &p_oid) {
MultiplayerSpawner *spawner = rep_state->get_spawner(p_oid);
MultiplayerSynchronizer *sync = rep_state->get_synchronizer(p_oid);
Node *node = Object::cast_to<Node>(ObjectDB::get_instance(p_oid));
ERR_FAIL_COND_V(!node || !spawner || !spawner->is_multiplayer_authority(), ERR_BUG);
bool is_visible = !sync || sync->is_visible_to(p_peer);
// Spawn (and despawn) when needed.
HashSet<int> to_spawn;
HashSet<int> to_despawn;
if (p_peer) {
if (is_visible == rep_state->is_peer_spawn(p_peer, p_oid)) {
return OK;
}
if (is_visible) {
to_spawn.insert(p_peer);
} else {
to_despawn.insert(p_peer);
}
} else {
// Check visibility for each peers.
for (int pid : rep_state->get_peers()) {
bool peer_visible = is_visible || sync->is_visible_to(pid);
if (peer_visible == rep_state->is_peer_spawn(pid, p_oid)) {
continue;
}
if (peer_visible) {
to_spawn.insert(pid);
} else {
to_despawn.insert(pid);
}
}
}
if (to_spawn.size()) {
int len = 0;
_make_spawn_packet(node, len);
for (int pid : to_spawn) {
int path_id;
multiplayer->get_path_cache()->send_object_cache(spawner, pid, path_id);
_send_raw(packet_cache.ptr(), len, pid, true);
rep_state->peer_add_spawn(pid, p_oid);
}
}
if (to_despawn.size()) {
int len = 0;
_make_despawn_packet(node, len);
for (int pid : to_despawn) {
rep_state->peer_del_spawn(pid, p_oid);
_send_raw(packet_cache.ptr(), len, pid, true);
}
}
return OK;
}
Error SceneReplicationInterface::_send_raw(const uint8_t *p_buffer, int p_size, int p_peer, bool p_reliable) {
ERR_FAIL_COND_V(!p_buffer || p_size < 1, ERR_INVALID_PARAMETER);
ERR_FAIL_COND_V(!multiplayer, ERR_UNCONFIGURED);
ERR_FAIL_COND_V(!multiplayer->has_multiplayer_peer(), ERR_UNCONFIGURED);
#ifdef DEBUG_ENABLED
multiplayer->profile_bandwidth("out", p_size);
#endif
Ref<MultiplayerPeer> peer = multiplayer->get_multiplayer_peer();
peer->set_target_peer(p_peer);
peer->set_transfer_channel(0);
peer->set_transfer_mode(p_reliable ? MultiplayerPeer::TRANSFER_MODE_RELIABLE : MultiplayerPeer::TRANSFER_MODE_UNRELIABLE);
return peer->put_packet(p_buffer, p_size);
}
Error SceneReplicationInterface::_make_spawn_packet(Node *p_node, int &r_len) {
ERR_FAIL_COND_V(!multiplayer, ERR_BUG);
const ObjectID oid = p_node->get_instance_id();
MultiplayerSpawner *spawner = rep_state->get_spawner(oid);
ERR_FAIL_COND_V(!spawner || !p_node, ERR_BUG);
uint32_t nid = rep_state->get_net_id(oid);
ERR_FAIL_COND_V(!nid, ERR_UNCONFIGURED);
// Prepare custom arg and scene_id
uint8_t scene_id = spawner->find_spawnable_scene_index_from_object(oid);
bool is_custom = scene_id == MultiplayerSpawner::INVALID_ID;
Variant spawn_arg = spawner->get_spawn_argument(oid);
int spawn_arg_size = 0;
if (is_custom) {
Error err = MultiplayerAPI::encode_and_compress_variant(spawn_arg, nullptr, spawn_arg_size, false);
ERR_FAIL_COND_V(err, err);
}
// Prepare spawn state.
int state_size = 0;
Vector<Variant> state_vars;
Vector<const Variant *> state_varp;
MultiplayerSynchronizer *synchronizer = rep_state->get_synchronizer(oid);
if (synchronizer) {
ERR_FAIL_COND_V(synchronizer->get_replication_config().is_null(), ERR_BUG);
const List<NodePath> props = synchronizer->get_replication_config()->get_spawn_properties();
Error err = MultiplayerSynchronizer::get_state(props, p_node, state_vars, state_varp);
ERR_FAIL_COND_V_MSG(err != OK, err, "Unable to retrieve spawn state.");
err = MultiplayerAPI::encode_and_compress_variants(state_varp.ptrw(), state_varp.size(), nullptr, state_size);
ERR_FAIL_COND_V_MSG(err != OK, err, "Unable to encode spawn state.");
}
// Encode scene ID, path ID, net ID, node name.
int path_id = multiplayer->get_path_cache()->make_object_cache(spawner);
CharString cname = p_node->get_name().operator String().utf8();
int nlen = encode_cstring(cname.get_data(), nullptr);
MAKE_ROOM(1 + 1 + 4 + 4 + 4 + nlen + (is_custom ? 4 + spawn_arg_size : 0) + state_size);
uint8_t *ptr = packet_cache.ptrw();
ptr[0] = (uint8_t)SceneMultiplayer::NETWORK_COMMAND_SPAWN;
ptr[1] = scene_id;
int ofs = 2;
ofs += encode_uint32(path_id, &ptr[ofs]);
ofs += encode_uint32(nid, &ptr[ofs]);
ofs += encode_uint32(nlen, &ptr[ofs]);
ofs += encode_cstring(cname.get_data(), &ptr[ofs]);
// Write args
if (is_custom) {
ofs += encode_uint32(spawn_arg_size, &ptr[ofs]);
Error err = MultiplayerAPI::encode_and_compress_variant(spawn_arg, &ptr[ofs], spawn_arg_size, false);
ERR_FAIL_COND_V(err, err);
ofs += spawn_arg_size;
}
// Write state.
if (state_size) {
Error err = MultiplayerAPI::encode_and_compress_variants(state_varp.ptrw(), state_varp.size(), &ptr[ofs], state_size);
ERR_FAIL_COND_V(err, err);
ofs += state_size;
}
r_len = ofs;
return OK;
}
Error SceneReplicationInterface::_make_despawn_packet(Node *p_node, int &r_len) {
const ObjectID oid = p_node->get_instance_id();
MAKE_ROOM(5);
uint8_t *ptr = packet_cache.ptrw();
ptr[0] = (uint8_t)SceneMultiplayer::NETWORK_COMMAND_DESPAWN;
int ofs = 1;
uint32_t nid = rep_state->get_net_id(oid);
ofs += encode_uint32(nid, &ptr[ofs]);
r_len = ofs;
return OK;
}
Error SceneReplicationInterface::on_spawn_receive(int p_from, const uint8_t *p_buffer, int p_buffer_len) {
ERR_FAIL_COND_V_MSG(p_buffer_len < 14, ERR_INVALID_DATA, "Invalid spawn packet received");
int ofs = 1; // The spawn/despawn command.
uint8_t scene_id = p_buffer[ofs];
ofs += 1;
uint32_t node_target = decode_uint32(&p_buffer[ofs]);
ofs += 4;
MultiplayerSpawner *spawner = Object::cast_to<MultiplayerSpawner>(multiplayer->get_path_cache()->get_cached_object(p_from, node_target));
ERR_FAIL_COND_V(!spawner, ERR_DOES_NOT_EXIST);
ERR_FAIL_COND_V(p_from != spawner->get_multiplayer_authority(), ERR_UNAUTHORIZED);
uint32_t net_id = decode_uint32(&p_buffer[ofs]);
ofs += 4;
uint32_t name_len = decode_uint32(&p_buffer[ofs]);
ofs += 4;
ERR_FAIL_COND_V_MSG(name_len > uint32_t(p_buffer_len - ofs), ERR_INVALID_DATA, vformat("Invalid spawn packet size: %d, wants: %d", p_buffer_len, ofs + name_len));
ERR_FAIL_COND_V_MSG(name_len < 1, ERR_INVALID_DATA, "Zero spawn name size.");
// We need to make sure no trickery happens here, but we want to allow autogenerated ("@") node names.
const String name = String::utf8((const char *)&p_buffer[ofs], name_len);
ERR_FAIL_COND_V_MSG(name.validate_node_name() != name, ERR_INVALID_DATA, vformat("Invalid node name received: '%s'. Make sure to add nodes via 'add_child(node, true)' remotely.", name));
ofs += name_len;
// Check that we can spawn.
Node *parent = spawner->get_node_or_null(spawner->get_spawn_path());
ERR_FAIL_COND_V(!parent, ERR_UNCONFIGURED);
ERR_FAIL_COND_V(parent->has_node(name), ERR_INVALID_DATA);
Node *node = nullptr;
if (scene_id == MultiplayerSpawner::INVALID_ID) {
// Custom spawn.
ERR_FAIL_COND_V(p_buffer_len - ofs < 4, ERR_INVALID_DATA);
uint32_t arg_size = decode_uint32(&p_buffer[ofs]);
ofs += 4;
ERR_FAIL_COND_V(arg_size > uint32_t(p_buffer_len - ofs), ERR_INVALID_DATA);
Variant v;
Error err = MultiplayerAPI::decode_and_decompress_variant(v, &p_buffer[ofs], arg_size, nullptr, false);
ERR_FAIL_COND_V(err != OK, err);
ofs += arg_size;
node = spawner->instantiate_custom(v);
} else {
// Scene based spawn.
node = spawner->instantiate_scene(scene_id);
}
ERR_FAIL_COND_V(!node, ERR_UNAUTHORIZED);
node->set_name(name);
rep_state->peer_add_remote(p_from, net_id, node, spawner);
// The initial state will be applied during the sync config (i.e. before _ready).
int state_len = p_buffer_len - ofs;
if (state_len) {
pending_spawn = node->get_instance_id();
pending_buffer = &p_buffer[ofs];
pending_buffer_size = state_len;
}
parent->add_child(node);
spawner->emit_signal(SNAME("spawned"), node);
pending_spawn = ObjectID();
pending_buffer = nullptr;
pending_buffer_size = 0;
return OK;
}
Error SceneReplicationInterface::on_despawn_receive(int p_from, const uint8_t *p_buffer, int p_buffer_len) {
ERR_FAIL_COND_V_MSG(p_buffer_len < 5, ERR_INVALID_DATA, "Invalid spawn packet received");
int ofs = 1; // The spawn/despawn command.
uint32_t net_id = decode_uint32(&p_buffer[ofs]);
ofs += 4;
Node *node = nullptr;
Error err = rep_state->peer_del_remote(p_from, net_id, &node);
ERR_FAIL_COND_V(err != OK, err);
ERR_FAIL_COND_V(!node, ERR_BUG);
MultiplayerSpawner *spawner = rep_state->get_spawner(node->get_instance_id());
ERR_FAIL_COND_V(!spawner, ERR_DOES_NOT_EXIST);
ERR_FAIL_COND_V(p_from != spawner->get_multiplayer_authority(), ERR_UNAUTHORIZED);
if (node->get_parent() != nullptr) {
node->get_parent()->remove_child(node);
}
node->queue_delete();
spawner->emit_signal(SNAME("despawned"), node);
return OK;
}
void SceneReplicationInterface::_send_sync(int p_peer, uint64_t p_msec) {
const HashSet<ObjectID> &to_sync = rep_state->get_peer_sync_nodes(p_peer);
if (to_sync.is_empty()) {
return;
}
MAKE_ROOM(sync_mtu);
uint8_t *ptr = packet_cache.ptrw();
ptr[0] = SceneMultiplayer::NETWORK_COMMAND_SYNC;
int ofs = 1;
ofs += encode_uint16(rep_state->peer_sync_next(p_peer), &ptr[1]);
// Can only send updates for already notified nodes.
// This is a lazy implementation, we could optimize much more here with by grouping by replication config.
for (const ObjectID &oid : to_sync) {
if (!rep_state->update_sync_time(oid, p_msec)) {
continue; // nothing to sync.
}
MultiplayerSynchronizer *sync = rep_state->get_synchronizer(oid);
ERR_CONTINUE(!sync || !sync->get_replication_config().is_valid());
Node *node = rep_state->get_node(oid);
ERR_CONTINUE(!node);
uint32_t net_id = rep_state->get_net_id(oid);
if (net_id == 0 || (net_id & 0x80000000)) {
int path_id = 0;
bool verified = multiplayer->get_path_cache()->send_object_cache(sync, p_peer, path_id);
ERR_CONTINUE_MSG(path_id < 0, "This should never happen!");
if (net_id == 0) {
// First time path based ID.
net_id = path_id | 0x80000000;
rep_state->set_net_id(oid, net_id | 0x80000000);
}
if (!verified) {
// The path based sync is not yet confirmed, skipping.
continue;
}
}
int size;
Vector<Variant> vars;
Vector<const Variant *> varp;
const List<NodePath> props = sync->get_replication_config()->get_sync_properties();
Error err = MultiplayerSynchronizer::get_state(props, node, vars, varp);
ERR_CONTINUE_MSG(err != OK, "Unable to retrieve sync state.");
err = MultiplayerAPI::encode_and_compress_variants(varp.ptrw(), varp.size(), nullptr, size);
ERR_CONTINUE_MSG(err != OK, "Unable to encode sync state.");
// TODO Handle single state above MTU.
ERR_CONTINUE_MSG(size > 3 + 4 + 4 + sync_mtu, vformat("Node states bigger then MTU will not be sent (%d > %d): %s", size, sync_mtu, node->get_path()));
if (ofs + 4 + 4 + size > sync_mtu) {
// Send what we got, and reset write.
_send_raw(packet_cache.ptr(), ofs, p_peer, false);
ofs = 3;
}
if (size) {
ofs += encode_uint32(rep_state->get_net_id(oid), &ptr[ofs]);
ofs += encode_uint32(size, &ptr[ofs]);
MultiplayerAPI::encode_and_compress_variants(varp.ptrw(), varp.size(), &ptr[ofs], size);
ofs += size;
}
}
if (ofs > 3) {
// Got some left over to send.
_send_raw(packet_cache.ptr(), ofs, p_peer, false);
}
}
Error SceneReplicationInterface::on_sync_receive(int p_from, const uint8_t *p_buffer, int p_buffer_len) {
ERR_FAIL_COND_V_MSG(p_buffer_len < 11, ERR_INVALID_DATA, "Invalid sync packet received");
uint16_t time = decode_uint16(&p_buffer[1]);
int ofs = 3;
rep_state->peer_sync_recv(p_from, time);
while (ofs + 8 < p_buffer_len) {
uint32_t net_id = decode_uint32(&p_buffer[ofs]);
ofs += 4;
uint32_t size = decode_uint32(&p_buffer[ofs]);
ofs += 4;
Node *node = nullptr;
if (net_id & 0x80000000) {
MultiplayerSynchronizer *sync = Object::cast_to<MultiplayerSynchronizer>(multiplayer->get_path_cache()->get_cached_object(p_from, net_id & 0x7FFFFFFF));
ERR_FAIL_COND_V(!sync || sync->get_multiplayer_authority() != p_from, ERR_UNAUTHORIZED);
node = sync->get_node(sync->get_root_path());
} else {
node = rep_state->peer_get_remote(p_from, net_id);
}
if (!node) {
// Not received yet.
ofs += size;
continue;
}
const ObjectID oid = node->get_instance_id();
if (!rep_state->update_last_node_sync(oid, time)) {
// State is too old.
ofs += size;
continue;
}
MultiplayerSynchronizer *sync = rep_state->get_synchronizer(oid);
ERR_FAIL_COND_V(!sync, ERR_BUG);
ERR_FAIL_COND_V(size > uint32_t(p_buffer_len - ofs), ERR_BUG);
const List<NodePath> props = sync->get_replication_config()->get_sync_properties();
Vector<Variant> vars;
vars.resize(props.size());
int consumed;
Error err = MultiplayerAPI::decode_and_decompress_variants(vars, &p_buffer[ofs], size, consumed);
ERR_FAIL_COND_V(err, err);
err = MultiplayerSynchronizer::set_state(props, node, vars);
ERR_FAIL_COND_V(err, err);
ofs += size;
}
return OK;
}