fix(load): the respawn checkpoint follows ServerDoneLoadingAllObjects on every load

Live sent PlayerReachedRespawnCheckpoint right after
ServerDoneLoadingAllObjects on 143 of 157 captured loads, with a
rotation: the spawn point the player arrived at, or a checkpoint they
had reached before. DLU sent it before constructing the zone's objects,
only when a checkpoint was saved for the zone, and always unrotated.

It now goes right after ServerDoneLoadingAllObjects on every load: the
saved checkpoint when there is one (DLU saves no rotation for it, so
that one stays unrotated), otherwise the position and facing the
player loaded in at. Inferred: that the loaded-in spot matches live's
spawn point choice (live's is the spawn point object, a few tenths of
a unit from the player's start).

Check: log in fresh to a zone, die before touching any checkpoint and
respawn: you come back where you arrived, facing the same way; reach
a checkpoint, change zones and come back, die: you respawn at that
checkpoint.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dGame/dGameMessages/ZoneMessages.cpp

@@ -1,4 +1,5 @@
 #include "ZoneMessages.h"
+#include "MovementMessages.h"
 
 #include "BitStreamUtils.h"
 #include "CDClientManager.h"
@@ -35,6 +36,19 @@ namespace GameMessages {
 		return bitStream.Read(playerID);
 	}
 
+	void SendDoneLoading(const LWOOBJID player, const NiPoint3& savedCheckpoint, const NiPoint3& spawnPosition, const NiQuaternion& spawnRotation, const SystemAddress& sysAddr) {
+		ServerDoneLoadingAllObjects doneLoading;
+		doneLoading.target = player;
+		doneLoading.SendToClient(sysAddr);
+
+		PlayerReachedRespawnCheckpoint checkpoint;
+		checkpoint.target = player;
+		const bool hasSavedCheckpoint = savedCheckpoint != NiPoint3Constant::ZERO;
+		checkpoint.pos = hasSavedCheckpoint ? savedCheckpoint : spawnPosition;
+		checkpoint.rot = hasSavedCheckpoint ? QuatUtils::IDENTITY : spawnRotation;
+		checkpoint.SendToClient(sysAddr);
+	}
+
 	void SendPlayerReady(const LWOOBJID player, const LWOOBJID zoneControl, const SystemAddress& sysAddr) {
 		PlayerReady playerReady;
 		playerReady.target = player;

dGame/dGameMessages/ZoneMessages.h

@@ -47,6 +47,14 @@ namespace GameMessages {
 		ServerDoneLoadingAllObjects() : NetGameMsg(MessageType::Game::SERVER_DONE_LOADING_ALL_OBJECTS) {}
 	};
 
+	/**
+	 * Ends a player's load the way live did: ServerDoneLoadingAllObjects, then PlayerReachedRespawnCheckpoint with where
+	 * the player respawns in this zone (143 of 157 captured loads send the pair back to back, with a rotation).
+	 * That is their saved checkpoint for the zone when they have one (DLU saves no rotation for it, so it goes
+	 * unrotated), otherwise the spot and facing they loaded in at.
+	 */
+	void SendDoneLoading(LWOOBJID player, const NiPoint3& savedCheckpoint, const NiPoint3& spawnPosition, const NiQuaternion& spawnRotation, const SystemAddress& sysAddr);
+
 	// Server -> client, to one client.
 	struct InvalidZoneTransferList : public NetGameMsg {
 		InvalidZoneTransferList() : NetGameMsg(MessageType::Game::INVALID_ZONE_TRANSFER_LIST) {}

dWorldServer/WorldServer.cpp

@@ -1051,17 +1051,11 @@ void LoadPlayer(const SystemAddress& sysAddr) {
 			serverStates.Send(sysAddr);
 
 			const auto respawnPoint = player->GetCharacter()->GetRespawnPoint(Game::zoneManager->GetZone()->GetWorldID());
+			const auto spawnPosition = player->GetPosition();
+			const auto spawnRotation = player->GetRotation();
 
 			Game::entityManager->ConstructEntity(player, UNASSIGNED_SYSTEM_ADDRESS);
 
-			if (respawnPoint != NiPoint3Constant::ZERO) {
-				GameMessages::PlayerReachedRespawnCheckpoint respawnCheckpoint;
-				respawnCheckpoint.target = player->GetObjectID();
-				respawnCheckpoint.pos = respawnPoint;
-				respawnCheckpoint.rot = QuatUtils::IDENTITY;
-				respawnCheckpoint.SendToClient(player->GetSystemAddress());
-			}
-
 			// Before the models are constructed: the served meshes' checksums, so a client whose cached checksum is its own
 			// build's downloads the served mesh again (UgcManifest, docs/UgcServer.md)
 			if (g_CloneID != 0 && UgcManifest::ServesModels()) {
@@ -1141,9 +1135,7 @@ void LoadPlayer(const SystemAddress& sysAddr) {
 			invalidTransferList.bCustomerFeedbackOnExit = false;
 			invalidTransferList.bCustomerFeedbackOnInvalidMapTransfer = false;
 			invalidTransferList.SendToClient(sysAddr);
-			GameMessages::ServerDoneLoadingAllObjects doneLoading;
-			doneLoading.target = player->GetObjectID();
-			doneLoading.SendToClient(sysAddr);
+			GameMessages::SendDoneLoading(player->GetObjectID(), respawnPoint, spawnPosition, spawnRotation, sysAddr);
 
 			//Send the player it's mail count:
 			//update: this might not be needed so im going to try disabling this here.

tests/dGameTests/dGameMessagesTests/LoadSequenceTests.cpp

@@ -1,6 +1,7 @@
 #include "GameDependencies.h"
 #include "GameMessageTestUtils.h"
 
+#include "MovementMessages.h"
 #include "ZoneMessages.h"
 
 #include <gtest/gtest.h>
@@ -35,3 +36,30 @@ TEST_F(LoadSequenceTests, PlayerReadyWithoutZoneControlGoesToThePlayerOnly) {
 	ASSERT_EQ(sent.size(), 1u);
 	EXPECT_PACKET_EQ(FromHex("53 05 00 0c 00 00 00 00 01 00 00 00 00 00 00 10 fd 01"), FromCapture(sent[0]));
 }
+
+// Live: ServerDoneLoadingAllObjects, then right after it the respawn checkpoint with a rotation. Bytes: a live pair
+// from Avant Gardens Survival (a first load, so the spawn point) with the player ID replaced.
+TEST_F(LoadSequenceTests, RespawnCheckpointFollowsDoneLoading) {
+	const NiPoint3 spawn(35.218f, 365.7804f, -201.3283f);
+	const NiQuaternion facing(0.7015f, 0.0f, -0.7126f, 0.0f);
+	const auto sent = Capture([&] { GameMessages::SendDoneLoading(PLAYER, NiPoint3Constant::ZERO, spawn, facing, ClientAddress()); });
+	ASSERT_EQ(sent.size(), 2u);
+	EXPECT_PACKET_EQ(FromHex("53 05 00 0c 00 00 00 00 01 00 00 00 00 00 00 10 6a 06"), FromCapture(sent[0]));
+	EXPECT_PACKET_EQ(FromHex(
+		"53 05 00 0c 00 00 00 00 01 00 00 00 00 00 00 10 10 05 3b df 0c 42 e4 e3 b6 43 0b 54 49 c3 c0 ca 99 9f 80 00 00 00 "
+		"7a 36 1b 5f 80 00 00 00 00", 369), FromCapture(sent[1]));
+	for (const auto& packet : sent) {
+		EXPECT_EQ(packet.sysAddr, ClientAddress());
+		EXPECT_FALSE(packet.broadcast);
+	}
+}
+
+// A saved checkpoint wins over where the player loaded in; DLU keeps no rotation for it.
+TEST_F(LoadSequenceTests, SavedCheckpointIsSentUnrotated) {
+	const NiPoint3 saved(100.0f, 200.0f, 300.0f);
+	const auto sent = Capture([&] { GameMessages::SendDoneLoading(PLAYER, saved, NiPoint3(1.0f, 2.0f, 3.0f), NiQuaternion(0.7015f, 0.0f, -0.7126f, 0.0f), ClientAddress()); });
+	const auto checkpoints = SentGameMessages<GameMessages::PlayerReachedRespawnCheckpoint>(sent);
+	ASSERT_EQ(checkpoints.size(), 1u);
+	EXPECT_EQ(checkpoints[0].pos, saved);
+	EXPECT_EQ(checkpoints[0].rot, QuatUtils::IDENTITY);
+}