fix data race

examples/frameworkServer/main.go

@@ -18,7 +18,7 @@ import (
 )
 
 var motd = chat.Message{Text: "A Minecraft Server ", Extra: []chat.Message{{Text: "Powered by go-mc", Color: "yellow"}}}
-var addr = flag.String("Address", ":25565", "Listening address")
+var addr = flag.String("Address", "127.0.0.1:25565", "Listening address")
 var iconPath = flag.String("ServerIcon", "./server-icon.png", "The path to server icon")
 var maxPlayer = flag.Int("MaxPlayer", 16384, "The maximum number of players")
 var regionPath = flag.String("Regions", "./save/testdata/region/", "The region files")

server/gameplay.go

@@ -3,6 +3,7 @@ package server
 import (
 	"context"
 	_ "embed"
+	"sync"
 	"time"
 
 	"github.com/google/uuid"
@@ -23,6 +24,7 @@ type GamePlay interface {
 type Game struct {
 	*ecs.World
 	*ecs.Dispatcher
+	WorldLocker sync.Mutex
 	handlers    map[int32][]*PacketHandler
 	components  []Component
 }
@@ -68,7 +70,9 @@ func (g *Game) Run(ctx context.Context) {
 	for {
 		select {
 		case <-ticker.C:
+			g.WorldLocker.Lock()
 			g.Dispatcher.Run(g.World)
+			g.WorldLocker.Unlock()
 		case <-ctx.Done():
 			return
 		}
@@ -76,6 +80,7 @@ func (g *Game) Run(ctx context.Context) {
 }
 
 func (g *Game) AcceptPlayer(name string, id uuid.UUID, protocol int32, conn *net.Conn) {
+	g.WorldLocker.Lock()
 	eid := g.CreateEntity(
 		Client{
 			Conn:        conn,
@@ -90,6 +95,7 @@ func (g *Game) AcceptPlayer(name string, id uuid.UUID, protocol int32, conn *net
 	)
 	c := ecs.GetComponent[Client](g.World).GetValue(eid)
 	p := ecs.GetComponent[Player](g.World).GetValue(eid)
+	g.WorldLocker.Unlock()
 	defer c.packetQueue.Close()
 
 	go func() {

server/player/player.go

@@ -20,6 +20,7 @@ type playerSpawnSystem struct {
 func (p playerSpawnSystem) Update(w *ecs.World) {
 	clients := ecs.GetComponent[server.Client](w)
 	players := ecs.GetComponent[server.Player](w)
+	pos, rot := ecs.GetComponent[server.Pos](w), ecs.GetComponent[server.Rot](w)
 	profiles := ecs.GetComponent[PlayerProfile](w)
 	dimensionRes := ecs.GetResource[world.DimensionList](w)
 	players.AndNot(profiles.BitSetLike).Range(func(eid ecs.Index) {
@@ -35,6 +36,15 @@ func (p playerSpawnSystem) Update(w *ecs.World) {
 			panic("dimension " + profile.Dimension + " not found")
 		}
 		profiles.SetValue(eid, PlayerProfile{Dim: dim})
+		pos.SetValue(eid, server.Pos{
+			X: profile.Pos[0],
+			Y: profile.Pos[1],
+			Z: profile.Pos[2],
+		})
+		rot.SetValue(eid, server.Rot{
+			Yaw:   profile.Rotation[0],
+			Pitch: profile.Rotation[1],
+		})
 		client.WritePacket(server.Packet758(pk.Marshal(
 			packetid.ClientboundLogin,
 			pk.Int(eid),                     // Entity ID
@@ -59,7 +69,11 @@ func (p playerSpawnSystem) Update(w *ecs.World) {
 
 func SpawnSystem(g *server.Game, playerdataPath string) {
 	ecs.Register[PlayerProfile, *ecs.HashMapStorage[PlayerProfile]](g.World)
-	g.Dispatcher.Add(playerSpawnSystem{storage: storage{playerdataPath}}, "go-mc:player:SpawnSystem", nil)
+	g.Dispatcher.Add(
+		playerSpawnSystem{storage: storage{playerdataPath}},
+		"go-mc:player:SpawnSystem",
+		nil,
+	)
 }
 
 // PosAndRotSystem add a system to g.Dispatcher that