up3

server/session/handler_server_bound_loading_screen.go

@@ -0,0 +1,34 @@
+package session
+
+import (
+	"fmt"
+	"github.com/df-mc/dragonfly/server/world"
+	"github.com/sandertv/gophertunnel/minecraft/protocol/packet"
+	"sync/atomic"
+)
+
+// ServerBoundLoadingScreenHandler handles loading screen updates from the clients. It is used to ensure that
+// the server knows when the client is loading a screen, and when it is done loading it.
+type ServerBoundLoadingScreenHandler struct {
+	currentID  atomic.Uint32
+	expectedID atomic.Uint32
+}
+
+// Handle ...
+func (h *ServerBoundLoadingScreenHandler) Handle(p packet.Packet, s *Session, _ *world.Tx, _ Controllable) error {
+	pk := p.(*packet.ServerBoundLoadingScreen)
+	v, ok := pk.LoadingScreenID.Value()
+	expected := h.expectedID.Load()
+
+	switch {
+	case !ok || expected == 0:
+		return nil
+	case v != expected:
+		return fmt.Errorf("expected loading screen ID %d, got %d", expected, v)
+	case pk.Type == packet.LoadingScreenTypeEnd:
+		s.changingDimension.Store(false)
+		h.expectedID.Store(0)
+	}
+
+	return nil
+}