feat: complete native client rendering parity updates

extension/tests/port_login_flow_server.cpp

@@ -13,6 +13,7 @@
 
 #include <chrono>
 #include <cstdio>
+#include <cstdlib>
 #include <cstring>
 
 using namespace mtnet::classic;
@@ -23,6 +24,16 @@ constexpr std::uint32_t kHandshake = 0x2468ace0;
 constexpr int kHandshakeRetryLimit = 32; // game/src/desc.h HANDSHAKE_RETRY_LIMIT
 constexpr int kIdleMs = 20000;
 
+int fake_mob_count()
+{
+	const char* value = std::getenv("MT_FAKE_MOB_COUNT");
+	if (!value || !*value)
+		return 1;
+	char* end = nullptr;
+	const long count = std::strtol(value, &end, 10);
+	return *end == '\0' && count >= 1 && count <= 64 ? static_cast<int>(count) : 1;
+}
+
 // get_dword_time(): milliseconds on the server's clock.
 std::uint32_t now_ms()
 {
@@ -582,6 +593,20 @@ bool FakeLoginServer::ServeGame(Connection& c, int index)
 	mob_update.attack_speed = 100;
 	if (!c.Send(mob) || !c.Send(mob_update))
 		return Fail(name + ": send monster");
+	// Optional crowd for render profiling. Keep the primary dog and its click path clear so the
+	// existing combat test still attacks kMobVID; additional dogs are passive scenery.
+	const int mob_count = fake_mob_count();
+	for (int i = 1; i < mob_count; ++i)
+	{
+		GCCharacterAdd extra = mob;
+		extra.vid = kMobVID + static_cast<std::uint32_t>(i);
+		extra.x = kMobX - 350 - ((i - 1) % 8) * 170;
+		extra.y = kMobY + 250 + ((i - 1) / 8) * 190;
+		GCCharacterUpdate extra_update = mob_update;
+		extra_update.vid = extra.vid;
+		if (!c.Send(extra) || !c.Send(extra_update))
+			return Fail(name + ": send extra monster");
+	}
 	// An NPC is ADD + ADDITIONAL_INFO + UPDATE like a PC (the name is the mob_proto locale name).
 	GCCharacterAdd keeper = zeroed<GCCharacterAdd>();
 	keeper.header = HDR_GC_CHARACTER_ADD;