Import fork code

Netplay Refactor: Qt Redo Netplay Window

Added ggpo-x dependency.

Qt/Netplay:
Redone DirectIP Functionality
Integrate Netplay into the Pad Runahead system

Qt/Netplay: bring back in all the Netplay features besides the chat window thats still wip.

Qt/Netplay Rewire Netplay chat window

Qt/Netplay: Add Temporary alert stating this feature is not ready yet

Settings: Apply the right settings when netplay is active

Qt/Netplay: Fixed crashing causes my missing references in the gamelist also faster loading of the game at start of the session.

Netplay: fixed stuttery feeling at high ping due to wrong order of operations including input in time calculations.

Qt/Netplay Cleanup and fix stuttering at higher ping.

Qt/Netplay Cleanup and fix stuttering at higher ping.

src/core/netplay.cpp

@@ -0,0 +1,265 @@
+#include "netplay.h"
+#include "pad.h"
+#include "spu.h"
+#include "system.h"
+#include <bitset>
+
+// Netplay Impl
+Netplay::Session::Session() = default;
+
+Netplay::Session::~Session()
+{
+  Close();
+}
+
+int32_t Netplay::Session::Start(int32_t lhandle, uint16_t lport, std::string& raddr, uint16_t rport, int32_t ldelay,
+                                uint32_t pred)
+{
+  s_net_session.m_max_pred = pred;
+  /*
+  TODO: since saving every frame during rollback loses us time to do actual gamestate iterations it might be better to
+  hijack the update / save / load cycle to only save every confirmed frame only saving when actually needed.
+  */
+  GGPOSessionCallbacks cb{};
+
+  cb.advance_frame = NpAdvFrameCb;
+  cb.save_game_state = NpSaveFrameCb;
+  cb.load_game_state = NpLoadFrameCb;
+  cb.begin_game = NpBeginGameCb;
+  cb.free_buffer = NpFreeBuffCb;
+  cb.on_event = NpOnEventCb;
+
+  GGPOErrorCode result;
+
+  result = ggpo_start_session(&s_net_session.p_ggpo, &cb, "Duckstation-Netplay", 2, sizeof(Netplay::Input), lport,
+                              s_net_session.m_max_pred);
+
+  ggpo_set_disconnect_timeout(s_net_session.p_ggpo, 3000);
+  ggpo_set_disconnect_notify_start(s_net_session.p_ggpo, 1000);
+
+  for (int i = 1; i <= 2; i++)
+  {
+    GGPOPlayer player = {};
+    GGPOPlayerHandle handle = 0;
+
+    player.size = sizeof(GGPOPlayer);
+    player.player_num = i;
+
+    if (lhandle == i)
+    {
+      player.type = GGPOPlayerType::GGPO_PLAYERTYPE_LOCAL;
+      result = ggpo_add_player(s_net_session.p_ggpo, &player, &handle);
+      s_net_session.m_local_handle = handle;
+    }
+    else
+    {
+      player.type = GGPOPlayerType::GGPO_PLAYERTYPE_REMOTE;
+#ifdef _WIN32
+      strcpy_s(player.u.remote.ip_address, raddr.c_str());
+#else
+      strcpy(player.u.remote.ip_address, raddr.c_str());
+#endif
+      player.u.remote.port = rport;
+      result = ggpo_add_player(s_net_session.p_ggpo, &player, &handle);
+    }
+  }
+  ggpo_set_frame_delay(s_net_session.p_ggpo, s_net_session.m_local_handle, ldelay);
+
+  return result;
+}
+
+void Netplay::Session::Close()
+{
+  ggpo_close_session(s_net_session.p_ggpo);
+  s_net_session.p_ggpo = nullptr;
+  s_net_session.m_local_handle = GGPO_INVALID_HANDLE;
+  s_net_session.m_max_pred = 0;
+}
+
+bool Netplay::Session::IsActive()
+{
+  return s_net_session.p_ggpo != nullptr;
+}
+
+void Netplay::Session::RunIdle()
+{
+  ggpo_idle(s_net_session.p_ggpo);
+}
+
+void Netplay::Session::AdvanceFrame(uint16_t checksum)
+{
+  ggpo_advance_frame(s_net_session.p_ggpo, checksum);
+}
+
+void Netplay::Session::RunFrame(int32_t& waitTime)
+{
+  // run game
+  auto result = GGPO_OK;
+  int disconnectFlags = 0;
+  Netplay::Input inputs[2] = {};
+  // add local input
+  if (GetLocalHandle() != GGPO_INVALID_HANDLE)
+  {
+    auto inp = ReadLocalInput();
+    result = AddLocalInput(inp);
+  }
+  // advance game
+  if (GGPO_SUCCEEDED(result))
+  {
+    result = SyncInput(inputs, &disconnectFlags);
+    if (GGPO_SUCCEEDED(result))
+    {
+      // enable again when rolling back done
+      SPU::SetAudioOutputMuted(false);
+      System::NetplayAdvanceFrame (inputs, disconnectFlags);
+    }
+    else
+      RunIdle();
+  }
+  else
+    RunIdle();
+
+  waitTime = GetTimer()->UsToWaitThisLoop();
+}
+
+int32_t Netplay::Session::CurrentFrame()
+{
+  int32_t frame;
+  ggpo_get_current_frame(s_net_session.p_ggpo, frame);
+  return frame;
+}
+
+void Netplay::Session::CollectInput(uint32_t slot, uint32_t bind, float value)
+{
+  s_net_session.m_net_input[slot][bind] = value;
+}
+
+Netplay::Input Netplay::Session::ReadLocalInput()
+{
+  // get controller data of the first controller (0 internally)
+  Netplay::Input inp{0};
+  for (uint32_t i = 0; i < (uint32_t)DigitalController::Button::Count; i++)
+  {
+    if (s_net_session.m_net_input[0][i] >= 0.25f)
+      inp.button_data |= 1 << i;
+  }
+  return inp;
+}
+
+std::string& Netplay::Session::GetGamePath()
+{
+  return s_net_session.m_game_path;
+}
+
+void Netplay::Session::SetGamePath(std::string& path)
+{
+  s_net_session.m_game_path = path;
+}
+
+void Netplay::Session::SendMsg(const char* msg)
+{
+  ggpo_client_chat(s_net_session.p_ggpo, msg);
+}
+
+GGPOErrorCode Netplay::Session::SyncInput(Netplay::Input inputs[2], int* disconnect_flags)
+{
+  return ggpo_synchronize_input(s_net_session.p_ggpo, inputs, sizeof(Netplay::Input) * 2, disconnect_flags);
+}
+
+GGPOErrorCode Netplay::Session::AddLocalInput(Netplay::Input input)
+{
+  return ggpo_add_local_input(s_net_session.p_ggpo, s_net_session.m_local_handle, &input, sizeof(Netplay::Input));
+}
+
+GGPONetworkStats& Netplay::Session::GetNetStats(int32_t handle)
+{
+  ggpo_get_network_stats(s_net_session.p_ggpo, handle, &s_net_session.m_last_net_stats);
+  return s_net_session.m_last_net_stats;
+}
+
+int32_t Netplay::Session::GetPing()
+{
+  const int handle = GetLocalHandle() == 1 ? 2 : 1;
+  ggpo_get_network_stats(s_net_session.p_ggpo, handle, &s_net_session.m_last_net_stats);
+  return s_net_session.m_last_net_stats.network.ping;
+}
+
+uint32_t Netplay::Session::GetMaxPrediction()
+{
+  return s_net_session.m_max_pred;
+}
+
+GGPOPlayerHandle Netplay::Session::GetLocalHandle()
+{
+  return s_net_session.m_local_handle;
+}
+
+void Netplay::Session::SetInputs(Netplay::Input inputs[2])
+{
+  for (u32 i = 0; i < 2; i++)
+  {
+    auto cont = Pad::GetController(i);
+    std::bitset<sizeof(u32) * 8> buttonBits(inputs[i].button_data);
+    for (u32 j = 0; j < (u32)DigitalController::Button::Count; j++)
+      cont->SetBindState(j, buttonBits.test(j) ? 1.0f : 0.0f);
+  }
+}
+
+Netplay::LoopTimer* Netplay::Session::GetTimer()
+{
+  return &s_net_session.m_timer;
+}
+
+uint16_t Netplay::Session::Fletcher16(uint8_t* data, int count)
+{
+  uint16_t sum1 = 0;
+  uint16_t sum2 = 0;
+  int index;
+
+  for (index = 0; index < count; ++index)
+  {
+    sum1 = (sum1 + data[index]) % 255;
+    sum2 = (sum2 + sum1) % 255;
+  }
+
+  return (sum2 << 8) | sum1;
+}
+
+void Netplay::LoopTimer::Init(uint32_t fps, uint32_t frames_to_spread_wait)
+{
+  m_us_per_game_loop = 1000000 / fps;
+  m_us_ahead = 0;
+  m_us_extra_to_wait = 0;
+  m_frames_to_spread_wait = frames_to_spread_wait;
+  m_last_advantage = 0.0f;
+}
+
+void Netplay::LoopTimer::OnGGPOTimeSyncEvent(float frames_ahead)
+{
+  m_last_advantage = (1000.0f * frames_ahead / 60.0f);
+  m_last_advantage /= 2;
+  if (m_last_advantage < 0)
+  {
+    int t = 0;
+    t++;
+  }
+  m_us_extra_to_wait = (int)(m_last_advantage * 1000);
+  if (m_us_extra_to_wait)
+  {
+    m_us_extra_to_wait /= m_frames_to_spread_wait;
+    m_wait_count = m_frames_to_spread_wait;
+  }
+}
+
+int32_t Netplay::LoopTimer::UsToWaitThisLoop()
+{
+  int32_t timetoWait = m_us_per_game_loop;
+  if (m_wait_count)
+  {
+    timetoWait += m_us_extra_to_wait;
+    m_wait_count--;
+    if (!m_wait_count)
+      m_us_extra_to_wait = 0;
+  }
+  return timetoWait;
+}

src/core/netplay.h

@@ -0,0 +1,102 @@
+#pragma once
+
+#ifndef _NETPLAY_H
+#define _NETPLAY_H
+
+#include <array>
+#include <ggponet.h>
+#include <stdint.h>
+#include <string.h>
+#include <string>
+
+#include "common/timer.h"
+#include "digital_controller.h"
+#include "types.h"
+
+// C GGPO Event Callbacks. Should be defined in system.cpp
+extern "C" {
+bool NpAdvFrameCb(void* ctx, int flags);
+bool NpSaveFrameCb(void* ctx, uint8_t** buffer, int* len, int* checksum, int frame);
+bool NpLoadFrameCb(void* ctx, uint8_t* buffer, int len, int rb_frames, int frame_to_load);
+bool NpBeginGameCb(void* ctx, const char* game_name);
+void NpFreeBuffCb(void* ctx, void* buffer);
+bool NpOnEventCb(void* ctx, GGPOEvent* ev);
+}
+
+namespace Netplay {
+
+struct Input
+{
+  uint32_t button_data;
+};
+
+struct LoopTimer
+{
+public:
+  void Init(uint32_t fps, uint32_t frames_to_spread_wait);
+  void OnGGPOTimeSyncEvent(float frames_ahead);
+  // Call every loop, to get the amount of time the current iteration of gameloop should take
+  int32_t UsToWaitThisLoop();
+
+private:
+  float m_last_advantage = 0.0f;
+  int32_t m_us_per_game_loop = 0;
+  int32_t m_us_ahead = 0;
+  int32_t m_us_extra_to_wait = 0;
+  int32_t m_frames_to_spread_wait = 0;
+  int32_t m_wait_count = 0;
+};
+
+class Session
+{
+public:
+  Session();
+  ~Session();
+  // l = local, r = remote
+  static int32_t Start(int32_t lhandle, uint16_t lport, std::string& raddr, uint16_t rport, int32_t ldelay,
+                       uint32_t pred);
+
+  static void Close();
+  static bool IsActive();
+  static void RunIdle();
+ 
+  static void AdvanceFrame(uint16_t checksum = 0);
+  static void RunFrame(int32_t& waitTime);
+  static int32_t CurrentFrame();
+
+  static void CollectInput(uint32_t slot, uint32_t bind, float value);
+  static Netplay::Input ReadLocalInput();
+
+  static std::string& GetGamePath();
+  static void SetGamePath(std::string& path);
+  static void SendMsg(const char* msg);
+
+  static GGPOErrorCode SyncInput(Netplay::Input inputs[2], int* disconnect_flags);
+  static GGPOErrorCode AddLocalInput(Netplay::Input input);
+  static GGPONetworkStats& GetNetStats(int32_t handle);
+  static int32_t GetPing();
+  static uint32_t GetMaxPrediction();
+  static GGPOPlayerHandle GetLocalHandle();
+  static void SetInputs(Netplay::Input inputs[2]);
+
+  static Netplay::LoopTimer* GetTimer();
+  static uint16_t Fletcher16(uint8_t* data, int count);
+
+private:
+  Netplay::LoopTimer m_timer;
+  std::string m_game_path;
+  uint32_t m_max_pred = 0;
+
+  GGPOPlayerHandle m_local_handle = GGPO_INVALID_HANDLE;
+  GGPONetworkStats m_last_net_stats{};
+  GGPOSession* p_ggpo = nullptr;
+
+  std::array<std::array<float, 32>, NUM_CONTROLLER_AND_CARD_PORTS> m_net_input;
+};
+
+} // namespace Netplay
+
+// Netplay Instance
+static Netplay::Session s_net_session = Netplay::Session();
+
+#endif // !_NETPLAY_H

src/core/pad.cpp

@@ -169,12 +169,12 @@ void Pad::Reset()
 bool Pad::ShouldAvoidSavingToState()
 {
   // Currently only runahead, will also be used for netplay.
-  return g_settings.IsRunaheadEnabled();
+  return g_settings.IsRunaheadEnabled() || Netplay::Session::IsActive();
 }
 
 u32 Pad::GetMaximumRollbackFrames()
 {
-  return g_settings.runahead_frames;
+  return (Netplay::Session::IsActive() ? Netplay::Session::GetMaxPrediction() : g_settings.runahead_frames);
 }
 
 bool Pad::DoStateController(StateWrapper& sw, u32 i)

src/core/system.cpp

@@ -33,6 +33,7 @@
 #include "mdec.h"
 #include "memory_card.h"
 #include "multitap.h"
+#include "netplay.h"
 #include "pad.h"
 #include "pgxp.h"
 #include "psf_loader.h"
@@ -207,6 +208,8 @@ static std::deque<MemorySaveState> s_runahead_states;
 static bool s_runahead_replay_pending = false;
 static u32 s_runahead_frames = 0;
 
+static std::deque<MemorySaveState> s_netplay_states;
+
 static TinyString GetTimestampStringForFileName()
 {
   return TinyString::FromFmt("{:%Y-%m-%d_%H-%M-%S}", fmt::localtime(std::time(nullptr)));
@@ -1538,7 +1541,7 @@ void System::Execute()
 
     // this can shut us down
     Host::PumpMessagesOnCPUThread();
-    if (!IsValid())
+    if (!IsValid() || Netplay::Session::IsActive())
       return;
 
     if (s_frame_step_request)
@@ -1565,6 +1568,38 @@ void System::Execute()
   }
 }
 
+void System::ExecuteNetplay()
+{
+  // frame timing
+  s32 timeToWait;
+  std::chrono::steady_clock::time_point start, next, now;
+  start = next = now = std::chrono::steady_clock::now();
+  while (Netplay::Session::IsActive() && System::IsRunning())
+  {
+    now = std::chrono::steady_clock::now();
+    if (now >= next)
+    {
+      Netplay::Session::RunFrame(timeToWait);
+      next = now + std::chrono::microseconds(timeToWait);
+      s_next_frame_time += timeToWait;
+      // this can shut us down
+      Host::PumpMessagesOnCPUThread();
+      if (!IsValid() || !Netplay::Session::IsActive())
+        break;
+
+      const bool skip_present = g_host_display->ShouldSkipDisplayingFrame();
+      Host::RenderDisplay(skip_present);
+      if (!skip_present && g_host_display->IsGPUTimingEnabled())
+      {
+        s_accumulated_gpu_time += g_host_display->GetAndResetAccumulatedGPUTime();
+        s_presents_since_last_update++;
+      }
+
+      System::UpdatePerformanceCounters();
+    }
+  }
+}
+
 void System::RecreateSystem()
 {
   Assert(!IsShutdown());
@@ -4431,3 +4466,163 @@ void System::SetTimerResolutionIncreased(bool enabled)
     timeEndPeriod(1);
 #endif
 }
+
+void System::StartNetplaySession(s32 local_handle, u16 local_port, std::string& remote_addr, u16 remote_port,
+                                 s32 input_delay, std::string& game_path)
+{
+  // dont want to start a session when theres already one going on.
+  if (Netplay::Session::IsActive())
+    return;
+  // set game path for later loading during the begin game callback
+  Netplay::Session::SetGamePath(game_path);
+  // set netplay timer
+  const u32 fps = (s_region == ConsoleRegion::PAL ? 50 : 60);
+  Netplay::Session::GetTimer()->Init(fps, 180);
+  // create session
+  int result = Netplay::Session::Start(local_handle, local_port, remote_addr, remote_port, input_delay, 8);
+  if (result != GGPO_OK)
+  {
+    Log_ErrorPrintf("Failed to Create Netplay Session! Error: %d", result);
+  }
+}
+
+void System::StopNetplaySession()
+{
+  if (!Netplay::Session::IsActive())
+    return;
+  s_netplay_states.clear();
+  Netplay::Session::Close();
+}
+
+void System::NetplayAdvanceFrame(Netplay::Input inputs[], int disconnect_flags)
+{
+  Netplay::Session::SetInputs(inputs);
+  System::DoRunFrame();
+  Netplay::Session::AdvanceFrame();
+}
+
+bool NpBeginGameCb(void* ctx, const char* game_name)
+{
+  // close system if its already running
+  if (System::IsValid())
+    System::ShutdownSystem(false);
+  // fast boot the selected game and wait for the other player
+  auto param = SystemBootParameters(Netplay::Session::GetGamePath());
+  param.override_fast_boot = true;
+  if (!System::BootSystem(param))
+  {
+    System::StopNetplaySession();
+    return false;
+  }
+  // Fast Forward to Game Start
+  SPU::SetAudioOutputMuted(true);
+  while (s_internal_frame_number < 2)
+    System::DoRunFrame();
+  SPU::SetAudioOutputMuted(false);
+  return true;
+}
+
+bool NpAdvFrameCb(void* ctx, int flags)
+{
+  Netplay::Input inputs[2] = {};
+  int disconnectFlags;
+  Netplay::Session::SyncInput(inputs, &disconnectFlags);
+  System::NetplayAdvanceFrame(inputs, disconnectFlags);
+  return true;
+}
+
+bool NpSaveFrameCb(void* ctx, uint8_t** buffer, int* len, int* checksum, int frame)
+{
+  bool result = false;
+  // give ggpo something so it doesnt complain.
+  u8 dummyData = 43;
+  *len = sizeof(u8);
+  *buffer = (unsigned char*)malloc(*len);
+  if (!*buffer)
+    return false;
+  memcpy(*buffer, &dummyData, *len);
+  // store state for later.
+  int pred = Netplay::Session::GetMaxPrediction();
+  if (frame < pred && s_netplay_states.size() < pred)
+  {
+    MemorySaveState save;
+    result = System::SaveMemoryState(&save);
+    s_netplay_states.push_back(std::move(save));
+  }
+  else
+  {
+    // reuse streams
+    result = System::SaveMemoryState(&s_netplay_states[frame % pred]);
+  }
+  return result;
+}
+
+bool NpLoadFrameCb(void* ctx, uint8_t* buffer, int len, int rb_frames, int frame_to_load)
+{
+  // Disable Audio For upcoming rollback
+  SPU::SetAudioOutputMuted(true);
+  return System::LoadMemoryState(s_netplay_states[frame_to_load % Netplay::Session::GetMaxPrediction()]);
+}
+
+bool NpOnEventCb(void* ctx, GGPOEvent* ev)
+{
+  char buff[128];
+  std::string msg;
+  switch (ev->code)
+  {
+    case GGPOEventCode::GGPO_EVENTCODE_CONNECTED_TO_PEER:
+      sprintf(buff, "Netplay Connected To Player: %d", ev->u.connected.player);
+      msg = buff;
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_SYNCHRONIZING_WITH_PEER:
+      sprintf(buff, "Netplay Synchronzing: %d/%d", ev->u.synchronizing.count, ev->u.synchronizing.total);
+      msg = buff;
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_SYNCHRONIZED_WITH_PEER:
+      sprintf(buff, "Netplay Synchronized With Player: %d", ev->u.synchronized.player);
+      msg = buff;
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_DISCONNECTED_FROM_PEER:
+      sprintf(buff, "Netplay Player: %d Disconnected", ev->u.disconnected.player);
+      msg = buff;
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_RUNNING:
+      msg = "Netplay Is Running";
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_CONNECTION_INTERRUPTED:
+      sprintf(buff, "Netplay Player: %d Connection Interupted, Timeout: %d", ev->u.connection_interrupted.player,
+              ev->u.connection_interrupted.disconnect_timeout);
+      msg = buff;
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_CONNECTION_RESUMED:
+      sprintf(buff, "Netplay Player: %d Connection Resumed", ev->u.connection_resumed.player);
+      msg = buff;
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_CHAT:
+      sprintf(buff, "%s", ev->u.chat.msg);
+      msg = buff;
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_TIMESYNC:
+      Netplay::Session::GetTimer()->OnGGPOTimeSyncEvent(ev->u.timesync.frames_ahead);
+      break;
+    case GGPOEventCode::GGPO_EVENTCODE_DESYNC:
+      sprintf(buff, "Netplay Desync Detected!: Frame: %d, L:%u, R:%u", ev->u.desync.nFrameOfDesync,
+              ev->u.desync.ourCheckSum, ev->u.desync.remoteChecksum);
+      msg = buff;
+      break;
+    default:
+      sprintf(buff, "Netplay Event Code: %d", ev->code);
+      msg = buff;
+  }
+  if (!msg.empty())
+  {
+    Host::OnNetplayMessage(msg);
+    Log_InfoPrintf("%s", msg.c_str());
+  }
+  return true;
+}
+
+void NpFreeBuffCb(void* ctx, void* buffer)
+{
+  free(buffer);
+}

src/core/system.h

@@ -3,6 +3,7 @@
 
 #pragma once
 #include "common/timer.h"
+#include "netplay.h"
 #include "settings.h"
 #include "timing_event.h"
 #include "types.h"
@@ -19,11 +20,10 @@ class Controller;
 struct CheatCode;
 class CheatList;
 
-namespace BIOS
+namespace BIOS {
-{
 struct ImageInfo;
 struct Hash;
-}
+} // namespace BIOS
 
 struct SystemBootParameters
 {
@@ -227,6 +227,9 @@ bool SaveResumeState();
 /// Runs the VM until the CPU execution is canceled.
 void Execute();
 
+/// Runs the VM and netplay loop. when the netplay loop cancels it switches to normal execute mode.
+void ExecuteNetplay();
+
 /// Switches the GPU renderer by saving state, recreating the display window, and restoring state (if needed).
 void RecreateSystem();
 
@@ -452,6 +455,11 @@ void UpdateMemorySaveStateSettings();
 bool LoadRewindState(u32 skip_saves = 0, bool consume_state = true);
 void SetRunaheadReplayFlag();
 
+/// Netplay
+void StartNetplaySession(s32 local_handle, u16 local_port, std::string& remote_addr, u16 remote_port, s32 input_delay,
+                         std::string& game_path);
+void StopNetplaySession();
+void NetplayAdvanceFrame(Netplay::Input inputs[], int disconnect_flags);
 } // namespace System
 
 namespace Host {
@@ -500,4 +508,6 @@ bool IsFullscreen();
 
 /// Alters fullscreen state of hosting application.
 void SetFullscreen(bool enabled);
+// netplay
+void OnNetplayMessage(std::string& message);
 } // namespace Host

src/duckstation-qt/mainwindow.cpp

@@ -50,6 +50,7 @@
 #ifdef _WIN32
 #include "common/windows_headers.h"
 #include <Dbt.h>
+#include <WinSock2.h>
 #endif
 
 Log_SetChannel(MainWindow);
@@ -105,6 +106,12 @@ MainWindow::MainWindow() : QMainWindow(nullptr)
 #if !defined(_WIN32) && !defined(__APPLE__)
   s_use_central_widget = DisplayContainer::isRunningOnWayland();
 #endif
+
+#if defined(_WIN32)
+  // Setup WinSock
+  WSADATA wd = {};
+  WSAStartup(MAKEWORD(2, 2), &wd);
+#endif
 }
 
 MainWindow::~MainWindow()
@@ -119,6 +126,8 @@ MainWindow::~MainWindow()
 
 #ifdef _WIN32
   unregisterForDeviceNotifications();
+  // Cleanup WinSock
+  WSACleanup();
 #endif
 #ifdef __APPLE__
   FrontendCommon::RemoveThemeChangeHandler(this);
@@ -1556,9 +1565,13 @@ void MainWindow::setupAdditionalUi()
   m_status_fps_widget->hide();
 
   m_status_vps_widget = new QLabel(m_ui.statusBar);
-  m_status_vps_widget->setFixedSize(125, 16);
+  m_status_vps_widget->setFixedSize(120, 16);
   m_status_vps_widget->hide();
 
+  m_status_ping_widget = new QLabel(m_ui.statusBar);
+  m_status_ping_widget->setFixedSize(110, 16);
+  m_status_ping_widget->hide();
+
   m_settings_toolbar_menu = new QMenu(m_ui.toolBar);
   m_settings_toolbar_menu->addAction(m_ui.actionSettings);
   m_settings_toolbar_menu->addAction(m_ui.actionViewGameProperties);
@@ -1764,6 +1777,7 @@ void MainWindow::updateStatusBarWidgetVisibility()
   Update(m_status_resolution_widget, s_system_valid && !s_system_paused, 0);
   Update(m_status_fps_widget, s_system_valid && !s_system_paused, 0);
   Update(m_status_vps_widget, s_system_valid && !s_system_paused, 0);
+  Update(m_status_ping_widget, s_system_valid && !s_system_paused && m_netplay_window != nullptr, 0);
 }
 
 void MainWindow::updateWindowTitle()
@@ -2089,6 +2103,9 @@ void MainWindow::connectSignals()
   addThemeToMenu(tr("Dark Fusion (Blue)"), QStringLiteral("darkfusionblue"));
   addThemeToMenu(tr("QDarkStyle"), QStringLiteral("qdarkstyle"));
   updateMenuSelectedTheme();
+
+  // Netplay UI , TODO
+  connect(m_ui.actionCreateNetplaySession, &QAction::triggered, this, &MainWindow::onNetplaySessionCreated);
 }
 
 void MainWindow::addThemeToMenu(const QString& name, const QString& key)
@@ -2752,6 +2769,28 @@ void MainWindow::onCPUDebuggerClosed()
   m_debugger_window = nullptr;
 }
 
+void MainWindow::onNetplaySessionCreated()
+{
+  Assert(!m_netplay_window);
+
+  m_netplay_window = new NetplayWidget(this);
+  m_netplay_window->setWindowIcon(windowIcon());
+  m_netplay_window->setWindowTitle("Netplay Session");
+  m_netplay_window->setWindowFlags(windowFlags() | Qt::WindowMinimizeButtonHint);
+  m_netplay_window->show();
+
+  m_ui.menuNetplay->setDisabled(true);
+
+  connect(m_netplay_window, &NetplayWidget::finished, [this]() {
+    Assert(m_netplay_window);
+
+    m_netplay_window->deleteLater();
+    m_netplay_window = nullptr;
+
+    m_ui.menuNetplay->setDisabled(false);
+  });
+}
+
 void MainWindow::onToolsOpenDataDirectoryTriggered()
 {
   QtUtils::OpenURL(this, QUrl::fromLocalFile(QString::fromStdString(EmuFolders::DataRoot)));

src/duckstation-qt/mainwindow.h

@@ -16,6 +16,7 @@
 #include "displaywidget.h"
 #include "settingsdialog.h"
 #include "ui_mainwindow.h"
+#include <netplaywidget.h>
 
 class QLabel;
 class QThread;
@@ -89,6 +90,7 @@ public:
   ALWAYS_INLINE QLabel* getStatusResolutionWidget() const { return m_status_resolution_widget; }
   ALWAYS_INLINE QLabel* getStatusFPSWidget() const { return m_status_fps_widget; }
   ALWAYS_INLINE QLabel* getStatusVPSWidget() const { return m_status_vps_widget; }
+  ALWAYS_INLINE QLabel* getStatusPingWidget() const { return m_status_ping_widget; }
 
 public Q_SLOTS:
   /// Updates debug menu visibility (hides if disabled).
@@ -168,6 +170,8 @@ private Q_SLOTS:
   void openCPUDebugger();
   void onCPUDebuggerClosed();
 
+  void onNetplaySessionCreated();
+
 protected:
   void showEvent(QShowEvent* event) override;
   void closeEvent(QCloseEvent* event) override;
@@ -262,6 +266,7 @@ private:
   QLabel* m_status_renderer_widget = nullptr;
   QLabel* m_status_fps_widget = nullptr;
   QLabel* m_status_vps_widget = nullptr;
+  QLabel* m_status_ping_widget = nullptr;
   QLabel* m_status_resolution_widget = nullptr;
 
   QMenu* m_settings_toolbar_menu = nullptr;
@@ -273,6 +278,7 @@ private:
   MemoryCardEditorDialog* m_memory_card_editor_dialog = nullptr;
   CheatManagerDialog* m_cheat_manager_dialog = nullptr;
   DebuggerWindow* m_debugger_window = nullptr;
+  NetplayWidget* m_netplay_window = nullptr;
 
   std::string m_current_game_title;
   std::string m_current_game_serial;

src/duckstation-qt/mainwindow.ui

@@ -17,7 +17,7 @@
    <string>DuckStation</string>
   </property>
   <property name="windowIcon">
-   <iconset>
+   <iconset resource="resources/resources.qrc">
     <normaloff>:/icons/duck.png</normaloff>:/icons/duck.png</iconset>
   </property>
   <widget class="QStackedWidget" name="mainContainer"/>
@@ -27,7 +27,7 @@
      <x>0</x>
      <y>0</y>
      <width>800</width>
-     <height>22</height>
+     <height>21</height>
     </rect>
    </property>
    <widget class="QMenu" name="menuSystem">
@@ -237,8 +237,15 @@
     <addaction name="separator"/>
     <addaction name="actionOpenDataDirectory"/>
    </widget>
+   <widget class="QMenu" name="menuNetplay">
+    <property name="title">
+     <string>Netplay</string>
+    </property>
+    <addaction name="actionCreateNetplaySession"/>
+   </widget>
    <addaction name="menuSystem"/>
    <addaction name="menuSettings"/>
+   <addaction name="menuNetplay"/>
    <addaction name="menu_View"/>
    <addaction name="menu_Tools"/>
    <addaction name="menuDebug"/>
@@ -472,7 +479,7 @@
   </action>
   <action name="actionGitHubRepository">
    <property name="icon">
-    <iconset>
+    <iconset resource="resources/resources.qrc">
      <normaloff>:/icons/github.png</normaloff>:/icons/github.png</iconset>
    </property>
    <property name="text">
@@ -481,7 +488,7 @@
   </action>
   <action name="actionIssueTracker">
    <property name="icon">
-    <iconset>
+    <iconset resource="resources/resources.qrc">
      <normaloff>:/icons/IssueTracker.png</normaloff>:/icons/IssueTracker.png</iconset>
    </property>
    <property name="text">
@@ -490,7 +497,7 @@
   </action>
   <action name="actionDiscordServer">
    <property name="icon">
-    <iconset>
+    <iconset resource="resources/resources.qrc">
      <normaloff>:/icons/discord.png</normaloff>:/icons/discord.png</iconset>
    </property>
    <property name="text">
@@ -508,7 +515,7 @@
   </action>
   <action name="actionAboutQt">
    <property name="icon">
-    <iconset>
+    <iconset resource="resources/resources.qrc">
      <normaloff>:/icons/QT.png</normaloff>:/icons/QT.png</iconset>
    </property>
    <property name="text">
@@ -517,7 +524,7 @@
   </action>
   <action name="actionAbout">
    <property name="icon">
-    <iconset>
+    <iconset resource="resources/resources.qrc">
      <normaloff>:/icons/duck_64.png</normaloff>:/icons/duck_64.png</iconset>
    </property>
    <property name="text">
@@ -976,6 +983,11 @@
     <string>Cover Downloader</string>
    </property>
   </action>
+  <action name="actionCreateNetplaySession">
+   <property name="text">
+    <string>Create Session</string>
+   </property>
+  </action>
  </widget>
  <resources>
   <include location="resources/resources.qrc"/>

src/duckstation-qt/netplaywidget.cpp

@@ -0,0 +1,210 @@
+#include "netplaywidget.h"
+#include "ui_netplaywidget.h"
+#include <QtWidgets/qmessagebox.h>
+#include <common/log.h>
+#include <core/controller.h>
+#include <qthost.h>
+
+Log_SetChannel(NetplayWidget);
+
+NetplayWidget::NetplayWidget(QWidget* parent) : QDialog(parent), m_ui(new Ui::NetplayWidget)
+{
+  m_ui->setupUi(this);
+  FillGameList();
+  SetupConnections();
+  SetupConstraints();
+  CheckControllersSet();
+}
+
+NetplayWidget::~NetplayWidget()
+{
+  StopSession();
+  delete m_ui;
+}
+
+void NetplayWidget::FillGameList()
+{
+  // Get all games and fill the list later to know which game to boot.
+  s32 numGames = GameList::GetEntryCount();
+  for (s32 i = 0; i < numGames; i++)
+  {
+    const auto& entry = GameList::GetEntryByIndex(i);
+    std::string baseFilename = entry->path.substr(entry->path.find_last_of("/\\") + 1);
+    m_ui->cbSelectedGame->addItem(
+      QString::fromStdString("[" + entry->serial + "] " + entry->title + " | " + baseFilename));
+    m_available_games.push_back(entry->path);
+  }
+}
+
+void NetplayWidget::SetupConnections()
+{
+  // connect netplay window messages
+  connect(g_emu_thread, &EmuThread::onNetplayMessage, this, &NetplayWidget::OnMsgReceived);
+  // connect sending messages when the chat button has been pressed
+  connect(m_ui->btnSendMsg, &QPushButton::pressed, [this]() {
+    // check if message aint empty and the complete message ( message + name + ":" + space) is below 120 characters
+    auto msg = m_ui->tbNetplayChat->toPlainText().trimmed();
+    QString completeMsg = m_ui->lePlayerName->text().trimmed() + ": " + msg;
+    if (completeMsg.length() > 120)
+      return;
+    m_ui->lwChatWindow->addItem(completeMsg);
+    m_ui->tbNetplayChat->clear();
+    if (!g_emu_thread)
+      return;
+    g_emu_thread->sendNetplayMessage(completeMsg);
+  });
+
+  // switch between DIRECT IP and traversal options
+  connect(m_ui->cbConnMode, &QComboBox::currentIndexChanged, [this]() {
+    // zero is DIRECT IP mode
+    const bool action = (m_ui->cbConnMode->currentIndex() == 0 ? true : false);
+    m_ui->frDirectIP->setVisible(action);
+    m_ui->frDirectIP->setEnabled(action);
+    m_ui->btnStartSession->setEnabled(action);
+    m_ui->tabTraversal->setEnabled(!action);
+    m_ui->btnTraversalJoin->setEnabled(!action);
+    m_ui->btnTraversalHost->setEnabled(!action);
+  });
+
+  // actions to be taken when stopping a session.
+  auto fnOnStopSession = [this]() {
+    m_ui->btnSendMsg->setEnabled(false);
+    m_ui->tbNetplayChat->setEnabled(false);
+    m_ui->btnStopSession->setEnabled(false);
+    m_ui->btnStartSession->setEnabled(true);
+    m_ui->btnTraversalHost->setEnabled(true);
+    m_ui->btnTraversalJoin->setEnabled(true);
+    m_ui->lblHostCodeResult->setText("XXXXXXXXX-");
+    StopSession();
+  };
+
+  // check session when start button pressed if there is the needed info depending on the connection mode
+  auto fnCheckValid = [this, fnOnStopSession]() {
+    const bool action = (m_ui->cbConnMode->currentIndex() == 0 ? true : false);
+    if (CheckInfoValid(action))
+    {
+      m_ui->btnSendMsg->setEnabled(true);
+      m_ui->tbNetplayChat->setEnabled(true);
+      m_ui->btnStopSession->setEnabled(true);
+      m_ui->btnStartSession->setEnabled(false);
+      m_ui->btnTraversalHost->setEnabled(false);
+      m_ui->btnTraversalJoin->setEnabled(false);
+      if (!StartSession(action))
+        fnOnStopSession();
+    }
+  };
+  connect(m_ui->btnStartSession, &QPushButton::pressed, fnCheckValid);
+  connect(m_ui->btnTraversalJoin, &QPushButton::pressed, fnCheckValid);
+  connect(m_ui->btnTraversalHost, &QPushButton::pressed, fnCheckValid);
+  // when pressed revert back to the previous ui state so people can start a new session.
+  connect(m_ui->btnStopSession, &QPushButton::pressed, fnOnStopSession);
+}
+
+void NetplayWidget::SetupConstraints()
+{
+  m_ui->lwChatWindow->setWordWrap(true);
+  m_ui->sbLocalPort->setRange(0, 65535);
+  m_ui->sbRemotePort->setRange(0, 65535);
+  m_ui->sbInputDelay->setRange(0, 10);
+  m_ui->leRemoteAddr->setMaxLength(15);
+  m_ui->lePlayerName->setMaxLength(12);
+  QString IpRange = "(?:[0-1]?[0-9]?[0-9]|2[0-4][0-9]|25[0-5])";
+  QRegularExpression IpRegex("^" + IpRange + "(\\." + IpRange + ")" + "(\\." + IpRange + ")" + "(\\." + IpRange + ")$");
+  QRegularExpressionValidator* ipValidator = new QRegularExpressionValidator(IpRegex, this);
+  m_ui->leRemoteAddr->setValidator(ipValidator);
+}
+
+bool NetplayWidget::CheckInfoValid(bool direct_ip)
+{
+  if (!direct_ip)
+  {
+    QMessageBox errBox;
+    errBox.setFixedSize(500, 200);
+    errBox.information(this, "Netplay Session", "Traversal Mode is not supported yet!");
+    errBox.show();
+    return false;
+  }
+
+  bool err = false;
+  // check nickname, game selected and player selected.
+  if (m_ui->lePlayerName->text().trimmed().isEmpty() || m_ui->cbSelectedGame->currentIndex() == 0 ||
+      m_ui->cbLocalPlayer->currentIndex() == 0)
+    err = true;
+  // check if direct ip details have been filled in
+  if (direct_ip && (m_ui->leRemoteAddr->text().trimmed().isEmpty() || m_ui->sbRemotePort->value() == 0 ||
+                    m_ui->sbLocalPort->value() == 0))
+    err = true;
+  // check if host code has been filled in
+  if (!direct_ip && m_ui->leHostCode->text().trimmed().isEmpty() &&
+      m_ui->tabTraversal->currentWidget() == m_ui->tabJoin)
+    err = true;
+  // if an err has been found throw
+  if (err)
+  {
+    QMessageBox errBox;
+    errBox.setFixedSize(500, 200);
+    errBox.information(this, "Netplay Session", "Please fill in all the needed fields!");
+    errBox.show();
+    return !err;
+  }
+  // check if controllers are set
+  err = !CheckControllersSet();
+  // everything filled in. inverse cuz we would like to return true if the info is valid.
+  return !err;
+}
+
+bool NetplayWidget::CheckControllersSet()
+{
+  bool err = false;
+  // check whether its controllers are set right
+  for (u32 i = 0; i < 2; i++)
+  {
+    const Controller::ControllerInfo* cinfo = Controller::GetControllerInfo(g_settings.controller_types[i]);
+    if (!cinfo || cinfo->type != ControllerType::DigitalController)
+    {
+      err = true;
+    }
+  }
+  // if an err has been found throw popup
+  if (err)
+  {
+    QMessageBox errBox;
+    errBox.information(this, "Netplay Session",
+                       "Please make sure the controllers are both enabled and set as Digital Controllers");
+    errBox.setFixedSize(500, 200);
+    errBox.show();
+  }
+  // controllers are set right
+  return !err;
+}
+
+bool NetplayWidget::StartSession(bool direct_ip)
+{
+  if (!g_emu_thread)
+    return false;
+
+  int localHandle = m_ui->cbLocalPlayer->currentIndex();
+  int inputDelay = m_ui->sbInputDelay->value();
+  quint16 localPort = m_ui->sbLocalPort->value();
+  const QString& remoteAddr = m_ui->leRemoteAddr->text();
+  quint16 remotePort = m_ui->sbRemotePort->value();
+  const QString& gamePath = QString::fromStdString(m_available_games[m_ui->cbSelectedGame->currentIndex() - 1]);
+
+  if (!direct_ip)
+    return false; // TODO: Handle Nat Traversal and use that information by overriding the information above.
+
+  g_emu_thread->startNetplaySession(localHandle, localPort, remoteAddr, remotePort, inputDelay, gamePath);
+  return true;
+}
+
+void NetplayWidget::StopSession()
+{
+  if (!g_emu_thread)
+    return;
+  g_emu_thread->stopNetplaySession();
+}
+
+void NetplayWidget::OnMsgReceived(const QString& msg) 
+{
+  m_ui->lwChatWindow->addItem(msg);
+}

src/duckstation-qt/netplaywidget.h

@@ -0,0 +1,34 @@
+#ifndef NETPLAYWIDGET_H
+#define NETPLAYWIDGET_H
+
+#include <QtWidgets/QDialog>
+#include <frontend-common/game_list.h>
+
+namespace Ui {
+class NetplayWidget;
+}
+
+class NetplayWidget : public QDialog
+{
+  Q_OBJECT
+
+public:
+  explicit NetplayWidget(QWidget* parent = nullptr);
+  ~NetplayWidget();
+
+private:
+  void FillGameList();
+  void SetupConnections();
+  void SetupConstraints();
+  bool CheckInfoValid(bool direct_ip);
+  bool CheckControllersSet();
+  bool StartSession(bool direct_ip);
+  void StopSession();
+  void OnMsgReceived(const QString& msg);
+
+private:
+  Ui::NetplayWidget* m_ui;
+  std::vector<std::string> m_available_games;
+};
+
+#endif // NETPLAYWIDGET_H

src/duckstation-qt/netplaywidget.ui

@@ -0,0 +1,710 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>NetplayWidget</class>
+ <widget class="QDialog" name="NetplayWidget">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>700</width>
+    <height>448</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="minimumSize">
+   <size>
+    <width>700</width>
+    <height>448</height>
+   </size>
+  </property>
+  <property name="maximumSize">
+   <size>
+    <width>700</width>
+    <height>448</height>
+   </size>
+  </property>
+  <property name="font">
+   <font>
+    <kerning>true</kerning>
+   </font>
+  </property>
+  <property name="windowTitle">
+   <string>Dialog</string>
+  </property>
+  <property name="modal">
+   <bool>false</bool>
+  </property>
+  <widget class="QFrame" name="frMain">
+   <property name="geometry">
+    <rect>
+     <x>0</x>
+     <y>0</y>
+     <width>701</width>
+     <height>461</height>
+    </rect>
+   </property>
+   <property name="sizePolicy">
+    <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
+     <horstretch>0</horstretch>
+     <verstretch>0</verstretch>
+    </sizepolicy>
+   </property>
+   <property name="minimumSize">
+    <size>
+     <width>701</width>
+     <height>461</height>
+    </size>
+   </property>
+   <property name="maximumSize">
+    <size>
+     <width>701</width>
+     <height>461</height>
+    </size>
+   </property>
+   <property name="frameShape">
+    <enum>QFrame::StyledPanel</enum>
+   </property>
+   <property name="frameShadow">
+    <enum>QFrame::Raised</enum>
+   </property>
+   <widget class="Line" name="line_2">
+    <property name="geometry">
+     <rect>
+      <x>0</x>
+      <y>40</y>
+      <width>711</width>
+      <height>20</height>
+     </rect>
+    </property>
+    <property name="orientation">
+     <enum>Qt::Horizontal</enum>
+    </property>
+   </widget>
+   <widget class="QPlainTextEdit" name="tbNetplayChat">
+    <property name="enabled">
+     <bool>false</bool>
+    </property>
+    <property name="geometry">
+     <rect>
+      <x>380</x>
+      <y>400</y>
+      <width>231</width>
+      <height>41</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>10</pointsize>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="plainText">
+     <string>...
+</string>
+    </property>
+   </widget>
+   <widget class="QPushButton" name="btnSendMsg">
+    <property name="enabled">
+     <bool>false</bool>
+    </property>
+    <property name="geometry">
+     <rect>
+      <x>620</x>
+      <y>400</y>
+      <width>61</width>
+      <height>41</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>11</pointsize>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="text">
+     <string>Send</string>
+    </property>
+   </widget>
+   <widget class="Line" name="line">
+    <property name="geometry">
+     <rect>
+      <x>350</x>
+      <y>50</y>
+      <width>21</width>
+      <height>411</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>9</pointsize>
+      <italic>false</italic>
+      <bold>false</bold>
+      <underline>false</underline>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="orientation">
+     <enum>Qt::Vertical</enum>
+    </property>
+   </widget>
+   <widget class="QListWidget" name="lwChatWindow">
+    <property name="geometry">
+     <rect>
+      <x>380</x>
+      <y>60</y>
+      <width>301</width>
+      <height>331</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>11</pointsize>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="verticalScrollBarPolicy">
+     <enum>Qt::ScrollBarAsNeeded</enum>
+    </property>
+    <property name="horizontalScrollBarPolicy">
+     <enum>Qt::ScrollBarAlwaysOff</enum>
+    </property>
+    <item>
+     <property name="text">
+      <string/>
+     </property>
+    </item>
+   </widget>
+   <widget class="QFrame" name="frDirectIP">
+    <property name="enabled">
+     <bool>true</bool>
+    </property>
+    <property name="geometry">
+     <rect>
+      <x>9</x>
+      <y>220</y>
+      <width>341</width>
+      <height>171</height>
+     </rect>
+    </property>
+    <property name="autoFillBackground">
+     <bool>true</bool>
+    </property>
+    <property name="frameShape">
+     <enum>QFrame::StyledPanel</enum>
+    </property>
+    <property name="frameShadow">
+     <enum>QFrame::Raised</enum>
+    </property>
+    <widget class="QWidget" name="formLayoutWidget">
+     <property name="geometry">
+      <rect>
+       <x>10</x>
+       <y>0</y>
+       <width>321</width>
+       <height>161</height>
+      </rect>
+     </property>
+     <layout class="QGridLayout" name="gridLayout_2">
+      <item row="2" column="1">
+       <widget class="QSpinBox" name="sbRemotePort">
+        <property name="font">
+         <font>
+          <pointsize>11</pointsize>
+          <kerning>true</kerning>
+         </font>
+        </property>
+        <property name="maximum">
+         <number>65535</number>
+        </property>
+        <property name="singleStep">
+         <number>1</number>
+        </property>
+        <property name="stepType">
+         <enum>QAbstractSpinBox::DefaultStepType</enum>
+        </property>
+        <property name="value">
+         <number>2000</number>
+        </property>
+       </widget>
+      </item>
+      <item row="1" column="1" colspan="2">
+       <widget class="QLineEdit" name="leRemoteAddr">
+        <property name="font">
+         <font>
+          <pointsize>11</pointsize>
+          <kerning>true</kerning>
+         </font>
+        </property>
+        <property name="text">
+         <string/>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="0">
+       <widget class="QLabel" name="lblLocalPort">
+        <property name="font">
+         <font>
+          <pointsize>11</pointsize>
+          <kerning>true</kerning>
+         </font>
+        </property>
+        <property name="text">
+         <string>Local Port :</string>
+        </property>
+       </widget>
+      </item>
+      <item row="1" column="0">
+       <widget class="QLabel" name="lblRemoteAddr">
+        <property name="font">
+         <font>
+          <pointsize>11</pointsize>
+          <kerning>true</kerning>
+         </font>
+        </property>
+        <property name="text">
+         <string>Remote Address :</string>
+        </property>
+       </widget>
+      </item>
+      <item row="2" column="0">
+       <widget class="QLabel" name="lblRemotePort">
+        <property name="font">
+         <font>
+          <pointsize>11</pointsize>
+          <kerning>true</kerning>
+         </font>
+        </property>
+        <property name="text">
+         <string>Remote Port :</string>
+        </property>
+       </widget>
+      </item>
+      <item row="2" column="2">
+       <widget class="QPushButton" name="btnStartSession">
+        <property name="enabled">
+         <bool>true</bool>
+        </property>
+        <property name="font">
+         <font>
+          <pointsize>11</pointsize>
+          <kerning>true</kerning>
+         </font>
+        </property>
+        <property name="text">
+         <string>Start Session</string>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="1" colspan="2">
+       <widget class="QSpinBox" name="sbLocalPort">
+        <property name="font">
+         <font>
+          <pointsize>11</pointsize>
+          <kerning>true</kerning>
+         </font>
+        </property>
+        <property name="maximum">
+         <number>65535</number>
+        </property>
+        <property name="singleStep">
+         <number>1</number>
+        </property>
+        <property name="stepType">
+         <enum>QAbstractSpinBox::DefaultStepType</enum>
+        </property>
+        <property name="value">
+         <number>1000</number>
+        </property>
+       </widget>
+      </item>
+     </layout>
+    </widget>
+   </widget>
+   <widget class="QLabel" name="lblGame">
+    <property name="geometry">
+     <rect>
+      <x>10</x>
+      <y>10</y>
+      <width>61</width>
+      <height>31</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>12</pointsize>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="text">
+     <string>Game : </string>
+    </property>
+   </widget>
+   <widget class="QComboBox" name="cbSelectedGame">
+    <property name="geometry">
+     <rect>
+      <x>70</x>
+      <y>10</y>
+      <width>611</width>
+      <height>31</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>10</pointsize>
+      <bold>true</bold>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="maxVisibleItems">
+     <number>8</number>
+    </property>
+    <item>
+     <property name="text">
+      <string>SELECT A GAME</string>
+     </property>
+    </item>
+   </widget>
+   <widget class="QPushButton" name="btnStopSession">
+    <property name="enabled">
+     <bool>false</bool>
+    </property>
+    <property name="geometry">
+     <rect>
+      <x>100</x>
+      <y>400</y>
+      <width>161</width>
+      <height>41</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>10</pointsize>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="text">
+     <string>Stop Session</string>
+    </property>
+   </widget>
+   <widget class="QTabWidget" name="tabTraversal">
+    <property name="enabled">
+     <bool>true</bool>
+    </property>
+    <property name="geometry">
+     <rect>
+      <x>20</x>
+      <y>220</y>
+      <width>321</width>
+      <height>171</height>
+     </rect>
+    </property>
+    <property name="font">
+     <font>
+      <pointsize>11</pointsize>
+      <kerning>true</kerning>
+     </font>
+    </property>
+    <property name="currentIndex">
+     <number>0</number>
+    </property>
+    <widget class="QWidget" name="tabJoin">
+     <attribute name="title">
+      <string>Join</string>
+     </attribute>
+     <widget class="QPushButton" name="btnTraversalJoin">
+      <property name="geometry">
+       <rect>
+        <x>220</x>
+        <y>60</y>
+        <width>81</width>
+        <height>31</height>
+       </rect>
+      </property>
+      <property name="font">
+       <font>
+        <pointsize>11</pointsize>
+        <kerning>true</kerning>
+       </font>
+      </property>
+      <property name="text">
+       <string>Join</string>
+      </property>
+     </widget>
+     <widget class="QWidget" name="horizontalLayoutWidget_2">
+      <property name="geometry">
+       <rect>
+        <x>10</x>
+        <y>20</y>
+        <width>291</width>
+        <height>28</height>
+       </rect>
+      </property>
+      <layout class="QHBoxLayout" name="horizontalLayout_2">
+       <item>
+        <widget class="QLabel" name="lblHostCode">
+         <property name="enabled">
+          <bool>true</bool>
+         </property>
+         <property name="font">
+          <font>
+           <pointsize>11</pointsize>
+           <kerning>true</kerning>
+          </font>
+         </property>
+         <property name="text">
+          <string>Host Code :</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QLineEdit" name="leHostCode">
+         <property name="font">
+          <font>
+           <pointsize>11</pointsize>
+           <kerning>true</kerning>
+          </font>
+         </property>
+        </widget>
+       </item>
+      </layout>
+     </widget>
+    </widget>
+    <widget class="QWidget" name="tabHost">
+     <property name="font">
+      <font>
+       <pointsize>10</pointsize>
+       <kerning>true</kerning>
+      </font>
+     </property>
+     <attribute name="title">
+      <string>Host</string>
+     </attribute>
+     <widget class="QPushButton" name="btnTraversalHost">
+      <property name="geometry">
+       <rect>
+        <x>10</x>
+        <y>20</y>
+        <width>81</width>
+        <height>31</height>
+       </rect>
+      </property>
+      <property name="font">
+       <font>
+        <pointsize>11</pointsize>
+        <kerning>true</kerning>
+       </font>
+      </property>
+      <property name="text">
+       <string>Host</string>
+      </property>
+     </widget>
+     <widget class="QWidget" name="horizontalLayoutWidget">
+      <property name="geometry">
+       <rect>
+        <x>10</x>
+        <y>60</y>
+        <width>281</width>
+        <height>31</height>
+       </rect>
+      </property>
+      <layout class="QHBoxLayout" name="horizontalLayout">
+       <item>
+        <widget class="QLabel" name="lblHostCode2">
+         <property name="font">
+          <font>
+           <pointsize>11</pointsize>
+           <kerning>true</kerning>
+          </font>
+         </property>
+         <property name="text">
+          <string>Host Code :</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QLabel" name="lblHostCodeResult">
+         <property name="font">
+          <font>
+           <pointsize>11</pointsize>
+           <kerning>true</kerning>
+          </font>
+         </property>
+         <property name="text">
+          <string>XXXXXXXXX-</string>
+         </property>
+         <property name="textInteractionFlags">
+          <set>Qt::LinksAccessibleByMouse|Qt::TextSelectableByMouse</set>
+         </property>
+        </widget>
+       </item>
+      </layout>
+     </widget>
+    </widget>
+   </widget>
+   <widget class="QWidget" name="gridLayoutWidget">
+    <property name="geometry">
+     <rect>
+      <x>20</x>
+      <y>60</y>
+      <width>321</width>
+      <height>151</height>
+     </rect>
+    </property>
+    <layout class="QGridLayout" name="gridLayout">
+     <item row="2" column="0">
+      <widget class="QLabel" name="lblPlayer">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <property name="text">
+        <string>Player :</string>
+       </property>
+      </widget>
+     </item>
+     <item row="2" column="1">
+      <widget class="QComboBox" name="cbLocalPlayer">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <bold>true</bold>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <item>
+        <property name="text">
+         <string>NOT SET</string>
+        </property>
+       </item>
+       <item>
+        <property name="text">
+         <string>1</string>
+        </property>
+       </item>
+       <item>
+        <property name="text">
+         <string>2</string>
+        </property>
+       </item>
+      </widget>
+     </item>
+     <item row="3" column="0">
+      <widget class="QLabel" name="lblInputDelay">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <property name="text">
+        <string>Input Delay :</string>
+       </property>
+      </widget>
+     </item>
+     <item row="1" column="1">
+      <widget class="QLineEdit" name="lePlayerName">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <property name="text">
+        <string>Duck!</string>
+       </property>
+      </widget>
+     </item>
+     <item row="3" column="1">
+      <widget class="QSpinBox" name="sbInputDelay">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <property name="maximum">
+        <number>30</number>
+       </property>
+       <property name="singleStep">
+        <number>1</number>
+       </property>
+       <property name="stepType">
+        <enum>QAbstractSpinBox::DefaultStepType</enum>
+       </property>
+       <property name="value">
+        <number>1</number>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <widget class="QComboBox" name="cbConnMode">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <bold>true</bold>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <item>
+        <property name="text">
+         <string>DIRECT IP</string>
+        </property>
+       </item>
+       <item>
+        <property name="text">
+         <string>TRAVERSAL</string>
+        </property>
+       </item>
+      </widget>
+     </item>
+     <item row="0" column="0">
+      <widget class="QLabel" name="lblConnMode">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <property name="text">
+        <string>Connection Mode :</string>
+       </property>
+      </widget>
+     </item>
+     <item row="1" column="0">
+      <widget class="QLabel" name="lblPlayerName">
+       <property name="font">
+        <font>
+         <pointsize>11</pointsize>
+         <kerning>true</kerning>
+        </font>
+       </property>
+       <property name="text">
+        <string>Nickname : </string>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </widget>
+   <zorder>tabTraversal</zorder>
+   <zorder>frDirectIP</zorder>
+   <zorder>line_2</zorder>
+   <zorder>tbNetplayChat</zorder>
+   <zorder>btnSendMsg</zorder>
+   <zorder>line</zorder>
+   <zorder>lwChatWindow</zorder>
+   <zorder>lblGame</zorder>
+   <zorder>cbSelectedGame</zorder>
+   <zorder>btnStopSession</zorder>
+   <zorder>gridLayoutWidget</zorder>
+  </widget>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

src/duckstation-qt/qthost.cpp

@@ -461,6 +461,12 @@ void EmuThread::startFullscreenUI()
   wakeThread();
 }
 
+void Host::OnNetplayMessage(std::string& message)
+{
+  QString msg(message.c_str());
+  emit g_emu_thread->onNetplayMessage(msg);
+}
+
 void EmuThread::stopFullscreenUI()
 {
   if (!isOnThread())
@@ -1065,6 +1071,48 @@ void EmuThread::reloadPostProcessingShaders()
   System::ReloadPostProcessingShaders();
 }
 
+void EmuThread::startNetplaySession(int local_handle, quint16 local_port, const QString& remote_addr,
+                                    quint16 remote_port, int input_delay, const QString& game_path)
+{
+  if (!isOnThread())
+  {
+    QMetaObject::invokeMethod(this, "startNetplaySession", Qt::QueuedConnection, Q_ARG(int, local_handle),
+                              Q_ARG(quint16, local_port), Q_ARG(const QString&, remote_addr),
+                              Q_ARG(quint16, remote_port), Q_ARG(int, input_delay), Q_ARG(const QString&, game_path));
+    return;
+  }
+  // disable block linking and disable rewind and runahead during a netplay session
+  g_settings.cpu_recompiler_block_linking = false;
+  g_settings.rewind_enable = false;
+  g_settings.runahead_frames = 0;
+
+  Log_WarningPrintf("Disabling block linking, runahead and rewind due to rollback.");
+
+  auto remAddr = remote_addr.trimmed().toStdString();
+  auto gamePath = game_path.trimmed().toStdString();
+  System::StartNetplaySession(local_handle, local_port, remAddr, remote_port, input_delay, gamePath);
+}
+
+void EmuThread::sendNetplayMessage(const QString& message)
+{
+  if (!isOnThread())
+  {
+    QMetaObject::invokeMethod(this, "sendNetplayMessage", Qt::QueuedConnection, Q_ARG(const QString&, message));
+    return;
+  }
+  Netplay::Session::SendMsg(message.toStdString().c_str());
+}
+
+void EmuThread::stopNetplaySession()
+{
+  if (!isOnThread())
+  {
+    QMetaObject::invokeMethod(this, "stopNetplaySession", Qt::QueuedConnection);
+    return;
+  }
+  System::StopNetplaySession();
+}
+
 void EmuThread::runOnEmuThread(std::function<void()> callback)
 {
   callback();
@@ -1416,7 +1464,10 @@ void EmuThread::run()
   {
     if (System::IsRunning())
     {
-      System::Execute();
+      if (Netplay::Session::IsActive())
+        System::ExecuteNetplay();
+      else
+        System::Execute();
     }
     else
     {
@@ -1659,6 +1710,14 @@ void EmuThread::updatePerformanceCounters()
     m_last_speed = speed;
     m_last_video_fps = vfps;
   }
+
+  const s32 ping = Netplay::Session::GetPing();
+  if (m_last_ping != ping)
+  {
+    QMetaObject::invokeMethod(g_main_window->getStatusPingWidget(), "setText", Qt::QueuedConnection,
+                              Q_ARG(const QString&, tr("Netplay Ping: %1 ").arg(ping, 0, 'f', 0)));
+    m_last_ping = ping;
+  }
 }
 
 void EmuThread::resetPerformanceCounters()

src/duckstation-qt/qthost.h

@@ -143,6 +143,7 @@ Q_SIGNALS:
   void achievementsRefreshed(quint32 id, const QString& game_info_string, quint32 total, quint32 points);
   void achievementsChallengeModeChanged();
   void cheatEnabled(quint32 index, bool enabled);
+  void onNetplayMessage(const QString& message);
 
 public Q_SLOTS:
   void setDefaultSettings(bool system = true, bool controller = true);
@@ -187,6 +188,10 @@ public Q_SLOTS:
   void setCheatEnabled(quint32 index, bool enabled);
   void applyCheat(quint32 index);
   void reloadPostProcessingShaders();
+  void startNetplaySession(int local_handle, quint16 local_port, const QString& remote_addr, quint16 remote_port,
+                           int input_delay, const QString& game_path);
+  void stopNetplaySession();
+  void sendNetplayMessage(const QString& message);
 
 private Q_SLOTS:
   void stopInThread();
@@ -232,6 +237,7 @@ private:
   float m_last_video_fps = std::numeric_limits<float>::infinity();
   u32 m_last_render_width = std::numeric_limits<u32>::max();
   u32 m_last_render_height = std::numeric_limits<u32>::max();
+  u32 m_last_ping = std::numeric_limits<u32>::max();
   GPURenderer m_last_renderer = GPURenderer::Count;
 };
 

src/frontend-common/input_manager.cpp

@@ -11,6 +11,7 @@
 #include "core/controller.h"
 #include "core/host.h"
 #include "core/system.h"
+#include "core/netplay.h"
 #include "imgui_manager.h"
 #include "input_source.h"
 
@@ -713,6 +714,12 @@ void InputManager::AddPadBindings(SettingsInterface& si, const std::string& sect
                     if (!System::IsValid())
                       return;
 
+                    if (Netplay::Session::IsActive())
+                    {
+                      Netplay::Session::CollectInput(pad_index, bind_index, value);
+                      return;
+                    }
+
                     Controller* c = System::GetController(pad_index);
                     if (c)
                       c->SetBindState(bind_index, value);