[App] Add support for Discord rich presence.

src/xenia/app/emulator_window.cc

@@ -7,12 +7,15 @@
  ******************************************************************************
  */
 
+#include <gflags/gflags.h>
+
 #include "xenia/app/emulator_window.h"
 
 // Autogenerated by `xb premake`.
 #include "build/version.h"
 
 #include "third_party/imgui/imgui.h"
+#include "xenia/app/discord/discord_presence.h"
 #include "xenia/base/clock.h"
 #include "xenia/base/debugging.h"
 #include "xenia/base/logging.h"
@@ -26,6 +29,8 @@
 #include "xenia/ui/imgui_dialog.h"
 #include "xenia/ui/imgui_drawer.h"
 
+DEFINE_bool(discord, false, "Enable Discord rich presence");
+
 namespace xe {
 namespace app {
 
@@ -80,6 +85,11 @@ bool EmulatorWindow::Initialize() {
     return false;
   }
 
+  if (FLAGS_discord) {
+    discord::DiscordPresence::InitializeDiscord();
+    discord::DiscordPresence::NotPlaying();
+  }
+
   UpdateTitle();
 
   window_->on_closed.AddListener([this](UIEvent* e) { loop_->Quit(); });
@@ -334,6 +344,9 @@ void EmulatorWindow::FileOpen() {
 void EmulatorWindow::FileClose() {
   if (emulator_->is_title_open()) {
     emulator_->TerminateTitle();
+    if (FLAGS_discord) {
+      discord::DiscordPresence::NotPlaying();
+    }
   }
 }
 
@@ -431,6 +444,9 @@ void EmulatorWindow::UpdateTitle() {
     auto game_title = emulator()->game_title();
     title += xe::format_string(L" | [%.8X] %s", emulator()->title_id(),
                                game_title.c_str());
+    if (FLAGS_discord) {
+      discord::DiscordPresence::PlayingTitle(game_title);
+    }
   }
 
   auto graphics_system = emulator()->graphics_system();