DiscordRPC: Show session time in Discord Rich Presence

pcsx2/VMManager.cpp

@@ -192,6 +192,7 @@ static bool s_screensaver_inhibited = false;
 static PINEServer s_pine_server;
 
 static bool s_discord_presence_active = false;
+static time_t s_discord_presence_time_epoch = std::time(nullptr);
 
 bool VMManager::PerformEarlyHardwareChecks(const char** error)
 {
@@ -2775,6 +2776,7 @@ void VMManager::SaveSessionTime(const std::string& prev_serial)
 	}
 
 	s_session_start_time = ctime;
+	s_discord_presence_time_epoch = std::time(nullptr);
 }
 
 u64 VMManager::GetSessionPlayedTime()
@@ -3108,7 +3110,7 @@ void VMManager::UpdateDiscordPresence()
 	DiscordRichPresence rp = {};
 	rp.largeImageKey = "4k-pcsx2";
 	rp.largeImageText = "PCSX2 Emulator";
-	rp.startTimestamp = std::time(nullptr);
+	rp.startTimestamp = s_discord_presence_time_epoch;
 	rp.details = s_title.empty() ? "No Game Running" : s_title.c_str();
 
 	std::string state_string;