From b2d0d7f9e504b43ac8b8dbd7c1d6d3360b014eb2 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sun, 9 Oct 2022 14:50:45 +0200
Subject: [PATCH] - normalize the timer with the app start, not the epoch.

This ensures smaller values and less wraparounds with integer values in scripts.
---
 source/common/utility/i_time.cpp | 18 +++++++++++++++---
 source/common/utility/i_time.h   |  2 ++
 source/core/gamecontrol.cpp      |  2 +-
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/source/common/utility/i_time.cpp b/source/common/utility/i_time.cpp
index 4f2ac96cb..51ad0359d 100644
--- a/source/common/utility/i_time.cpp
+++ b/source/common/utility/i_time.cpp
@@ -44,6 +44,7 @@
 //
 //==========================================================================
 
+static uint64_t StartupTimeNS;
 static uint64_t FirstFrameStartTime;
 static uint64_t CurrentFrameStartTime;
 static uint64_t FreezeTime;
@@ -52,11 +53,22 @@ int GameTicRate = 35;	// make sure it is not 0, even if the client doesn't set i
 
 double TimeScale = 1.0;
 
-static uint64_t GetClockTimeNS()
+static uint64_t GetTimePoint()
 {
 	using namespace std::chrono;
-	if (TimeScale == 1.0) return (uint64_t)(duration_cast<nanoseconds>(steady_clock::now().time_since_epoch()).count());
-	else return (uint64_t)((duration_cast<microseconds>(steady_clock::now().time_since_epoch()).count()) * (uint64_t)(TimeScale * 1000));
+	return (uint64_t)(duration_cast<nanoseconds>(steady_clock::now().time_since_epoch()).count());
+}
+
+void I_InitTime()
+{
+	StartupTimeNS = GetTimePoint();
+}
+
+static uint64_t GetClockTimeNS()
+{
+	auto tp = GetTimePoint() - StartupTimeNS;
+	if (TimeScale == 1.0) return tp;
+	else return tp / 1000 * TimeScale * 1000;
 }
 
 static uint64_t MSToNS(unsigned int ms)
diff --git a/source/common/utility/i_time.h b/source/common/utility/i_time.h
index d9501ea96..e5d3d5c8d 100644
--- a/source/common/utility/i_time.h
+++ b/source/common/utility/i_time.h
@@ -5,6 +5,8 @@
 extern int GameTicRate;
 extern double TimeScale;
 
+void I_InitTime();
+
 // Called by D_DoomLoop, sets the time for the current frame
 void I_SetFrameTime();
 
diff --git a/source/core/gamecontrol.cpp b/source/core/gamecontrol.cpp
index bf87d8b3d..a8d130f6d 100644
--- a/source/core/gamecontrol.cpp
+++ b/source/core/gamecontrol.cpp
@@ -554,7 +554,7 @@ void System_MenuDim();
 int GameMain()
 {
 	int r;
-
+	I_InitTime();
 	SetConsoleNotifyBuffer();
 	sysCallbacks =
 	{