From be5419e77c7fafec69720577443f9cf758e141ca Mon Sep 17 00:00:00 2001
From: Mitchell Richters <mjr4077au@gmail.com>
Date: Tue, 25 Aug 2020 17:50:09 +1000
Subject: [PATCH] - i_time: Add `I_GetBuildTimeFrac()`.

* Currently not needed, but adding for feature parity.
---
 source/common/utility/i_time.cpp | 14 ++++++++++++++
 source/common/utility/i_time.h   |  3 ++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/source/common/utility/i_time.cpp b/source/common/utility/i_time.cpp
index 2103c9830..ce14e52d4 100644
--- a/source/common/utility/i_time.cpp
+++ b/source/common/utility/i_time.cpp
@@ -79,6 +79,11 @@ static uint64_t TicToNS(int tic)
 	return static_cast<uint64_t>(tic) * 1'000'000'000 / GameTicRate;
 }
 
+static uint64_t BuildTicToNS(int tic)
+{
+	return static_cast<uint64_t>(tic) * 1'000'000'000 / 120;
+}
+
 void I_SetFrameTime()
 {
 	// Must only be called once per frame/swapbuffers.
@@ -184,6 +189,15 @@ double I_GetTimeFrac()
 	return (CurrentFrameStartTime - ticStartTime) / (double)(ticNextTime - ticStartTime);
 }
 
+double I_GetBuildTimeFrac()
+{
+	int currentTic = NSToBuildTic(CurrentFrameStartTime - FirstFrameStartTime);
+	uint64_t ticStartTime = FirstFrameStartTime + BuildTicToNS(currentTic);
+	uint64_t ticNextTime = FirstFrameStartTime + BuildTicToNS(currentTic + 1);
+
+	return (CurrentFrameStartTime - ticStartTime) / (double)(ticNextTime - ticStartTime);
+}
+
 void I_FreezeTime(bool frozen)
 {
 	if (frozen)
diff --git a/source/common/utility/i_time.h b/source/common/utility/i_time.h
index 230765053..1f28df893 100644
--- a/source/common/utility/i_time.h
+++ b/source/common/utility/i_time.h
@@ -12,13 +12,14 @@ int I_GetTime();
 // same, but using nanoseconds
 uint64_t I_GetTimeNS();
 
-// Called by Build games in liew of totalclock, returns current time in tics at ticrate of 120.
+// Called by Build games in lieu of totalclock, returns current time in tics at ticrate of 120.
 int I_GetBuildTime();
 
 // Reset timer variables to zero when called.
 void I_ResetTime();
 
 double I_GetTimeFrac();
+double I_GetBuildTimeFrac();
 
 // like I_GetTime, except it waits for a new tic before returning
 int I_WaitForTic(int);