From 3d5f225702bbb9cae9a52ec00ff1a32304d8eb71 Mon Sep 17 00:00:00 2001
From: mazmazz <mar.marcoz@outlook.com>
Date: Sun, 9 Sep 2018 20:18:43 -0400
Subject: [PATCH] Replace firsttic with decrement timer

---
 src/p_lights.c | 16 ++++++++--------
 src/p_saveg.c  |  8 ++++----
 src/p_spec.h   |  4 ++--
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/src/p_lights.c b/src/p_lights.c
index 8be3d793c..77d05dad3 100644
--- a/src/p_lights.c
+++ b/src/p_lights.c
@@ -356,16 +356,16 @@ void P_FadeLightBySector(sector_t *sector, INT32 destvalue, INT32 speed, boolean
 
 	if (ticbased)
 	{
-		ll->duration = abs(speed);
-		ll->speed = FixedFloor(FixedDiv(destvalue - sector->lightlevel, ll->duration))/FRACUNIT;
+		ll->ticbased = ticbased;
+		ll->timer = abs(speed);
+		ll->speed = FixedFloor(FixedDiv(destvalue - sector->lightlevel, ll->timer))/FRACUNIT;
 		if (!ll->speed)
 			ll->speed = (destvalue < sector->lightlevel) ? -1 : 1;
-		ll->interval = max(FixedFloor(FixedDiv(ll->duration, abs(destvalue - sector->lightlevel)))/FRACUNIT, 1);
-		ll->firsttic = gametic;
+		ll->interval = max(FixedFloor(FixedDiv(ll->timer, abs(destvalue - sector->lightlevel)))/FRACUNIT, 1);
 	}
 	else
 	{
-		ll->duration = -1;
+		ll->timer = -1;
 		ll->speed = abs(speed);
 	}
 }
@@ -385,14 +385,14 @@ void P_FadeLight(INT16 tag, INT32 destvalue, INT32 speed, boolean ticbased)
   */
 void T_LightFade(lightlevel_t *ll)
 {
-	if (ll->duration >= 0) // tic-based
+	if (ll->ticbased)
 	{
-		if (gametic - ll->firsttic >= ll->duration)
+		if (--ll->timer <= 0)
 		{
 			ll->sector->lightlevel = (INT16)ll->destlevel; // set to dest lightlevel
 			P_RemoveLighting(ll->sector); // clear lightingdata, remove thinker
 		}
-		else if (!((gametic - ll->firsttic) % ll->interval))
+		else if (!(ll->timer % ll->interval))
 		{
 			if (ll->speed < 0)
 				ll->sector->lightlevel = max(ll->sector->lightlevel + (INT16)ll->speed, (INT16)ll->destlevel);
diff --git a/src/p_saveg.c b/src/p_saveg.c
index 8ec5b5ea8..eefee072d 100644
--- a/src/p_saveg.c
+++ b/src/p_saveg.c
@@ -1539,9 +1539,9 @@ static void SaveLightlevelThinker(const thinker_t *th, const UINT8 type)
 	WRITEUINT32(save_p, SaveSector(ht->sector));
 	WRITEINT32(save_p, ht->destlevel);
 	WRITEINT32(save_p, ht->speed);
-	WRITEINT32(save_p, ht->duration);
+	WRITEUINT8(save_p, (UINT8)ht->ticbased);
+	WRITEINT32(save_p, ht->timer);
 	WRITEUINT32(save_p, ht->interval);
-	WRITEUINT32(save_p, (UINT32)ht->firsttic);
 }
 
 //
@@ -2515,9 +2515,9 @@ static inline void LoadLightlevelThinker(actionf_p1 thinker)
 	ht->sector = LoadSector(READUINT32(save_p));
 	ht->destlevel = READINT32(save_p);
 	ht->speed = READINT32(save_p);
-	ht->duration = READINT32(save_p);
+	ht->ticbased = (boolean)READUINT8(save_p);
+	ht->timer = READINT32(save_p);
 	ht->interval = READUINT32(save_p);
-	ht->firsttic = (tic_t)READUINT32(save_p);
 	if (ht->sector)
 		ht->sector->lightingdata = ht;
 	P_AddThinker(&ht->thinker);
diff --git a/src/p_spec.h b/src/p_spec.h
index c2c4c8976..1e327c5f2 100644
--- a/src/p_spec.h
+++ b/src/p_spec.h
@@ -140,9 +140,9 @@ typedef struct
 	INT32 speed;       ///< Speed at which to change light level.
 
 	// Tic-based behavior
-	INT32 duration;    ///< If <0, do not use tic-based behavior. If 0, set instantly. If >0, fade lasts this duration.
+	boolean ticbased;  ///< Tic-based logic
+	INT32 timer;    ///< Tic-based timer
 	UINT32 interval;   ///< Interval to deduct light level
-	tic_t firsttic;    ///< First gametic to count from
 } lightlevel_t;
 
 #define GLOWSPEED 8