From 5cf288a05c8e1f2d438a93d484e3808d421d0f50 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Tue, 3 Nov 2020 07:14:39 +0100
Subject: [PATCH] - changed the trip bomb indexing to use a separate counter
 for robustness.

---
 source/games/duke/src/player_d.cpp | 5 ++++-
 source/games/duke/src/savegame.cpp | 1 +
 source/games/duke/src/spawn_d.cpp  | 3 ++-
 source/games/duke/src/types.h      | 1 +
 4 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/source/games/duke/src/player_d.cpp b/source/games/duke/src/player_d.cpp
index 8cd788408..304c21f8f 100644
--- a/source/games/duke/src/player_d.cpp
+++ b/source/games/duke/src/player_d.cpp
@@ -890,7 +890,10 @@ static void shootlaser(DDukeActor* actor, int p, int sx, int sy, int sz, int sa)
 			}
 		}
 
-		bomb->s.hitag = bomb->GetIndex();	// sigh...
+		// this originally used the sprite index as tag to link the laser segments.
+		// This value is never used again to reference an actor by index. Decouple this for robustness.
+		ud.bomb_tag = (ud.bomb_tag + 1) & 32767;
+		bomb->s.hitag = ud.bomb_tag;
 		S_PlayActorSound(LASERTRIP_ONWALL, bomb);
 		bomb->s.xvel = -20;
 		ssp(bomb, CLIPMASK0);
diff --git a/source/games/duke/src/savegame.cpp b/source/games/duke/src/savegame.cpp
index c973477a7..0cb9cfc67 100644
--- a/source/games/duke/src/savegame.cpp
+++ b/source/games/duke/src/savegame.cpp
@@ -379,6 +379,7 @@ void GameInterface::SerializeGameState(FSerializer& arc)
 			("marker", ud.marker)
 			("ffire", ud.ffire)
 			("levelclock", ud.levelclock)
+			("bomb_tag", ud.bomb_tag)
 
 			.Array("sectorextra", sectorextra, numsectors)
 			("rtsplaying", rtsplaying)
diff --git a/source/games/duke/src/spawn_d.cpp b/source/games/duke/src/spawn_d.cpp
index bda23f9f1..a6da2433d 100644
--- a/source/games/duke/src/spawn_d.cpp
+++ b/source/games/duke/src/spawn_d.cpp
@@ -339,7 +339,8 @@ int spawn_d(int j, int pn)
                 sp->yrepeat=5;
 
                 act->SetOwner(act);
-                sp->hitag = i; // hijack
+                ud.bomb_tag = (ud.bomb_tag + 1) & 32767;
+                sp->hitag = ud.bomb_tag;
 
                 sp->xvel = 16;
                 ssp(act, CLIPMASK0);
diff --git a/source/games/duke/src/types.h b/source/games/duke/src/types.h
index d76e0a277..35be0880f 100644
--- a/source/games/duke/src/types.h
+++ b/source/games/duke/src/types.h
@@ -132,6 +132,7 @@ struct user_defs
 
 	short from_bonus;
 	short last_level, secretlevel;
+	short bomb_tag;
 
 	int const_visibility;