From 48073a2cd6c0c0e577af92d86ff2a4fcb11f63cd Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sun, 29 Aug 2021 14:42:05 +0200
Subject: [PATCH] - sanitized the abuse of using XSPRITE's target field to pass
 along some info with explosions.

This is neither safe nor future proof, so now it uses a separate variable.
---
 source/games/blood/src/actor.cpp    | 5 +++--
 source/games/blood/src/bloodactor.h | 4 +++-
 source/games/blood/src/callback.cpp | 4 +---
 source/games/blood/src/loadsave.cpp | 3 ++-
 source/games/blood/src/nnexts.cpp   | 2 +-
 5 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/source/games/blood/src/actor.cpp b/source/games/blood/src/actor.cpp
index 33b54bc7e..56e181791 100644
--- a/source/games/blood/src/actor.cpp
+++ b/source/games/blood/src/actor.cpp
@@ -5633,6 +5633,7 @@ void actExplodeSprite(DBloodActor* actor)
 	pSprite->type = nType;
 	const EXPLOSION* pExplodeInfo = &explodeInfo[nType];
 	actor->SetTarget(nullptr);
+	actor->explosionhackflag = true;
 	pXSprite->data1 = pExplodeInfo->ticks;
 	pXSprite->data2 = pExplodeInfo->quakeEffect;
 	pXSprite->data3 = pExplodeInfo->flashEffect;
@@ -5976,9 +5977,9 @@ static void actCheckExplosion()
 			{
 				if (pXSprite->data1 && CheckProximity(pDude, x, y, z, nSector, radius))
 				{
-					if (pExplodeInfo->dmg && pXSprite->target_i == 0)
+					if (pExplodeInfo->dmg && actor->explosionhackflag)
 					{
-						pXSprite->target_i = 1;
+						actor->explosionhackflag = false;
 						actDamageSprite(Owner, dudeactor, kDamageFall, (pExplodeInfo->dmg + Random(pExplodeInfo->dmgRng)) << 4);
 					}
 					if (pExplodeInfo->dmgType) ConcussSprite(actor, dudeactor, x, y, z, pExplodeInfo->dmgType);
diff --git a/source/games/blood/src/bloodactor.h b/source/games/blood/src/bloodactor.h
index 2b0585628..010e2817a 100644
--- a/source/games/blood/src/bloodactor.h
+++ b/source/games/blood/src/bloodactor.h
@@ -97,13 +97,15 @@ public:
 	SPRITEMASS spriteMass;
 	GENDUDEEXTRA genDudeExtra;
 
-	int cumulDamage;
+	int cumulDamage; // this one's transient and does not need to be saved.
+	bool explosionhackflag; // this originally hijacked the target field which is not safe when working with pointers.
 
 	DBloodActor() :index(int(this - base())) { /*assert(index >= 0 && index < kMaxSprites);*/ }
 	DBloodActor& operator=(const DBloodActor& other) = default;
 
 	void Clear()
 	{
+		explosionhackflag = false;
 		dudeSlope = 0;
 		dudeExtra = {};
 		spriteMass = {};
diff --git a/source/games/blood/src/callback.cpp b/source/games/blood/src/callback.cpp
index 7cbacbab0..5410c193e 100644
--- a/source/games/blood/src/callback.cpp
+++ b/source/games/blood/src/callback.cpp
@@ -385,9 +385,7 @@ void FinishHim(DBloodActor* actor, int) // 13
 {
     if (!actor) return;
     spritetype* pSprite = &actor->s();
-    int nXSprite = pSprite->extra;
-    XSPRITE* pXSprite = &actor->x();
-    if (IsPlayerSprite(pSprite) && playerSeqPlaying(&gPlayer[pSprite->type - kDudePlayer1], 16) && pXSprite->target_i == gMe->nSprite)
+    if (actor->IsPlayerActor() && playerSeqPlaying(&gPlayer[pSprite->type - kDudePlayer1], 16) && actor == gMe->actor())
         sndStartSample(3313, -1, 1, 0);
 }
 
diff --git a/source/games/blood/src/loadsave.cpp b/source/games/blood/src/loadsave.cpp
index 269b40220..0274a2d65 100644
--- a/source/games/blood/src/loadsave.cpp
+++ b/source/games/blood/src/loadsave.cpp
@@ -482,7 +482,8 @@ FSerializer& Serialize(FSerializer& arc, const char* keyname, DBloodActor& w, DB
 		if (w.hasX())
 		{
 			arc("dudeslope", w.dudeSlope, def->dudeSlope)
-				("dudeextra", w.dudeExtra, def->dudeExtra);
+				("dudeextra", w.dudeExtra, def->dudeExtra)
+				("explosionflag", w.explosionhackflag, def->explosionhackflag);
 
 			if (gModernMap)
 			{
diff --git a/source/games/blood/src/nnexts.cpp b/source/games/blood/src/nnexts.cpp
index 077523dfe..7d24d681e 100644
--- a/source/games/blood/src/nnexts.cpp
+++ b/source/games/blood/src/nnexts.cpp
@@ -6995,7 +6995,7 @@ void useTargetChanger(DBloodActor* sourceactor, DBloodActor* actor)
 
             if (aiFightDudeCanSeeTarget(actor, pDudeInfo, pMateTargetActor)) 
             {
-                if (pXMateTarget->target_i < 0) 
+                if (pMateTargetActor->GetTarget() == nullptr) 
                 {
                     aiSetTarget(pMateTargetActor, actor);
                     if (pMateTargetActor->IsDudeActor() && !isActive(pMateTargetActor))