PCExhumed: Fixed Ignited sprite anim issue that could cause invalid array access.

* Fixes #638.

source/games/exhumed/src/aistuff.h

@@ -27,10 +27,16 @@ BEGIN_PS_NS
 
 // anims
 
+enum
+{
+    kAnimFlag1 = (1 << 2),
+    kAnimLoop  = (1 << 4)
+};
+
 void InitAnims();
 void DestroyAnim(DExhumedActor* nAnim);
 DExhumedActor* BuildAnim(DExhumedActor* actor, int val, int val2, const DVector3& pos, sectortype* pSector, double nScale, int nFlag);
-
+void UnlinkIgnitedAnim(DExhumedActor* pActor);
 void FuncAnim(int, int, int, int);
 void BuildExplosion(DExhumedActor* actor);
 void BuildSplash(DExhumedActor* actor, sectortype* pSector);

source/games/exhumed/src/anims.cpp

@@ -54,6 +54,36 @@ void InitAnims()
     nSavePointSeq = SeqOffsets[kSeqItems] + 12;
 }
 
+/*
+    Use when deleting an ignited sprite to check if any anims reference it. 
+    Will remove the Anim's loop flag and set the source (the ignited sprite's) sprite reference to -1.
+    FuncAnim() will then delete the anim on next call for this anim.
+
+    Without this, the anim will hold reference to a sprite which will eventually be reused, but the anim code
+    will continue to manipulate its hitag value. This can break runlist records for things like LavaDude
+    limbs that store these in the sprite hitag.
+
+    Specifically needed for IgniteSprite() anims which can become orphaned from the source sprite (e.g a bullet)
+    when the bullet sprite is deleted.
+*/
+void UnlinkIgnitedAnim(DExhumedActor* pActor)
+{
+    // scan the active anims (that aren't in the 'free' section of AnimsFree[])
+    ExhumedStatIterator it(500);
+    while (auto itActor = it.Next())
+    {
+        if (itActor->spr.statnum == kStatIgnited)
+        {
+            // .hitag holds the sprite number of the source 'sprite that's on fire' sprite
+            if (pActor == itActor->pTarget)
+            {
+                itActor->nAction &= ~kAnimLoop; // clear the animation loop flag
+                itActor->pTarget = nullptr; // set the sprite reference to -1
+            }
+        }
+    }
+}
+
 void DestroyAnim(DExhumedActor* pActor)
 {
     if (pActor)

source/games/exhumed/src/exhumed.cpp

@@ -18,6 +18,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 #include "ns.h"
 #include "engine.h"
 #include "exhumed.h"
+#include "aistuff.h"
 #include "sequence.h"
 #include "names.h"
 #include "player.h"
@@ -603,6 +604,7 @@ void DeleteActor(DExhumedActor* actor)
         bestTarget = nullptr;
     }
 
+    UnlinkIgnitedAnim(actor);
     actor->Destroy();
 }