commit d6693cc9e17fdbee7033e47b7b8da249da118d8f
Author:     Simon Howard <fraggle@gmail.com>
AuthorDate: Wed Oct 19 23:26:23 2011 +0000
Commit:     Simon Howard <fraggle@gmail.com>
CommitDate: Wed Oct 19 23:26:23 2011 +0000

    Fix lockups in Hexen and Strife when playing with more than four
    players.

    Subversion-branch: /branches/v2-branch
    Subversion-revision: 2444
---
 src/hexen/p_enemy.c  | 12 ++++++++++--
 src/strife/p_enemy.c | 12 ++++++++++--
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/hexen/p_enemy.c b/src/hexen/p_enemy.c
index 456cc7a9..a8477b22 100644
--- a/src/hexen/p_enemy.c
+++ b/src/hexen/p_enemy.c
@@ -539,8 +539,16 @@ boolean P_LookForPlayers(mobj_t * actor, boolean allaround)
     }
     sector = actor->subsector->sector;
     c = 0;
-    stop = (actor->lastlook - 1) & 3;
-    for (;; actor->lastlook = (actor->lastlook + 1) & 3)
+
+    // NOTE: This behavior has been changed from the Vanilla behavior, where
+    // an infinite loop can occur if players 0-3 all quit the game. Although
+    // technically this is not what Vanilla does, fixing this is highly
+    // desirable, and having the game simply lock up is not acceptable.
+    // stop = (actor->lastlook - 1) & 3;
+    // for (;; actor->lastlook = (actor->lastlook + 1) & 3)
+
+    stop = (actor->lastlook + MAXPLAYERS - 1) % MAXPLAYERS;
+    for (;; actor->lastlook = (actor->lastlook + 1) % MAXPLAYERS)
     {
         if (!playeringame[actor->lastlook])
             continue;
diff --git a/src/strife/p_enemy.c b/src/strife/p_enemy.c
index 79e6ffb8..c7104a75 100644
--- a/src/strife/p_enemy.c
+++ b/src/strife/p_enemy.c
@@ -803,9 +803,17 @@ P_LookForPlayers
     sector = actor->subsector->sector;

     c = 0;
-    stop = (actor->lastlook-1)&3;

-    for ( ; ; actor->lastlook = (actor->lastlook+1)&3 )
+    // NOTE: This behavior has been changed from the Vanilla behavior, where
+    // an infinite loop can occur if players 0-3 all quit the game. Although
+    // technically this is not what Vanilla does, fixing this is highly
+    // desirable, and having the game simply lock up is not acceptable.
+    // stop = (actor->lastlook - 1) & 3;
+    // for (;; actor->lastlook = (actor->lastlook + 1) & 3)
+
+    stop = (actor->lastlook + MAXPLAYERS - 1) % MAXPLAYERS;
+
+    for ( ; ; actor->lastlook = (actor->lastlook + 1) % MAXPLAYERS)
     {
         if (!playeringame[actor->lastlook])
             continue;