From: JadingTsunami <JadingTsunami@users.noreply.github.com>
Date: Fri, 26 Jul 2024 17:54:09 -0700
Subject: [PATCH] [Credit to dsda-doom] Fix cl11+ monster search time bug.

* Credit to dsda-doom:
https://github.com/kraflab/dsda-doom/

* Fix cl11+ bug that slows down maps with large monster counts.

* See here for details:
https://github.com/kraflab/dsda-doom/commit/\
dc29f0ce801f6ff910ae3fc3e6b1210ac79e87cf

--- prboom-plus.old/prboom2/src/p_enemy.c
+++ prboom-plus/prboom2/src/p_enemy.c
@@ -922,6 +922,18 @@
       current_actor = actor;
       current_allaround = allaround;
 
+      // credit - from dsda-doom
+      // https://github.com/kraflab/dsda-doom/commit/dc29f0ce801f6ff910ae3fc3e6b1210ac79e87cf
+      // There is a bug in cl11+ that causes the player to get added
+      //   to the monster friend list when damaged to below 50% health.
+      // This causes all monsters to believe friend monsters exist.
+      // The search algorithm is expensive and massively so on maps with many monsters.
+      // We still need to match rng calls for demo sync, but PIT_FindTarget is a no op.
+      if (((mobj_t *) cap->cnext)->player && cap->cnext == cap->cprev) {
+          P_Random(pr_friends);
+          return false;
+      }
+
       // Search first in the immediate vicinity.
 
       if (!P_BlockThingsIterator(x, y, PIT_FindTarget))