From 3bb2602f5b3ffddc3fd4be863010aa43514cd5ea Mon Sep 17 00:00:00 2001
From: BjossiAlfreds <bjornalfredsson@yahoo.com>
Date: Fri, 30 Sep 2022 15:25:18 +0000
Subject: [PATCH] Prevent dead bodies from obstructing elevators and falling
 through them

---
 src/g_phys.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/g_phys.c b/src/g_phys.c
index b594d97..678cef3 100644
--- a/src/g_phys.c
+++ b/src/g_phys.c
@@ -53,7 +53,10 @@ SV_TestEntityPosition(edict_t *ent)
 		return NULL;
 	}
 
-	if (ent->clipmask)
+	/* dead bodies are supposed to not be solid so lets
+	   ensure they only collide with BSP during pushmoves
+	*/
+	if (ent->clipmask && !(ent->svflags & SVF_DEADMONSTER))
 	{
 		mask = ent->clipmask;
 	}
@@ -518,6 +521,17 @@ retry:
 
 	trace = gi.trace(start, ent->mins, ent->maxs, end, ent, mask);
 
+	/* startsolid treats different-content volumes
+	   as continuous, like the bbox of a monster/player
+	   and the floor of an elevator. So do another trace
+	   that only collides with BSP so that we make a best
+	   effort to keep these entities inside non-solid space
+	*/
+	if (trace.startsolid && (mask & ~MASK_SOLID))
+	{
+		trace = gi.trace (start, ent->mins, ent->maxs, end, ent, MASK_SOLID);
+	}
+
 	VectorCopy(trace.endpos, ent->s.origin);
 	gi.linkentity(ent);