Waypoint Spawning

Uses object MT_WAYPOINT, mapthing type 2001
Placing one by itself will always place it on the floor or ceiling (depending on object flip)
Placing one alongside another that uses Object Special will make the original use the z height of the 2nd
Angle will be used to determine the waypoint's ID
Z Height (threshold on mobjs) will be used to determine the ID of the previous waypoint
Waypoints with the Ambush Flag will be unable to be respawned at (reactiontime on mobjs internally)

src/info.c

@@ -15195,7 +15195,7 @@ mobjinfo_t mobjinfo[NUMMOBJTYPES] =
 
 	{           // MT_WAYPOINT
 		2001,           // doomednum
-		S_NULL,         // spawnstate
+		S_UNKNOWN,         // spawnstate
 		1000,           // spawnhealth
 		S_NULL,         // seestate
 		sfx_None,       // seesound
@@ -15216,7 +15216,7 @@ mobjinfo_t mobjinfo[NUMMOBJTYPES] =
 		100,            // mass
 		0,              // damage
 		sfx_None,       // activesound
-		MF_NOBLOCKMAP|MF_NOSECTOR|MF_NOCLIP|MF_NOGRAVITY, // flags
+		MF_NOBLOCKMAP/*|MF_NOSECTOR*/|MF_NOCLIP|MF_NOGRAVITY, // flags
 		S_NULL          // raisestate
 	},
 

src/p_mobj.c

@@ -9641,6 +9641,26 @@ void P_SpawnMapThing(mapthing_t *mthing)
 		else
 			mthing->z = (INT16)(z>>FRACBITS);
 	}
+	else if (i == MT_WAYPOINT && !(mthing->options & MTF_OBJECTSPECIAL))
+	{
+		// just gets set on either the floor or ceiling
+		boolean flip = (!!(mobjinfo[i].flags & MF_SPAWNCEILING) ^ !!(mthing->options & MTF_OBJECTFLIP));
+
+		// applying offsets! (if any)
+		if (flip)
+		{
+			z = ONCEILINGZ;
+		}
+		else
+		{
+			z = ONFLOORZ;
+		}
+
+		if (z == ONFLOORZ)
+			mthing->z = 0;
+		else
+			mthing->z = (INT16)(z>>FRACBITS);
+	}
 	else
 	{
 		fixed_t offset = 0;
@@ -9893,6 +9913,24 @@ ML_NOCLIMB : Direction not controllable
 	case MT_TRAPGOYLELONG:
 		if (mthing->angle >= 360)
 			mobj->tics += 7*(mthing->angle / 360) + 1; // starting delay
+		break;
+	case MT_WAYPOINT:
+		if (!(mthing->options & MTF_OBJECTSPECIAL))
+		{
+			// Z is already altered to account for proper height
+			// Use threshold to store the previous waypoint ID
+			// Angle is being used for the current waypoint ID
+			mobj->threshold = ((mthing->options >> ZSHIFT));
+		}
+		if (mthing->options & MTF_AMBUSH)
+		{
+			mobj->reactiontime = 1;
+		}
+		else
+		{
+			mobj->reactiontime = 0;
+		}
+		break;
 	default:
 		break;
 	}

src/p_setup.c

@@ -915,6 +915,24 @@ void P_ScanThings(INT16 mapnum, INT16 wadnum, INT16 lumpnum)
 }
 #endif
 
+static void P_SetWaypointsHeight(mapthing_t *mt)
+{
+	mapthing_t *mt2 = mapthings;
+	size_t i;
+	for (i = 0; i < nummapthings; i++, mt2++)
+	{
+		if (!(mt2->type == mobjinfo[MT_WAYPOINT].doomednum && (mt2->options & MTF_OBJECTSPECIAL)))
+			continue;
+
+		if (mt->angle == mt2->angle) // same waypoint id
+		{
+			mt->z = mt2->z;
+			mt->mobj->z = mt2->mobj->z;
+			P_RemoveMobj(mt2->mobj);
+		}
+	}
+}
+
 //
 // P_LoadThings
 //
@@ -1050,6 +1068,12 @@ static void P_LoadThings(void)
 
 			P_SpawnHoopsAndRings (mt);
 		}
+
+		if (mt->type == mobjinfo[MT_WAYPOINT].doomednum && !(mt->options & MTF_OBJECTSPECIAL))
+		{
+			// use any "2nd" waypoint mobjs to set the height of original, then remove the 2nds mobjs
+			P_SetWaypointsHeight(mt);
+		}
 	}
 }