Add Radius Action thing

Thing type 4096, activates its action when a player enters the specified radius

src/deh_tables.c

@@ -5810,6 +5810,8 @@ const char *const MOBJTYPE_LIST[] = {  // array length left dynamic for sanity t
 	"MT_BATTLEUFO_BEAM",
 
 	"MT_POWERUP_AURA",
+
+	"MT_SCRIPT_THING",
 };
 
 const char *const MOBJFLAG_LIST[] = {

src/info.c

@@ -30313,6 +30313,33 @@ mobjinfo_t mobjinfo[NUMMOBJTYPES] =
 		MF_NOBLOCKMAP|MF_NOGRAVITY|MF_NOCLIPHEIGHT|MF_SCENERY, // flags
 		S_NULL          // raisestate
 	},
+
+	{           // MT_SCRIPT_THING
+		4096,           // doomednum
+		S_INVISIBLE,    // spawnstate
+		1000,           // spawnhealth
+		S_NULL,         // seestate
+		sfx_None,       // seesound
+		0,              // reactiontime
+		sfx_None,       // attacksound
+		S_NULL,         // painstate
+		0,              // painchance
+		sfx_None,       // painsound
+		S_NULL,         // meleestate
+		S_NULL,         // missilestate
+		S_NULL,         // deathstate
+		S_NULL,         // xdeathstate
+		sfx_None,       // deathsound
+		0,              // speed
+		16*FRACUNIT,    // radius
+		16*FRACUNIT,    // height
+		0,              // display offset
+		0,              // mass
+		0,              // damage
+		sfx_None,       // activesound
+		MF_NOBLOCKMAP|MF_NOCLIP|MF_NOCLIPHEIGHT|MF_NOCLIPTHING|MF_NOGRAVITY|MF_SCENERY, // flags
+		S_NULL          // raisestate
+	},
 };
 
 skincolor_t skincolors[MAXSKINCOLORS] = {

src/info.h

@@ -7000,6 +7000,8 @@ typedef enum mobj_type
 
 	MT_POWERUP_AURA,
 
+	MT_SCRIPT_THING,
+
 	MT_FIRSTFREESLOT,
 	MT_LASTFREESLOT = MT_FIRSTFREESLOT + NUMMOBJFREESLOTS - 1,
 	NUMMOBJTYPES

src/p_mobj.c

@@ -6716,6 +6716,49 @@ static void P_MobjSceneryThink(mobj_t *mobj)
 	case MT_ARKARROW:
 		Obj_ArkArrowThink(mobj);
 		break;
+	case MT_SCRIPT_THING:
+	{
+		if (mobj->thing_args[2] != 0)
+		{
+			// turned off
+			break;
+		}
+
+		UINT8 i;
+		for (i = 0; i < MAXPLAYERS; i++)
+		{
+			if (playeringame[i] == false)
+			{
+				continue;
+			}
+
+			player_t *player = &players[i];
+			if (P_MobjWasRemoved(player->mo) == true)
+			{
+				continue;
+			}
+
+			fixed_t dist = R_PointToDist2(
+				mobj->x, mobj->y,
+				player->mo->x, player->mo->y
+			);
+
+			if (dist < mobj->thing_args[0] * FRACUNIT)
+			{
+				P_ActivateThingSpecial(mobj, player->mo);
+
+				if (mobj->thing_args[1] == 0)
+				{
+					P_RemoveMobj(mobj);
+					return;
+				}
+
+				break;
+			}
+		}
+
+		break;
+	}
 	case MT_VWREF:
 	case MT_VWREB:
 	{