From 69cddfe538bcfd173c8fd315e9fd38b668146413 Mon Sep 17 00:00:00 2001
From: Procyonae <45432782+Procyonae@users.noreply.github.com>
Date: Sat, 6 Jan 2024 04:50:03 +0000
Subject: [PATCH] Fixed special optional overmap field (#70677)

* Initial Commit

* Test special

* Revert test special

* Astyle

* Update OVERMAP.md

* Astyle better
---
 doc/OVERMAP.md  | 12 ++++++------
 src/overmap.cpp | 32 ++++++++++++++++----------------
 2 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/doc/OVERMAP.md b/doc/OVERMAP.md
index 9f097617d5947..308b6cb11dd45 100644
--- a/doc/OVERMAP.md
+++ b/doc/OVERMAP.md
@@ -439,11 +439,11 @@ Depending on the subtype, there are further relevant fields:
 
 ### Fixed special overmaps
 
-| Identifier  |                                Description                                 |
-| ----------- | -------------------------------------------------------------------------- |
-| `point`     | `[ x, y, z]` of the overmap terrain within the special.                    |
-| `overmap`   | Id of the `overmap_terrain` to place at the location.                      |
-| `locations` | List of `overmap_location` ids that this overmap terrain may be placed on. |
+| Identifier  |                                                                                      Description                                                                                           |
+| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| `point`     | `[ x, y, z]` of the overmap terrain within the special.                                                                                                                                    |
+| `overmap`   | Id of the `overmap_terrain` to place at the location. If ommited no overmap_terrain is placed but the point will still be checked for valid locations when deciding if placement is valid. |
+| `locations` | List of `overmap_location` ids that this overmap terrain may be placed on. Overrides the specials overall `locations` field.                                                               |
 
 ### Connections
 
@@ -453,7 +453,7 @@ Depending on the subtype, there are further relevant fields:
 | `terrain`    | Will go away in favor of `connection` eventually. Use `road`, `subway`, `sewer`, etc.              |
 | `connection` | Id of the `overmap_connection` to build. Optional for now, but you should specify it explicitly.   |
 | `from`       | Optional point `[ x, y, z]` within the special to treat as the origin of the connection.           |
-| `existing`   | Boolean, default false. If the special requires a preexisting terrain to spawn.				          	|
+| `existing`   | Boolean, default false. If the special requires a preexisting terrain to spawn.                    |
 
 ### Example mutable special
 
diff --git a/src/overmap.cpp b/src/overmap.cpp
index 5fccb9a7aee63..29336229ace4e 100644
--- a/src/overmap.cpp
+++ b/src/overmap.cpp
@@ -1422,21 +1422,21 @@ struct fixed_overmap_special_data : overmap_special_data {
 
         for( const overmap_special_terrain &elem : terrains ) {
             const tripoint_om_omt location = origin + om_direction::rotate( elem.p, dir );
-            result.omts_used.push_back( location );
-            const oter_id tid = elem.terrain->get_rotated( dir );
-
-            om.ter_set( location, tid );
-
-            if( blob ) {
-                for( int x = -2; x <= 2; x++ ) {
-                    for( int y = -2; y <= 2; y++ ) {
-                        const tripoint_om_omt nearby_pos = location + point( x, y );
-                        if( !overmap::inbounds( nearby_pos ) ) {
-                            continue;
-                        }
-                        if( one_in( 1 + std::abs( x ) + std::abs( y ) ) &&
-                            elem.can_be_placed_on( om.ter( nearby_pos ) ) ) {
-                            om.ter_set( nearby_pos, tid );
+            if( !( elem.terrain == oter_str_id::NULL_ID() ) ) {
+                result.omts_used.push_back( location );
+                const oter_id tid = elem.terrain->get_rotated( dir );
+                om.ter_set( location, tid );
+                if( blob ) {
+                    for( int x = -2; x <= 2; x++ ) {
+                        for( int y = -2; y <= 2; y++ ) {
+                            const tripoint_om_omt nearby_pos = location + point( x, y );
+                            if( !overmap::inbounds( nearby_pos ) ) {
+                                continue;
+                            }
+                            if( one_in( 1 + std::abs( x ) + std::abs( y ) ) &&
+                                elem.can_be_placed_on( om.ter( nearby_pos ) ) ) {
+                                om.ter_set( nearby_pos, tid );
+                            }
                         }
                     }
                 }
@@ -2755,7 +2755,7 @@ void overmap_special::load( const JsonObject &jo, const std::string &src )
         case overmap_special_subtype::fixed: {
             shared_ptr_fast<fixed_overmap_special_data> fixed_data =
                 make_shared_fast<fixed_overmap_special_data>();
-            mandatory( jo, was_loaded, "overmaps", fixed_data->terrains );
+            optional( jo, was_loaded, "overmaps", fixed_data->terrains );
             if( is_special ) {
                 optional( jo, was_loaded, "connections", fixed_data->connections );
             }