Fix identical omts spawning over themselves

CleverRaven · Sep 25, 2023 · 84b9403 · 84b9403
1 parent 95360a3
commit 84b9403
Showing 1 changed file with 19 additions and 1 deletion.
diff --git a/src/savegame.cpp b/src/savegame.cpp
@@ -657,8 +657,26 @@ void overmap::unserialize( const JsonObject &jsobj )
         } else if( name == "predecessors" ) {
             std::vector<std::pair<tripoint_om_omt, std::vector<oter_id>>> flattened_predecessors;
             om_member.read( flattened_predecessors, true );
+            std::vector<oter_id> deduped_predecessors;
             for( std::pair<tripoint_om_omt, std::vector<oter_id>> &p : flattened_predecessors ) {
-                predecessors_.insert( std::move( p ) );
+                // TODO remove after 0.H release.
+                // Deduplicate identical/redundant linear predecessors
+                // Prior versions of mapgen would cause things like roads to 'spawn over' themselves
+                // This would cause city roads with every tile either occupied by monster or wrecks
+                // that would even spawn over themselves.
+                deduped_predecessors.reserve( p.second.size() );
+                for( const oter_id &id : p.second ) {
+                    oter_type_str_id oti = id->get_type_id();
+                    if( !oti->is_linear() || ( deduped_predecessors.empty() ||
+                                               deduped_predecessors.back()->get_type_id() != id->get_type_id() ) ) {
+                        deduped_predecessors.emplace_back( id );
+                    }
+                }
+                predecessors_.insert_or_assign( p.first, std::move( deduped_predecessors ) );
+
+                // Reuse allocations because it's a good habit.
+                deduped_predecessors = std::move( p.second );
+                deduped_predecessors.clear();
             }
         }
     }