Reorganize source files into logical subdirectories

Co-authored-by: Hirek193 <23196899+Hirek193@users.noreply.github.com>

scene/scenenodegroups.h

@@ -0,0 +1,78 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+#pragma once
+
+#include "scenenode.h"
+#include "widgets/map_objects.h"
+
+namespace scene {
+
+struct basic_group {
+// members
+    std::vector<scene::basic_node *> nodes;
+    std::vector<basic_event *> events;
+};
+
+// holds lists of grouped scene nodes
+class node_groups {
+    // NOTE: during scenario deserialization encountering *.inc file causes creation of a new group on the group stack
+    // this allows all nodes listed in this *.inc file to be grouped and potentially modified together by the editor.
+public:
+// constructors
+    node_groups() = default;
+// methods
+    // requests creation of a new node group. returns: handle to the group
+    group_handle
+        create();
+    // indicates creation of current group ended. returns: handle to the parent group or null_handle if group stack is empty
+    group_handle
+        close();
+	// update minimap objects
+	void
+	    update_map();
+    // returns current active group, or null_handle if group stack is empty
+    group_handle
+        handle() const;
+    // places provided node in specified group
+    void
+        insert( scene::group_handle const Group, scene::basic_node *Node );
+    // places provided event in specified group
+    void
+        insert( scene::group_handle const Group, basic_event *Event );
+    // grants direct access to specified group
+    scene::basic_group &
+        group( scene::group_handle const Group ) {
+            return m_groupmap[ Group ]; }
+    // sends basic content of the class in legacy (text) format to provided stream
+    void
+        export_as_text( std::ostream &Output, bool const Dirty ) const;
+
+private:
+// types
+    using group_map = std::unordered_map<scene::group_handle, scene::basic_group>;
+// methods
+    // removes specified group from the group list and group information from the group's nodes
+    void
+        erase( group_map::const_iterator Group );
+    // creates handle for a new group
+    group_handle
+        create_handle();
+    bool
+        assign_cross_switch(map::track_switch&sw, std::string &sw_name, const std::string &id, size_t idx);
+// members
+    group_map m_groupmap; // map of established node groups
+    std::stack<scene::group_handle> m_activegroup; // helper, group to be assigned to newly created nodes
+};
+
+extern node_groups Groups;
+
+} // scene
+
+//---------------------------------------------------------------------------