Display: cleaned up overlay map getter interface

Instead of a pointer to a member of a derived class, used a virtual function implemented
in both derived classes (game_display and editor_display) that return an reference to the
appropriate object.

Also removed the overlay.hpp include from display.hpp. We can forward-declare the overlay
struct.

src/display.cpp

@@ -131,7 +131,6 @@ display::display(const display_context* dc,
 	, activeTeam_(0)
 	, map_screenshot_(false)
 	, reach_map_()
-	, overlays_(nullptr)
 	, fps_handle_(0)
 	, drawn_hexes_(0)
 	, idle_anim_(preferences::idle_anim())
@@ -295,25 +294,25 @@ void display::add_overlay(const map_location& loc,
 			get_location_y(loc) + hex_size() / 2, halo, loc
 		);
 
-		overlays_->emplace(loc, overlay(img, halo, halo_handle, team_name, item_id, visible_under_fog));
+		get_overlays().emplace(loc, overlay(img, halo, halo_handle, team_name, item_id, visible_under_fog));
 	}
 }
 
 void display::remove_overlay(const map_location& loc)
 {
-	overlays_->erase(loc);
+	get_overlays().erase(loc);
 }
 
 void display::remove_single_overlay(const map_location& loc, const std::string& toDelete)
 {
 	// Iterate through the values with key of loc
-	auto itors = overlays_->equal_range(loc);
+	auto itors = get_overlays().equal_range(loc);
 
 	while(itors.first != itors.second) {
 		const overlay& o = itors.first->second;
 
 		if(o.image == toDelete || o.halo == toDelete || o.id == toDelete) {
-			overlays_->erase(itors.first++);
+			get_overlays().erase(itors.first++);
 		} else {
 			++itors.first;
 		}
@@ -1695,7 +1694,7 @@ void display::draw_gamemap()
 	//
 	// On-map overlays, such as [item]s.
 	//
-	for(const auto& overlay_record : *overlays_) {
+	for(const auto& overlay_record : get_overlays()) {
 		const map_location& o_loc = overlay_record.first;
 
 		if(shrouded(o_loc)) {

src/display.hpp

@@ -39,6 +39,7 @@ class map_labels;
 class arrow;
 class reports;
 class team;
+struct overlay;
 
 namespace halo
 {
@@ -59,7 +60,6 @@ class manager;
 #include "image.hpp" //only needed for enums (!)
 #include "key.hpp"
 #include "map/hex_rect.hpp"
-#include "overlay.hpp"
 #include "sdl/rect.hpp"
 #include "sdl/surface.hpp"
 #include "sdl/texture.hpp"
@@ -935,9 +935,9 @@ protected:
 
 	typedef std::multimap<map_location, overlay> overlay_map;
 
-private:
-	overlay_map* overlays_;
+	virtual overlay_map& get_overlays() = 0;
 
+private:
 	/** Handle for the label which displays frames per second. */
 	int fps_handle_;
 	/** Count work done for the debug info displayed under fps */
@@ -962,12 +962,6 @@ private:
 
 	tod_color color_adjust_;
 
-public:
-	void replace_overlay_map(overlay_map* overlays)
-	{
-		overlays_ = overlays;
-	}
-
 protected:
 	static display* singleton_;
 };

src/editor/editor_display.cpp

@@ -17,6 +17,7 @@
 #include "editor/editor_display.hpp"
 #include "lexical_cast.hpp"
 #include "ogl/utils.hpp"
+#include "overlay.hpp"
 #include "reports.hpp"
 #include "sdl/texture.hpp"
 #include "team.hpp"
@@ -134,4 +135,9 @@ const time_of_day& editor_display::get_time_of_day(const map_location& /*loc*/)
 	return controller_.get_current_map_context().get_time_manager()->get_time_of_day();
 }
 
+display::overlay_map& editor_display::get_overlays()
+{
+	return controller_.get_current_map_context().get_overlays();
+}
+
 } //end namespace editor

src/editor/editor_display.hpp

@@ -51,6 +51,9 @@ protected:
 	virtual void draw_hex_cursor(const map_location& loc) override;
 	virtual void draw_hex_overlays() override;
 
+	/** Inherited from display. */
+	virtual overlay_map& get_overlays() override;
+
 	const SDL_Rect get_clip_rect() override;
 
 	std::set<map_location> brush_locations_;

src/editor/map/context_manager.cpp

@@ -99,9 +99,6 @@ void context_manager::refresh_on_context_change()
 
 	// TODO register the tod_manager with the gui?
 	resources::tod_manager = get_map_context().get_time_manager();
-
-	gui().replace_overlay_map(&get_map_context().get_overlays());
-
 	resources::classification = &get_map_context().get_classification();
 
 	gui().init_flags();

src/game_display.cpp

@@ -33,6 +33,7 @@
 #include "map/label.hpp"
 #include "map/map.hpp"
 #include "ogl/utils.hpp"
+#include "overlay.hpp"
 #include "preferences/game.hpp"
 #include "reports.hpp"
 #include "resources.hpp"
@@ -70,7 +71,6 @@ game_display::game_display(game_board& board, std::weak_ptr<wb::manager> wb,
 	, mode_(RUNNING)
 	, needs_rebuild_(false)
 {
-	replace_overlay_map(&overlay_map_);
 #ifdef USE_GL_RENDERING
 	gl::clear_screen();
 #else
@@ -692,3 +692,8 @@ bool game_display::maybe_rebuild()
 	}
 	return false;
 }
+
+display::overlay_map& game_display::get_overlays()
+{
+	return overlay_map_;
+}

src/game_display.hpp

@@ -142,6 +142,9 @@ protected:
 
 	virtual void draw_hex_overlays() override;
 
+	/** Inherited from display. */
+	virtual overlay_map& get_overlays() override;
+
 public:
 	/** Set the attack direction indicator. */
 	void set_attack_indicator(const map_location& src, const map_location& dst);