move a helper function for unit invisibility to display_context

src/display_context.cpp

@@ -22,6 +22,32 @@
 
 #include <boost/foreach.hpp>
 
+bool display_context::would_be_discovered(const map_location & loc, int side_num, bool see_all)
+{
+	map_location adjs[6];
+	get_adjacent_tiles(loc,adjs);
+
+	BOOST_FOREACH(const map_location &u_loc, adjs)
+	{
+		unit_map::const_iterator u_it = units().find(u_loc);
+		if (!u_it.valid()) {
+			continue;
+		}
+		const unit & u = *u_it;
+		if (teams()[side_num-1].is_enemy(u.side()) && !u.incapacitated()) {
+			// Enemy spotted in adjacent tiles, check if we can see him.
+			// Watch out to call invisible with see_all=true to avoid infinite recursive calls!
+			if(see_all) {
+				return true;
+			} else if (!teams()[side_num-1].fogged(u_loc)
+			&& !u.invisible(u_loc, true)) {
+				return true;
+			}
+		}
+	}
+	return false;
+}
+
 const unit * display_context::get_visible_unit(const map_location & loc, const team &current_team, bool see_all) const
 {
 	if (!map().on_board(loc)) return NULL;

src/display_context.hpp

@@ -55,6 +55,15 @@ class display_context {
 	virtual const gamemap & map() const = 0;
 	virtual const unit_map & units() const = 0;
 
+	// Helper for is_visible_to_team
+
+	/**
+	 * Given a location and a side number, indicates whether an invisible unit of that side at that
+	 * location would be revealed (perhaps ambushed), based on what team side_num can see.
+	 * If see_all is true then the calculation ignores fog, and enemy ambushers.
+	 */
+	bool would_be_discovered(const map_location & loc, int side_num, bool see_all = true);
+
 	// Needed for reports
 
 	const unit * get_visible_unit(const map_location &loc, const team &current_team, bool see_all = false) const;

src/unit.cpp

@@ -20,6 +20,7 @@
 #include "unit.hpp"
 #include "global.hpp"
 
+#include "display_context.hpp"
 #include "formula_string_utils.hpp"     // for vgettext
 #include "game_board.hpp"               // for game_board
 #include "game_data.hpp"
@@ -2012,31 +2013,7 @@ bool unit::invisible(const map_location& loc, bool see_all) const
 	static const std::string hides("hides");
 	bool is_inv = get_ability_bool(hides,loc);
 	if(is_inv){
-		const std::vector<team>& teams = *resources::teams;
-
-		map_location adjs[6];
-		get_adjacent_tiles(loc,adjs);
-
-		BOOST_FOREACH(const map_location &u_loc, adjs)
-		{
-			unit_map::iterator u_it = resources::units->find(u_loc);
-			if (!u_it.valid()) {
-				continue;
-			}
-			unit & u = *u_it;
-			if (teams[side_-1].is_enemy(u.side()) && !u.incapacitated()) {
-				// Enemy spotted in adjacent tiles, check if we can see him.
-				// Watch out to call invisible with see_all=true to avoid infinite recursive calls!
-				if(see_all) {
-					is_inv = false;
-					break;
-				} else if (!teams[side_-1].fogged(u_loc)
-				&& !u.invisible(u_loc, true)) {
-					is_inv = false;
-					break;
-				}
-			}
-		}
+		is_inv = (resources::gameboard ? !resources::gameboard->would_be_discovered(loc, side_,see_all) : true);
 	}
 
 	if(see_all) {