New constant for unused special locations. fix #752

src/scenario/area.hpp

@@ -26,6 +26,13 @@ enum {
 	AREA_HUGE = 128,
 };
 
+// x of 100 used to be used to indicate an unused location
+// or a place to temporarily move monsters out of the tile grid completely.
+// I don't know why a negative number wasn't used instead?
+// But in case there is a good reason for that, I'm shifting the placeholder
+// value to a new, much larger, positive constant, that we *could* change again later.
+const int LOC_UNUSED = AREA_HUGE * 2;
+
 class cArea {
 public:
 	const size_t max_dim;

src/scenario/outdoors.cpp

@@ -72,8 +72,10 @@ void cOutdoors::import_legacy(legacy::outdoor_record_type& old){
 	for(short i = 0; i < 18; i++){
 		special_locs[i].x = old.special_locs[i].x;
 		special_locs[i].y = old.special_locs[i].y;
-		if(old.special_locs[i].x == 100)
+		if(old.special_locs[i].x == 100){
+			special_locs[i].x = LOC_UNUSED;
 			special_locs[i].spec = -1;
+		}
 		else special_locs[i].spec = old.special_id[i];
 	}
 	city_locs.resize(8);

src/scenario/town.cpp

@@ -38,8 +38,10 @@ void cTown::import_legacy(legacy::town_record_type& old){
 	for(short i = 0; i < 50; i++){
 		special_locs[i].x = old.special_locs[i].x;
 		special_locs[i].y = old.special_locs[i].y;
-		if(old.special_locs[i].x == 100)
+		if(old.special_locs[i].x == 100){
+			special_locs[i].x = LOC_UNUSED;
 			special_locs[i].spec = -1;
+		}
 		else special_locs[i].spec = old.spec_id[i];
 		cField temp;
 		temp.import_legacy(old.preset_fields[i]);
@@ -83,13 +85,13 @@ cTown::cTown(cScenario& scenario, size_t dim) : cArea(dim), scenario(&scenario),
 	town_chop_key = -1;
 	for(short i = 0; i < wandering.size(); i++) {
 		wandering[i] = d_wan;
-		// x of 100 indicates an unset wandering monster location
-		wandering_locs[i].x = 100;
+		// unset wandering monster location
+		wandering_locs[i].x = LOC_UNUSED;
 	}
 	lighting_type = LIGHT_NORMAL;
 	for(short i = 0; i < 4; i++) {
-		// x of 100 indicates an unset starting location
-		start_locs[i].x = 100;
+		// unset starting location
+		start_locs[i].x = LOC_UNUSED;
 		exits[i].spec = -1;
 		exits[i].x = -1;
 		exits[i].y = -1;

src/scenedit/scen.actions.cpp

@@ -2401,8 +2401,7 @@ void set_terrain(location l,ter_num_t terrain_type,stroke_ter_changes_t& stroke_
 		auto iter = std::find(signs.begin(), signs.end(), l);
 		if(iter == signs.end()) {
 			iter = std::find_if(signs.begin(), signs.end(), [cur_area](const sign_loc_t& sign) {
-				// TODO x of 100 is no longer a valid way to represent nonexistence
-				if(sign.x == 100) return true;
+				if(sign.x == LOC_UNUSED) return true;
 				ter_num_t ter = cur_area->terrain(sign.x,sign.y);
 				return scenario.ter_types[ter].special != eTerSpec::IS_A_SIGN;
 			});