undo/redo edit placed creatures

src/scenario/monster.cpp

@@ -1035,3 +1035,21 @@ bool cMonster::operator==(const cMonster& other) {
 	CHECK_EQ(other, see_spec);
 	return true;
 }
+
+bool cTownperson::operator==(const cTownperson& other) {
+	CHECK_EQ(other, number);
+	CHECK_EQ(other, start_attitude);
+	CHECK_EQ(other, start_loc);
+	CHECK_EQ(other, mobility);
+	CHECK_EQ(other, time_flag);
+	CHECK_EQ(other, spec1);
+	CHECK_EQ(other, spec2);
+	CHECK_EQ(other, spec_enc_code);
+	CHECK_EQ(other, time_code);
+	CHECK_EQ(other, monster_time);
+	CHECK_EQ(other, personality);
+	CHECK_EQ(other, special_on_kill);
+	CHECK_EQ(other, special_on_talk);
+	CHECK_EQ(other, facial_pic);
+	return true;
+}

src/scenario/monster.hpp

@@ -98,6 +98,10 @@ public:
 	short special_on_kill, special_on_talk;
 	pic_num_t facial_pic;
 	
+	// For detecting actual changes to town monsters in the editor
+	bool operator==(const cTownperson& other);
+	bool operator!=(const cTownperson& other) { return !(*this == other); }
+
 	void import_legacy(legacy::creature_start_type old);
 	cTownperson();
 	cTownperson(location loc, mon_num_t num, const cMonster& monst);

src/scenedit/scen.actions.cpp

@@ -1015,9 +1015,15 @@ static bool handle_terrain_action(location the_point, bool ctrl_hit) {
 				break;
 			}
 			case MODE_EDIT_CREATURE: //edit monst
-				for(short x = 0; x < town->creatures.size(); x++)
+				for(short x = 0; x < town->creatures.size(); x++){
 					if(monst_on_space(spot_hit,x)) {
+						cTownperson old_creature = town->creatures[x];
 						edit_placed_monst(x);
+						if(town->creatures[x] != old_creature){
+							undo_list.add(action_ptr(new aEditPlacedCreature(x, old_creature, town->creatures[x])));
+							update_edit_menu();
+						}
+					}
 				}
 				overall_mode = MODE_DRAWING;
 				break;

src/scenedit/scen.undo.cpp

@@ -320,3 +320,13 @@ bool aEditPlacedItem::redo_me() {
 	town->preset_items[which] = new_item;
 	return true;
 }
+
+bool aEditPlacedCreature::undo_me() {
+	town->creatures[which] = old_creature;
+	return true;
+}
+
+bool aEditPlacedCreature::redo_me() {
+	town->creatures[which] = new_creature;
+	return true;
+}

src/scenedit/scen.undo.hpp

@@ -108,6 +108,19 @@ public:
 		which(which), old_item(old_item), new_item(new_item) {}
 };
 
+/// Action which edits a creature in a town
+class aEditPlacedCreature : public cTerrainAction {
+	size_t which;
+	cTownperson old_creature;
+	cTownperson new_creature;
+	bool undo_me() override;
+	bool redo_me() override;
+public:
+	aEditPlacedCreature(size_t which, cTownperson old_creature, cTownperson new_creature) :
+		cTerrainAction("Edit Placed Creature", new_creature.start_loc),
+		which(which), old_creature(old_creature), new_creature(new_creature) {}
+};
+
 /// Action which places or erases creature(s) in a town
 class aPlaceEraseCreature : public cTerrainAction {
 	bool placed;