Implement Go Back stack for talk mode. Fix #726

src/game/boe.dlgutil.cpp

@@ -83,6 +83,22 @@ short store_talk_face_pic;
 int current_talk_node;
 extern std::vector<word_rect_t> talk_words;
 
+// "Go Back" stack: When pressing the "Go Back" button, we don't just want to reverse through
+// the nodes the player has seen, because they might change game state the first time, causing
+// you to go backwards to a node that would behave differently than it did before.
+// The "Go Back" stack allows you to reverse through exactly what the dialog engine has showed you,
+// in a read-only fashion as long as you only go backwards.
+struct dialog_history_t {
+	bool can_record;
+
+	bool special_node;
+	// Store node numbers for shop nodes.
+	int node;
+	// Store text for normal dialog nodes.
+	std::pair<std::string, std::string> text;
+};
+std::vector<dialog_history_t> dialog_history;
+
 // Shopping vars
 
 // 1 - 499 ... regular items
@@ -193,7 +209,9 @@ bool start_shop_mode(short which,short cost_adj,std::string store_name, bool can
 	return true;
 }
 
+// This is for the legacy "Go Back" button behavior, and for some reason doesn't always work:
 static void update_last_talk(int new_node) {
+	if(has_feature_flag("talk-go-back", "StackV1")) return;
 	// Store last node in the Go Back button
 	for(word_rect_t& word : talk_words) {
 		if(word.word != "Go Back") continue;
@@ -222,6 +240,7 @@ void end_shop_mode() {
 	if(store_pre_shop_mode == MODE_TALKING) {
 		save_talk_str1 = "You conclude your business.";
 		save_talk_str2 = "";
+		can_save_talk = false;
 		place_talk_str(save_talk_str1, save_talk_str2, 0, dummy_rect);
 		update_last_talk(TALK_BUSINESS);
 	}else{
@@ -633,6 +652,13 @@ void set_up_shop_array() {
 	}
 }
 
+std::vector<std::string> preset_words = {
+	"Look", "Name", "Job",
+	"Buy", "Sell", "Record",
+	"Done", "Go Back",
+	"Ask About...",
+};
+
 static void reset_talk_words() {
 	// first initialise talk_words here
 	talk_words.clear();
@@ -642,12 +668,6 @@ static void reset_talk_words() {
 		{210, 389}, {190, 366},
 		{4, 343}
 	};
-	static const std::vector<std::string> preset_words = {
-		"Look", "Name", "Job",
-		"Buy", "Sell", "Record",
-		"Done", "Go Back",
-		"Ask About...",
-	};
 	TextStyle style;
 	style.font = FONT_DUNGEON;
 	style.pointSize = TALK_WORD_SIZE;
@@ -655,6 +675,8 @@ static void reset_talk_words() {
 	// Place buttons at bottom.
 	for(short i = 0; i < preset_words.size(); i++) {
 		if(talk_end_forced && i != 6 && i != 5) continue;
+		if(!can_save_talk && i == 5) continue;
+		if(has_feature_flag("talk-go-back", "StackV1") && dialog_history.size() < 2 && i == 7) continue;
 
 		std::string word = preset_words[i];
 		location tl = preset_word_locs[i];
@@ -682,6 +704,7 @@ static void reset_talk_words() {
 }
 
 void start_talk_mode(short m_num,short personality,mon_num_t monst_type,short store_face_pic) {
+	dialog_history.clear();
 	rectangle area_rect;
 
 	store_personality = personality;
@@ -705,6 +728,7 @@ void start_talk_mode(short m_num,short personality,mon_num_t monst_type,short st
 	overall_mode = MODE_TALKING;
 	talk_end_forced = false;
 
+	can_save_talk = true;
 	reset_talk_words();
 	
 	stat_screen_mode = MODE_SHOP;
@@ -713,9 +737,9 @@ void start_talk_mode(short m_num,short personality,mon_num_t monst_type,short st
 	// Bring up and place first strings.
 	save_talk_str1 = univ.town.cur_talk().people[personality % 10].look;
 	save_talk_str2 = "";
-	can_save_talk = true;
 	
 	place_talk_str(save_talk_str1, "", 0, dummy_rect);
+	dialog_history.push_back({true, false, -1, {save_talk_str1, save_talk_str2}});
 	
 	put_item_screen(stat_window);
 	give_help(5,6);
@@ -799,12 +823,10 @@ static void show_job_bank(int which_bank, std::string title) {
 	job_dlg.run();
 }
 
-void handle_talk_node(int which_talk_entry) {
+void handle_talk_node(int which_talk_entry, bool is_redo) {
 	if(which_talk_entry == TALK_DUNNO)
 		return;
 
-	reset_talk_words();
-
 	short get_pc,s1 = -1,s2 = -1;
 	char asked[4];
 	
@@ -817,35 +839,32 @@ void handle_talk_node(int which_talk_entry) {
 			save_talk_str1 = univ.town.cur_talk().people[store_personality % 10].dunno;
 			save_talk_str2 = "";
 			if(save_talk_str1.length() < 2) save_talk_str1 = "You get no response.";
-			place_talk_str(save_talk_str1, "", 0, dummy_rect);
 			update_last_talk(TALK_DUNNO);
-			return;
+			goto FINISH_TALK_NODE;
 		case TALK_BUSINESS: // This one only reachable via "go back".
-			place_talk_str("You conclude your business.", "", 0, dummy_rect);
+			can_save_talk = false;
+			save_talk_str1 = "You conclude your business.";
 			save_talk_str2 = "";
 			update_last_talk(TALK_BUSINESS);
-			return;
+			goto FINISH_TALK_NODE;
 		case TALK_LOOK:
 		SPECIAL_LOOK:
 			save_talk_str1 = univ.town.cur_talk().people[store_personality % 10].look;
 			save_talk_str2 = "";
-			place_talk_str(save_talk_str1, "", 0, dummy_rect);
 			update_last_talk(TALK_LOOK);
-			return;
+			goto FINISH_TALK_NODE;
 		case TALK_NAME:
 		SPECIAL_NAME:
 			save_talk_str1 = univ.town.cur_talk().people[store_personality % 10].name;
 			save_talk_str2 = "";
-			place_talk_str(save_talk_str1, "", 0, dummy_rect);
 			update_last_talk(TALK_NAME);
-			return;
+			goto FINISH_TALK_NODE;
 		case TALK_JOB:
 		SPECIAL_JOB:
 			save_talk_str1 = univ.town.cur_talk().people[store_personality % 10].job;
 			save_talk_str2 = "";
-			place_talk_str(save_talk_str1, "", 0, dummy_rect);
 			update_last_talk(TALK_JOB);
-			return;
+			goto FINISH_TALK_NODE;
 		case TALK_BUY:
 		SPECIAL_BUY:
 			which_talk_entry = scan_for_response("purc");
@@ -862,11 +881,6 @@ void handle_talk_node(int which_talk_entry) {
 			if(which_talk_entry == -1) goto SPECIAL_DUNNO;
 			break;
 		case TALK_RECORD:
-			if(!can_save_talk) {
-				// TODO the button shouldn't be shown if it won't work, no?
-				play_sound(1);
-				return;
-			}
 			if(univ.party.save_talk(univ.town->talking.people[store_personality%10].title, univ.town->name, save_talk_str1, save_talk_str2)) {
 				give_help(57,0);
 				play_sound(0);
@@ -878,8 +892,27 @@ void handle_talk_node(int which_talk_entry) {
 		SPECIAL_DONE:
 			end_talk_mode();
 			return;
-		case TALK_BACK: // only if there's nothing to go back to
-			return; // so, there's nothing to do here
+		case TALK_BACK:
+			// In legacy behavior, this should only happen if there's nothing to go back to. In that case, do nothing.
+			if(has_feature_flag("talk-go-back", "StackV1")){
+				if(!dialog_history.empty()){
+					dialog_history_t last_state;
+					do{
+						last_state = dialog_history.back();
+						dialog_history.pop_back();
+						if(last_state.special_node){
+							handle_talk_node(last_state.node, true);
+							return;
+						}
+					// If they ended up in the same node, don't treat it as a step back until we get to different text.
+					}while(!dialog_history.empty() && save_talk_str1 == last_state.text.first && save_talk_str2 == last_state.text.second);
+					can_save_talk = last_state.can_record;
+					save_talk_str1 = last_state.text.first;
+					save_talk_str2 = last_state.text.second;
+					goto FINISH_TALK_NODE;
+				}
+			}
+			return;
 		case TALK_ASK: // ask about
 			save_talk_str1 = get_text_response("Ask about what?", 8);
 			strncpy(asked, save_talk_str1.c_str(), 4);
@@ -953,13 +986,13 @@ void handle_talk_node(int which_talk_entry) {
 			save_talk_str2 = "";
 			break;
 		case eTalkNode::TRAINING:
+			save_talk_str1 = "You conclude your training.";
+			save_talk_str2 = "";
+			can_save_talk = false;
 			if((get_pc = select_pc(eSelectPC::ONLY_LIVING,"Train who?")) < 6) {
-				can_save_talk = false;
 				spend_xp(get_pc,1, nullptr);
 			}
-			save_talk_str1 = "You conclude your training.";
-			return;
-			
+			goto RECORD_WHICH_NODE;
 		case eTalkNode::SHOP:
 			if(!start_shop_mode(b,a,save_talk_str1,true)){
 				if(!start_shop_mode_other_pc()){
@@ -976,7 +1009,7 @@ void handle_talk_node(int which_talk_entry) {
 			}else{
 				can_save_talk = false;
 			}
-			return;
+			goto RECORD_WHICH_NODE;
 		case eTalkNode::JOB_BANK:
 			if(a < univ.party.job_banks.size() && univ.party.job_banks[a].anger >= 50) {
 				save_talk_str1 = save_talk_str2;
@@ -984,26 +1017,26 @@ void handle_talk_node(int which_talk_entry) {
 				break;
 			} else {
 				show_job_bank(a, save_talk_str1.c_str());
-				return;
+				goto RECORD_WHICH_NODE;
 			}
 		case eTalkNode::SELL_WEAPONS:
 			can_save_talk = false;
 			stat_screen_mode = MODE_SELL_WEAP;
 			put_item_screen(stat_window);
 			give_help(42,43);
-			break;
+			goto RECORD_WHICH_NODE;
 		case eTalkNode::SELL_ARMOR:
 			can_save_talk = false;
 			stat_screen_mode = MODE_SELL_ARMOR;
 			put_item_screen(stat_window);
 			give_help(42,43);
-			break;
+			goto RECORD_WHICH_NODE;
 		case eTalkNode::SELL_ITEMS:
 			can_save_talk = false;
 			stat_screen_mode = MODE_SELL_ANY;
 			put_item_screen(stat_window);
 			give_help(42,43);
-			break;
+			goto RECORD_WHICH_NODE;
 		case eTalkNode::IDENTIFY:
 			stat_screen_mode = MODE_IDENTIFY,
 			give_help(44, 0);
@@ -1020,7 +1053,7 @@ void handle_talk_node(int which_talk_entry) {
 			shop_recharge_limit = b;
 			shop_recharge_amount = c;
 			put_item_screen(stat_window);
-			break;
+			goto RECORD_WHICH_NODE;
 		case eTalkNode::BUY_INFO:
 			if(univ.party.gold < a) {
 				save_talk_str1 = save_talk_str2;
@@ -1087,12 +1120,11 @@ void handle_talk_node(int which_talk_entry) {
 					univ.party.gold -= a;
 					put_pc_screen();
 					iter->property = false;
-					save_talk_str2 = "";
 				} else {
 					save_talk_str1 = "There are no horses left.";
-					save_talk_str2 = "";
 					can_save_talk = false;
 				}
+				save_talk_str2 = "";
 			}
 			break;
 		case eTalkNode::BUY_SPEC_ITEM:
@@ -1132,7 +1164,7 @@ void handle_talk_node(int which_talk_entry) {
 			break;
 		case eTalkNode::BUY_TOWN_LOC:
 			if(univ.scenario.towns[b]->can_find) {
-				// TODO: Uh, is something supposed to happen here?
+				save_talk_str1 = "You've already learned that.";
 			}
 			else if(univ.party.gold < a) {
 				save_talk_str1 = save_talk_str2;
@@ -1192,9 +1224,20 @@ void handle_talk_node(int which_talk_entry) {
 			put_item_screen(stat_window);
 			break;
 	}
-	
+
+	if(false){
+	RECORD_WHICH_NODE:
+		if(!is_redo) dialog_history.push_back({false, true, which_talk_entry, {"", ""}});
+		place_talk_str(save_talk_str1,save_talk_str2,0,dummy_rect);
+		reset_talk_words();
+		return;
+	}
+
+FINISH_TALK_NODE:
+	dialog_history.push_back({can_save_talk, false, -1, {save_talk_str1, save_talk_str2}});
 	place_talk_str(save_talk_str1,save_talk_str2,0,dummy_rect);
 	reset_talk_words();
+	return;
 }
 
 bool handle_talk_event(location p, cFramerateLimiter& fps_limiter) {

src/game/boe.dlgutil.hpp

@@ -13,7 +13,7 @@ void handle_info_request(int what_picked);
 void set_up_shop_array();
 void start_talk_mode(short m_num,short personality,mon_num_t monst_type,short store_face_pic);
 void end_talk_mode();
-void handle_talk_node(int which_talk_entry);
+void handle_talk_node(int which_talk_entry, bool is_redo = false);
 bool handle_talk_event(location p, cFramerateLimiter& fps_limiter);
 void handle_talk_spec(short ttype,char* place_string1,char* place_string2);
 void store_responses();

src/game/boe.main.cpp

@@ -114,6 +114,8 @@ std::map<std::string,std::vector<std::string>> feature_flags = {
 	// New in-game save file picker
 	{"file-picker-dialog", {"V1"}},
 	{"scenario-meta-format", {"V2"}},
+	// Talk mode
+	{"talk-go-back", {"StackV1"}},
 	// Bugs required for several VoDT test replays to run faithfully
 	{"empty-wandering-monster-bug", {"fixed"}},
 	{"too-many-extra-wandering-monsters-bug", {"fixed"}}

src/game/boe.newgraph.cpp

@@ -941,6 +941,8 @@ void click_talk_rect(word_rect_t word) {
 	place_talk_face();
 }
 
+extern std::vector<std::string> preset_words;
+
 // color 0 - regular  1 - darker
 void place_talk_str(std::string str_to_place,std::string str_to_place2,short color,rectangle c_rect) {
 	rectangle area_rect;
@@ -981,9 +983,12 @@ void place_talk_str(std::string str_to_place,std::string str_to_place2,short col
 		style.colour = PRESET_WORD_OFF;
 	else 
 		style.colour = PRESET_WORD_ON;
-	for(short i = 0; i < 9; i++) {
-		if(!talk_end_forced || i == 6 || i == 5)
+	int i = 0;
+	for(std::string preset : preset_words) {
+		if(talk_words[i].word == preset){
 			win_draw_string(talk_gworld(),talk_words[i].rect,talk_words[i].word,eTextMode::LEFT_TOP,style);
+			i++;
+		}
 	}
 	
 	style.colour = Colours::NAVY;