Reorganize initialization error reporting

- Invalid game id -> sys_error() in GameId::GameId()
- Unknown crc32 -> SDL_ShowSimpleMessageBox() in GameId::GameId()
- Cannot open ADISK.DAT -> sys_error() in NACT::NACT()

src/sdlmain.cpp

@@ -31,13 +31,6 @@ SDL_Window* create_window(const GameId& game_id)
 	if (game_id.title) {
 		title += ": ";
 		title += game_id.title;
-	} else {
-		SDL_ShowSimpleMessageBox(
-			SDL_MESSAGEBOX_WARNING, "system3",
-			"Unable to determine game ID.\n"
-			"If you are running a modified game, please specify 'game = <original-game-id>' in system3.ini.\n"
-			"See README.md for more information.",
-			NULL);
 	}
 
 	SDL_Init(SDL_INIT_VIDEO);
@@ -81,9 +74,6 @@ int main(int argc, char *argv[])
 		return 0;
 	}
 	GameId game_id(config);
-	if (!game_id.is_valid()) {
-		sys_error("No game files in the current directory.");
-	}
 
 	g_window = create_window(game_id);
 	g_renderer = SDL_CreateRenderer(g_window, -1, 0);

src/sys/dri.h

@@ -17,6 +17,7 @@ class Dri {
 public:
 	void open(const char* file_name);
 	std::vector<uint8_t> load(int page);
+	bool loaded() const { return !link_table.empty(); }
 
 	static std::vector<uint8_t> load_mda(const GameId& game_id, int page);
 

src/sys/game_id.cpp

@@ -197,12 +197,21 @@ GameId::GameId(const Config& config)
 				break;
 			}
 		}
+		if (!entry)
+			sys_error("Unknown game ID: %s", config.game_id.c_str());
 	} else {
 		uint32_t crc32_a = calc_crc32("ADISK.DAT");
 		uint32_t crc32_b = calc_crc32("BDISK.DAT");
 		entry = lookup(crc32_a, crc32_b);
-		if (!entry)
+		if (crc32_a && !entry) {
 			WARNING("Cannot determine game id. crc32_a: %08x, crc32_b: %08x", crc32_a, crc32_b);
+			SDL_ShowSimpleMessageBox(
+				SDL_MESSAGEBOX_WARNING, "system3",
+				"Unable to determine game ID.\n"
+				"If you are running a modified game, please specify 'game = <original-game-id>' in system3.ini.\n"
+				"See README.md for more information.",
+				NULL);
+		}
 	}
 	if (entry) {
 		game = entry->game;

src/sys/nact.cpp

@@ -53,6 +53,8 @@ NACT::NACT(const Config& config, const GameId& game_id)
 		sco.open("AGAME.DAT");
 	else
 		sco.open("ADISK.DAT");
+	if (!sco.loaded())
+		sys_error("Cannot open scenario file");
 	sco.page_jump(0, 2);
 
 	// 各種クラス生成

src/sys/scenario.h

@@ -11,6 +11,7 @@ class Encoding;
 class Scenario {
 public:
 	void open(const char* file_name) { adisk.open(file_name); }
+	bool loaded() const { return adisk.loaded(); }
 	void page_jump(int page, int addr);
 	int default_addr() { return data_[0] | data_[1] << 8; }