Split config transparency settings into base and extra fields

This is to avoid incorrect settings when loading in trunk,
as the min/max clamping is not bitwise.
In particular having all options set in trunk when transparent vehicles
in tunnels was set.

src/settings.cpp

@@ -2123,6 +2123,8 @@ static void RemoveEntriesFromIni(IniFile &ini, const SettingTable &table)
  */
 void LoadFromConfig(bool startup)
 {
+	PreTransparencyOptionSave();
+
 	ConfigIniFile generic_ini(_config_file, &_config_file_text);
 	ConfigIniFile private_ini(_private_file);
 	ConfigIniFile secrets_ini(_secrets_file);
@@ -2171,12 +2173,16 @@ void LoadFromConfig(bool startup)
 		extern void ScheduleErrorMessage(ErrorList &datas);
 		ScheduleErrorMessage(_settings_error_list);
 		if (FindWindowById(WC_ERRMSG, 0) == nullptr) ShowFirstError();
+	} else {
+		PostTransparencyOptionLoad();
 	}
 }
 
 /** Save the values to the configuration file */
 void SaveToConfig()
 {
+	PreTransparencyOptionSave();
+
 	ConfigIniFile generic_ini(_config_file);
 	ConfigIniFile private_ini(_private_file);
 	ConfigIniFile secrets_ini(_secrets_file);

src/table/settings/misc_settings.ini

@@ -295,19 +295,37 @@ cat      = SC_BASIC
 [SDTG_VAR]
 name     = ""transparency_options""
 type     = SLE_UINT
-var      = _transparency_opt
+var      = _transparency_opt_base
 def      = 0
 min      = 0
-max      = 0x3FF
+max      = 0xFFFFFFFF
+cat      = SC_BASIC
+
+[SDTG_VAR]
+name     = ""extra_transparency_options""
+type     = SLE_UINT
+var      = _transparency_opt_extra
+def      = 0
+min      = 0
+max      = 0xFFFFFFFF
 cat      = SC_BASIC
 
 [SDTG_VAR]
 name     = ""transparency_locks""
 type     = SLE_UINT
-var      = _transparency_lock
+var      = _transparency_lock_base
 def      = 0
 min      = 0
-max      = 0x3FF
+max      = 0xFFFFFFFF
+cat      = SC_BASIC
+
+[SDTG_VAR]
+name     = ""extra_transparency_locks""
+type     = SLE_UINT
+var      = _transparency_lock_extra
+def      = 0
+min      = 0
+max      = 0xFFFFFFFF
 cat      = SC_BASIC
 
 [SDTG_VAR]

src/transparency.h

@@ -37,10 +37,17 @@ enum TransparencyOption {
 typedef uint TransparencyOptionBits; ///< transparency option bits
 extern TransparencyOptionBits _transparency_opt;
 extern TransparencyOptionBits _transparency_lock;
+extern TransparencyOptionBits _transparency_opt_base;
+extern TransparencyOptionBits _transparency_lock_base;
+extern TransparencyOptionBits _transparency_opt_extra;
+extern TransparencyOptionBits _transparency_lock_extra;
 extern TransparencyOptionBits _invisibility_opt;
 extern byte _display_opt;
 extern byte _extra_display_opt;
 
+void PreTransparencyOptionSave();
+void PostTransparencyOptionLoad();
+
 /**
  * Check if the transparency option bit is set
  * and if we aren't in the game menu (there's never transparency)

src/transparency_gui.cpp

@@ -22,10 +22,33 @@
 
 TransparencyOptionBits _transparency_opt;  ///< The bits that should be transparent.
 TransparencyOptionBits _transparency_lock; ///< Prevent these bits from flipping with X.
+TransparencyOptionBits _transparency_opt_base;   ///< Separate base and extra fields for config save/load.
+TransparencyOptionBits _transparency_lock_base;  ///< "
+TransparencyOptionBits _transparency_opt_extra;  ///< "
+TransparencyOptionBits _transparency_lock_extra; ///< "
 TransparencyOptionBits _invisibility_opt;  ///< The bits that should be invisible.
 byte _display_opt; ///< What do we want to draw/do?
 byte _extra_display_opt;
 
+void PreTransparencyOptionSave()
+{
+	auto handler = [](TransparencyOptionBits value, TransparencyOptionBits &base, TransparencyOptionBits &extra) {
+		base = value & 0x1FF;
+		extra = (value >> 9) & 0x1;
+	};
+	handler(_transparency_opt, _transparency_opt_base, _transparency_opt_extra);
+	handler(_transparency_lock, _transparency_lock_base, _transparency_lock_extra);
+}
+
+void PostTransparencyOptionLoad()
+{
+	auto handler = [](TransparencyOptionBits base, TransparencyOptionBits extra) -> TransparencyOptionBits {
+		return (base & 0x3FF) | ((extra & 0x1) << 9);
+	};
+	_transparency_opt = handler(_transparency_opt_base, _transparency_opt_extra);
+	_transparency_lock = handler(_transparency_lock_base, _transparency_lock_extra);
+}
+
 class TransparenciesWindow : public Window
 {
 public: