ShowStringPic: Support Var(Indirect) for system name and font name

Author: Ghabry

src/game_interpreter.cpp

@@ -4680,7 +4680,31 @@ bool Game_Interpreter::CommandManiacShowStringPicture(lcf::rpg::EventCommand con
 	}
 
 	params.system_name = components[2];
+	uint32_t var_id = 0;
+	auto mode = delims[1] - 1;
+	if (mode > 0) {
+		if (!ManiacPatch::DecodeStringToInt(params.system_name, var_id)) {
+			Output::Warning("ShowStringPic: Bad system name arg (id={}, arg={})", pic_id, components[2]);
+			return true;
+		}
+
+		params.system_name = Main_Data::game_strings->GetWithMode(
+			params.system_name, mode, var_id, *Main_Data::game_variables
+		);
+	}
+
 	text.font_name = components[3];
+	mode = delims[2] - 1;
+	if (mode > 0) {
+		if (!ManiacPatch::DecodeStringToInt(text.font_name, var_id)) {
+			Output::Warning("ShowStringPic: Bad font name arg (id={}, arg={})", pic_id, components[2]);
+			return true;
+		}
+
+		text.font_name = Main_Data::game_strings->GetWithMode(
+			text.font_name, mode, var_id, *Main_Data::game_variables
+		);
+	}
 
 	params.texts = {text};
 

src/maniac_patch.cpp

@@ -834,6 +834,51 @@ std::string_view ManiacPatch::GetLcfDescription(int data_type, int id, bool is_d
 	return {};
 }
 
+bool ManiacPatch::DecodeStringToInt(std::string_view str, uint32_t& out) {
+	/*
+	Is a custom 5 bit encoding:
+
+	For the rightmost character c the value is:
+	c - A + 1
+
+	For all other characters c with index i the value is:
+	(c - a + 1) << (i * 5)
+
+	Due to integer overflow the max string length is 6.
+	*/
+
+	out = 0;
+
+	if (!(str.size() > 0 && str.size() <= 6)) {
+		return false;
+	}
+
+	auto in_range = [](uint32_t value) {
+		return value >= 0 && value < 32;
+	};
+
+	out = (str.back() - 'A' + 1);
+
+	if (!in_range(out)) {
+		return false;
+	}
+
+	str.remove_suffix(1);
+
+	for (size_t i = 0; i < str.size(); ++i) {
+		uint32_t result = (str[i] - 'a' + 1);
+
+		if (!in_range(result)) {
+			return false;
+		}
+
+		int chidx = str.size() - i;
+		out += (result << (chidx * 5));
+	}
+
+	return out;
+}
+
 bool ManiacPatch::GlobalSave::Load() {
 	if (!Player::IsPatchManiac()) {
 		return true;

src/maniac_patch.h

@@ -38,6 +38,17 @@ namespace ManiacPatch {
 	std::string_view GetLcfName(int data_type, int id, bool is_dynamic);
 	std::string_view GetLcfDescription(int data_type, int id, bool is_dynamic);
 
+	/**
+	 * Decodes an encoded string as used by the ShowStringPicture to the number
+	 * representation.
+	 *
+	 * @param str String to decode
+	 * @param out The number represented by the string
+	 *
+	 * @return Whether the decoding was successful (this function will reject malformed strings)
+	 */
+	bool DecodeStringToInt(std::string_view str, uint32_t& out);
+
 	namespace GlobalSave {
 		/**
 		* Attempts to load Save.lgs from the save directory.