LUA

LUA is an imperative programming language, designed in 1993 by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, and Waldemar Celes, members of the Computer Graphics Technology Group (Tecgraf) at PUC-Rio, the Pontifical University of Rio de Janeiro, in Brazil. "Lua" means "Moon" in Portuguese. Lua is used in SimCity 4 for the generation of help texts, creation of rewards and other types of codes.

More information about Lua can be found on the official site and on Wikipedia.

Use in SimCity 4

Lua has many uses in SimCity 4, as mentioned above. The exact format used can vary depending on the use. The formats below are courtesy of Karybdis.

Instance by: CRC24Polynomial = 0x01864cfb, CRC24Seed = 0x00b704ce, return (CRC24(from, false) | 0xFF000000)

• LUAAdvice
• LUADefs
• LUAAdvisors
• LUAMission
• LUAObject
• LUASystem
• LUATutorials

Binary LUA

The following format is for binary Lua scripts, and was developed by Quaxi.

Here are the first things known about the .objLua and .globalObjLua:

General Format

	DWord: 1b 4c 75 61   (ID)
	Byte: Version    
	16-Bytes: Header
	    ---> Root "Function Block"

Function Block

	Dword: Character count n
	n-Byte: Name of the Function (null terminated)
	5-Byte: unknown
	Byte: argument Count
	Byte: unknown
	Byte: stack Size
	
	12-Byte: 00

	4-Byte: constant counter 
	    ---> Loop Constant Block
	
	4-Byte: functions counter
	    ---> Loop Function Block

	4-Byte: instruction counter
	    ---> Loop Instruction Block

Instruction Block

(a=Operand a, b=Operand b, c=Operand c, o=Opcode):

	Dword: aaaa aaaa bbbb bbbb bccc cccc ccoo oooo    

This Document lists the available opcodes: http://www.tecgraf.puc-rio.br/~lhf/ftp/doc/sblp2005.pdf

Constant Block

	Byte: ConstantType
	    ----> Constant Data

List of Known Constant Data Types

0x00 = Empty, Null -  This seems to mark an empty block
0x03 = Number
          DWord: Unknown
          DWord: Unknown
0x04 = Strings
          DWord: Length n of the following PString
          n-Bytes: Instruction Name, null-terminated