Lua C++ Extension DLL Example

[Null 45 3,048]

This DLL extends the Lua system by adding two new C++ functions for the Lua code to call. The first function computes the binary logarithm of the specified number, and the second function returns the NAM version string if that mod is installed.

The DLL is intended as a demo/example for DLL and Lua developers. Its only in-game functionality is showing a message box upon entering an established city, which probably isn't very interesting for most users.

Download: https://github.com/0xC0000054/sc4-lua-extension-example/releases

Source Code: https://github.com/0xC0000054/sc4-lua-extension-example

System Requirements

• Windows 10 or later

The DLL may work on Windows 7, but I am not able to test that.

Installation

1. Close SimCity 4.
2. Copy SC4LuaExtensionExample.dll and LuaExtensionExample.dat into the top-level of the Plugins folder in the SimCity 4 installation directory or Documents/SimCity 4 directory.
3. Start SimCity 4.

Usage

The game's Urgent Advice dialogs must be enabled for the plugin to work. It will show a Lua C++ Function Test message box upon entering an established city.

The code used to show the Urgent Advice dialog is adapted from code created by @CorinaMarie.

Troubleshooting

The plugin should write a SC4LuaExtensionExample.log file in the same folder as the plugin.
The log contains status information for the most recent run of the plugin.

[CorinaMarie 29,621]

Tested:

[Kel9509 1,407]

I'm just seeing this now and I'm wondering about the possibilities that this test example might allow.  What sort of game functions (currently coded in C++?) could also be adopted to LUA? 

I'm interested in possibly adopting buildings to create a custom query similar to how Cori/Cyclone Boom did here: 

 

[Null 45 3,048]

3 hours ago, Kel9509 said:

What sort of game functions (currently coded in C++?) could also be adopted to LUA? 

In theory the C++ side could call any of the game systems that are available in the city view. Maxis did that with the the ordinance Lua functions (ordinance_set_on, ordinance_name, etc.), those methods interact with the ordinance simulator.

The game.g_nnn variables in that Cori/Cyclone Boom UI are just numbers or strings that the game tosses over to the Lua side.

[Kel9509 1,407]

2 hours ago, Null 45 said:

In theory the C++ side could call any of the game systems that are available in the city view. Maxis did that with the the ordinance Lua functions (ordinance_set_on, ordinance_name, etc.), those methods interact with the ordinance simulator.

The game.g_nnn variables in that Cori/Cyclone Boom UI are just numbers or strings that the game tosses over to the Lua side.

Ok.  I guess I don't know enough about the game systems to understand what we're still missing in Lua, which otherwise would need C++ functionality to view.  I don't know what I'm missing, I guess.

[CorinaMarie 29,621]

I've no idea if it's possible, but we might be able to create interesting new mods if everything the Auto Run Cheats DLL can do could be called from LUA. This would allow popup messages with those as linkys and one could agree by clicking them.

[Null 45 3,048]

1 hour ago, CorinaMarie said:

I've no idea if it's possible, but we might be able to create interesting new mods if everything the Auto Run Cheats DLL can do could be called from LUA.

Executing cheats should be possible, e.g. having a lua_extensions_execute_cheat command that could run everything that the cheat box can. But the Auto Run Cheats DLL has access to game notifications that are not present in Lua, and I don't think many of those notifications could be exposed to Lua.

[Kel9509 1,407]

Would it be possible to create a cheat that permits you to run any variable Simcity4 has?  For instance, you could enter a cheat code to bring up a dialog box that permits you to enter in any variable, like "#game.g_num_parks#", which is the variable that displays the number of parks, and that result would display somewhere?  Or is that too much?

[Null 45 3,048]

4 hours ago, Kel9509 said:

Would it be possible to create a cheat that permits you to run any variable Simcity4 has?

A cheat code that takes the token name as a parameter would be easier to implement than a dialog, the cheat code could then show a message box with the result.

Text token is the official name of the #variable# blocks that the game can replace with a new value, I guessed as much based on the fact that the string handling class is called detokenizer. But after searching for token in the SimCity_1.dat I discovered that one of the leftover Lua files is the Maxis Lua programming reference (TGI 0xCA63E2A3, 0x4A5E8EF6, 0xFFAEC42B), which confirmed the name.

@CorinaMarie or others may have already known about that Maxis Lua programming reference. Interestingly there are a few more format strings listed in that file which the game's Lua files don't appear to use.

The date and time format strings appear to be broken, but the following format strings work. None of these values support floating point because Maxis decided to convert the Lua double to an integer before passing it to the formatting methods. This is understandable for the money formatting, but is strange behavior for the other number types.

#m@500000# prints the 500000 value as §500,000 in English, it would possibly change the format for the user's chosen UI language.

#n@2000# prints the 2000 value as 2,000 in English, it would possibly change the format for the user's chosen UI language.

#s@2000# prints the 2000 value as 2000 in English, it would possibly change the format for the user's chosen UI language.

#p@200# prints the 200 value as 200% in English, it would possibly change the format for the user's chosen UI language.