Game framework compatible DLL loading (and other modding discoveries)

[simmaster07 1,220]

Hey everyone,

After SC4Fix, I went on a hiatus for college and decided to turn my attention to loading DLLs into the game using native methods. SC4Fix works but uses a really hackish method where it overwrites bits of code that would unload DLLs the game doesn't recognize. This is something that I've wanted to do for six years since Paul Pedriana (very graciously) sent me some incomplete but critical code for making proper SC4 DLLs.

I recently threw out all of the code I wrote and started from scratch with Paul's code as a starting point. Using the Aspyr port of the game for cross-checking (since it holds a lot of debug information that the Windows version doesn't have), I finally managed to create a DLL that the game can load, recognize, and communicate with. This also essentially gives us the foundation of the SimCity 4 SDK that would be needed for accomplishing more advanced tasks.

• Source Code
• Test DLL

What I have right now is pretty basic: SC4 can load the DLL, recognize it as a real framework DLL, and our code can subscribe to game events like PostAppInit, PostFrameWorkInit, PreAppShutdown, and others. I feel that the next step would be to expand the code to replicate the functionality of the Extra Cheats DLL. Buggi has partial source code that includes the most crucial components aside from the rest of the SDK, and I've managed to assemble a basic SDK to work with, so this should be done pretty soon.

  

The best part about having this kind of DLL is that it works with every Windows version of SC4 at least, and probably works with the Mac version (but I haven't tested this) — v610, v638, v640, and v641 should all be able to use this with no problem because the API never changes.

---

As an aside, while investigating how DLLs are loaded by the game, I also learned that you can create INI files that tell the game whether or not to load certain DLLs.

You can create a file in the Plugins folder called DLLName.ini (where DLLName corresponds to the filename of the DLL minus the file extension) with the following content:

Quote

[Admin]
Enabled=true

Changing "true" to "false" stops the game from loading the DLL, and changing it back to true allows it to load again. Pretty neat in my opinion, and I hadn't seen this documented anywhere else, so I figured I'd share it here.

---

Final aside, I'm planning on making this a general development thread for myself so I don't have to make a new thread for everything I find. Once I have more to report on I'll probably change the title of this thread.

[simmaster07 1,220]

After adding a class for the SC4App interface, I just got a reconstructed extra cheats DLL to work completely from scratch:

• Source Code
• Test DLL

This DLL offers all the same functionality as Buggi's extra cheats DLL, but is capable of being compiled from scratch.

EDIT: The source code linked above is just as of that DLL's compilation. More up-to-date code can be found here.

[MushyMushy 3,617]

Wow, this is great! I'm assuming, based off of what I've read about DLLs before, that this could lead to the possibility of making much more advanced mods? From my understanding the ability to load DLLs would allow modders to add/change things that they can't change right now because it would require modifying files that we aren't allowed to mess with - is that right?

[simmaster07 1,220]

3 hours ago, MushyMushy said:

Wow, this is great! I'm assuming, based off of what I've read about DLLs before, that this could lead to the possibility of making much more advanced mods? From my understanding the ability to load DLLs would allow modders to add/change things that they can't change right now because it would require modifying files that we aren't allowed to mess with - is that right?

Quite possibly. The thing is that this literally hasn't been done before by the modding community; only Maxis/EA would know the extent of this kind of modding, and they're bound by NDAs that prevent them from discussing code internals to this extent. It's hard to tell how far we can go with DLLs, especially since we're only starting off with this minimal API recreation which lacks functions for interfacing with a lot of stuff like the prop manager and network simulator.

[Cyclone Boom 16,875]

Well done, this is all very interesting.

It would be monumental if this could open the door to new modding areas.

[Mister Giggles 310]

If my previous experiences with .DLL loading are anything to go by, then there is little that cannot be done. It boils down to the skill of the programmer and the knowledge available to them.

Having this native solution is ideal, Simmaster, and I thank you for making it.

[InvisiChem 121]

I wish there was Karma points here. lol. Deserves about 100 of them.

[simmaster07 1,220]

On 5/18/2016 at 2:21 PM, Cyclone Boom said:

Well done, this is all very interesting.

It would be monumental if this could open the door to new modding areas.

It's highly dependent on how easy it is to override prewritten game functions. On the SC4Devotion discussion on Buggi's source code, someone listed (years ago) a handful of functions that would need to be modified to, say, add a new menu button. It's not clear that I can do this by simply calling into SimCity's API, but I don't have enough info to conclusively rule that out.

If there are existing game functions for features that were disabled before shopping, obviously we could start by reactivating them, similar to the extra cheats DLL. The Cutting Room Floor notes that upgradeable city halls were modeled but not programmed, and I'm curious to see if that's possible.

[simmaster07 1,220]

In the latest round of changes to the API reconstruction, the framework is now able to subscribe to and receive messages from the game, and to send messages for other DLLs and parts of the game listening for them. The most relevant code added can be found here in the DLL director.

The proof-of-concept DLL can be found here, and here's a relatively boring screenshot of it in action:

More technical details follow.

---

From what I understand, each DLL director gets a reference to the GZCOM framework, which acts as a sort of coordinator for different types of components of the game. Namely, the framework controls the application, services, and hooks.

Hooks are what we've been dealing with primarily up to this point. The extra cheats DLL is a hook that waits until just before the app initializes, where it then proceeds to enable debug functionality and extra cheats. Hooks mostly relate to major events in the framework, which are all named in the cIGZFrameWorkHooks interface.

Services are classes which process logic on each tick (what appears to be each frame) of the game or on each idle interval when the game is not doing work. The application (here, cISC4App) seems to be a special type of service that coordinates the game logic.

One of the most important services in the game is the message server, which is responsible for allowing different components to communicate with each other by sending and receiving messages. SimCity 4 actually has two different types of messages: cGZMessage, which behaves like a plain structure with a message type ID and three fields; and cIGZMessage2, which behaves more like an object and is extended by cIGZMessage2Standard, cIGZMouseMessage, cIGZKeyMessage, and cIGZCanvasMessage. Non-UI code exclusively sends GZMessage and Message2Standard-type messages.

As there are two different types of messages, there are two different message servers: cIGZMessageServer and cIGZMessageServer2, which act almost identically. Game classes can send a message, which will immediately inform anyone who subscribes to that message's type, or post a message. Posting a message places the message in a queue for delivery and may be deferred for delivery until the game has free CPU time to process it. However, specifying it as a high priority message sends it straight to the front of the queue.

The message server also allows you to add a notification class, which must implement a DoMessage method for receiving messages. Unless a specific target is given for a message, it gets sent to all classes subscribed to it, which is what I've done with the latest proof of concept.

In our case, we subscribe to a message with ID 0xea8ae29a (or 3,934,970,522 in decimal), which is sent when the game has finished loading a city, whether new or existing. It's currently unknown what the data fields for this message contain. It's also unknown what other messages exist that can be subscribed to, though this is what I plan to explore next.

[Mister Giggles 310]

...is it too early to make ridiculous and impossible demands of you?

I hope not!

[simmaster07 1,220]

3 hours ago, Mister Giggles said:

...is it too early to make ridiculous and impossible demands of you?

I hope not!

In all fairness, just engineering a DLL that can take advantage of SC4's own API has been a pretty ridiculous and impossible demand up to this point. 

[patfirefghtr 160]

OK so ive been using the Fix and so far less CTD's which makes me very happy and excited to be playing again!!! Now I gotta beta this lol

[simmaster07 1,220]

9 hours ago, patfirefghtr said:

OK so ive been using the Fix and so far less CTD's which makes me very happy and excited to be playing again!!! Now I gotta beta this lol

Nothing too exciting as far as testing goes here so far. A lot of work is focused on exposing more functionality for programmers to make their own DLLs. I've just been developing some proofs of concept to show that this actually works.

---

Anyway, I started getting into identifying message IDs and remembered that this game is dense. One method of sending messages has just over 230 different message triggers, and that's just one way of sending them. I don't think I'll be sifting through message IDs for all of these functions by hand, so I'm going to have to automate this. In the meantime, here's a partial list.

0x44778230 - cSC424HourClock::DoHourChanged
0x44778231 - cSC424HourClock::DoHourChanged

0x44778232 - cSC424HourClock::ChangeVisualTime: hour changed
0x44778233 - cSC424HourClock::ChangeVisualTime: >= 5 minutes passed?
0x44778234 - cSC424HourClock::ChangeVisualTime: day/night transition

0x44778235 - cSC424HourClock::Pause: time stopped
0x44778236 - cSC424HourClock::HiddenPause: time stopped

0xAA7A014D - cSC4Demolition: something demolished?
0xEA1F0DCD - cSC4DisasterInstancePipeBurst - demolition by pipe burst

0xAA1B2002 - cSC4DisasterLayer::DisasterHasEnded

0xEA65224E - cSC4ObliterateCity::GoToEndState

0xAA650861 - cSC4ObliterateCity::Init
0x2A611B51 - cSC4ObliterateCity::Init

0x4A7FB7E9 - cSC4Simulator::DoSetSimSpeed
0xAA7FB7E0 - cSC4Simulator::Pause
0x4A7FB7E2 - cSC4Simulator::HiddenPause
0xAA7FB7E0 - cSC4Simulator::Resume
0x4A7FB7E2 - cSC4Simulator::HiddenResume
0x4A7FB807 - cSC4Simulator::EmergencyPause
0x4A7FB807 - cSC4Simulator::EmergencyResume
0x66956814 - cSC4Simulator::SimulateTimePassage: day passed
0x66956815 - cSC4Simulator::SimulateTimePassage: week passed
0x66956816 - cSC4Simulator::SimulateTimePassage: month passed
0x66956817 - cSC4Simulator::SimulateTimePassage: year passed

0x6716A4E6 - cSC4WeatherSimulator::DoWeeklySimulation
0x6716A4E5 - cSC4WeatherSimulator::DoMonthlySimulation

-906529349 - cSC4App::ApplyVideoPreferences

0x26D31EC2 - cSC4App::PartialCloseCity
0x26D31EC3 - cSC4App::PartialCloseCity

0x26D31EC0 - cSC4City::NewCity (pre-init?)
0x2B96B3EA - cSC4City::NewCity
0x26D31EC1 - cSC4City::NewCity
0xAB96B05F - cSC4City::NewCity
0xEA8AE29A - cSC4City::NewCity (post-init?)

cSC4City::NewCity messages repeat in cSC4::LoadCity, but
0x26D31EC1's first parameter changes from 1 to 0, which
seems to indicate when a city is new or existing.

0xba44eb51 - cSC4App::OnIdle: seems like an OnTick message

0x4a44667f - SC4SendProgressMessage: city init messages?

0x49a780b2 - SendFatalExceptionNotification

0x29a89b05 - cSC4App::RequestQuit (and RequestQuitFromRegion)
One of the fields probably identifies if quitting from region

0x26c63343 - cSC4App::SaveCity (pre-save?)
0x26c63345 - cSC4App::SaveCity (post-write?)

0x26d31ec4 - cSC4City::SetEstablished: true
0x26d31ec5 - cSC4City::SetEstablished: false
0x0ab99380 - cSC4City::SetCityName
0x0ab99381 - cSC4City::SetMayorName

0x89efa536 - cSC4LandfillDeveloper::RecordHistoryData
0xea418d8f - sReportDealStatus

0x8a0d15da - cSC4NeighborsSimulator::CreateConnection
0xea0d163e - cSC4NeighborsSimulator::DeleteConnection

0x69247dc5 - cSC4TrafficSimulator::UpdateStrikes
0x0c05e4c3 - cSC4TrafficSimulator::CheckForAccident (accident occurred)
0x69247dc8 - cSC4TrafficSimulator::ApplyPotholeChanges
Also for DoRailChanged and DoRoadChanged

0xa8daf511 - cSC4PoliceSimulator::BeginStrike
0xa8daf512 - cSC4PoliceSimulator::EndStrike
0x2a614892 - cSC4PoliceSimulator::EndJailbreak
0x2a614891 - cSC4PoliceSimulator::BeginJailbreak

0x08f415fe - cSC4FlammabilitySimulator::EndOfCycle
0x87cc75b3 - cSC4LandValueSimulator::DoEndOfSimulationCycle

0xaa667ce2 - cSC4ParkManager::BeginZooEscape

Once the SC4Devotion server move is done, I plan on moving this documentation over to their wiki so I can keep things up-to-date there without having to flood this thread with updates every time I find a new message ID.

DLLs should be able to subscribe to all of these messages, and these messages also include data fields that could be useful as well, so it's pretty cool to have this.

  Edited May 29, 2016 by simmaster07  
Oops a typo

[Bombardiere 591]

Thank you for your work. This is great. Sadly I don't have skill to help or take this further. I know olny how to make some BATs. That is limit of my skills.

 

[rsc204 21,808]

9 hours ago, patfirefghtr said:

OK so ive been using the Fix and so far less CTD's which makes me very happy and excited to be playing again!!! Now I gotta beta this lol

You can call it a Beta, but almost 6 months in and to my mind, it's simply a fix. It works, despite much testing to force a CTD, they simply don't happen. The number of times I rage-quit after these CTDs cost me a lot of work, was starting to impact my enjoyment of the game.

Since installing the fix, the only CTD I encountered was when I screwed up some slope mods and accidently left some conflicts behind. Other than my own errors, the game has been solid, this fix is something every player should have installed.

[simmaster07 1,220]

A quick update on documentation.

Apparently the SC4Devotion wiki is alright to use despite the forums being down. However, as it turns out I don't think I've ever gotten editor privileges. It doesn't appear that the wiki is being actively maintained either, as evidenced by the article on CTDs still saying that the puzzle-piece/TE lot crash is unfixable. 

I've set up a small wiki on the GitHub repository for the API to document my findings in more detail and dump stuff like lists of IDs there. If you know C++ and think this thread is pretty disorganized, feel free to check in there. I've also been making incremental changes there to introduce new interfaces and document stuff that had previously been marked as unknown. Feel free to watch the repo to keep up with the changes; otherwise, I don't intend to post about more incremental changes unless I come out with a more advanced proof-of-concept DLL.

[Tarkus 6,932]

Once the server move is done at SC4D, I'd be happy to grant you editor rights.  I'd do it now, but with the site currently existing in a weird quantum limbo state between two servers at present, I'd be concerned about any edits done now getting lost.

-Tarkus

[APSMS 1,892]

@simmaster07 I have updated the page with relevant information. Hopefully you will be able to add to it when SC4Devotion is back online.

[simmaster07 1,220]

Here's a new proof-of-concept, albeit a dodgier one. This is an example of a DLL that adds two new cheat codes to the game:

https://github.com/nsgomez/gzcom-dll/releases/tag/poc-newcheats

Namely:

• Chernobyl: makes all tiles in a city radioactive
• RoentgenBeGone: removes radioactivity on all city tiles

So if you wanted to make your city a nuclear wasteland without resorting to triggering actual nuclear meltdowns, or if you had a nuclear meltdown after making significant progress on a city without saving, you're all set with this DLL. I'm still trying to figure out what functions are in the other simulators (radiation is in the pollution simulator) so that I can make an "extra extra cheats DLL" and upload that to the STEX.

However, there is a caveat to using this DLL. If you try to save and exit to region, the game will crash out. The same probably happens when saving and exiting to desktop as well, but less noticeably. For whatever reason, the game saves completely, and reopening it will show the game completely irradiated/clean of radioactivity. If you don't use the cheats after reopening, the game doesn't crash.

I'm not sure what's causing it or what adverse effects this would have on the game if you were to continue playing, which is another reason I'm not cool with uploading this to a file exchange right now. I also wouldn't recommend using this on any major cities you have if you don't have backups ready.

It doesn't seem to be related to actually adding cheats in itself, since simply popping up a message box instead of actually changing radioactivity states doesn't cause anything to go wrong when exiting. It probably is just related to how the game deals with the radiation grid, but I have to play around with the other types of simulators and see if messing with stuff there would also cause issues similar to this.

But yeah, extra cheat codes that look like they kind of work. It's fun stuff.

[mrsmartman 200]

This could make SC4 on steroids.

[LivingInThePast 364]

The "hooks" mentioned is probably the framework that allows it to accept new expansion packs. Considering that SimCity 4 seemed ready to go for all sorts of expansion packs, this could really open up the possibility of adding Rush Hour-level expansions into SimCity. The mind boggles with possibilities.

[simmaster07 1,220]

@LivingInThePast Hooks in SC4 aren't actually hooks in the traditional sense. They act more like events, which are triggered at certain points in the app initialization and shutdown process. I'd imagine most expansion pack functionality is done by listening to and sending messages that affect game behavior. I'd have to look at how the Rush Hour expansion pack specifically, as opposed to SimCity 4 Deluxe, works in that sense.

[bien1500 35]

12 hours ago, simmaster07 said:

@LivingInThePast Hooks in SC4 aren't actually hooks in the traditional sense. They act more like events, which are triggered at certain points in the app initialization and shutdown process. I'd imagine most expansion pack functionality is done by listening to and sending messages that affect game behavior. I'd have to look at how the Rush Hour expansion pack specifically, as opposed to SimCity 4 Deluxe, works in that sense.

Doesn't the Deluxe installer just install both in one sitting instead of having to run two separate installers?

[rsc204 21,808]

So far as I know, the Rush Hour addons are integrated into the SC DAT files, with an additional one added EP1.DAT. They also changed the main executable too, so likely there were some code changes at a fundamental level also.

[simmaster07 1,220]

On 7/12/2016 at 5:27 AM, bien1500 said:

Doesn't the Deluxe installer just install both in one sitting instead of having to run two separate installers?

It does, and it has a combined executable. I was curious as to whether SimCity 4 + Rush Hour, as opposed to Deluxe, had separate executables, but as @rsc204 pointed out this doesn't seem to be the case. I know The Sims 2 has the same engine as SimCity 4 and uses separate executables for each expansion pack as well, but these seem to be refinements of the base game code as opposed to DLL-like addons.

[LivingInThePast 364]

On 7/15/2016 at 6:56 PM, simmaster07 said:

It does, and it has a combined executable. I was curious as to whether SimCity 4 + Rush Hour, as opposed to Deluxe, had separate executables, but as @rsc204 pointed out this doesn't seem to be the case. I know The Sims 2 has the same engine as SimCity 4 and uses separate executables for each expansion pack as well, but these seem to be refinements of the base game code as opposed to DLL-like addons.

SimCity 4 Deluxe was released at the same time as Rush Hour IIRC so any new players could jump directly into what was the superior version of the game (I think we can all agree on that, as Rush Hour basically was what SimCity 4 was supposed to be out of the door, really). At that point, I imagine future EPs would still be possible, compatible with at least Deluxe and RH-upgraded versions. I would love to hear from anyone at Maxis share some ideas for planned add-ons that never would see the light of day.

[simmaster07 1,220]

Hey everyone, I'm going to start this post by acknowledging that it's been a long while since I've had an update on this. That said, I'm going to jump right into another update.

Back in May I noted:

On 5/21/2016 at 0:57 PM, simmaster07 said:

If there are existing game functions for features that were disabled before shopping, obviously we could start by reactivating them, similar to the extra cheats DLL. The Cutting Room Floor notes that upgradeable city halls were modeled but not programmed, and I'm curious to see if that's possible.

Now that I've found a small bit of time in my schedule to revisit this, I decided to focus my efforts on working toward a proof-of-concept mod that enables city hall upgrades as originally intended by Maxis. A bit of background if you're not aware: SimCity 4 was supposed to ship with three different stages of City Halls, similar to how airports work. All of the models, lots and exemplars exist in the game, but there is no code for actually upgrading the lot. Instead, it's been required to treat them as entirely separate rewards in order to make use of the second and third stages for City Hall.

Using the programming for airports as a baseline, I've reached a point where I can:

1. Detect when a city hall is placed in a city, or when a pre-existing city is loaded with a city hall in it.
2. Send messages to the advice system that are intended to trigger an upgrade after certain population thresholds.
3. Detect when the user says whether or not they would like to upgrade city hall.

But, the major caveat is that right now, if you were to say "Yes" and upgrade city hall to the next stage, nothing will happen. The DLL can detect that you've said yes to the upgrade, but there is currently no code to actually swap the lots like an airport. I'm working on that and expect I can get it done soon, but in the meantime it's worth looking at the interaction between the DLL and the game core to see how I've gotten this far.

For illustrative purposes, here's the prompt that appears when a city with a population at or above 95,000 wants to upgrade its city hall to stage 3:

The player is presented with a dialogue from a rather upset Neil Fairbanks pleading with the mayor to expand city hall to reclaim his office space. There is a DAT file that goes along with the DLL in order to load a Lua script that creates this dialogue, which is all standard stuff and mostly boilerplate from the airport upgrade advice records. Here's an excerpt:

--<snip>
-- Advice record
-- City Hall wants to expand from stage 1 or 2 to stage 3

a = create_advice_cityplanning('391d338a')
a.trigger   = "1"
a.event     = hex2dec('d788e345')
a.frequency = tuning_constants.ADVICE_FREQUENCY_VERY_LOW
a.timeout   = tuning_constants.ADVICE_TIMEOUT_MEDIUM
a.title     = [[text@35af92cc City Offices Battling for City Hall Space]]
a.message   = [[text@35af92cb Mayor, the upshot is that our city has grown immensely and so has our government. The downside is we're having serious trouble fitting all our departments in one building. Camille's office is outside now, we've been forced to move Monique's office into a broom closet, and Jamil is gradually taking over the city planning offices. Shall we expand city hall?  <a href="#link_id#game.event_feedback();game.retire_advice(1)">YES</a> <a href="#link_id#game.retire_advice(1)">NO</a>]]
a.priority  = tuning_constants.ADVICE_PRIORITY_URGENT
a.mood      = advice_moods.BAD_JOB
--<snip>

First we create an advice record with some arbitrary and unique hexadecimal GUID ('391d338a') which only appears to exist for the sake of having a unique advice record. What's really important is that we specify a.event, another GUID ('d788e345') which is specified and sent by the DLL. Initially, the event for this GUID is only sent to the advice system in order to display the dialogue. However, the link for YES calls a function, game.event_feedback(), which takes the event that was passed to the advice system and rebroadcasts it to the rest of the game as an event, affirming that the user is choosing to upgrade city hall. Any game code, including DLLs, can listen for this event, and we take advantage of this like we would for any other event we want.

There are a few other events that we want to listen for as well. First, we want to know when a month has passed so that we can check the population of the city (and whether to upgrade) every month. We also want to know when an occupant is added or removed to the game in order to check whether some building being plopped is a stage 1 city hall. Occupants include props, automata, buildings and utilities — more or less anything that exists in the game world that is not plain terrain. @CorinaMarie documented a short list of IDs for them here, but the only type of occupant we want to monitor is buildings.

The game includes a pointer to the Occupant object as part of the message's data. We first check that the Occupant is a building, then check that it belongs to the occupant group for Rewards. From there, we can treat the occupant as a property holder — some entity that has exemplar properties — and try to get the property for the city exclusion group, which is used by the rewards simulator such that only one building per exclusion group can be plopped in the city. Each city hall stage has its own exclusion group, which is how it was possible to plop the three different stages of city halls. If it turns out that the building we're looking at is a city hall, we save a reference to it.

Lastly, when we're loading an existing city, we get a reference to the game's occupant manager and use it to iterate over all building occupants in the game and put it through same process we used to determine if individually plopped buildings are city halls. We stop either when there are no more buildings to check or when we've found the first city hall occupant in the game.

With this procedure, we can find a city hall instance in a city either when loaded or when plopped, keep track of it, prompt the user when we want to upgrade and call some code when they do. Bearing all of this in mind, the only remaining step is taking the procedure for when the upgrade is confirmed and modifying it so that we replace the city hall lot with the next stage instead of just showing a message box.

Even without this mod being fully completed, we can now:

• Use the game's native methods to search for specific buildings or types of buildings
• Create unique events for the advice system
• Show advice dialog boxes for any arbitrary event we want
• Check the exemplar properties of occupants in the game
• Create cheat codes that execute whatever code we like
• Detect events such as months passing or buildings being plopped and removed

The code linked above isn't as clear as I'd like it to be and so I would like to clean it up and annotate it with comments.

[Tarkus 6,932]

It's always like a holiday when this thread gets an update--this is, once again, some really amazing, groundbreaking stuff.  I can't wait to see where you go next!

By the way, once we completed the server move at SC4D, I went in and set up your Editor rights set up on the Wiki, as requested.  Let me know if you encounter any difficulties, or have any questions.

-Tarkus

[CorinaMarie 29,605]

Woot! I'm happy to see you have a chance to work on this some more. I predict you'll have additional exciting things for us in the future. I already recommend your SC4Fix.dll to every new SimCity4ite who comes into chat as well as in my posted list of must have stuff for those who freshly install the game.

4 hours ago, simmaster07 said:

@CorinaMarie documented a short list of IDs for them here, but the only type of occupant we want to monitor is buildings.

A day or two after my post there I realized that one I hadn't determined would be the Clouds and/or Fog. Since I always have them off in my game I wouldn't notice when my mod would hide them. That thread died so I didn't bother to go update it. I could try to find my notes from then if it would help, but as you only need to know buildings, I'm certain it's not necessary for your efforts here.

Keep up the good work. Go, go, go!

[simmaster07 1,220]

EDIT: It's on the STEX now.

Mod upload coming soon, watch this space. While I work on polishing an outlying crash when exiting cities, the full source code can be found by following this link. The main change from the last post is the implementation of the UpgradeCityHall method. 

  Edited October 28, 2016 by simmaster07  
Add STEX download link