SimCity 2000 — Static Recompilation

Static recompilation of SimCity 2000 (Maxis, Windows 95 edition, SIMCITY.EXE built 1996-03-07) from its shipping binary to native C. Every function in the game — the simulation, the isometric renderer, and the statically linked MFC and C runtime — is lifted to C and compiled into a new Windows program. No emulator.

Built on the pcrecomp toolchain and following its shared house style for recompilation projects.

Generated source is not distributed. You supply your own copy of the game; the lifter runs on your machine and writes the C into a gitignored folder.

Status

v0.4.0 — alpha. It plays: build a city, save it, load it, watch it animate. Windows, and Linux under Wine.

The recompiled program generates maps, takes building tools (power plants, zones, roads), saves and loads cities through the game's own File dialogs, and animates its palette on a 32-bit desktop. Checked against the original: the same saved city, run for the same time in the original SIMCITY.EXE and in the recompiled one, ends with the same funds to the dollar, and a city saved by the recompiled game loads in the original. Everything on screen below is the game's own code, recompiled.

Title screen and main menu	Start New City: a generated map
February 1900: toolbar up, "Power Plant Needed"	CITIES\NYC.SC2, loaded and simulating
Palette animation, emulated on a 32-bit desktop	A coal plant, zones and roads, placed with the tools
File > Save City As, in today's common dialog

Area	State
Lift	9,870 functions from pcrecomp's own catalog (7,045 from IDA's), 0 lift errors
Startup, MFC, dialogs, menus, toolbar	Working
Terrain generation, map rendering	Working
Building: power plants, power lines, zones, roads	Working
Simulation	Matches the original: same save, same funds after the same run
Save City As, Load City (File dialogs)	Working, with a compatibility fix the original also needs
Loading a city from the command line	Working
Palette animation (traffic, lights)	Working: the host emulates a 256-colour palette display
Intro movie	Skipped — the game looks for the CD, and says so
Sound and music	Working in play (not checked by the headless runs)
Frontend window: filters, glow, CRT, menu bar, cheats, speed slider	Working (the default; --classic for the game's own windows)
Save slots, mods (built-in and DLL)	Working
Speed	The game's own speeds, plus a slider; African Swallow is paced (below)

Needs pcrecomp#23 (the function catalog without IDA) until it merges; build against its branch via PCRECOMP (below).

What's added on top

The game runs as it shipped. Everything here is optional and sits around it: the host draws the game's frame in its own window and adds a menu bar next to the game's own menus. --classic turns all of it off and shows the game's original windows.

Menu	What it does
Graphics	Filters: nearest (original pixels), smooth, sharp bilinear, Scale2x. Integer scaling. Glow on bright, saturated pixels (lights, fire), with strength and threshold. A CRT look: curvature, scanlines, shadow mask, vignette.
Effects	Day and night, seasons and weather, drawn by recolouring the game's own 256-colour palette, the way 1996 hardware would have. Driven by the game's calendar and its weather. Adjustable cycle length and night depth. See docs/effects.md.
Play	A speed slider, 5% to 800% on top of the game's own speed setting. African Swallow is paced at twice Cheetah: the original runs it flat out, and on a modern PC a new city's whole first year went by in a fifth of a second. Also: mouse wheel zooms, and autosave every 5, 10 or 30 minutes.
Saves	Numbered save slots, save and load in one click. The game's File dialog is answered for you.
Mods	Built-in mods (Always sunny) and mod DLLs from mods\, with a small C API. mods/stipend is the worked example. See docs/mods.md.
Cheats	Add $10,000, $100,000 or $1,000,000, or hold funds where they are.
Debug	A city stats window (date, weather, funds, time of day) and frame timings.
Display	Fullscreen (F11), vsync.

Settings are remembered in build\sc2k.ini. Dialogs work in the frontend window: scroll bars, the mouse wheel and the arrow keys included. More in docs/frontend.md.

For development and testing:

• --headless runs the game where nothing reaches your screens (works over RDP), and --record films it to MP4.
• --input plays scripted mouse and keyboard input.
• --native runs the original SIMCITY.EXE under the same recorder and script, as the reference to compare against.
• Tracing via environment variables (Usage, below).

Getting Started

You need the Windows 95 version of SimCity 2000: the CD Collection or Special Edition disc, which has a WIN95\SC2K folder with SIMCITY.EXE in it. (The DOS and Windows 3.1 versions are different programs and are not supported.)

Quick start

• The installer: download it from the releases (Windows or Linux), choose your disc, its .iso, or a folder with the Win95 SIMCITY.EXE, and press Build. It is recomp-launcher with launcher/launcher.json, and it runs the scripts below.
• Windows: double-click Setup.cmd. It installs what is missing (Python, LLVM, the Visual Studio Build Tools), copies the game into game\, lifts and builds, and leaves SimCity 2000 (recomp).cmd to play.
• Linux: ./setup.sh. The same steps, but the Windows sc2k.exe is cross-compiled with clang-cl (build.sh, against the MSVC runtime and SDK that xwin downloads) and played under Wine with SimCity 2000 (recomp).sh. It needs clang, lld, llvm, cmake, ninja and wine (32-bit) from your package manager, and says which are missing. Under Wine the game plays in its own windows (--classic): the frontend's extras (filters, effects, the speed slider, save slots, mods) are Windows-only for now. There is no native Linux host yet.

A rerun skips the steps that are done; -Force / --force redoes them.

Step by step

Prerequisites, all on Windows 10 or 11:

• Visual Studio 2022 or Build Tools 2022, with the x86 C++ libraries
• LLVM 17 or newer (for clang-cl), CMake 3.20+, Ninja
• Python 3.11+ with capstone and pefile (py -3 -m pip install capstone pefile)
• ffmpeg on PATH, only for --record
• A checkout of pcrecomp, either next to this one (..\tools) or anywhere, named by the PCRECOMP environment variable (both run_lift.py and tools\build.cmd read it)

No commercial tools: the function catalog comes from pcrecomp's disasm32. IDA Pro is optional (see below). Until pcrecomp#23 merges, check out its branch (feat/disasm32-lift-without-ida); main's disasm32 makes a catalog the game stalls on.

1. Copy the disc's WIN95\SC2K folder into game\, so that game\SIMCITY.EXE exists.
2. Lift:

   py -3 run_lift.py
   

   The first run writes the function catalog, analysis\d32_funcs.json, with disasm32 (a few minutes; delete the file to make it again). Expected: functions 9870 errors 0 files 25.
3. Build: tools\build.cmd. Expected: build\sc2k.exe, about 15 MB.
4. Run: build\sc2k.exe game\SIMCITY.EXE. The first line is [host] ...\SIMCITY.EXE mapped at 0x00400000, 9870 lifted functions, 0 unresolved imports.

With IDA Pro 9.x (idalib) the catalog can come from IDA instead, and the lift is about half the size (7,045 functions, a 7 MB exe):

copy game\SIMCITY.EXE work\ida_SIMCITY.EXE
py -3.11 ..\tools\tools\ida\ida_funcs.py  work\ida_SIMCITY.EXE analysis\ida_funcs.json
py -3.11 ..\tools\tools\ida\ida_export.py work\ida_SIMCITY.EXE analysis\ida_codemap.json --key va
py -3 run_lift.py --catalog analysis\ida_funcs.json

Usual trip-ups: py vs python (use the py launcher; the Microsoft Store python alias is not a real interpreter), and a PATH change that needs a new terminal. tools\build.cmd sets up the Visual Studio environment itself.

Usage

build\sc2k.exe [--headless] [--record out.mp4] [--fps N] [--seconds N]
               [--input SCRIPT] [--native] [path\to\SIMCITY.EXE] [game arguments...]

• --headless runs the game on a private desktop: it runs and paints, but nothing appears on your screen. Works over RDP. The game's frame is a fixed 1600×960 there, so scripted coordinates do not depend on your resolution.
• --record out.mp4 films every window of the game through ffmpeg.
• --seconds N exits after N seconds.
• Anything after the game's path goes to the game; a city file opens that city: build\sc2k.exe game\SIMCITY.EXE CITIES\NYC.SC2.
• The game plays in the host's own window by default, with the menus in What's added on top. --classic shows the game's own windows instead.
• Mods: built-in and DLL mods with a small C API (docs/mods.md); SC2K_MODS="Always sunny,City stipend" switches them on without the menu.
• --native runs the original SIMCITY.EXE instead, on the same desktop with the same recorder and script: the reference to compare against.
• --input SCRIPT plays scripted input, T:verb args separated by ;, with T in seconds: click X,Y, press X,Y,MS (hold, for a tool's variants menu), drag X1,Y1,X2,Y2 (zones, roads), key VK, type TEXT, command ID (a menu item, e.g. 0x8026 Save City As, 0x8021 Load City), and wait TITLE (until a window with that title shows; later steps count from then).

Save the current city as TESTCITY, headless:

build\sc2k.exe --headless --seconds 60 ^
    --input "35:command 0x8026; 36:wait Save As; 38:type TESTCITY; 40:key 13" ^
    game\SIMCITY.EXE game\DEFAULT.SC2

Diagnostics, as environment variables: SC2K_APITRACE=1 logs every Win32 call by name; SC2K_CBTRACE=1 every call from Windows into the game; SC2K_WATCH=1 prints where the guest is once a second; SC2K_REGTRACE=1 logs registry access; SC2K_CAPTRACE=1 lists the game's windows during a recording.

Settings live where the game always kept them, under HKEY_CURRENT_USER\Software\Maxis\SimCity 2000. On first run the host fills in what the installer would have written, without overwriting anything present.

How it works

docs/architecture.md covers the design: the game image is mapped at its original address, its imports are bound to the real Win32 API, and callbacks from Windows into the game are caught with a DEP trap. docs/bringup-notes.md has the problems that took the longest to find, and docs/effects.md the optional effects, and docs/frontend.md the frontend window.

Building from source

See Step by step above. run_lift.py and CMakeLists.txt document each step.

License

MIT — see LICENSE. This covers the code in this repository only. SimCity 2000 is © Maxis / Electronic Arts; no game code or data is included.