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PlotinusRedux's GUI improvements and renderer for SMACX

PRACX was written by PlotinusRedux and is maintained by DrazharLn, both of (forum thread). PRACX is permissively licensed free software.

PRACX implements these improvements to the UI:

  • Configurable full screen resolution
  • Working windowed mode
    • Toggle with alt+enter
  • Custom menu for PRACX options
  • Mouse over support for view mode V
  • Scrolling
    • Pixel level scrolling
    • Right click and drag scrolling
    • Configurable edge scroll zone size and speed
    • Mouse wheel scrolls in menus
  • Zooming
    • Pixel-level re-centering: no more screen zigzag
    • Right-click and drag scrolling
    • Mouse wheel zooms in and out
    • Automatically sets reasonable min, max, and increment values for the current resolution
    • Configurable # of increments between min and max zoom
    • Details (units, cities, improvements, etc.) are now shown even when fully zoomed out
  • Overlays
    • Resource overlay with ALT+R: normal/current yield of tile/potential yield
      • Potential yield is the nutrient output with a farm + mineral output with a mine + energy output with solar panels
      • Yields are displayed as though for a faction with no max resource limits to make it easier to plan where to place your bases
    • Terrain overlay with ALT+T: normal/faction ownership/elevation/rainfall/rockiness
    • City mode: unworked tiles show potential yield in a translucent outline (configurable)
    • Existing terrain survey mode T has an extra mode: where only fungus and forests are hidden

PRACX is a patch for the Windows version of the game, but it runs fine under Wine (better than under windows 10 for some people!). The unofficially patched Windows version running under Wine is a better experience than the old GNU/Linux port, in my opinion, anyway. Similarly for other OSs.


You must install this over a version of the .exe that has had the DRM removed. Any of the unofficial patches will do.

Download the latest installer from the releases page. You'll want PRACX.v1.11.exe or something similar. Running the installer puts our .dlls in your SMAC folder, patches SMAC's binary to use them and re-enables alt+tab if it has been disabled (as it is by the GOG installer).

The installer makes backups of files it replaces in _backup_v{version number}.


The entire patch may be temporarily disabled by setting Disabled=1 in the [PRACX] section of Alpha Centauri.Ini in the application's directory. It may be permanently disabled by deleting prac.dll and prax.dll in the application's directory or by running the uninstaller.


PRACX will create it's own settings section in Alpha Centauri.Ini if it doesn't exist. Settings are generally configurable from the in-game menu too and will be reflected in this file.

Here's an example with some settings changed:



SMAC and perhaps especially PRACX may work badly on Windows 10 Creators Update. Make sure you enable DirectPlay.


You may also be interested in:


You don't need to read this if you just want to use the patch ;)


This needs to be built with Visual Studio, or some compiler with equivalent inline ASM semantics (not gcc). Because Microsoft don't have a stable commandline API to their compilers, you will likely have to fiddle to get this to work.

I install msys2 and use a unix-like terminal to do development. When things are working correctly, all you need to do is make, and the binaries and installer will be generated in ./bin for you.

Unfortunately, the build system is fragile and may not work for you without fiddling with MSVC. As a first port of call, check that the path in msbuild.workaround is correct for your machine then read on.


The easiest way to build is to download the latest version of visual studio and install the C++ and XP tools, import the project and make sure the platform toolset for each "solution" is set to some XP toolset. For v141_xp, for example. Other faffery might be required.

After that you can either build from VS or open the "Developer Command Prompt" and run msbuild path/to/project.

I take the path from the developer command prompt and use it in msbuild.workaround, which is used by the Makefile.

Packaging (installer)

PRACX is packaged with NSIS. The makefile knows how to do this and will emit an installer in ./bin, if makensis exists on your PATH.

If you don't like make, just point NSIS at the script in InstallScript.

Code overview

From shared/pracx.cpp:

This library is intended to be imported by the SMAC binary and to then cause SMAC to call functions in this library, sometimes instead of certain of its traditional components, sometimes purely in addition.

PRACX inserts extra code into SMAC's native map rendering and drawing code, as well as some aspects of base management screens. PRACX also registers to receive user interaction events from the OS's window manager and can control scrolling and zooming behaviour, amongst other things.

The combined effect is that PRACX replaces the main UI of the game, allowing new features and overlays to be implemented in C++, rather than hacked into terran(x).exe in assembly.

Function names beginning with "PRACX" belong to the PRACX functions, these are called from the SMAC binary (terran(x).exe). SMAC is hacked to call these functions by the HOOK function at the bottom of this file.

Functions called from m_pAC are functions in the SMAC binary (SMAC functions).

Other functions are typically unexported helper functions for the PRACX functions.

"Thunk"s are bits of assembly code that are used mostly to insert function calls into the SMAC code where previously the code did not call any functions.

The m_ST structure contains the value of configuration options as read from Alpha Centauri.ini

Most comments (including this header) were written by Draz. If they have question marks, they're guesses. If they don't, they're confident guesses :)

I've commented on the purpose of most functions and other chunks of code, and in a bit more detail about some aspects, but the commentary is still lacking, especially for some of the more complicated functions.

Of course, this code is tightly coupled with the SMACX code, so a complete understanding of what's going on isn't possible without looking at the dissassembled code for that, but maintenance of this code and some extensions might now be possible.