OpenXcom

OpenXcom is an open-source clone of the popular "UFO: Enemy Unknown" ("X-COM: UFO Defense" in the USA release) and "X-COM: Terror From the Deep" videogames by Microprose, licensed under the GPL and written in C++ / SDL.

See more info at the website and the wiki.

Uses modified code from SDL_gfx (LGPL) with permission from author.

Realistic accuracy and cover system

Video

Features:

• Precise probabilities distrubution. Accuracy number represents real chance to hit, which wasn't the case with "classic" x-com accuracy. New accuracy works just like dice rolling in D&D - for 40% accuracy shot, the game rolls random number in 1-100 range, where 1-40 counts as hit, and 41-100 as miss.
• Less shooting spread. Cone of fire is more tight, making it possible to use it tactically. You can intentionally aim to a target, trying to get other targets in fire range - to a greater efficiency than in "classic". Bear in mind, that units aim to the middle of the exposed part of target, so shots spread around that point.
• Type of shot (aimed/snap/auto) affects spread. For the same final accuracy, aimed shot will miss closer to a target, snap/auto will be less accurate, and auto with one-handed weapon will be even worse. Combined with reduced spread, it provides a variety of options, for example with high exposive type of ammo, which is much more potent now, especially at long ranges.
• Soldiers raise weapon to aim. For an aimed shot or while kneeling, soldiers will raise their weapons to eye level. That means, if they see an enemy - they can shoot it. For example, now it's possible to fire a shot targeting sectoid (16 voxels high unit) while kneeling behind a stone wall.
• Cover matters! For every shot, accuracy is multiplied by percent of targets surface, visible to attacker. taking into consideration how accuracy rolls, every bit of cover can determine the difference between life and death. A piece of wooden fence, landing gear of Skyranger or its ramp, high crops or even that lone head of cabbage. Everything.
• Accidental suicide / frienly fire protection. After rolling a miss, game looks for some "missing" trajectory. If target is far enough, that trajectory will never be selected if it ends on nearest two tiles from the attacker. That means, you can shoot with rockets or high explosive ammunition through windows, from Skyranger ramp, throught narrow gaps, near your nearest teammates without a fear of accidently blowing yourself up. Not applies to guided-type weapons, like blaster launcher - they still use classic accuracy
• Less confusing close-range accuracy numbers. In "classic" x-com, dispayed accuracy doesn't match with real, especially in close range shooting, where the real one is much higher. In this mod, there are two formulas for close range. First one gives accuracy multiplier. For aimed shots, last 10 tiles to target give you additional +0.1 to accuracy multiplier, up to x2 for point-blank shot. For snap/auto, it's +0.2 multiplier for last 5 tiles. If your accuracy is not enough to get upper cap with x2 multiplier, another formula applies, where delta between that cap and your accuracy is divided by number of tiles to target evenly. You'll gain maximum possible accuracy for point-blank either way, but first formula makes it possible to get that number even from a distance, if soldier is good at shooting.
• Min/max accuracy caps at 5%/95% respectively. For 5% or less - kneeling grants additional 2%, and aiming another 3%

'Rejected features' fork

This is a fork from official master of OXCE+ which allows some new features which have been rejected by official OXCE+ developers. Currently there are 2 new features implemented:

More than 8 bases

Now, player can choose the limit of available bases to build using a new entry in file 'openxcom.cfg':

oxceMaxBases= maxNumBases

Default is 8 bases. If more than the 8 visible bases, player can scroll bases miniview using RMB at the edges of the miniview. A blue arrow appears when there are more bases at either edge.

Hangars reworked

Every hangar and craft has a "hangarType" tag, so a Hangar with an specific "hangarType" value can only store crafts with the same "hangarType". "hangaType" tag can be given at both facilities and crafts, in their corresponding YAML ruleset. If no tag is given, that craft/hangar will have a "-1" default tag, so their behavior will be the same as in vanilla engine. Another feature added is the possibility of allocate more than 1 craft at an specific hangar facility, so all crafts will be shown at Basescape, and can be right-clicked to go to craft screen. If more than craft is defined for an hangar facility, a new YAML tag "craftSlots" should be defined in the hangar ruleset. This tag will be followed by as many "position entries" as crafts are allowed in the hangar. Every position is a "- [x, y, z]" entry, where x,y are position offesets respect to the center of the hangar sprite, and z is ignored. This way, modders can choose where they want to place crafts in an hangar which allows more than one.

An "example MOD" is included in "Examples" folder. Though this mod is a submod of the fantastic master mod "The Xcom Files", you can adapt it to any other mod or vanilla game, which needed using differentiated hangars and/or more than 1 craft per hangar.

Windows Binary

For convenience, a ZIP file with windows binary has been added to folder 'WindowsBinaries'. This exe has been tested to work in a Windows10 machine (64 bits), thought it has not been intensively tested. It also include extra Language files needed for some specific features

Link to Windows Binary

You can just place the binary and folder in the game folder of the original one, and just click it when you want start the game with these new features.

Installation

OpenXcom requires a vanilla copy of the X-COM resources -- from either or both of the original games. If you own the games on Steam, the Windows installer will automatically detect it and copy the resources over for you.

If you want to copy things over manually, you can find the Steam game folders at:

UFO: "Steam\SteamApps\common\XCom UFO Defense\XCOM"
TFTD: "Steam\SteamApps\common\X-COM Terror from the Deep\TFD"

Do not use modded versions (e.g. with XcomUtil) as they may cause bugs and crashes. Copy the UFO subfolders to the UFO subdirectory in OpenXcom's data or user folder and/or the TFTD subfolders to the TFTD subdirectory in OpenXcom's data or user folder (see below for folder locations).

Mods

Mods are an important and exciting part of the game. OpenXcom comes with a set of standard mods based on traditional XcomUtil and UFOExtender functionality. There is also a mod portal website with a thriving mod community with hundreds of innovative mods to choose from.

To install a mod, go to the mods subdirectory in your user directory (see below for folder locations). Extract the mod into a new subdirectory. WinZip has an "Extract to" option that creates a directory whose name is based on the archive name. It doesn't really matter what the directory name is as long as it is unique. Some mods are packed with extra directories at the top, so you may need to move files around inside the new mod directory to get things straighted out. For example, if you extract a mod to mods/LulzMod and you see something like:

mods/LulzMod/data/TERRAIN/
mods/LulzMod/data/Rulesets/

and so on, just move everything up a level so it looks like:

mods/LulzMod/TERRAIN/
mods/LulzMod/Rulesets/

and you're good to go! Enable your new mod on the Options -> Mods page in-game.

Directory Locations

OpenXcom has three directory locations that it searches for user and game files:

Folder Type	Folder Contents
user	mods, savegames, screenshots
config	game configuration
data	UFO and TFTD data files, standard mods, common resources

Each of these default to different paths on different operating systems (shown below). For the user and config directories, OpenXcom will search a list of directories and use the first one that already exists. If none exist, it will create a directory and use that. When searching for files in the data directory, OpenXcom will search through all of the named directories, so some files can be installed in one directory and others in another. This gives you some flexibility in case you can't copy UFO or TFTD resource files to some system locations. You can also specify your own path for each of these by passing a commandline argument when running OpenXcom. For example:

openxcom -data "$HOME/bin/OpenXcom/usr/share/openxcom"

or, if you have a fully self-contained installation:

openxcom -data "$HOME/games/openxcom/data" -user "$HOME/games/openxcom/user" -config "$HOME/games/openxcom/config"

Windows

User and Config folder:

• C:\Documents and Settings\<user>\My Documents\OpenXcom (Windows 2000/XP)
• C:\Users\<user>\Documents\OpenXcom (Windows Vista/7)
• <game directory>\user
• .\user

Data folders:

• C:\Documents and Settings\<user>\My Documents\OpenXcom\data (Windows 2000/XP)
• C:\Users\<user>\Documents\OpenXcom\data (Windows Vista/7/8)
• <game directory>
• . (the current directory)

Mac OS X

User and Config folder:

• $XDG_DATA_HOME/openxcom (if $XDG_DATA_HOME is defined)
• $HOME/Library/Application Support/OpenXcom
• $HOME/.openxcom
• ./user

Data folders:

• $XDG_DATA_HOME/openxcom (if $XDG_DATA_HOME is defined)
• $HOME/Library/Application Support/OpenXcom (if $XDG_DATA_HOME is not defined)
• $XDG_DATA_DIRS/openxcom (for each directory in $XDG_DATA_DIRS if $XDG_DATA_DIRS is defined)
• /Users/Shared/OpenXcom
• . (the current directory)

Linux

User folder:

• $XDG_DATA_HOME/openxcom (if $XDG_DATA_HOME is defined)
• $HOME/.local/share/openxcom (if $XDG_DATA_HOME is not defined)
• $HOME/.openxcom
• ./user

Config folder:

• $XDG_CONFIG_HOME/openxcom (if $XDG_CONFIG_HOME is defined)
• $HOME/.config/openxcom (if $XDG_CONFIG_HOME is not defined)

Data folders:

• $XDG_DATA_HOME/openxcom (if $XDG_DATA_HOME is defined)
• $HOME/.local/share/openxcom (if $XDG_DATA_HOME is not defined)
• $XDG_DATA_DIRS/openxcom (for each directory in $XDG_DATA_DIRS if $XDG_DATA_DIRS is defined)
• /usr/local/share/openxcom
• /usr/share/openxcom
• . (the current directory)

Configuration

OpenXcom has a variety of game settings and extras that can be customized, both in-game and out-game. These options are global and affect any old or new savegame.

For more details please check the wiki.

Development

OpenXcom requires the following developer libraries:

• SDL (libsdl1.2)
• SDL_mixer (libsdl-mixer1.2)
• SDL_gfx (libsdl-gfx1.2), version 2.0.22 or later
• SDL_image (libsdl-image1.2)
• yaml-cpp, version 0.5.3 or later

The source code includes files for the following build tools:

• Microsoft Visual C++ 2010 or newer
• Xcode
• Make (see Makefile.simple)
• CMake

It's also been tested on a variety of other tools on Windows/Mac/Linux. More detailed compiling instructions are available at the wiki, along with pre-compiled dependency packages.