**Note:** This is a quite technical document intended for those that are interested in compiling EmulationStation from source code, or would like to customize the configuration. If you just want to start using the software, check out the [User Guide](USERGUIDE.md) instead.
EmulationStation-DE is developed and compiled using both Clang/LLVM and GCC on Unix, Clang/LLVM on macOS and GCC (MinGW) on Windows. I'm intending to get Clang/LLVM working on Windows as well.
The code has a few dependencies. For building, you'll need CMake and development packages for cURL, FreeImage, FreeType, libVLC, pugixml, SDL2 and RapidJSON.
Note that you can also profile either a normal build or a debug build, but it's normally recommended to use the profiling build as it's compiled with optimizations while retaining the debug symbols. But if you need to alternate between Valgrind and the normal debugger the optimizations can be very annoying and therefore a normal debug build could be recommended in that instance.
Another useful tool is **scan-build**, assuming you use Clang/LLVM. This is a static analyzer that runs during compilation to provide a very helpful HTML report of potential bugs (well it should be actual bugs but some false positives could be included). You need to run it for both the cmake and make steps, here's an example:
```
scan-build cmake -DCMAKE_BUILD_TYPE=Debug .
scan-build make -j6
```
You open the report with the **scan-view** command which lets you browse it using your web browser. Note that the compilation time is much higher when using the static analyzer compared to a normal compilation. As well this tool generates a lot of extra files and folders in the build tree, so it may make sense to run it on a separate copy of the ES source folder to avoid having to clean up all this extra data when the analysis has been completed.
Running multiple compile jobs in parallel is a good thing as it speeds up the build time a lot (scaling almost linearly). Here's an example telling make to run 6 parallel jobs:
It's important to know that this is not only the directory used by the install script, the CMAKE_INSTALL_PREFIX variable also modifies code inside ES used to locate the required program resources. So it's necessary that the install prefix corresponds to the location where the application will actually be installed.
This Clang debug build is LLVM "native", i.e. intended to be debugged using the LLVM project debugger LLDB. The problem is that this is still not well integrated with VSCode that I use for development so I need to keep using GDB. But this is problematic as the libstd++ data required by GDB is missing in the binary, making it impossible to see the values of for instance `std::string` variables.
It's possible to activate the additional debug info needed by GDB by using the flag `-D_GLIBCXX_DEBUG`. I've added this to CMakeLists.txt when using Clang, but this bloats the binary and makes the code much slower. Actually, instead of a 4% faster application startup, it's now 36% slower! The same goes for the binary size, instead of 17% smaller it's now 17% larger.
I'm expecting this to be resolved in the near future though, and as I think Clang is an interesting compiler, I use it as the default when working on the project (I sometimes test with GCC to make sure that it still builds the software correctly).
The home directory will always take precedence, and any resources or themes located there will override the ones in the installation path or in the path of the ES executable.
EmulationStation for macOS is built using Clang/LLVM which is the default compiler for this operating system. It's pretty straightforward to build software on this OS. Although it's a bizarre Unix variant with a very strange window manager, it is still a proper system with good tools. The main deficiency is that there is no native package manager, but as there are several third party package managers available, this can be partly compensated for. The use of one of them, `Homebrew`, is detailed below.
As for code editing, I use [VSCode](https://code.visualstudio.com). I suppose Xcode could be used instead but I have no experience with this tool and no interest in it as I want to use the same tools for all the operating systems that I develop on.
Install the Command Line Tools which include Clang/LLVM, Git, make etc. Simply open a terminal and enter the command `clang`. This will open a dialog that will let you download and install the tools.
Following this, install the Homebrew package manager which will simplify the rest of the installation greatly. Install it by runing the following in a terminal window:
Curl could optionally be installed too, but normally the version shipped with macOS is fine to use.
Finally, install VLC/libVLC:
```
brew cask install vlc
```
**Some additional/optional steps:**
Enable developer mode to avoid annoying password requests when attaching the debugger to a process:
```
sudo /usr/sbin/DevToolsSecurity --enable
```
It makes me wonder who designed this functionality and what was their thinking, but a simple command is enough to not having to ponder this any further.
If required, define SDKROOT. This is only needed if during compilation you get error messages regarding missing include files. Running the following will properly setup the development environment paths:
After building ES and trying to execute the application, there could be issues with finding the dynamic link libraries for VLC as these are not installed into a standard location but rather into the /Applications folder. As such, you may need to set the DYLD_LIBRARY_PATH environmental variable to find the VLC libraries. Note that this is not intended or required for the release build that will be shipped in a DMG installer or if you manually install ES using 'make install'. It's only needed to be able to run the ES binary from the build directory. The following will of course only be active during your session, and you need to set the variable for each terminal window that you want to start ES from, unless you add it to your shell profile file:
**Note:** According to the SDL documentation, there could be issues with attempting to run ES from the build directory when using a High DPI display as the required NSHighResolutionCapable key is not set as there is no Info.plist file available. In this case, doing a 'make install' and running ES from the installation folder would solve the problem. I've been unable to verify if this is really required though as I don't have the necessary hardware to test it on.
As macOS does not have any package manager which would have handled the library dependencies, we need to bundle the required shared libraries with the application. Copy the following .dylib files from their respective installation directories to the emulationstation-de build directory:
```
libSDL2-2.0.0.dylib
libcurl.4.dylib
libfreeimage.dylib
libfreetype.6.dylib
libvlc.dylib
libvlccore.dylib
```
Note that the filenames could be slightly different depending on what versions you have installed on your system.
In addition to these, you need to create a `plugins` directory and copy over the following VLC libraries, which are normally located in `/Applications/VLC.app/Contents/MacOS/plugins/`:
If you only want to build EmulationStation to be used on your own computer, there's the option to skip the entire bundling of the libraries and use the ones already installed using Homebrew, meaning you can skip the previous .dylib copying. To do so, run CMake with the following option:
```
cmake -DAPPLE_SKIP_INSTALL_LIBS=ON .
```
**Note:** This also affects the .dmg package generation using cpack, so if this options is enabled, the package will be unusable for everyone but yourself as the required libraries will not be bundled with the application.
On macOS you can then install the application as a normal user, i.e. no root privileges are required. Simply run the following to install the application to `/Applications/EmulationStation Desktop Edition.app`:
```
make install
```
This will be the directory structure for the installation:
**Note:** The resources directory is critical, without it the application won't start.
And it will look in the following locations for the themes, also in the listed order:
*`[HOME]/.emulationstation/themes/`
*`[ES EXECUTABLE DIRECTORY]/../Resources/themes/`
*`[ES EXECUTABLE DIRECTORY]/themes/`
A theme is not mandatory to start the application, but ES will be basically useless without it.
The home directory will always take precedence, and any resources or themes located there will override the ones in the installation path or in the path of the ES executable.
**Creating a .dmg installer:**
Simply run `cpack` to build a .dmg disk image/installer:
Even after considerable effort I've been unable to make CMake natively set correct rpaths for the EmulationStation binary on macOS. Therefore a hack/workaround is in place that uses install_name_tool to change absolute paths to rpaths for most of the bundled libraries.
This is certainly not perfect as the versions of the libraries are hardcoded inside es-app/CMakeLists.txt. Therefore always check that all the rpaths are set correctly if you intend to create a .dmg image that will be used on other computers than your own.
Simply run `otool -L EmulationStation` and verify that the result looks something like this:
```
EmulationStation:
@rpath/libcurl.4.dylib (compatibility version 7.0.0, current version 8.0.0)
@rpath/libfreeimage.dylib (compatibility version 3.0.0, current version 3.18.0)
@rpath/libfreetype.6.dylib (compatibility version 24.0.0, current version 24.2.0)
@rpath/libSDL2-2.0.0.dylib (compatibility version 13.0.0, current version 13.0.0)
/System/Library/Frameworks/Cocoa.framework/Versions/A/Cocoa (compatibility version 1.0.0, current version 22.0.0)
@rpath/libvlc.dylib (compatibility version 12.0.0, current version 12.0.0)
/System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL (compatibility version 1.0.0, current version 1.0.0)
/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 120.1.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1226.10.1)
```
If any of the lines that should start with @rpath instead has an absolute path, then you have a problem and need to modify the install_name_tools parameters in es-app/CMakeLists.txt, for example:
`/usr/local/opt/sdl2/lib/libSDL2-2.0.0.dylib (compatibility version 13.0.0, current version 13.0.0)`
This is the section that would need to be modified:
I did a brief evaluation of the Microsoft Visual C++ compiler (MSVC) but as far as I'm concerned it's an abomination so I won't cover it here and it won't be supported.
The OpenGL library shipped with Windows is unfortunately garbage, so the OpenGL Extension Wrangler (GLEW) library needs to be used as well to provide shader support. Its installation is explained below.
Make a copy of `mingw64/bin/mingw32-make` to `make` just for convenience and make sure that the necessary paths are defined for the PATH environmental variable.
I won't get into the details on how to configure Git, but there are many resources available online to support with this. The `Git Bash` shell is very useful though as it's somewhat reproducing a Unix environment using MinGW/MSYS.
It's strongly recommended to set line breaks to Unix-style (line feed only) directly in the editor, although it can also be configured in Git for conversion during commit. The source code for EmulationStation-DE only uses Unix-style line breaks.
Note that most GDB builds for Windows have broken Python support so that pretty printing won't work. The MinGW installation recommended in the previous step should work fine though.
This library needs to be compiled from source as the pre-built libraries don't seem to work with GCC. The GitHub repo seems to be somewhat broken as well, therefore the manual download is required. It's recommended to get the source in zip format and uncompress it to the same directory as the other libraries listed above.
Now simply build the required glew32.dll library:
```
unzip glew-2.1.0.zip
cd glew-2.1.0
make
```
You will probably see a huge amount of compile warnings, and the glewinfo.exe tool may fail to build, but we don't need it so it's not an issue.
The following packages are not readily available for Windows either, so clone the repos and build them yourself:
**Copy the required DLL files to the EmulationStation build directory:**
As there's no package manager in Windows and no way to handle dependencies, we need to ship all the required shared libraries with the application.
Copy the following files to the `emulationstation-de` build directory. Most of them will come from the packages that were provided in the previous steps of this guide:
In addition to these, you need to copy some libraries from the VLC `plugins` folder to be able to play video files. There is a subdirectory structure under the plugins folder and although there is no requirement to retain these as libVLC apparently looks recursively for the required .dll files, it still makes it a bit more tidy to keep the folder names for each type of plugin. The CMake install script will however copy all the contents of this plugins folder regardless of whether subdirectories are in use or not.
It's a bit tricky to know which libraries are really needed. But as the plugins directory is around 120 MB (as of VLC version 3.0.11), we definitely only want to copy the files we need.
The following files seem to be required to play most video and audio formats (place them in `emulationstation-de\plugins\`):
For some reason defining the '../include' path doesn't work when running CMake from PowerShell (and no, changing to backslash doesn't help). Instead use Bash, by running from a Git Bash shell.
Note that compilation time is much longer than on Unix or macOS, and linking time is excessive for a debug build (around 10 times longer on my computer). The debug binary is also much larger than on Unix.
The default installation directory suggested by the installer is `C:\Program Files\EmulationStation`. However this can of course be changed by the user.
ES will look in the following locations for the resources, in the listed order:
*`[HOME]\.emulationstation\resources\`
*`[ES EXECUTABLE DIRECTORY]\resources\`
**Note:** The resources directory is critical, without it the application won't start.
And it will look in the following locations for the themes, also in the listed order:
*`[HOME]\.emulationstation\themes\`
*`[ES EXECUTABLE DIRECTORY]\themes\`
The theme is not mandatory to start the application, but ES will be basically useless without it.
So the home directory will always take precedence, and any resources or themes located there will override the ones in the path of the ES executable.
The contents of f:\ should now look something like this:
```
EmulationStation
ES-Home
RetroArch
start_es.bat
```
Now run the batch script, ES should start and ask you to configure any attached controllers. Following this, check that everything works as expected, i.e. the gamelists are properly populated etc.
You can optionally skip the configuration of the controllers by copying any existing `es_input.cfg` file to `f:\ES-Home\.emulationstation\es_input.cfg`.
Exit ES and modify the file `f:\ES-Home\.emulationstation\es_systems.cfg` to point to the emulators on the portable media.
EmulationStation Desktop Edition ships with a comprehensive `es_systems.cfg` configuration file, and as the logic is to use a `%ROMPATH%` variable to locate the ROM files (with a corresponding setting in `es_settings.cfg`), normally you shouldn't need to modify this file to the same extent as previous versions of EmulationStation. Still, see below in this document on how to adjust the es_systems.cfg file if required.
Upon first startup of the application, if there is no es_systems.cfg file present, it will be copied from the template subdirectory inside the resources directory. This directory is located in the installation path of the application, for instance `/usr/local/share/emulationstation/resources/templates` on Unix, `/Applications/EmulationStation.app/Contents/Resources/resources/templates` on macOS and `C:\Program Files\EmulationStation\resources\templates` on Windows.
`~` is `$HOME` on Unix and macOS, and `%HOMEPATH%` on Windows.
**Note:** Keep in mind that you have to set up your emulators separately from EmulationStation, the es_systems.cfg file assumes that your emulator environment is properly configured.
On Unix it's assumed that RetroArch is using the default configuration directory location, i.e. the cores should be located in ~/.config/retroarch/cores. If you've installed RetroArch via a Snap package, make a symlink from the Snap .config directory:
This file contains all the settings supported by ES, at their default values. Normally you shouldn't need to modify this file manually, instead you should be able to use the menu inside ES to update all the necessary settings.
For the ROM directory, you can either change it manually in es_settings.cfg, or use the dialog that is shown on application startup to change the path to your liking.
**Note:** This complete configuration step can normally be skipped as you're presented with a dialog to change the ROM directory upon application startup if no game files are found.
By default, ES looks in `~/ROMs` for the ROM files, where they are expected to be grouped into directories corresponding to the game systems, for example:
There is also support to add the variable %ESPATH% to the ROM directory setting, this will expand to the path where the ES executable is started from. You would normally not need this, but the option is there, should you require it for some reason.
You normally don't need to modify this file manually as it's created by the built-in input configuration step. This procedure is detailed in the [User Guide](USERGUIDE.md#input-device-configuration).
If your controller and keyboard stop working, you can delete the `~/.emulationstation/es_input.cfg` file to make the input configuration screen re-appear on the next run.
As you can see above, you can override the home directory path using the `--home` flag. So by running for instance the command `emulationstation --home ~/games/emulation`, ES will use `~/games/emulation/.emulationstation` as its base directory.
The order EmulationStation displays systems reflects the order you define them in. In the case of the default es_systems.cfg file, the systems are listed in alphabetical order.
**Note:** A system *must* have at least one game present in its `path` directory, or ES will ignore it! If no valid systems are found, ES will report an error and quit.
`%BASENAME%` - Replaced with the "base" name of the path to the selected ROM. For example, a path of `/foo/bar.rom`, this tag would be `bar`. This tag is useful for setting up AdvanceMAME.
`%ROM_RAW%` - Replaced with the unescaped, absolute path to the selected ROM. If your emulator is picky about paths, you might want to use this instead of %ROM%, but enclosed in quotes.
`%EMUPATH%` - Replaced with the path to the emulator binary. This is expanded either using the PATH environmental variable of the operating system, or if an absolute emulator path is defined, this will be used instead. This variable is mostly useful to define the emulator core path for Windows, as this operating system does not have a standardized program installation directory structure.
`%ESPATH%` - Replaced with the path to the EmulationStation binary. Mostly useful for portable emulator installations, for example on a USB memory stick.
As of the fork to EmulationStation Desktop Edition, game media information no longer needs to be defined in the gamelist.xml files. Instead the application will look for any media matching the ROM filename. The media path where to look for game art is configurable either manually in `es_settings.cfg` or via the GUI. If configured manually in es_settings.cfg, it looks something like this:
You can use ES's [scraping](http://en.wikipedia.org/wiki/Web_scraping) tools to populate the gamelist.xml files. There are two ways to run the scraper:
* **If you want to scrape multiple games:** press the Start button to open the menu and choose the "SCRAPER" option. Adjust your settings and press "START".
* **If you just want to scrape one game:** find the game on the game list in ES and press the Select button. Choose "EDIT THIS GAME'S METADATA" and then press the "SCRAPE" button at the bottom of the metadata editor.
You can also edit metadata within ES by using the metadata editor - just find the game you wish to edit on the gamelist, press Select, and choose "EDIT THIS GAME'S METADATA."
The home directory can be overridden using the `--home` option from the command line, see above in this document for details regarding that.
An example gamelist.xml:
```xml
<gameList>
<game>
<path>./mm2.nes</path>
<name>Mega Man 2</name>
<desc>Mega Man 2 is a classic NES game which follows Mega Man as he murders eight robot masters in cold blood.</desc>
</game>
</gameList>
```
Everything is enclosed in a `<gameList>` tag. The information for each game or folder is enclosed in a corresponding tag (`<game>` or `<folder>`). Each piece of metadata is encoded as a string.
**gamelist.xml reference:**
There are a few types of metadata:
*`string` - just text.
*`float` - a floating-point decimal value (written as a string).
*`integer` - an integer value (written as a string).
*`datetime` - a date and, potentially, a time. These are encoded as an ISO string, in the following format: "%Y%m%dT%H%M%S%F%q". For example, the release date for Chrono Trigger is encoded as "19950311T000000" (no time specified).
Some metadata is also marked as "statistic" - these are kept track of by ES and do not show up in the metadata editor. They are shown in certain views (for example, the detailed view and the video view both show `lastplayed`, although the label can be disabled by the theme).
* If a value matches the default for a particular piece of metadata, ES will not write it to the gamelist.xml (for example, if `genre` isn't specified, ES won't write an empty genre tag)
There are numerous locations throughout ES where custom scripts will be executed if the option to do so has been enabled in the settings. You'll find the option on the Main menu under **Other settings**. By default it's deactivated so be sure to enable it to use this feature.
The approach is quite straightforward, ES will look for any files inside a script directory that correspond to the event that is triggered and execute all files located there.
As an example, let's create a log that will record the start and end time for each game we play, letting us see how much time we spend on retro-gaming.
**Note: The following example is for Unix systems, but it works the same in Windows (though .bat batch files are then used instead of shell scripts).**
The events when the game starts and ends are called **game-start** and **game-end** respectively. Finding these event names is easily achieved by starting ES with the **--debug** flag. If this is done, all attempts to execute custom event scripts will be logged to es_log.txt, including the event names.
So let's create the folders for these events in the scripts directory. The location of this directory is **~/.emulationstation/scripts/**.
After creating the directories, we need to create the scripts to log the actual game launch and game ending. The parameters that are passed to the scripts varies depending on the type of event, but for these events the two parameters are the absolute path to the game file, and the game name as shown in the gamelist.
Let's name the start script **game_start_logging.sh** with the following contents:
```
#!/bin/bash
TIMESTAMP=$(date +%Y-%m-%d' '%H:%M:%S)
echo Starting game "\""${2}"\"" "(\""${1}"\")" at $TIMESTAMP >> ~/.emulationstation/game_playlog.txt
```
And let's name the end script **game_end_logging.sh** with the following contents:
```
#!/bin/bash
TIMESTAMP=$(date +%Y-%m-%d' '%H:%M:%S)
echo "Ending game " "\""${2}"\"" "(\""${1}"\")" at $TIMESTAMP >> ~/.emulationstation/game_playlog.txt
```
After creating the two scripts, you should have something like this on the filesystem:
Don't forget to make the scripts executable (e.g. 'chmod 755 ./game_start_logging.sh').
If we now start ES with the debug flag and launch a game, something like the following should show up in es_log.txt:
```
Aug 05 14:19:24 Debug: Scripting::fireEvent(): game-start "/home/myusername/ROMs/nes/Legend\ of\ Zelda,\ The.zip" "The Legend Of Zelda"
Aug 05 14:19:24 Debug: Executing: /home/myusername/.emulationstation/scripts/game-start/game_start_logging.sh "/home/myusername/ROMs/nes/Legend\ of\ Zelda,\ The.zip" "The Legend Of Zelda"
.
.
Aug 05 14:27:15 Debug: Scripting::fireEvent(): game-end "/home/myusername/ROMs/nes/Legend\ of\ Zelda,\ The.zip" "The Legend Of Zelda"
Aug 05 14:27:15 Debug: Executing: /home/myusername/.emulationstation/scripts/game-end/game_end_logging.sh "/home/myusername/ROMs/nes/Legend\ of\ Zelda,\ The.zip" "The Legend Of Zelda"
```
Finally after running some games, ~/.emulationstation/game_playlog.txt should contain something like the following:
```
Starting game "The Legend Of Zelda" ("/home/myusername/ROMs/nes/Legend\ of\ Zelda,\ The.zip") at 2020-08-05 14:19:24
Ending game "The Legend Of Zelda" ("/home/myusername/ROMs/nes/Legend\ of\ Zelda,\ The.zip") at 2020-08-05 14:27:15
Starting game "Quake" ("/home/myusername/ROMs/ports/Quakespasm/quakespasm.sh") at 2020-08-05 14:38:46
Ending game "Quake" ("/home/myusername/ROMs/ports/Quakespasm/quakespasm.sh") at 2020-08-05 15:13:58
Starting game "Pirates!" ("/home/myusername/ROMs/c64/Multidisk/Pirates/Pirates!.m3u") at 2020-08-05 15:15:24
Ending game "Pirates!" ("/home/myusername/ROMs/c64/Multidisk/Pirates/Pirates!.m3u") at 2020-08-05 15:17:11
