# Taisei Project – Environment Variables

## Introduction

Some of Taisei’s more advanced configuration options are delegated to environment variables. This document attempts to describe them all.

Generally you don’t need to set any of them. They are intended for developers and advanced users only. Therefore, familiarity with the concept is assumed.

In addition to the variables listed here, those processed by our runtime dependencies (such as SDL) also take effect, unless stated otherwise.

## Variables

### Virtual filesystem

TAISEI_RES_PATH
  Default: unset

  If set, overrides the default resource directory path. This is where Taisei looks for game data. The default path is platform and build specific:

  - On macOS, it will be the Contents/Resources/data directory inside of the Taisei.app bundle.

  - On Linux, *BSD, and most other Unix-like systems (without -DRELATIVE), it will be $prefix/share/taisei. This path is static and determined at compile time.

  - On Windows and other platforms when built with -DRELATIVE, it will be the data directory relative to the executable (or to whatever SDL_GetBasePath returns on the given platform).

TAISEI_STORAGE_PATH
  Default: unset

  If set, overrides the default storage directory path. This is where Taisei saves your configuration, progress, screenshots and replays. Taisei also loads custom data from the resources subdirectory in there, if any, in addition to the stock assets. The custom resources shadow the default ones if the names clash. The default path is platform specific, and is equivalent to the return value of SDL_GetPrefPath("", "taisei"):

  - On Windows, it’s %APPDATA%\taisei.

  - On macOS, it’s $HOME/Library/Application Support/taisei.

  - On Linux, *BSD, and most other Unix-like systems, it’s $XDG_DATA_HOME/taisei or $HOME/.local/share/taisei.

### Resources

TAISEI_NOASYNC
  Default: 0

  If 1, disables asynchronous loading. Increases loading times, might slightly reduce CPU and memory usage during loads. Generally not recommended unless you encounter a race condition bug, in which case you should report it.

TAISEI_NOUNLOAD
  Default: 0

  If 1, loaded resources are never unloaded. Increases memory usage, reduces filesystem reads and loading times over time.

TAISEI_NOPRELOAD
  Default: 0

  If 1, disables preloading. All resources are only loaded as they are needed. Reduces loading times and memory usage, but may cause stuttering during gameplay.

TAISEI_PRELOAD_REQUIRED
  Default: 0

  If 1, the game will crash with an error message when it attempts to use a resource that hasn’t been previously preloaded. Useful for developers to debug missing preloads.

TAISEI_PRELOAD_SHADERS
  Default: 0

  If 1, Taisei will load all shader programs at startup. This is mainly useful for developers to quickly ensure that none of them fail to compile.

### Video and OpenGL

TAISEI_PREFER_SDL_VIDEODRIVERS
  Default: wayland,mir,cocoa,windows,x11

  List of SDL video backends that Taisei will attempt to use, in the specified order, before falling back to SDL’s default. Entries may be separated by spaces, commas, colons, and semicolons. This variable is ignored if SDL_VIDEODRIVER is set.

TAISEI_VIDEO_DRIVER
  Default: unset
  Deprecated

  Use SDL_VIDEODRIVER instead.

TAISEI_RENDERER
  Default: gl33

  Selects the rendering backend to use. Currently available options are:

  > - gl33: the OpenGL 3.3 Core renderer

  > - gles30: the OpenGL ES 3.0 renderer

  > - gles20: the OpenGL ES 2.0 renderer

  > - null: the no-op renderer (nothing is displayed)

  Note that the actual subset of usable backends, as well as the default choice, can be controlled by build options. The gles backends are not built by default.

TAISEI_LIBGL
  Default: unset

  OpenGL library to load instead of the default. The value has a platform-specific meaning (it’s passed to the equivalent of dlopen). Takes precedence over SDL_OPENGL_LIBRARY if set. Has no effect if Taisei is linked to libgl (which is not recommended, because it’s not portable).

TAISEI_GL_DEBUG
  Default: 0

  Enables OpenGL debugging. A debug context will be requested, all OpenGL messages will be logged, and errors are fatal. Requires the KHR_debug or ARB_debug_output extension.

TAISEI_GL_EXT_OVERRIDES
  Default: unset

  Space-separated list of OpenGL extensions that are assumed to be supported, even if the driver says they aren’t. Prefix an extension with - to invert this behaviour. Might be used to work around bugs in some weird/ancient/broken drivers, but your chances are slim. Note that this only affects code paths that actually test for the given extensions, not the actual OpenGL functionality. Some OpenGL implementations (such as Mesa) provide their own mechanisms for controlling extensions. You most likely want to use that instead.

TAISEI_FRAMERATE_GRAPHS
  Default: 0 for release builds, 1 for debug builds

  If 1, framerate graphs will be drawn on the HUD.

TAISEI_OBJPOOL_STATS
  Default: 0

  Displays some statistics about usage of in-game objects.

### Timing

TAISEI_HIRES_TIMER
  Default: 1

  If 1, tries to use the system’s high resolution timer to limit the game’s framerate. Disabling this is not recommended; it will likely make Taisei run slower or faster than intended and the reported FPS will be less accurate.

TAISEI_FRAMELIMITER_SLEEP
  Default: 3

  If over 0, tries to give up processing time to other applications while waiting for the next frame, if at least frame_time / this_value amount of time is remaining. Increasesing this value reduces CPU usage, but may harm performance. Set to 0 for the v1.2 default behaviour.

TAISEI_FRAMELIMITER_COMPENSATE
  Default: 1

  If 1, the framerate limiter may let frames finish earlier than normal after sudden frametime spikes. This achieves better timing accuracy, but may hurt fluidity if the framerate is too unstable.

TAISEI_FRAMELIMITER_LOGIC_ONLY
  Default: 0
  Experimental

  If 1, only the logic framerate will be capped; new rendering frames will be processed as quickly as possible, with no delay. This inherently desynchronizes logic and rendering frames, and therefore, some logic frames may be dropped if rendering is too slow. However, unlike with the synchronous mode, the game speed will remain roughly constant in those cases. TAISEI_FRAMELIMITER_SLEEP, TAISEI_FRAMELIMITER_COMPENSATE, and the frameskip setting have no effect in this mode.

### Miscellaneous

TAISEI_GAMEMODE
  Default: 1
  Linux only

  If 1, enables automatic integration with Feral Interactive’s GameMode daemon. Only meaningful for GameMode-enabled builds.

### Logging

Taisei’s logging system currently has five basic levels and works by dispatching messages to a few output handlers. Each handler has a level filter, which is configured by a separate environment variable. All of those variables work the same way: their value looks like an IRC mode string, and represents a modification of the handler’s default settings. If this doesn’t make sense, take a look at the Examples section.

#### The levels

- Debug (d) is the most verbose level. It contains random information about internal workings of the game and is disabled for release builds at source level.

- Info (i) logs some events that are expected to occur during normal operation, for example when a spell is unlocked or a screenshot is taken.

- Warning (w) usually complains about misuse of the engine features, deprecations, unimplemented functionality, other small anomalies that aren’t directly detrimental to functionality.

- Error (e) alerts of non-critical errors, for example a missing optional resource, corrupted progress data, or failure to save a replay due to insufficient storage space or privileges.

- Fatal (f) is an irrecoverable failure condition. Such an event most likely signifies a programming error or a broken installation. The game will immediately crash after writing a message with this log level. On some platforms, it will also display a graphical message box.

- All (a) is not a real log level, but a shortcut directive representing all possible log levels. See Examples for usage.

#### The variables

TAISEI_LOGLVLS_CONSOLE
  Default: +a (All)

  Controls what log levels may go to the console. This acts as a master switch for TAISEI_LOGLVLS_STDOUT and TAISEI_LOGLVLS_STDERR.

TAISEI_LOGLVLS_STDOUT
  Default: +di (Debug, Info)

  Controls what log levels go to standard output. Log levels that are disabled by TAISEI_LOGLVLS_CONSOLE are ignored.

TAISEI_LOGLVLS_STDERR
  Default: +wef (Warning, Error, Fatal)

  Controls what log levels go to standard error. Log levels that are disabled by TAISEI_LOGLVLS_CONSOLE are ignored.

TAISEI_LOGLVLS_FILE
  Default: +a (All)

  Controls what log levels go to the log file ({storage directory}/log.txt).

TAISEI_LOG_ASYNC
  Default: 1

  If 1, log messages are written asynchronously from a background thread. This mostly benefits platforms where writing to the console or files is very slow (such as Windows). You may want to disable this when debugging.

TAISEI_LOG_ASYNC_FAST_SHUTDOWN
  Default: 0

  If 1, don’t wait for the whole log queue to be written when shutting down. This will make the game quit faster if log writing is slow, at the expense of log integrity. Ignored if TAISEI_LOG_ASYNC is disabled.

#### Examples

- In release builds: print Info messages to stdout, in addition to Warnings, Errors, and Fatals as per default:

  System Message: WARNING/2 (../doc/ENVIRON.rst, line 295)

  Cannot analyze code. Pygments package not found.

      .. code:: sh

          TAISEI_LOGLVLS_STDOUT=+i

- In Debug builds: remove Debug and Info output from the console:

  System Message: WARNING/2 (../doc/ENVIRON.rst, line 301)

  Cannot analyze code. Pygments package not found.

      .. code:: sh

          TAISEI_LOGLVLS_STDOUT=-di

  OR:

  System Message: WARNING/2 (../doc/ENVIRON.rst, line 307)

  Cannot analyze code. Pygments package not found.

      .. code:: sh

          TAISEI_LOGLVLS_CONSOLE=-di

- Don’t save anything to the log file:

  System Message: WARNING/2 (../doc/ENVIRON.rst, line 313)

  Cannot analyze code. Pygments package not found.

      .. code:: sh

          TAISEI_LOGLVLS_FILE=-a

- Don’t print anything to the console:

  System Message: WARNING/2 (../doc/ENVIRON.rst, line 319)

  Cannot analyze code. Pygments package not found.

      .. code:: sh

          TAISEI_LOGLVLS_CONSOLE=-a

- Don’t save anything to the log file, except for Errors and Fatals:

  System Message: WARNING/2 (../doc/ENVIRON.rst, line 325)

  Cannot analyze code. Pygments package not found.

      .. code:: sh

          TAISEI_LOGLVLS_FILE=-a+ef

- Print everything except Debug to stderr, nothing to stdout:

  System Message: WARNING/2 (../doc/ENVIRON.rst, line 331)

  Cannot analyze code. Pygments package not found.

      .. code:: sh

          TAISEI_LOGLVLS_STDOUT=-a
          TAISEI_LOGLVLS_STDERR=+a-d