The Ink-Fungus Gateway is (no surprise here) a gateway between Ink and Fungus. Ink is a scripting language for interactive fiction, developed by Inkle. Fungus is a visual storytelling and scripting tool for Unity.
The Ink-Fungus Gateway is available as a free package on the Unity Asset Store.
The best way to find out how the Gateway works is by checking the interactive documentation, provided as a playable Unity scene in the InkFungus/Documentation subfolder of this package. The interactive documentation is also playable in the browser on the author's itch.io page. This documentation is a useful reference for all the features of this tool. A good knowledge of Unity, Ink and Fungus is required to make games or other sorts of interactive text-and-pictures software using the Ink-Fungus Gateway.
Code-wise, the Gateway is mostly a set of MonoBehaviour components and new Fungus Commands. They manipulate the Ink engine so that it can plug into Fungus and provide ways to influence the Ink story flow from Fungus.
The Ink-Fungus Gateway was created by Mauro Vanetti in 2020, during the pandemic, and released to the public domain.
It can be used freely, also for commercial games and other purposes. It can be modified and restributed, as long as credits to the original version are provided and the same free license applies. As an exception, no game of a racist, fascist or sexist character can be created using this tool or its derivatives. Why? Because screw nazis.
Ink is a free software created and maintained by Inkle Studios with the support of their open-source community.
Fungus is a free software originally created by Chris Gregan and currently maintained by a vibrant community of open-source developers.
Hopefully, you can become part of the community of developers of the Ink-Unity Gateway, too.
- Create an empty scene or open a scene you want to augment with Ink and Fungus.
- Import the Fungus package in the scene.
- Import the Ink Unity Integration package in the scene.
- Find the Tools > Fungus > Create submenu. You have to create 3 objects from there:
- First of all, create the Ink-Fungus Gateway in your scene. Click on Tools > Fungus > Create > Ink-Fungus Gateway.
- Then, create a Fungus SayDialog. Click on Tools > Fungus > Create > Say Dialog.
- Finally, create a Fungus MenuDialog. Click on Tools > Fungus > Create > Menu Dialog.
- You're also going to need an Ink script file. That's just a text file with a .ink extension. Put it somewhere in your project.
That's it.
You now have three key GameObjects in your scene:
- The
Ink-Fungus Gatewaywith ist most importantNarrative Directorhighly configurable component. It also includes a predefined Fungus Flowchart calledGateway Flowchartwhich is used by the default handling of narrative branchings. - The
SayDialog(a standard Fungus object) and all its childrens, grandchildren etc. - The
MenuDialog(another standard Fungus object) and all its childrens, grandchildren etc.
You can and should customise these objects, to modify their appearance and behaviour.
A .ink file containing the script of the interactive story is the core of any project based on the Ink-Fungus Gateway. Such a file will be written in the Ink language. Ink files are automatically compiled for usage by the Ink Unity Integration plugin provided by Inkle.
The Ink file asset used must be set in the Narrative Director component of the Ink-Fungus Gateway GameObject at Basic Settings > Ink.
Text lines in the selected Ink file are automatically displayed using the default or selected SayDialog GameObject. All Ink features, such as variations, variables interpolation etc. can be used to smartly generate text.
You don't always want the text to be displayed right away when the game starts. For this reason, the visual part of the game (Fungus-based) is going to initiate the narrative part (Ink-based). To this aim, the Narrative Director starts in pause mode.
The new Fungus command Ink/Resume Narrative is the way to go when you want Ink to start piloting your game. After that, the system will just process the Ink script and display its contents in the Fungus SayDialog.
Ink scripts can contain tags. An Ink tag is a hash sign (#) followed by one or more words. Some tags are picked up by the Narrative Director and interpreted as special instructions.
# pause: the narrative will pause indefinitely after the line is displayed. Such indefinite pausing can only be ended by explicitly resuming the narrative flow.
# pause N: the narrative will pause for N seconds, where N can be any float number such as 10 or 3.5.
The Fungus command Ink/Resume Narrative terminates the pause and resumes the story flow and it works both for indefinite and timed pauses.
When pausing or resuming happens, an ink pause or ink resume message is broadcast to all Fungus flowcharts, which can react accordingly.
In Fungus, every SayDialog contains parameters indicating where and how the text lines (Story Text) and the speaker's name (Name Text) are to be displayed. Check the Fungus documentation for details.
The Gateway introduces a conventional syntax to set up the SayDialog on the fly.
Text lines can be "plain" and contain no indication about who's speaking. No special syntax is required in this default case.
Once upon a time, there was a plain story line.
But a label with the speaker's name might be required instead. In order to indicate the speaker's name, it has to be put at the line's beginning, followed by a blank space and a quote sign (").
Narrator "Let me tell you a nice story with a speaker's name in display.
The quote sign does not need to be "closed" at the end of the line (but it can, and the closing sign will not be displayed). Quotes can be used in the usual way within the text:
Narrator "Let me tell you a "nice" story with a speaker's name in display.
Fungus Characters can also be used in the conversation system. The only difference is that the speaker's label corresponds to the name of a GameObject containing a Fungus Character component. Every GameObject representing a character must be uniquely named for this syntax to work properly.
Character1 "Let me introduce myself: I'm the first character.
Character2 "Glad to know you. I'm the second character of this story.
In this case, the SayDialog will be set up according to the Fungus Character's settings. The name displayed in the label will not be the GameObject name in the Unity Hierarchy, but, as expected, the value of property Name Text within the Character component. If a Character has the Set Say Dialog property pointing to another SayDialog, that one will be used instead.
If a character has a portrait, it will be displayed next to its name label in the SayDialog (this is standard Fungus). Characters can have multiple portraits, and one can be picked by writing a question mark followed by a portait tag:
Character1?smiling "Let me introduce myself: I'm the first character!
Character2?shy "Hm, OK.
The portait tag is just any substring of the portait file name. The Gateway will look for a file containing it among the character's portaits. If no portrait tag is specified, the first portrait in the list will be used as default.
The colours of the name labels are defined character-wise, but a default colour for those speaker names that correspond to no character can also be configured. The default colour for character-less labels is specified in the Default Character Color property of the Narrative Director.
Branchings with different options are defined in the Ink script according to the syntax of Ink. The Gateway assigns the options to the choices buttons of the Fungus MenuDialog through the predefined Gateway Flowchart. The appearance and behaviour of the menu can be modified by altering the MenuDialog as in vanilla Fungus.
The standard MenuDialog have a maximum of 6 option buttons. This means that the Ink script should not include more than 6 choices in any branching unless the MenuDialog is properly extended. In that case, the Gateway Flowchart must also be replaced or extended to include more than 6 options.
The Gateway sends a stream of messages to the Fungus flowcharts describing what's going on in the Ink-based narrative part.
Any event name always starts with ink, as in ink pause or ink refresh n. The ink prefix can be modified or removed altogether, though, in the Narrative Director's settings.
Such messages may be intercepted by Fungus flowcharts in order to trigger the activation of blocks. In this way the visual side of the game can react to the story flow.
When pausing or resuming happen, an ink pause or ink resume message is broadcast to all Fungus flowcharts. This can be useful to rearrange the screen and switch from the narrative mode to the visual mode, enable/disable controls etc.
When the story reaches a stop, an "ink stop" message is broadcast to all Fungus flowcharts. The stop event can mark the very end of the game or just a dead end of the narrative flow. The Ink/Jump To command can be used to get out of such dead ends. An ink resume message is also broadcast when, usually after a stop, a jump command is issued.
Loading and saving is described in details among the advanced features of the Gateway. Saving and loading happen in "slots" and slots can be told apart using their names.
At each save event, an ink save message is broadcast to all Fungus flowcharts. Another, more detailed message, is also broadcast, i.e. ink save X where X is replaced with the actual slot name.
There is also a lot of automatic saving going on in the auto, precheckpoint and checkpoint slots. These saves are not notified to Fungus.
The same happens with loading, ink load is broadcast followed by ink load X where X is replaced with the actual slot name.
There is also a special event for the outcome of the loading attempt: ink load ok or ink load fail.
(Don't call your saving slots ok or fail or auto or precheckpoint or checkpoint because that would mess everything up.)
These messages can be useful to display a floppy-disk icon, to prepare the scene to restart in another location etc.
Some variables are shared between the Fungus (visual) side and the Ink (narrative) side. The bidirectional updating is handled by the Gateway.
Every time a Fungus variable is automatically updated by the Gateway, two messages are broadcast to all affected Fungus flowcharts:
- a generic ink refresh message,
- and a more detailed ink refresh X where X is replaced with the variable name.
Flowcharts lacking any reference to the updated variable are not going to receive the message.
These messages can be useful to trigger a refresh behaviour, e.g. updating a score on screen or showing/hiding an item in the scene or inventory.
Whenever the narrative reaches a new knot or stitch, two messages are broadcast to all Fungus flowcharts:
- If it is a new knot, the message sent will be ink at K where K is the knot name.
- If it is a new stitch, the message sent will be ink at K.S where K is the knot name and S is the stitch name.
In all cases, a generic ink at message will also be sent.
These messages can be useful to change the scene according to the proceeding of the narrative, e.g. by fading in a new background picture or music track.
Any unrecognized tag in the Ink script is echoed in the form of a broadcast message sent to all Fungus flowcharts.
To avoid interference with messages sent by other parts of the project, messages coming from Ink start with ink. For instance, a custom tag like this:
# fadeout 5
…will be translated as ink fadeout 5.
Global variables exist both in Ink and in Fungus, although there are some subtle differences between them:
- You can only have integers, floats, strings and Booleans in Ink. Other variable types that exist in Fungus cannot be synchronised as they are.
- You have lists in Ink, but not in Fungus. They undergo a special treatment.
The Ink-Fungus Gateway takes care of keeping in sync global variables that share the same name.
In order to do that, when a variable changes on the Fungus side, the Gateway needs to know, which can be done by executing the Sync Variables command. This new Fungus command can be found looking for Ink/Sync Variables in the command list.
When a variable changes on the Ink side, the Gateway detects it and the shared variable is automatically updated on the Fungus side. ink refresh messages are sent.
A working model for a Fungus flowchart to handle a shared global variable is the Variable Processor prefab included in the Ink-Fungus Gateway package. A Variable Processor can be created in your scene by clicking on Tools > Fungus > Create > Variable Processor. Please read the notes and comments in the Variable Processor's flowchart to find out how to adapt it to your needs.
If your interactive story is driven by the Ink script, you don't need any "jumps". The flow of your story can just follow the branching and weaving and tunnelling defined in your Ink script.
But you may want to have the visual (Unity/Fungus) side of your game drive the narrative sometimes. For example, you might make a game in which you freely walk around and sometimes you meet an NPC and a conversation begins. One of several possible ways to do that is using the new Fungus command Ink/Jump To.
The Jump To command is executed with a K or K.S parameter, where K is the destination knot and S is the optional destination stitch. When the command is executed, the story flow jumps to the new location within the Ink script. Variables (including those recording visited stitches and options) are preserved, but not the story flow stack.
Jumps are more useful in visual-driven games such as point-and-click adventures. Visual novels, on the opposite, are usually story-driven.
An example of safe usage of jumps is showcased in the interactive documentation. It uses Fungus blocks listening to ink stop and ink resume events as switches between story and visual controls.
Lists are a special kind of variables in Ink. Ink lists must be treated as a collection of Booleans (true/false) in Fungus, each Boolean variable representing whether a particular item is in the list (true) or not (false).
In order to establish a connection between Ink lists and Fungus Booleans, the global Booleans in Fungus are to be called LIST__ITEM where LIST is the Ink list name and ITEM is the Ink list item name.
As with ordinary variables, whenever a Boolean is modified on the Fungus side, the Gateway must be notified with an Ink/Sync Variables command so that the Ink side can be updated accordingly by including or excluding the corresponding item in the corresponding list.
The Narrative Director component of the Ink-Fungus Gateway GameObject has several settings that can be altered via the Inspector.
The settings are grouped in 4 areas in the Narrative Director's parameters form.
This area is very straightforward. The only required value is the Ink field: you need to place your Ink script asset here.
The Say Dialog and Menu Dialog fields can be left empty: if there is only one instance of each required Fungus object, the Gateway will find it. If for some reason there are multiple Say Dialog and Menu Dialog objects, they can be specified there. Both values can also be replaced at runtime by executing the new Fungus commands called Ink/Replace Say Dialog and Ink/Replace Menu Dialog. This advanced feature can deliver interesting results, e.g. by differentiating conversation options from other sorts of menus (inventory, shops etc.).
The Default Character Color field specifies the text colour used for the speaker label when no corresponding Character is available. When a speaker name corresponds to an existing Fungus Character GameObject, their specific label colour is used.
Flags are binary (true/false) values that control some optional behaviours of the Gateway. Flags are set to their default values unless they are altered by the Ink script itself.
There are two ways to modify the value of a flag in the Ink script: permanent and temporary.
Permanent changes to a flag are applied after an on FLAG or off FLAG tag are processed (replace FLAG with the flag name, of course). Imagine this as permanently switching on or off that particular flag.
Permanently switch off the echo feature. # off echo
Permanently switch on the auto feature. # on auto
Temporary changes last only for the time span of a conversation line (including the multiple-option menu if it's the line preceding a choice). Temporary changes to a flag are applied when a yes FLAG or no FLAG tag are processed (again: replace FLAG with the flag name).
Temporarily switch off the hide feature. # no hide
Temporarily switch on the timer feature. # yes timer
To sum up: default flags are overriden by on/off tags, and both are temporarily overriden by yes/no tags.
The hide flag controls whether the last conversation line before a choice is kept in display or not when the options are shown. Ink does not allow for tags in choice options, therefore the on/off/yes/no hide tags are to be applied to the previous line.
The echo flag controls whether choices are treated as answers that are to be echoed back into the conversation. Notice that Ink was designed to treat them like that (as if the echo flag was always on) and has some special syntax to do that smartly. Again: Ink does not allow for tags in choice options, therefore the on/off/yes/no echo tags are to be applied to the previous line.
The auto flag controls whether the narrative proceeds automatically as soon as the text has been displayed, or not. Fungus conversation lines can be typed in gradually, therefore switching this flag on can make sense in some situations. It can also be useful for some dramatic effect. Remember that the speed, style and sound effects of typing can be tweaked in Fungus, altering the properties of the Say Dialog component.
The verbatim ("literally") flag controls the regular expression used to extract the optional speaker's name and portait from each Ink line. When the verbatim flag is on, Ink lines are rendered using only the Ink syntax, otherwise they also pass through the Gateway's parser.
The timer flag controls whether there is a maximum time to pick an option when the narrative branches. The timer is a feature of the Fungus conversation system, this flag only enables or disables it. When timer is on, the user has 5 seconds to pick an option, otherwise the first option in the list will be automatically selected. Once more: Ink does not allow for tags in choice options, therefore the "on/off/yes/no timer" tags are to be applied to the previous line. The countdown time can be changed in the Advanced Settings area of the Inspector and through the timer tag (not flag!).
Some Ink events trigger the broadcasting of messages to the Fungus flowcharts. The Gateway handles these communications. In order to enable the adaptation of an Ink layer to a pre-existing Fungus game prototype, such messages are configurable.
First of all, every message has a universal prefix, ink followed by a blank space. This can be modified: it's the Prefix For All Messages. The blank space, if required, must also part of the prefix.
One can also remove the prefix altogether. In this case, watch out for colliding messages coming from Fungus itself or some Unity script.
The other properties just list all existing special messages sent by the Gateway and allow for them to be modified. Obviously, the Fungus Flowchart blocks should listen to the right messages.
This area is only for advanced users.
The Regex parameter defines how incoming lines from the Ink engine are parsed by the Gateway to extract the optional character and portait parts. This is done through named groups in a regular expression. The main named group is called "text", there is an optional group named "character" and an even-more-optional group named "portrait". The regex is so complex because it needs to be lenient with the quote signs. This regex allow for quotes to be used in the actual text as long as they are properly opened and closed. There are some limitations in the characters available for the speaker label and the portrait tag, which can be a problem for some. As long as there are the grouped names "text", "character" and "portrait", an alternative regex can be used instead of the default one. The default regex is:
/^(?<character>[\w\-]*)(\?(?<portrait>[\w\-]+))? "(?<text>(("[^"]*")|([^"]+))+?)"?[ ]*$/
The Gateway Flowchart parameter defines the Fungus Flowchart used to handle the player's choice at branching points of the story flow. Basically, what the Gateway does is associating each option with the corresponding block inside a special flowchart. According to the option picked by the player, the new command Ink/Choose Option is called with a 0-based integer argument. If for any reason this behaviour were to be delegated to another flowchart, that can be specified here.
The Choice Time parameter defines the default duration (in seconds) of the countdown. The countdown is switched on by the timer flag and limits the time available for the player to pick an option when a MenuDialog is shown. This is the default value but the choice time can also be modified in the Ink Script like this:
From now on, we get one minute every time we have to choose something. # timer 60
In most projects heavily relying on Fungus, implementing a save-and-load system in parallel with Ink is going to be a nightmare. The Gateway provides some tricks to help the process but please consider this feature as almost experimental and prone to failure.
The Ink-Fungus Gateway allows for saving the Ink state in two different modes: snapshot and checkpoint.
By executing the new command Ink/Save Snapshot (which can be done from a Fungus Flowchart block) you save the current state at the moment when the current conversation line was displayed. Subsequent changes in variables (done through Fungus) are not going to be saved.
By invoking another new command, Ink/Save Checkpoint, you save the story state at the beginning of the current knot and stitch.
This follows two different styles of saving used in many video games, even though it doesn't really allow for moment-to-moment save. Obviously you can restrict the saving even more than that, by letting that happen only at some special milestones of your game, like chapters.
Both save styles ask for a slot name. This is going to be used to form the file names for the save files (each save is several files).
Notice that there is a lot of automatic saving going on, using slots auto, precheckpoint and checkpoint. Don't call your slots like that.
The default slot name for manual saves is, predictably, manual. If you just need one slot, use that one.
To load what you saved in a slot, execute Ink/Load with the slot name as an argument.
Messages are broadcast at save and load events.
Remember that everything Fungus (and even worse, everything Unity out of Fungus) is not going to be magically stored in your Ink save files. The Gateway can tell Ink to save the state of the narrative but not the state of the visuals, including the non-global variables etc. This has to be managed separately and simultaneously in Unity/Fungus.
Localization is complicated. Fungus has its own way of translating text, which is fine but it's not what we're using in the Gateway.
The best way to localize an Ink script is to write another Ink script with the same knots-and-stitches structure, the same variables, the same logic. The Gateway helps in switching between "twin" Ink scripts in different language, by means of the Alternate Language Narrative Director component. This is a MonoBehaviour script provided with this package.
In interactive narrative, as in narrative in general, there cannot always be a 1-to-1 relationship between translated sentences. For this reason, the checkpoint logic is applied to language switching in the Gateway. This means that if the player switches to a new language, they have to start from the last checkpoint. That's why we have the precheckpoint save slot: that's where we rewind our story back to, when we switch language.
In order to add extra languages to your game, you need to attach one instance of the Alternate Language Narrative Director component per extra language. The Alternate Language Narrative Director component has two properties: a language tag and the corresponding Ink script. Be careful in keeping the translated Ink script identical to the original version as far as knots, stitches, variables and logic are concerned.
The new command Ink/Switch Language must be executed with a language tag argument in order to switch to the corresponding translation. When the Ink/Switch Language is executed with an empty argument, it restores the original language.
Also, consider other paths. For example, you may force the player to pick a language at the beginning and then stick with it. This solution would only require one multi-lingual Ink file (but every knot and stitch must be duplicated).