A Unity extension, that allows to create branching dialogs through a visual editor that support requirements and actions. Localization is done per dialog. A bit of scripting is required to implement custom requirements and actions. A single Dialog is constructed in this format:

• [Title]
• [Text]
• Choice 1
• Choice x

1. Create a dialog collection via Right-clicking in the Project panel or choosing Assets from the menu, then Create -> Dialog Collection.
2. Click Edit from the inspector of the newly created asset.
3. Add Conversations (edit dialogs by clicking them) in the editor window.
4. Add the ConversationEngine Component to an Npc for example and drag the asset to its Dialogs field.
5. Implement the interfaces IDialogRelevant[Player/Npc/World] for each part. (world can also be left out if not needed)

Starting a conversation is done via:

var dialog = referenceToConversationEngine.GetAvailableTopics(npc, player, worldContext/null, language);

If multiple Topics are available, this will return a Conversation with its type set to TopicList (topics as Answers) , else it's returned like a dialog (Title/Text/Answers) and the type is set to SingleDialog.

Responding (selecting a topic or an answer) is done via:

var newDialog = referenceToConversationEngine.Answer(npc, player, worldContext/null, dialog, answer, language)

where dialog is the reference to the previous and answer is a selection from its list.

To support more languages add the corresponding entry in the DialogLanguage enum (make sure to not shuffle the order, or existing dialogs will have incorrect labels for their strings).

To implement more requirements, inherit from DialogRequirement in the DialogSystem.Requirements namespace. For actions, inherit from DialogOptionAction inside DialogSystem.Actions.
By creating new classes this way, use the ReadableName attribute on them to specify a distinct (short) name which will show up in the editor interface. Editable variables in them should be public or marked with [SerializeField] OR have DrawComplexGui overridden to display the fields in the editor (in the second case return true from the overridden function).

A test scene can be found in the DialogSystem/Test folder.
The IDIalogRelevantPlayer interface already has some sample methods declared for the test scene. For a clean project, remove the Test folder with its content and these methods from the player interface.