The title and descriptions of Quests and Tasks can include parameters, so that you can substitute variable values into your strings.
This works the same way as text formatting in Unreal using named parameters, for example:
Collect the {ItemName}
You might want to do this rather than having branches in your quest lines, where the aim and structure of the quest is the same but the details are variable.
Quest definitions are static, so whenever you retrieve the title or description
directly from the definitions, the parameters will still be as written in the
original definition, e.g. {ItemName}.
However, when you call GetTitle() on the quest state that you get from the
Progression object, parameters will be replaced with values
wherever possible.
Therefore in your quest UI you should always get the title and description from
the state objects on USuqsProgression.
To provide parameter values, you should implement the ISuqsParameterProvider
interface on one or more of your objects.
The implementation requires a single function, GetQuestParameters.
You're given the identifier of the quest, and optionally the
identifier of the task that the text relates to (might be None if it's the
top-level quest). You also get a Params object, which you can populate with
values. Here's a simple version in Blueprints:
In this case I'm not bothering to check the IDs of the quest/task, I'm just setting up some parameters. It doesn't actually matter whether the text uses all these parameters or not, they're just available if referenced. But, if you need to provide different values for different quests/tasks and use a single provider to do it all, you can make parameter setting conditional on Quest/Task ID if you want.
To actually receive the GetQuestParameters call, you need to register your provider with the
USuqsProgression object you use for tracking quest progress (see Progression):
Providers are all given the opportunity to set parameters, in the order you register them.
Important: Providers are held by SUQS as a weak pointer; this is to allow you to use normal world objects to provide parameters, without worrying about them being kept alive beyond their normal lifespan (they will safely be unregistered when they've been garbage collected). But this also means you must have a strong pointer to your provider object somewhere to prevent it being garbage collected.
SUQS detects whether a title / description has parameters or not, and only calls parameter providers when needed.