Custom quests in UEFN 43.00

The Progression API left experimental in 43.00: a custom quest can be published. There is no editor tool for it; a quest is Verse. The facts below were read from the project's own digests and a minimal quest was compiled in the lab (compile only: it has not been run in a session, and publishing one has not been tried).

When to use

• "Collect 10 coins", "talk to three NPCs", "finish the course": a goal with progress and an end.
• A reward or a notification when something is completed, tracked per player.

When not to use: a plain score or timer (use a device and a variable), an ordered chain of steps without tracking (use the ordered objectives recipe), saving progress between sessions (use verse-patterns, persistable data).

The pieces (all in the digests)

• objective: has a state (Inactive, Active, Complete) and a progress text. progress_objective counts up to RequiredProgress.
• quest: an objective that players join and abandon; has join, abandon and complete events. basic_quest is "do X, get Y": it completes by itself when its objective completes and grants its rewards once.
• quest_collection: groups quests (use fort_quest_collection). quest_category sorts them for the player.
• quest_participant: who plays. For a player use agent_quest_participant{Agent := Player}; quest_participant_info tells whether they contribute, observe or receive.
• quest_reward: what the quest grants (entitlement_quest_reward for an entitlement). Leave the rewards empty for a quest without one.
• Devices that show progress to the player: objective_device, timed_objective_device, tracker_device, progress_based_mesh_device.

Workflow

1. Say the quest in one line: who, what, how many, what reward. Ask only what is missing.
2. Subclass basic_quest, make a progress_objective with RequiredProgress, put the quest in a collection, join the player, activate, advance with SetProgress. Start from references/quest-minimal.verse.txt.
3. Bind every result: Join and Activate return a result, and _ := does not compile.
4. Subscribe to the quest's complete event for the reward moment and the feedback (see game-feel-uefn).
5. Build, then playtest one player: progress text and the complete event must both print.

Rules (symptom, cause, remedy)

• Error 3600 on progress_objective{}: RequiredProgress must be set in the archetype; a later SetRequiredProgress is too late.
• Error 3512 on a case over objective_state: the enum is open; add a default clause.
• Errors 3514/3532 on _ := ...: give the result a name.
• Quest never completes: the objective was not activated, or progress was set on another objective than the quest's.
• Several players: one participant per player; progress is per participant, not shared, unless the design says so.
• Experimental: nothing in these classes is marked experimental in the Verse digest, and the compiler printed no warning. The UnrealEngine digest was not scanned for it: read it before promising a publish.

Class list with signatures: references/quest-minimal.verse.txt compiles against them; the full digest lines are in the editor's Verse.digest.verse and UnrealEngine.digest.verse.