Scenes

Gamefic plots use scenes to handle player interactions. Player characters participate in one or more scenes every game turn.

How Scenes Work

Each scene has a start and a finish. The start is executed either at the beginning of the turn or whenever the scene is cued (see the “prepare and cue” section). The finish executes after the game engine receives player input.

Note that characters can only participate in one scene at a time. If a character cues a new scene, the current scene will be discarded.

The scene’s finish is typically responsible for processing player input. In a text adventure, for example, the default scene will treat the input as a command to be performed by the player’s character.

Scene Types

Activity

The default scene type for most plots. Activity parses player input into an action performed by the player’s character. In a text adventure, whenever players execute a command like GO NORTH or GET LAMP, they’re in an Activity scene.

The plot’s default_scene attribute is Activity unless an author changes it.

Conclusion

A scene that ends the plot (or the player’s participation in it).

The plot provides a default_conclusion that can be used to end the game.

Introduction

The scene that begins the player’s participation in the plot. Every plot has a single introduction that gets defined by the introduction method.

MultipleChoice

A scene that requires the player to select from one of several options.

MultipleScene

A specialized MultipleChoice scene. Each available option is mapped to a scene. The selected scene will be cued when the MultipleScene ends.

Pause

A scene that waits for player input before proceeding to the next turn. In a text adventure, for example, a Pause will ask the player to press enter to continue. This can be useful when the author wants to bring attention to a block of text or split a long passage into smaller parts.

YesOrNo

A scene which can only proceed after the player selects Yes or No.

Scene Methods

Plots provide several helper methods to simplify creation of various scene types.

• introduction
• conclusion
• pause
• multiple_choice
• multiple_scene
• yes_or_no
• question
• custom

A Simple Cutscene

The following example pauses the game in response to the READ command.

Gamefic.script do
  introduction do |actor|
    actor.tell "You're in a library."
  end

  respond :read do |actor|
    actor.prepare @reading
  end

  @reading = pause do |actor|
    actor.tell "You spend some time with a good book."
    actor.prepare default_scene
  end
end

The result:

$ rake ruby:run

You're in a library.

> read

You spend some time with a good book.

Press enter to continue...

>

prepare and cue

Characters enter scenes via the prepare and cue methods. The difference between the methods is subtle but significant. The prepare method specifies a scene to enter at the beginning of the next turn. The cue method starts the new scene immediately.

Consider the example cutscene above. The READ action calls actor.prepare @reading, which means the @reading scene starts at the beginning of the next turn. If the action called actor.cue @reading instead, the player would not be prompted to continue, because the @reading scene would start immediately and prepare default_scene for the next turn.

In most cases, authors should use prepare instead of cue.

Note that only one scene can be prepared at a time. When a character prepares for a new scene, any previously prepared scene is discarded.

Characters also have a conclude method that is functionally equivalent to cue, except it requires the specified scene to be a Conclusion.

Next: Creating subplots