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NG Design Document/Use Cases/Games

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Use Case Name

Contents

Customize On-screen Overlay

Goal Control the direction and pacing of the narrative through constraint of interaction at certain points.
Summary Almost all games require times when interaction is limited due cut-scenes, extended (interactive) dialogues, or staging areas such as a game lobby. This involves bringing up a new HUD over the scene where player is forced to view some display or choose some option.
Actors Players, Designer
Preconditions
  1. Player has the game installed and is in-game
Triggers
  1. Designer desires to control the narrative with a custom HUD
  2. Player triggers some pre-set condition which causes the HUD to be overlaid
Basic path
  1. Designer creates a custom HUD, custom interactive elements, and triggers for the HUD
  2. Agent downloads and caches the custom HUD as a game asset
  3. Player triggers the HUD and views its contents
  4. Agent traps all user inputs and maps them to the topmost HUD, but only where the HUD is overlaid
  5. Player makes some choice(s) by activating some interactive elements
  6. Conditions for the HUD are met, and the display is removed
Alternative paths
Exceptional paths
Postconditions Conditions required by the game designer are met, and input gathered from the user.


Use Case Name

Customize World Logic

Goal Create classes of objects with special properties or behaviors.
Summary The default simulation treats every object equally (except perhaps avatars). However narratives have archetypal classes, such as hero, witch, dragon, space-ship. For story-telling purposes, we wish to create such classes and have different rules apply to them.

For example, a bomb object may deal out damage to any object in proximity, or casting a magic spell may cause the player to be rendered immobile.

Actors Agent, Simulator, Object, Rule Module, Programmer, Designer
Preconditions
  1. Player has game installed and is in-game
Triggers Programmer desires to enforce rules which do no come default with a generic simulator
Basic path
  1. Programmer uses the agent and simulator API to create a module that receives input messages, and generates custom I/O, and custom output message, according to game-specific logic
  2. Designer places an object in-world of a recognized type
  3. Object generates messages during its lifetime
  4. Rule module receives messages referencing this type of object, and sends out messages to affect the correct behavior
Alternative paths
Exceptional paths
Postconditions Certain types of object behave in unique and entertaining ways.


Use Case Name

Customize User Interface

Goal Give the player a limited set of interactions appropriate to the gameplay.
Summary While the set of possible actions a player can take should be quite large, the game logic dictated by gameplay will constrain those options. The user interface should reflect only the options available according to the game logic.
Actors Players, Agent, Programmer
Preconditions
  1. Player has the game installed and is in-game
Triggers
  1. Designer desires to constrain in-world player interactions.
Basic path
  1. Programmer creates custom game logic and custom UI description which reflects interaction options
  2. Agent downloads the UI description and uses it to lay out the user interface
Alternative paths
Exceptional paths
Postconditions UI reflects the actual gameplay possibilities.


Use Case Name

Create Complex Effects with Client-Side Scripts

Goal Create complex effects and behaviours without creating one object per effect on the simulator or sending effects one at a time.
Summary Client-side scripts can be used to create complex visual, audio or other type of effects only relevant for the agent. These effects don't usually affect the game logic in any way. For example creating 30 second fireworks with hundreds of particle systems and dozens of sounds with precise timing can be done by creating one client-side script which in turn handles everything related to the fireworks.
Actors Agent, Players, Designer
Preconditions
  1. Player has the game installed and is in-game
Triggers
  1. Designer and programmer desire to make a complex visual effect involving multiple particle systems and sounds timed in a certain way and lasting a certain time.
  2. Players triggers some condition triggering the effect
Basic path
  1. Designer creates a script containing the effect logic and saves it
  2. Designer creates a trigger to the world which activates the effect
  3. Player triggers the effect
  4. The script is downloaded to the agent. Assets referenced in the script are downloaded to the agent if not already there.
  5. Script execution is started and effects are created according to the script.
  6. Script is executed to the end.
Alternative paths
Exceptional paths
Postconditions The complex visual effect is shown to the player.
Use Case Name

Control Player with Novel Input Devices

Goal Enable new interactions and game-play modes through novel input devices.
Summary As hardware become more capable, and visual quality improves, new modes of game-play become possible for the first time. However it is increasingly the case that the standard input devices such as mouse and keyboard, even traditional game-pad, are the bottleneck slowing innovation. Things like motion sensors, gyros, infra-red sensors, etc., enable new classes of interactions.

Examples of novel input devices include game controllers, "3D mice", Nintendo(tm)'s Wii-mote, etc.

Actors Agent, Players, Designer
Preconditions
  1. Player has the game installed and is in-game
Triggers
  1. Player plugs in the device.
Basic path
  1. Programmer creates a mapping file from device codes to commands that can be understood by the Agent
  2. Player installs mapping file
Alternative paths
Exceptional paths
Postconditions
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