Chord / The World / Sound, music, and images

Sound, music, and images

A story declares its media assets once, by name, and then plays or shows them from any statement body. The files live under the project's assets/ directory and ship with the browser build; a client that cannot play a kind of media simply ignores the cue, and the when client has … condition lets the story say something else instead.

Declaring assets

define sound night-wind from "audio/night-wind.wav"
define sound boiler-thump from "audio/boiler-thump.wav"
define music dawn-theme from "audio/dawn-theme.wav"
define image folly-photograph from "images/folly-photograph.png"

Three kinds: a sound is a one-shot cue, music is a track, an image is a picture. The path is relative to assets/. Every play or show names one of these declarations, and the compiler checks the name and the kind — a play music of a define sound is a diagnostic, and a misspelled asset carries a nearest-match suggestion.

Playing and showing

create the primer plunger
  aka plunger
  scenery
  in the Boiler Shed

  A stiff brass plunger on the boiler's flank.

  after the player pushing
    play sound boiler-thump when client has sound
    phrase primer-thumps
  end after

Statement	Effect
`play sound <name>`	play the sound once
`play music <name>`	start the track; add `looping` to repeat it
`stop music`	stop the track
`play ambient <name>`	loop a sound as a bed; `in <bed>` names a bed other than the default
`stop ambient`	stop the default bed; `stop ambient in <bed>` stops a named one
`show image <name>`	show the picture; `in <slot>` names where the page puts it
`hide image`	take the picture down
`transition <kind>`	a visual transition the client renders
`clear`	clear the client's prose pane

Every one of these takes the ordinary when <condition> suffix, so a cue can wait on a state or a client capability:

create the Iron Gates
  a room

  Wrought-iron gates stand open on one hinge apiece.

  after the player entering while the player has the deed
    play music dawn-theme when client has music
    win fernhill-saved
  end after

client has sound, client has music, and client has images are true when the client running the story can play that kind of media. A cue without the guard is harmless on a client that cannot honour it — the guard is for the story that wants to say something different when the music cannot play.

Ambients follow the player

An ambient is a looping bed the rooms of a region can share. Start it on arrival and stop it on leaving, and the wind follows the player across the grounds and stops at the door:

create the Grounds
  a region
  containing the Gravel Drive, the Fountain Court

  after the player entering
    play ambient night-wind when client has sound
  end after

  after the player leaving
    stop ambient when client has sound
  end after

The Fernhill walkthrough shows all three kinds wired into a complete story and played in the browser build.