OpenMW/mscripts/sound/jukebox.mn

/*
  OpenMW - The completely unofficial reimplementation of Morrowind
  Copyright (C) 2008  Nicolay Korslund
  Email: < korslund@gmail.com >
  WWW: http://openmw.snaptoad.com/

  This file (jukebox.mn) is part of the OpenMW package.

  OpenMW is distributed as free software: you can redistribute it
  and/or modify it under the terms of the GNU General Public License
  version 3, as published by the Free Software Foundation.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  version 3 along with this program. If not, see
  http://www.gnu.org/licenses/ .

 */

/*
   A simple jukebox with a playlist. It can play, stop, pause with
   fade in and fade out, and adjust volume.
*/

class Jukebox;

// Between 0 (off) and 1 (full volume)
float fadeLevel = 0.0;

// How much to fade in and out each second
float fadeInRate = 0.14;
float fadeOutRate = 0.30;

// Time between each fade step
float fadeInterval = 0.2;

// List of sounds to play
char[][] playlist;

// Name used for error messages
char[] name;

// Index of current song
int index;

// The music volume, set by the user. Does NOT change to adjust for
// fading, it is only updated when the user changes the volume
// settings. Updated from Config through updateVolume().
float musVolume;

bool isPlaying; // Is a song currently playing?
bool isPaused; // Is the song currently paused?

// Native functions to control music
native setSound(char[] filename);
native setVolume(float f);
native playSound();
native stopSound();
idle waitUntilFinished();

// Fade out and then stop the music. TODO: Rename these to resume()
// etc and use super.resume, when this is possible.
pause()
{
  isPaused = true;
  state = fadeOut;
}

resume()
{
  if(!Config.useMusic) return;

  if(isPaused) playSound();
  else next();

  isPaused = false;
  state = fadeIn;
}

// Stop the current song. Calling resume again after this is called
// will start a new song.
stop()
{
  stopSound();

  isPlaying = false;
  fadeLevel = 0.0;
  state = null;
}

play()
{
  if(!Config.useMusic) return;

  if(index >= playlist.length)
    return;

  setSound(playlist[index]);
  setVolume(musVolume*fadeLevel);
  playSound();

  isPlaying = true;
  isPaused = false;

  state = playing;
}

// Play the next song in the playlist
next()
{
  if(!Config.useMusic) return;

  if(isPlaying)
    stop();

  // Find the index of the next song, if any
  if(playlist.length == 0) return;

  if(++index >= playlist.length)
    {
      index = 0;
      randomize();
    }

  play();
}

// Set the new music volume setting.
updateVolume(float f)
{
  musVolume = f;
  if(isPlaying)
    setVolume(musVolume*fadeLevel);
}

setPlaylist(char[][] lst)
{
  playlist = lst;
  randomize();
}

// Randomize playlist.
randomize()
{
  if(playlist.length < 2) return;

  foreach(int i, char[] s; playlist)
    {
      // Index to switch with
      int idx = randInt(i,playlist.length-1);

      // To avoid playing the same song twice in a row, don't set the
      // first song to the previous last.
      if(i == 0 && idx == playlist.length-1)
        idx--;

      if(idx == i) // Skip if swapping with self
        continue;

      playlist[i] = playlist[idx];
      playlist[idx] = s;
    }
}

// Fade in
state fadeIn
{
 begin:
  setVolume(musVolume*fadeLevel);

  sleep(fadeInterval);

  fadeLevel += fadeInterval*fadeInRate;

  if(fadeLevel >= 1.0)
    {
      fadeLevel = 1.0;
      setVolume(musVolume);
      state = playing;
    }
  goto begin;
}

// Fade out
state fadeOut
{
 begin:
  sleep(fadeInterval);

  fadeLevel -= fadeInterval*fadeOutRate;

  if(fadeLevel <= 0.0)
    {
      fadeLevel = 0.0;
      stopSound();
      isPlaying = false;

      state = null;
    }

  setVolume(musVolume*fadeLevel);
  goto begin;
}

state playing
{
 begin:
  setVolume(musVolume);
  fadeLevel = 1.0;

  while(true)
    {
      // Wait for the song to play. Will return imediately if the song has
      // already stopped or if no song is playing
      waitUntilFinished();

      // Start playing the next song
      next();
    }
}