realitix/vulk

'''Audio module

This module contains all audio related classes.
'''
import logging
import sdl2
from sdl2 import sdlmixer as mixer
from sdl2.ext.compat import byteify

from vulk.exception import SDL2Error, SoundError


logger = logging.getLogger()


class VulkAudio():
    '''This class is only used in baseapp.

    It initializes and close the audio system.
    '''
    def open(self, configuration):
        '''Open and configure audio system

        *Parameters:*

        - `configuration`: Configuration parameters from Application
        '''
        if sdl2.SDL_InitSubSystem(sdl2.SDL_INIT_AUDIO) != 0:
            msg = "Cannot initialize audio system: %s" % sdl2.SDL_GetError()
            logger.critical(msg)
            raise SDL2Error(msg)

        if mixer.Mix_OpenAudio(mixer.MIX_DEFAULT_FREQUENCY,
                               mixer.MIX_DEFAULT_FORMAT, 2, 1024):
            msg = "Cannot open mixed audio: %s" % mixer.Mix_GetError()
            logger.critical(msg)
            raise SDL2Error(msg)

        mixer.Mix_AllocateChannels(configuration.audio_channel)

        logger.info("Audio initialized")

    def close(self):
        '''Close the audio system'''
        mixer.Mix_CloseAudio()
        sdl2.SDL_Quit(sdl2.SDL_INIT_AUDIO)
        logger.info("Audio stopped")


class Sound():
    '''
    Sound effects are small audio samples, usually no longer than a few
    seconds, that are played back on specific game events such as a character
    jumping or shooting a gun.

    Sound effects can be stored in various formats. Vulk is based on SDL2 and
    thus supports WAVE, AIFF, RIFF, OGG, and VOC files.
    '''

    def __init__(self, path):
        '''Load the sound file

        *Parameters:*

        - `path`: Path to the sound file
        '''
        self.sample = mixer.Mix_LoadWAV(byteify(path, "utf-8"))

        if not self.sample:
            msg = "Cannot load file %s" % path
            logger.error(msg)
            raise SoundError(msg)

    def play(self, volume=1.0, repeat=1):
        '''
        Play the sound

        *Parameters:*

        - `volume`: Sound volume 0.0 to 1.0
        - `repeat`: Number of time to repeat the sound, 0=infinity

        *Returns:*

        Channel id of the sound
        '''
        channel = mixer.Mix_PlayChannel(-1, self.sample, repeat-1)
        if channel == -1:
            msg = "Cannot play the sound: %s" % mixer.Mix_GetError()
            logger.error(msg)
            raise SoundError(msg)

        mixer.Mix_Volume(channel, int(mixer.MIX_MAX_VOLUME * volume))
        return channel


class Music():
    '''
    For any sound that's longer than a few seconds it is preferable to stream
    it from disk instead of fully loading it into RAM. Vulk provides a Music
    class that lets you do that.

    Music can be stored in various formats. Vulk is based on SDL2 and
    thus supports WAVE, MOD, MIDI, OGG, MP3, FLAC files.

    **Note: You can play only one music at a time**
    '''

    def __init__(self, path):
        '''Load the music file

        *Parameters:*

        - `path`: Path to the music file
        '''
        self.music = mixer.Mix_LoadMUS(byteify(path, "utf-8"))

        if not self.music:
            msg = "Cannot load file %s" % path
            logger.error(msg)
            raise SoundError(msg)

    def play(self, volume=1.0, repeat=1):
        '''
        Play the music

        *Parameters:*

        - `volume`: Sound volume 0.0 to 1.0
        - `repeat`: Number of time to repeat the sound, 0=infinity

        *Returns:*

        Channel id of the sound
        '''
        if not repeat:
            repeat = -1

        result = mixer.Mix_PlayMusic(self.music, repeat)
        if result == -1:
            msg = "Cannot play the music: %s" % mixer.Mix_GetError()
            logger.error(msg)
            raise SoundError(msg)

        mixer.Mix_VolumeMusic(int(mixer.MIX_MAX_VOLUME * volume))