def allocated_channels(self):
"""
The number of channels currently allocated by SDL_mixer.
Seems to default to 8.
"""
return mix_call(Mix_AllocateChannels, -1)
def background_parse(self, data):
file = rw_from_object(io.BytesIO(data))
# ^^^^ is a pure-python emulation, does not need cleanup.
return mix_call(Mix_LoadWAV_RW,
file,
False,
_check_error=lambda rv: not rv)
def background_parse(self, data):
# Band-aid over some synchronization issues
# https://github.com/ppb/pursuedpybear/issues/619
while not any(query_spec()):
time.sleep(0)
file = rw_from_object(io.BytesIO(data))
# ^^^^ is a pure-python emulation, does not need cleanup.
return mix_call(Mix_LoadWAV_RW,
file,
False,
_check_error=lambda rv: not rv)
def __exit__(self, *exc):
# Unregister callback and release reference
mix_call(Mix_ChannelFinished, _filler_channel_finished)
self._finished_callback = None
# Cleanup SDL_mixer
mix_call(Mix_CloseAudio)
mix_call(Mix_Quit)
super().__exit__(*exc)
def query_spec():
"""
Helpful wrapper around Mix_QuerySpec()
"""
frequency = ctypes.c_int()
format = ctypes.c_uint16()
channels = ctypes.c_int()
count = mix_call(
Mix_QuerySpec,
ctypes.byref(frequency),
ctypes.byref(format),
ctypes.byref(channels),
_check_error=lambda rv: rv == 0 and Mix_GetError(),
)
return count, frequency, format, channels
def on_play_sound(self, event, signal):
sound = event.sound
chunk = event.sound.load()
try:
channel = mix_call(
Mix_PlayChannel,
-1, # Auto-pick channel
chunk,
0, # Do not repeat
_check_error=lambda rv: rv == -1)
except SdlMixerError as e:
if not str(e).endswith("No free channels available"):
raise
self.logger.warn(
"Attempted to play sound, but there were no available channels."
)
else:
self._currently_playing[
channel] = sound # Keep reference of playing asset
def __enter__(self):
super().__enter__()
mix_call(
Mix_OpenAudio,
44100, # Sample frequency, 44.1 kHz is CD quality
AUDIO_S16SYS, # Audio, 16-bit, system byte order. IDK is signed makes a difference
2, # Number of output channels, 2=stereo
4096, # Chunk size. TBH, this is a magic knob number.
# ^^^^ Smaller is more CPU, larger is less responsive.
# A lot of the performance-related recommendations are so dated I'm
# not sure how much difference it makes.
_check_error=lambda rv: rv == -1)
mix_call(Mix_Init,
MIX_INIT_FLAC | MIX_INIT_MOD | MIX_INIT_MP3 | MIX_INIT_OGG)
self.allocated_channels = 16
# Register callback, keeping reference for later cleanup
self._finished_callback = channel_finished(self._on_channel_finished)
mix_call(Mix_ChannelFinished, self._finished_callback)
def allocated_channels(self, value):
mix_call(Mix_AllocateChannels, value)
def volume(self, value):
mix_call(Mix_VolumeChunk, self.load(), int(value * MIX_MAX_VOLUME))
def volume(self):
"""
The volume setting of this chunk, from 0.0 to 1.0
"""
return mix_call(Mix_VolumeChunk, self.load(), -1) / MIX_MAX_VOLUME