Documentation
¶
Overview ¶
Package mixer provies access to the SDL2_mixer library.
Index ¶
- Constants
- func AllocateChannels(numchans int) int
- func CloseAudio()
- func ExpireChannel(channel, ticks int) int
- func FadeInChannel(channel int, chunk Chunk, loops, ms int) (int, error)
- func FadeInChannelTimed(channel int, chunk Chunk, loops, ms, ticks int) (int, error)
- func FadeOutChannel(which, ms int) int
- func FadeOutMusic(ms int) error
- func GetChunkDecoder(index int) string
- func GetMusicDecoder(index int) string
- func GetNumChunkDecoders() int
- func GetNumMusicDecoders() int
- func GetSoundFonts() string
- func HaltChannel(channel int)
- func HaltMusic()
- func Init(flags InitFlags) error
- func LinkedVersion() *sdl.Version
- func OpenAudio(frequency int, format AudioFormat, channels, chunksize int) error
- func Pause(channel int)
- func PauseMusic()
- func Paused(channel int) int
- func PausedMusic() bool
- func PlayChannel(channel int, chunk Chunk, loops int) (int, error)
- func PlayChannelTimed(channel int, chunk Chunk, loops, ticks int) (int, error)
- func Playing(channel int) int
- func PlayingMusic() bool
- func Quit()
- func ReserveChannels(num int) int
- func Resume(channel int)
- func ResumeMusic()
- func RewindMusic()
- func SetMusicCMD(command string) int
- func SetMusicPosition(position float64) int
- func SetSoundFonts(paths string) int
- func VERSION(v *sdl.Version)
- func Volume(channel, volume int) int
- func VolumeMusic(volume int) int
- type AudioFormat
- type Chunk
- type Fading
- type InitFlags
- type Music
- type MusicType
Constants ¶
const ( MAJOR_VERSION = C.SDL_MIXER_MAJOR_VERSION MINOR_VERSION = C.SDL_MIXER_MINOR_VERSION PATCHLEVEL = C.SDL_MIXER_PATCHLEVEL )
Variables ¶
This section is empty.
Functions ¶
func AllocateChannels ¶
AllocateChannels sets the number of channels being mixed. This can be called multiple times, even with sounds playing. If numchans is less than the current number of channels, then the higher channels will be stopped, freed, and therefore not mixed any longer. It returns the number of channels allocated.
Note: If numchans is zero, AllocateChannels will free all mixing channels, however music will still play.
func CloseAudio ¶
func CloseAudio()
CloseAudio shuts down and cleans up the mixer API. After calling this all audio is stopped, the device is closed, and the mixer functions should not be used. You may, of course use OpenAudio to start the functionality again.
Note: This function does not do anything until you have called it the same number of times that you called OpwnAudio. You may use QuerySpec to find out how many times CloseAudio needs to be called before the device is actually closed.
func ExpireChannel ¶
ExpireChannel halts playback on channel, or all channels if channel is -1, after ticks milliseconds.
ExpireChannel returns the number of channels set to expire. Whether or not they are active.
func FadeInChannel ¶
Same as PlayChannel, but the chunk fades in over ms milliseconds.
func FadeInChannelTimed ¶
Same as PlayChannelTimed, but the chunk fades in over ms milliseconds.
func FadeOutChannel ¶
FadeOutChannel gradually fades out playback on channel which, or all channels if which is -1, over ms milliseconds starting from now. The channel(s) will be halted after the fade out is completed. Only channels that are playing are set to fade out, including paused channels.
FadeOutChannel returns the number of channel set to fade out.
func FadeOutMusic ¶
FadeOutMusic gradually fades out music over ms milliseconds starting from now. The music will be halted after the fade is completed.
func GetChunkDecoder ¶
GetChunkDecoder gets the name of the chunk decoder at index. You must successfully call OpenAudio before calling the function.
func GetMusicDecoder ¶
GetMusicDecoder gets the name of the music decoder at index. You must successfully call OpenAudio before calling the function.
func GetNumChunkDecoders ¶
func GetNumChunkDecoders() int
GetNumChunkDecoders gets the number of chunk decoders mixer provides. You must successfully call OpenAudio before calling the function.
func GetNumMusicDecoders ¶
func GetNumMusicDecoders() int
GetNumMusicDecoders gets the number of music decoders mixer provides. You must successfully call OpenAudio before calling the function.
func GetSoundFonts ¶
func GetSoundFonts() string
func HaltChannel ¶
func HaltChannel(channel int)
HaltChannel halts the playback on channel, or all channels if channel is -1.
func HaltMusic ¶
func HaltMusic()
HaltMusic halts the playback of music. This interrupts music fader effects.
func Init ¶
Init loads dynamic libraries and prepares them for use. Flags should be one or more flags from InitFlags OR'd together. It returns an error if a library fails to load.
func LinkedVersion ¶
LinkedVersion gets the version of the dynamically linked SDL2_mixer library. It should not be used to fill a version structure, instead you should use VERSION.
func OpenAudio ¶
func OpenAudio(frequency int, format AudioFormat, channels, chunksize int) error
OpenAudio opens the mixer with a certain audio format. frequency is the output sampling frequency in samples per second (Hz). format is the output sample format. channels is the number of sound channels in output, it has nothing to do with mixing channels. chunksize is the size of each mixer sample. If it is too small the sound may skip on slow systems, if it is too large the sound effects will lag behind the action. OpenAudio also allocates 8 mixing channels.
SDL must be initialized with INIT_AUDIO before calling OpenAudio.
Common settings are:
frequency: 44100 or 22050 format: AUDIO_S16SYS channels: 2 (stereo) or 1 (mono) chunksize: 512, 1024, 2048, or 4096
func Pause ¶
func Pause(channel int)
Pause pause playback on channel, or all channels if channel is -1. You may still halt a paused channel.
Note: Only channels which are actively playing will be paused.
func PauseMusic ¶
func PauseMusic()
PauseMusic pauses the music playback. You may halt paused music.
Note: Music can only be paused if it is actively playing.
func Paused ¶
Paused tells you if channel is paused, or not. If channel is -1 it returns the number of paused channels, otherwise it returns 0 if channel is not paused or 1 if it is paused.
func PlayChannel ¶
PlayChannel plays an audio chunk on a specific channel. If the specified channel is -1, play on the first free channel. If loops is greater then zero, loop the sound that many times. If loops is -1, loop inifinitely. Returns which channel was used to play the sound.
func PlayChannelTimed ¶
PlayChannelTimed is the same as PlayChannel, but the sound is played at most ticks milliseconds.
func Playing ¶
Playing tells you if channel is playing, or not. It does not check if the channel has been paused.
Playing returns zero if the channel is not playing, or 1 if it is playing. If channel is -1, it returns the number of channels that are playing.
func PlayingMusic ¶
func PlayingMusic() bool
PlayingMusic tells you if music is actively playing, or not. It does not check if the channel has been paused.
func ReserveChannels ¶
ReserveChannels reserves the first channels (0 -> n-1) for the application, i.e. don't allocate them dynamically to the next sample if requested with a -1 value below. Returns the number of reserved channels.
func Resume ¶
func Resume(channel int)
Resume unpauses channel, or all playing and paused channels if channel is -1.
func ResumeMusic ¶
func ResumeMusic()
ResumeMusics unpauses the music. This is safe to use on halted, paused, and already playing music.
func RewindMusic ¶
func RewindMusic()
RewindMusic rewinds the music to the start. This is safe to use on halted, paused, and already playing music. It is not useful to rewind the music Immediately after starting playback, because it starts at the beginning by default.
RewindwMusic does not work for all music formats.
func SetMusicCMD ¶
SetMusicCMD sets the system command that is used to play music. The command should be a complete command, as if typed in to the command line, but it should expect the filename to be added as teh last argument. Set command to and empty string to turn off using an external command for music.
When SetMusicCMD is called any music playing is halted. The music file to play is set by calling LoadMUS(filename), and the filename is appended as the last argument on the commandline. The command will be sent signals SIGTERM to halt, SIGSTOP to pause, and SIGCONT to resume. The command program should react correctly to those signals for it to function properly with SDL2_Mixer. Volume should be set in the music player's command if the music player supports that.
Notes: Playing music through an external command may not work if the sound driver does not support multiple openings of the audio device. Also commands are not totally portable, so be careful.
func SetMusicPosition ¶
SetMusicPosition sets the postion of the currently playing music. The position takes different meaning for different music sources. It only works on the music types listed below.
Position meanings:
MOD: position is cast to a uint16 and used for a pattern number in the module. Passing zero is similar to rewinding the song. OGG, FLAC, MP3_MAD, and MODPLUG: Jumps to the position seconds from the beginning of the song. MP3: Jumps to the position seconds from the current position in the stream. So you may want to call RewindMusic before this. Does not go in Reverse.
func SetSoundFonts ¶
func Volume ¶
Volume sets the volume for any allocated channel. If channel is -1 then all channels are set at once. The volume is applied during the final mix, along with the sample volume. So setting this volume to 64 will halve the output of all samples played on the specified channel. All channels default to a volume of 128, which is the max. Newly allocated channels will have the max volume set, so setting all channels volumes does not affect subsequent channel allocations.
If volume is less then 0 then the volume will not be set.
Volume returns the current volume of the channel. If channel is -1, the average volume is returned.
func VolumeMusic ¶
VolumeMusic sets the volume for music. Setting the volume during a fade will not work, the faders use this function to perform their effect! Setting volume while using an external music player set by SetMusicCMD will have no effect.
If volume is less then 0 then the volume will not be set.
VolumeMusic returns the previous volume setting
Types ¶
type AudioFormat ¶
type AudioFormat uint16
const ( AUDIO_U8 AudioFormat = C.AUDIO_U8 // Unsigned 8-bit samples AUDIO_S8 AudioFormat = C.AUDIO_S8 // Signed 8-bit samples AUDIO_U16LSB AudioFormat = C.AUDIO_U16LSB // Unsigned 16-bit samples AUDIO_S16LSB AudioFormat = C.AUDIO_S16LSB // Signed 16-bit samples AUDIO_U16MSB AudioFormat = C.AUDIO_U16MSB // As above, but big-endian byte order AUDIO_S16MSB AudioFormat = C.AUDIO_S16MSB // As above, but big-endian byte order AUDIO_U16 AudioFormat = C.AUDIO_U16 AUDIO_S16 AudioFormat = C.AUDIO_S16 // Native audio byte ordering AUDIO_U16SYS AudioFormat = C.AUDIO_U16SYS AUDIO_S16SYS AudioFormat = C.AUDIO_S16SYS // Same as MIX_DEFAULT_FORMAT )
func QuerySpec ¶
func QuerySpec() (format AudioFormat, frequency, channels, opened int)
QuerySpec returns what the actual audio device parameters are. opened is the number of times the device was opened or 0 on error.
type Chunk ¶
type Chunk struct {
// contains filtered or unexported fields
}
The internal format for an audio chunk.
func LoadWAVFromReader ¶
LoadWAVFromReader loads an io.Reader into a Chunk.
type Fading ¶
type Fading int
const ( NO_FADING Fading = C.MIX_NO_FADING FADING_OUT Fading = C.MIX_FADING_OUT FADING_IN Fading = C.MIX_FADING_IN )
func FadingChannel ¶
FadingChannel tells you if which channel is fading in, out, or not at all. It does not tell you if the channel is playing anything, or paused.
Note which can not be -1.
func FadingMusic ¶
func FadingMusic() Fading
FadingMusic tells you if the music is fading in, out, or not at all. It does not tell you if the channel is playing anything, or paused.
type InitFlags ¶
type InitFlags int32
const ( INIT_FLAC InitFlags = C.MIX_INIT_FLAC INIT_MOD InitFlags = C.MIX_INIT_MOD INIT_MP3 InitFlags = C.MIX_INIT_MP3 INIT_OGG InitFlags = C.MIX_INIT_OGG INIT_FLUIDSYNTH InitFlags = C.MIX_INIT_FLUIDSYNTH )
type Music ¶
type Music struct {
// contains filtered or unexported fields
}
The internal format for a music chunk.
func LoadMUSFromReader ¶
LoadMUSFromReader loads an io.Reader into a Music.
func (Music) FadeInPos ¶
FadeInPos is the same as FadeIn, but the music will be started at position. position has different meanings for different types of music files, see SetMusicPosition for more information.
type MusicType ¶
type MusicType int32
const ( MUS_NONE MusicType = C.MUS_NONE MUS_CMD MusicType = C.MUS_CMD MUS_WAV MusicType = C.MUS_WAV MUS_MOD MusicType = C.MUS_MOD MUS_MID MusicType = C.MUS_MID MUS_OGG MusicType = C.MUS_OGG MUS_MP3 MusicType = C.MUS_MP3 MUS_MP3_MAD MusicType = C.MUS_MP3_MAD MUS_FLAC MusicType = C.MUS_FLAC MUS_MODPLUG MusicType = C.MUS_MODPLUG )
Source Files