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sokol.audio #

fn buffer_frames #

fn buffer_frames() int

buffer_frames - return the actual backend buffer size in number of frames

fn channels #

fn channels() int

channels - return the actual number of channels

fn expect #

fn expect() int

expect - get current number of frames to fill packet queue; use in combination with audio.push

fn fclamp #

fn fclamp(x f32, flo f32, fhi f32) f32

fclamp - helper function to 'clamp' a number to a certain range

Example

realsample := audio.fclamp(sample, -1.0, 1.0)

fn is_valid #

fn is_valid() bool

is_valid - true after setup if audio backend was successfully initialized

fn max #

fn max(x int, y int) int

max - helper function to return the larger of two numbers

NOTE: math.max returns f32 values, this returns int values

Example

larger := audio.max(1, 5) // larger == 5

fn min #

fn min(x int, y int) int

min - helper function to return the smaller of two numbers

NOTE: math.min returns f32 values, this returns int values

Example

smaller := audio.min(1, 5) // smaller == 1

fn push #

fn push(frames &f32, num_frames int) int

push - push sample frames from main thread, returns number of frames actually pushed

fn query #

fn query() C.saudio_desc

query - return a copy of the original saudio_desc struct

fn sample_rate #

fn sample_rate() int

sample_rate - return the actual sample rate

fn setup #

fn setup(desc C.saudio_desc)

setup - setup sokol-audio

fn shutdown #

fn shutdown()

shutdown - shutdown sokol-audio

fn suspended #

fn suspended() bool

suspended returns true if audio context is currently suspended (only in WebAudio backend, all other backends return false)

fn user_data #

fn user_data() voidptr

userdata - return the saudio_desc.user_data pointer

type FNStreamingCB #

type FNStreamingCB = fn (buffer &f32, num_frames int, num_channels int)

callback function for stream_cb in [C.saudio_desc] when calling audio.setup()

sokol callback functions run in a separate thread

This function will be called with a reference to the C buffer and the maximum number of frames and channels the audio backend is expecting in its buffer.

Terms:

  • sample - a 32-bit floating point number from -1.0 to +1.0 representing the waveform amplitude at that instant
  • frame - one sample for each channel at that instant

To determine the number of samples expected, do num_frames * num_channels.
Then, write up to that many f32 samples into buffer using unsafe operations.

Do not write more data to the buffer than it is requesting, but you may write less. The buffer is initialized with zeroes, so unwritten data will result in audio silence.

Examples

unsafe { C.memcpy(buffer, &samples, samples.len * int(sizeof(f32))) }
unsafe { mut b := buffer; for i, sample in samples { b[i] = sample } }

fn (FNStreamingCB) str #

fn (x FNStreamingCB) str() string

type FnStreamingCBWithUserData #

type FnStreamingCBWithUserData = fn (buffer &f32, num_frames int, num_channels int, user_data voidptr)

callback function for stream_userdata_cb to use in C.saudio_desc when calling audio.setup()

sokol callback functions run in a separate thread

This function operates the same way as [FNStreamingCB] but it passes customizable user_data to the callback. This is the method to use if your audio data is stored in a struct or array. Identify the user_data when you call audio.setup() and that object will be passed to the callback as the last arg.

Examples

mut soundbuffer := []f32
soundbuffer << previously_parsed_wavfile_bytes
audio.setup(stream_userdata_cb: mycallback, user_data: soundbuffer)
fn mycallback(buffer &f32, num_frames int, num_channels int, mut sb []f32) { ... }

fn (FnStreamingCBWithUserData) str #

fn (x FnStreamingCBWithUserData) str() string

struct C.saudio_desc #

struct C.saudio_desc {
	sample_rate        int
	num_channels       int
	buffer_frames      int
	packet_frames      int
	num_packets        int
	stream_cb          FNStreamingCB
	stream_userdata_cb FnStreamingCBWithUserData
	user_data          voidptr
}

only one of stream_cb or stream_userdata_cb should be used

default values (internal to sokol C library):

variable default note
sample_rate 44100 higher sample rates take more memory but are higher quality
num_channels 1 for stereo sound, this should be 2
buffer_frames 2048 buffer size in frames, larger is more latency, smaller means higher CPU
packet_frames 128 push model only, number of frames that will be pushed in each packet
num_packets 64 for push model only, number of packets in the backend ringbuffer