import os import time import sokol.audio struct Player { mut: samples []f32 pos int finished bool } fn main() { if os.args.len < 2 { eprintln('Usage: play_wav file1.wav file2.wav ...') play_sounds([os.resource_abs_path('uhoh.wav')]) ? exit(1) } play_sounds(os.args[1..]) ? } fn play_sounds(files []string) ? { mut player := Player{} player.init() for f in files { if !os.exists(f) || os.is_dir(f) { eprintln('skipping "$f" (does not exist)') continue } fext := os.file_ext(f).to_lower() if fext != '.wav' { eprintln('skipping "$f" (not a .wav file)') continue } player.play_wav_file(f) ? } player.stop() } // fn audio_player_callback(buffer &f32, num_frames int, num_channels int, mut p Player) { if p.finished { return } ntotal := num_channels * num_frames nremaining := p.samples.len - p.pos nsamples := if nremaining < ntotal { nremaining } else { ntotal } if nsamples <= 0 { p.finished = true return } unsafe { C.memcpy(buffer, &p.samples[p.pos], nsamples * int(sizeof(f32))) } p.pos += nsamples } fn (mut p Player) init() { audio.setup( num_channels: 2 stream_userdata_cb: audio_player_callback user_data: p ) } fn (mut p Player) stop() { audio.shutdown() p.free() } fn (mut p Player) play_wav_file(fpath string) ? { println('> play_wav_file: $fpath') samples := read_wav_file_samples(fpath) ? p.finished = true p.samples << samples p.finished = false for !p.finished { time.sleep_ms(16) } p.free() } fn (mut p Player) free() { p.finished = false p.samples = []f32{} p.pos = 0 } // The read_wav_file_samples function below is based on the following sources: // http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html // http://www.lightlink.com/tjweber/StripWav/WAVE.html // http://www.lightlink.com/tjweber/StripWav/Canon.html // https://tools.ietf.org/html/draft-ema-vpim-wav-00 // NB: > The chunks MAY appear in any order except that the Format chunk // > MUST be placed before the Sound data chunk (but not necessarily // > contiguous to the Sound data chunk). struct RIFFHeader { riff [4]byte file_size u32 form_type [4]byte } struct RIFFChunkHeader { chunk_type [4]byte chunk_size u32 chunk_data voidptr } struct RIFFFormat { format_tag u16 // PCM = 1; Values other than 1 indicate some form of compression. nchannels u16 // Nc ; 1 = mono ; 2 = stereo sample_rate u32 // F avg_bytes_per_second u32 // F * M*Nc nblock_align u16 // M*Nc bits_per_sample u16 // 8 * M cbsize u16 // Size of the extension: 22 valid_bits_per_sample u16 // at most 8*M channel_mask u32 // Speaker position mask sub_format [16]byte // GUID } fn read_wav_file_samples(fpath string) ?[]f32 { mut res := []f32{} // eprintln('> read_wav_file_samples: $fpath -------------------------------------------------') mut bytes := os.read_bytes(fpath) ? mut pbytes := byteptr(bytes.data) mut offset := u32(0) rh := &RIFFHeader(pbytes) // eprintln('rh: $rh') if rh.riff != [byte(`R`), `I`, `F`, `F`]! { return error('WAV should start with `RIFF`') } if rh.form_type != [byte(`W`), `A`, `V`, `E`]! { return error('WAV should have `WAVE` form type') } if rh.file_size + 8 != bytes.len { return error('WAV should have valid lenght') } offset += sizeof(RIFFHeader) mut rf := &RIFFFormat(0) for { if offset >= bytes.len { break } // ch := &RIFFChunkHeader(unsafe { pbytes + offset }) offset += 8 + ch.chunk_size // eprintln('ch: $ch') // eprintln('p: $pbytes | offset: $offset | bytes.len: $bytes.len') // //////// if ch.chunk_type == [byte(`L`), `I`, `S`, `T`]! { continue } // if ch.chunk_type == [byte(`i`), `d`, `3`, ` `]! { continue } // if ch.chunk_type == [byte(`f`), `m`, `t`, ` `]! { // eprintln('`fmt ` chunk') rf = unsafe { &RIFFFormat(&ch.chunk_data) } // eprintln('fmt riff format: $rf') if rf.format_tag != 1 { return error('only PCM encoded WAVs are supported') } if rf.nchannels < 1 || rf.nchannels > 2 { return error('only mono or stereo WAVs are supported') } if rf.bits_per_sample !in [u16(8), 16] { return error('only 8 or 16 bits per sample WAVs are supported') } continue } // if ch.chunk_type == [byte(`d`), `a`, `t`, `a`]! { if rf == 0 { return error('`data` chunk should be after `fmt ` chunk') } // eprintln('`fmt ` chunk: $rf\n`data` chunk: $ch') mut doffset := 0 mut dp := byteptr(&ch.chunk_data) for doffset < ch.chunk_size { for c := 0; c < rf.nchannels; c++ { mut x := f32(0.0) mut step := 0 ppos := unsafe { dp + doffset } if rf.bits_per_sample == 8 { d8 := byteptr(ppos) x = (f32(*d8) - 128) / 128.0 step = 1 doffset++ } if rf.bits_per_sample == 16 { d16 := &i16(ppos) x = f32(*d16) / 32768.0 step = 2 } doffset += step if doffset < ch.chunk_size { res << x if rf.nchannels == 1 { // Duplicating single channel mono sounds, // produces a stereo sound, simplifying further processing: res << x } } } } } } return res }