4 files changed, 326 insertions, 0 deletions
diff --git a/v_windows/v/old/examples/sokol/sounds/melody.v b/v_windows/v/old/examples/sokol/sounds/melody.v
new file mode 100644
index 0000000..aa5ebc4
--- /dev/null
+++ b/v_windows/v/old/examples/sokol/sounds/melody.v
@@ -0,0 +1,75 @@
+import gg
+import gx
+import sokol.audio
+
+const credits = 'Based on the ByteBeat formula from: https://www.youtube.com/watch?v=V4GfkFbDojc \n "Techno" by Gabriel Miceli'
+
+struct AppState {
+mut:
+	gframe  int         // the current graphical frame
+	frame_0 int         // offset of the current audio frames, relative to the start of the music
+	frames  [2048]f32   // a copy of the last rendered audio frames
+	gg      &gg.Context // used for drawing
+}
+
+fn my_audio_stream_callback(buffer &f32, num_frames int, num_channels int, mut acontext AppState) {
+	mut soundbuffer := unsafe { buffer }
+	for frame := 0; frame < num_frames; frame++ {
+		t := int(f32(acontext.frame_0 + frame) * 0.245)
+		// "Techno" by Gabriel Miceli
+		y := (t * (((t / 10 | 0) ^ ((t / 10 | 0) - 1280)) % 11) / 2 & 127) +
+			(t * (((t / 640 | 0) ^ ((t / 640 | 0) - 2)) % 13) / 2 & 127)
+		for ch := 0; ch < num_channels; ch++ {
+			idx := frame * num_channels + ch
+			unsafe {
+				a := f32(byte(y) - 127) / 255.0
+				soundbuffer[idx] = a
+				acontext.frames[idx & 2047] = a
+			}
+		}
+	}
+	acontext.frame_0 += num_frames
+}
+
+fn main() {
+	println(credits)
+	mut state := &AppState{
+		gg: 0
+	}
+	audio.setup(
+		stream_userdata_cb: my_audio_stream_callback
+		user_data: state
+	)
+	state.gg = gg.new_context(
+		bg_color: gx.rgb(50, 50, 50)
+		width: 1024
+		height: 400
+		create_window: true
+		window_title: 'ByteBeat Music'
+		frame_fn: graphics_frame
+		user_data: state
+	)
+	state.gg.run()
+	audio.shutdown()
+}
+
+fn graphics_frame(mut state AppState) {
+	state.gframe++
+	state.gg.begin()
+	state.draw()
+	state.gg.end()
+}
+
+[inline]
+fn (mut state AppState) bsample(idx int) byte {
+	return byte(127 + state.frames[(state.gframe + idx) & 2047] * 128)
+}
+
+fn (mut state AppState) draw() {
+	// first, reset and setup ortho projection
+	for x in 0 .. 1024 {
+		mut y := 100 * (state.frames[2 * x] + state.frames[2 * x + 1])
+		state.gg.draw_line(x, 200, x, 200 + y, gx.rgba(state.bsample(x), state.bsample(x + 300),
+			state.bsample(x + 700), 255))
+	}
+}
diff --git a/v_windows/v/old/examples/sokol/sounds/simple_sin_tones.v b/v_windows/v/old/examples/sokol/sounds/simple_sin_tones.v
new file mode 100644
index 0000000..c327117
--- /dev/null
+++ b/v_windows/v/old/examples/sokol/sounds/simple_sin_tones.v
@@ -0,0 +1,42 @@
+import time
+import math
+import sokol.audio
+
+const (
+	sw          = time.new_stopwatch()
+	sw_start_ms = sw.elapsed().milliseconds()
+)
+
+[inline]
+fn sintone(periods int, frame int, num_frames int) f32 {
+	return math.sinf(f32(periods) * (2 * math.pi) * f32(frame) / f32(num_frames))
+}
+
+fn my_audio_stream_callback(buffer &f32, num_frames int, num_channels int) {
+	ms := sw.elapsed().milliseconds() - sw_start_ms
+	unsafe {
+		mut soundbuffer := buffer
+		for frame := 0; frame < num_frames; frame++ {
+			for ch := 0; ch < num_channels; ch++ {
+				idx := frame * num_channels + ch
+				if ms < 250 {
+					soundbuffer[idx] = 0.5 * sintone(20, frame, num_frames)
+				} else if ms < 300 {
+					soundbuffer[idx] = 0.5 * sintone(25, frame, num_frames)
+				} else if ms < 1500 {
+					soundbuffer[idx] *= sintone(22, frame, num_frames)
+				} else {
+					soundbuffer[idx] = 0.5 * sintone(25, frame, num_frames)
+				}
+			}
+		}
+	}
+}
+
+fn main() {
+	audio.setup(
+		stream_cb: my_audio_stream_callback
+	)
+	time.sleep(2000 * time.millisecond)
+	audio.shutdown()
+}
diff --git a/v_windows/v/old/examples/sokol/sounds/uhoh.wav b/v_windows/v/old/examples/sokol/sounds/uhoh.wav
new file mode 100644
index 0000000..cff9e3c
--- /dev/null
+++ b/v_windows/v/old/examples/sokol/sounds/uhoh.wav
diff --git a/v_windows/v/old/examples/sokol/sounds/wav_player.v b/v_windows/v/old/examples/sokol/sounds/wav_player.v
new file mode 100644
index 0000000..3c9419b
--- /dev/null
+++ b/v_windows/v/old/examples/sokol/sounds/wav_player.v
@@ -0,0 +1,209 @@
+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(16 * time.millisecond)
+	}
+	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 := &byte(bytes.data)
+	mut offset := u32(0)
+	rh := unsafe { &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 := unsafe { &RIFFChunkHeader(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 := unsafe { &byte(&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 := unsafe { &byte(ppos) }
+						x = (f32(*d8) - 128) / 128.0
+						step = 1
+						doffset++
+					}
+					if rf.bits_per_sample == 16 {
+						d16 := unsafe { &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
+}