1 files changed, 75 insertions, 0 deletions
diff --git a/v_windows/v/examples/sokol/sounds/melody.v b/v_windows/v/examples/sokol/sounds/melody.v
new file mode 100644
index 0000000..aa5ebc4
--- /dev/null
+++ b/v_windows/v/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))
+	}
+}