@@ -43,11 +43,9 @@ BRK

 	~Time.second ~current.second NEQ #01 JNZ BRK

 	~Time.second =current.second

-	~Time.second #03 AND ^$no-sound JNZ

-	#ffff =Audio.ch1adsr

+	#1444 =Audio.ch1adsr

 	~Time.second #1d ADD =Audio.ch1pitch

-	#ff =Audio.ch1vol

-	$no-sound

+	~Time.second #03 AND #4b MUL #0f ADD =Audio.ch1vol

 	( clear )

 	#0080 SCALEX #0080 SCALEY ~needles.sx ~needles.sy #00 ,draw-line JSR2

@@ -51,26 +51,29 @@ Uint8 font[][8] = {

 #define SAMPLE_FREQUENCY 48000

-static Uint32 note_periods[12] = { /* middle C (C4) is note 60 */

-	(Uint32) 0xfa7e * SAMPLE_FREQUENCY, /* C-1 */

-	(Uint32) 0xec6f * SAMPLE_FREQUENCY,

-	(Uint32) 0xdf2a * SAMPLE_FREQUENCY, /* D-1 */

-	(Uint32) 0xd2a4 * SAMPLE_FREQUENCY,

-	(Uint32) 0xc6d1 * SAMPLE_FREQUENCY, /* E-1 */

-	(Uint32) 0xbba8 * SAMPLE_FREQUENCY, /* F-1 */

-	(Uint32) 0xb120 * SAMPLE_FREQUENCY,

-	(Uint32) 0xa72f * SAMPLE_FREQUENCY, /* G-1 */

-	(Uint32) 0x9dcd * SAMPLE_FREQUENCY,

-	(Uint32) 0x94f2 * SAMPLE_FREQUENCY, /* A-1 */

-	(Uint32) 0x8c95 * SAMPLE_FREQUENCY,

-	(Uint32) 0x84b2 * SAMPLE_FREQUENCY  /* B-1 */

+static Uint32 note_periods[12] = {

+	/* middle C (C4) is note 60 */

+	(Uint32)0xfa7e * SAMPLE_FREQUENCY, /* C-1 */

+	(Uint32)0xec6f * SAMPLE_FREQUENCY,

+	(Uint32)0xdf2a * SAMPLE_FREQUENCY, /* D-1 */

+	(Uint32)0xd2a4 * SAMPLE_FREQUENCY,

+	(Uint32)0xc6d1 * SAMPLE_FREQUENCY, /* E-1 */

+	(Uint32)0xbba8 * SAMPLE_FREQUENCY, /* F-1 */

+	(Uint32)0xb120 * SAMPLE_FREQUENCY,

+	(Uint32)0xa72f * SAMPLE_FREQUENCY, /* G-1 */

+	(Uint32)0x9dcd * SAMPLE_FREQUENCY,

+	(Uint32)0x94f2 * SAMPLE_FREQUENCY, /* A-1 */

+	(Uint32)0x8c95 * SAMPLE_FREQUENCY,

+	(Uint32)0x84b2 * SAMPLE_FREQUENCY  /* B-1 */

 };

-static struct audio_channel {

+typedef struct audio_channel {

 	Uint32 period, count;

 	Sint32 age, a, d, s, r;

-	Sint16 volume, value;

-} channels[4];

+	Sint16 value[2];

+	Sint8 volume[2], phase;

+} Channel;

+Channel channels[4];

 static SDL_Window *gWindow;

 static SDL_Renderer *gRenderer;

@@ -236,39 +239,58 @@ togglezoom(Uxn *u)

 	redraw(pixels, u);

 }

+Sint16

+audio_envelope(Channel *c) {

+	if (c->age < c->a)

+		return 0x0888 * c->age / c->a;

+	else if (c->age < c->d)

+		return 0x0444 * (2 * c->d - c->a - c->age) / (c->d - c->a);

+	else if (c->age < c->s)

+		return 0x0444;

+	else if (c->age < c->r)

+		return 0x0444 * (c->r - c->age) / (c->r - c->s);

+	else

+		return 0x0000;

+}

+

 void

 audio_callback(void* userdata, Uint8* stream, int len) {

 	Sint16 *samples = (Sint16 *) stream;

 	int i, j;

-	len >>= 1; /* use len for number of samples, not bytes */

-	for (j = 0; j < len; ++j) samples[j] = 0;

+	len >>= 2; /* use len for number of samples, not bytes */

+	for (j = len * 2 - 1; j >= 0; --j) samples[j] = 0;

 	for (i = 0; i < 4; ++i) {

-		struct audio_channel *c = &channels[i];

-		if (!c->volume) continue;

+		Channel *c = &channels[i];

 		if (c->period < (1 << 20)) continue;

 		for (j = 0; j < len; ++j) {

 			c->age += 1;

 			c->count += 1 << 20;

 			while (c->count > c->period) {

-				int mul = c->value < 0 ? c->volume : -c->volume;

+				Sint16 mul;

 				c->count -= c->period;

-				if (c->age < c->a)

-					c->value = mul * c->age / c->a;

-				else if (c->age < c->d)

-					c->value = mul * (2 * c->d - c->a - c->age) / 2 / (c->d - c->a);

-				else if (c->age < c->s)

-					c->value = mul / 2;

-				else if (c->age < c->r)

-					c->value = mul * (c->r - c->age) / 2 / (c->r - c->s);

-				else

-					c->volume = c->value = 0;

+				c->phase = !c->phase;

+				mul = (c->phase * 2 - 1) * audio_envelope(c);

+				c->value[0] = mul * c->volume[0];

+				c->value[1] = mul * c->volume[1];

 			}

-			samples[j] += c->value;

+			samples[j * 2] += c->value[0];

+			samples[j * 2 + 1] += c->value[1];

 		}

 	}

 	(void) userdata;

 }

+void

+silence(void) {

+	int i;

+	for (i = 0; i < 4; ++i) {

+		Channel *c = &channels[i];

+		c->volume[0] = 0;

+		c->volume[1] = 0;

+		c->period = 0;

+	}

+}

+

 void

 quit(void)

 {

@@ -301,11 +323,12 @@ init(void)

 	if(!(pixels = (Uint32 *)malloc(WIDTH * HEIGHT * sizeof(Uint32))))

 		return error("Pixels", "Failed to allocate memory");

 	clear(pixels);

+	silence();

 	SDL_StartTextInput();

 	SDL_ShowCursor(SDL_DISABLE);

 	as.freq = SAMPLE_FREQUENCY;

 	as.format = AUDIO_S16;

-	as.channels = 1;

+	as.channels = 2;

 	as.callback = audio_callback;

 	as.samples = 2048;

 	audio_id = SDL_OpenAudioDevice(NULL, 0, &as, NULL, 0);

@@ -474,17 +497,18 @@ audio_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)

 {

 	Uint8 *m = u->ram.dat;

 	if (b0 & 1) {

-		Uint16 channel_addr = ptr + (b0 & 0x6);

-		struct audio_channel *c = &channels[(b0 & 0x6) >> 1];

+		Uint16 addr = ptr + (b0 & 0x6);

+		Channel *c = &channels[(b0 & 0x6) >> 1];

 		SDL_LockAudioDevice(audio_id);

-		c->period = note_periods[m[channel_addr + 8] % 12] >> (m[channel_addr + 8] / 12);

+		c->period = note_periods[m[addr + 8] % 12] >> (m[addr + 8] / 12);

 		c->count %= c->period;

-		c->volume = m[channel_addr + 9] << 5;

+		c->volume[0] = (m[addr + 9] >> 4) & 0xf;

+		c->volume[1] = m[addr + 9] & 0xf;

 		c->age = 0;

-		c->a = ((m[channel_addr] >> 4) & 0xf) * (SAMPLE_FREQUENCY >> 4);

-		c->d = c->a + (m[channel_addr] & 0xf) * (SAMPLE_FREQUENCY >> 4);

-		c->s = c->d + ((m[channel_addr + 1] >> 4) & 0xf) * (SAMPLE_FREQUENCY >> 4);

-		c->r = c->s + (m[channel_addr + 1] & 0xf) * (SAMPLE_FREQUENCY >> 4);

+		c->a = (SAMPLE_FREQUENCY >> 4) * ((m[addr] >> 4) & 0xf);

+		c->d = c->a + (SAMPLE_FREQUENCY >> 4) * (m[addr] & 0xf);

+		c->s = c->d + (SAMPLE_FREQUENCY >> 4) * ((m[addr + 1] >> 4) & 0xf);

+		c->r = c->s + (SAMPLE_FREQUENCY >> 4) * (m[addr + 1] & 0xf);

 		SDL_UnlockAudioDevice(audio_id);

 	}

 	return b1;