uxn

commit 6be1ab909d986fc695348856d40fd7e0657d7511
parent d0db60ae393489d58d9f98ea386fcb43832b5d07
Author: neauoire <aliceffekt@gmail.com>
Date:   Fri,  2 Apr 2021 11:52:29 -0700

Implemented ADSR envelopes.

Diffstat:
M
projects/examples/dev.time.usm
 | 
14
+++++---------
M
src/emulator.c
 | 
72
+++++++++++++++++++++++++++++++++++++++++++-----------------------------

2 files changed, 48 insertions(+), 38 deletions(-)
diff --git a/projects/examples/dev.time.usm b/projects/examples/dev.time.usm
@@ -11,14 +11,13 @@
 ;needles { hx 2 hy 2 mx 2 my 2 sx 2 sy 2 }
 ;line { x0 2 y0 2 x 2 y 2 sx 2 sy 2 dx 2 dy 2 e1 2 e2 2 }
 ;color { byte 1 }
-;ding { volume 1 }
 
 ( devices )
 
 |0100 ;Console { pad 8 char 1 byte 1 short 2 }
 |0110 ;Screen { width 2 height 2 pad 4 x 2 y 2 color 1 }
 |0120 ;Sprite { pad 8 x 2 y 2 addr 2 color 1 }
-|0170 ;Audio { ch1asdr 2 ch2asdr 2 ch3asdr 2 ch4asdr 2 ch1pitch 1 ch1vol 1 ch2pitch 1 ch2vol 1 ch3pitch 1 ch3vol 1 ch4pitch 1 ch4vol 1 }
+|0170 ;Audio { ch1adsr 2 ch2adsr 2 ch3adsr 2 ch4adsr 2 ch1pitch 1 ch1vol 1 ch2pitch 1 ch2vol 1 ch3pitch 1 ch3vol 1 ch4pitch 1 ch4vol 1 }
 |0190 ;Time { year 2 month 1 day 1 hour 1 minute 1 second 1 dow 1 doy 2 isdst 1 get 1 }
 |01F0 ;System { pad 8 r 2 g 2 b 2 }
 
@@ -38,20 +37,17 @@ BRK
 
 @FRAME
 	
-	~ding.volume
-	DUP #00 EQU ^$keep JNZ
-	DUP #04 SUB =ding.volume
-	$keep
-	=Audio.ch1vol
-
 	#00 =Time.get
 
 	( only draw once per second )
 	~Time.second ~current.second NEQ #01 JNZ BRK
 	~Time.second =current.second
 
+	~Time.second #03 AND ^$no-sound JNZ
+	#ffff =Audio.ch1adsr
 	~Time.second #1d ADD =Audio.ch1pitch
-	#fc =ding.volume
+	#ff =Audio.ch1vol
+	$no-sound
 
 	( clear )
 	#0080 SCALEX #0080 SCALEY ~needles.sx ~needles.sy #00 ,draw-line JSR2
diff --git a/src/emulator.c b/src/emulator.c
@@ -51,26 +51,25 @@ 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 {
 	Uint32 period, count;
-	int value;
-	Sint16 volume;
+	Sint32 age, a, d, s, r;
+	Sint16 volume, value;
 } channels[4];
 
 static SDL_Window *gWindow;
@@ -238,26 +237,36 @@ togglezoom(Uxn *u)
 }
 
 void
-audio_callback(void *userdata, Uint8 *stream, int len)
-{
-	Sint16 *samples = (Sint16 *)stream;
+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;
-	for(i = 0; i < 4; ++i) {
+	for (j = 0; j < len; ++j) samples[j] = 0;
+	for (i = 0; i < 4; ++i) {
 		struct audio_channel *c = &channels[i];
-		if(!c->volume) continue;
-		if(c->period < (1 << 20)) continue;
-		for(j = 0; j < len; ++j) {
+		if (!c->volume) continue;
+		if (c->period < (1 << 20)) continue;
+		for (j = 0; j < len; ++j) {
+			c->age += 1;
 			c->count += 1 << 20;
-			while(c->count > c->period) {
-				c->value = !c->value;
+			while (c->count > c->period) {
+				int mul = c->value < 0 ? c->volume : -c->volume;
 				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;
 			}
-			samples[j] += (c->value * 2 - 1) * c->volume;
+			samples[j] += c->value;
 		}
 	}
-	(void)userdata;
+	(void) userdata;
 }
 
 void
@@ -464,13 +473,18 @@ Uint8
 audio_poke(Uxn *u, Uint16 ptr, Uint8 b0, Uint8 b1)
 {
 	Uint8 *m = u->ram.dat;
-	if(b0 & 1) {
+	if (b0 & 1) {
 		Uint16 channel_addr = ptr + (b0 & 0x6);
 		struct audio_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->count %= c->period;
 		c->volume = m[channel_addr + 9] << 5;
+		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);
 		SDL_UnlockAudioDevice(audio_id);
 	}
 	return b1;