uxn

commit 8855b960571591ef0ba8899b376207937b55aa5b
parent 4622a8a061265fa767351ab65462cc6bda9c4f68
Author: Andrew Alderwick <andrew@alderwick.co.uk>
Date:   Sat, 17 Jul 2021 10:13:21 +0100

Started pausing the audio device when it's not in use

Diffstat:
M
src/devices/apu.c
 | 
7
++++---
M
src/devices/apu.h
 | 
2
+-
M
src/uxnemu.c
 | 
8
+++++---

3 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/src/devices/apu.c b/src/devices/apu.c
@@ -37,11 +37,11 @@ envelope(Apu *c, Uint32 age)
 	return 0x0000;
 }
 
-void
+int
 apu_render(Apu *c, Sint16 *sample, Sint16 *end)
 {
 	Sint32 s;
-	if(!c->advance || !c->period) return;
+	if(!c->advance || !c->period) return 0;
 	while(sample < end) {
 		c->count += c->advance;
 		c->i += c->count / c->period;
@@ -49,7 +49,7 @@ apu_render(Apu *c, Sint16 *sample, Sint16 *end)
 		if(c->i >= c->len) {
 			if(!c->repeat) {
 				c->advance = 0;
-				return;
+				return 1;
 			}
 			c->i %= c->len;
 		}
@@ -57,6 +57,7 @@ apu_render(Apu *c, Sint16 *sample, Sint16 *end)
 		*sample++ += s * c->volume[0] / 0x180;
 		*sample++ += s * c->volume[1] / 0x180;
 	}
+	return 1;
 }
 
 void
diff --git a/src/devices/apu.h b/src/devices/apu.h
@@ -24,6 +24,6 @@ typedef struct {
 	Uint8 pitch, repeat;
 } Apu;
 
-void apu_render(Apu *c, Sint16 *sample, Sint16 *end);
+int apu_render(Apu *c, Sint16 *sample, Sint16 *end);
 void apu_start(Apu *c, Uint16 adsr, Uint8 pitch);
 Uint8 apu_get_vu(Apu *c);
diff --git a/src/uxnemu.c b/src/uxnemu.c
@@ -51,11 +51,13 @@ error(char *msg, const char *err)
 static void
 audio_callback(void *u, Uint8 *stream, int len)
 {
-	int i;
+	int i, running = 0;
 	Sint16 *samples = (Sint16 *)stream;
 	SDL_memset(stream, 0, len);
 	for(i = 0; i < POLYPHONY; ++i)
-		apu_render(&apu[i], samples, samples + len / 2);
+		running += apu_render(&apu[i], samples, samples + len / 2);
+	if(!running)
+		SDL_PauseAudioDevice(audio_id, 1);
 	(void)u;
 }
 
@@ -162,7 +164,6 @@ init(void)
 	audio_id = SDL_OpenAudioDevice(NULL, 0, &as, NULL, 0);
 	if(!audio_id)
 		return error("Audio", SDL_GetError());
-	SDL_PauseAudioDevice(audio_id, 0);
 	return 1;
 }
 
@@ -300,6 +301,7 @@ audio_talk(Device *d, Uint8 b0, Uint8 w)
 		c->repeat = !(d->dat[0xf] & 0x80);
 		apu_start(c, mempeek16(d->dat, 0x8), d->dat[0xf] & 0x7f);
 		SDL_UnlockAudioDevice(audio_id);
+		SDL_PauseAudioDevice(audio_id, 0);
 	}
 }