miscHEADmaster

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 12 insertions, 7 deletions

diff --git a/dogwhistle.c b/dogwhistle.c
index 2d48b82..894d7e3 100644
--- a/dogwhistle.c
+++ b/dogwhistle.c
@@ -7,9 +7,10 @@
 /* TODO add support for selecting output device and backend */
 /* TODO add support for selecting volume */
 /* TODO add support for pausing and exiting */
+/* TODO prefer loudspeakers over headphones */
+/* TODO use bus to listen for incoming phone calls and pause when arriving */
 
 #define UTYPE   uint32_t
-#define SMIN    INT32_MIN
 #define SMAX    INT32_MAX
 #define FORMAT  SND_PCM_FORMAT_U32
 
@@ -23,10 +24,10 @@ int
 main(int argc, char *argv[])
 {
 	UTYPE *buffer;
-	snd_pcm_uframes_t i, buflen = SAMPLE_RATE;
+	snd_pcm_uframes_t i, buflen, wavelen;
 	snd_pcm_sframes_t n;
 	snd_pcm_t *sound_handle = NULL;
-	unsigned long int freq = 16000;
+	double freq = 16000;
 	double volume = (double)0.1f, imul, omul;
 	int r;
 
@@ -46,19 +47,23 @@ main(int argc, char *argv[])
 		eprintf("snd_pcm_set_params: %s\n", snd_strerror(r));
 
 	/* Generate tone */
+	buflen = wavelen = (snd_pcm_uframes_t)((double)SAMPLE_RATE / freq);
+	if ((snd_pcm_uframes_t)freq > 1)
+		buflen *= (snd_pcm_uframes_t)freq;
 	buffer = emallocn((size_t)buflen, sizeof(*buffer), 0);
 	omul = volume * SMAX * 2;
-	imul = 2 * (double)freq / (double)SAMPLE_RATE;
 #ifdef __GNUC__
 # pragma GCC diagnostic push
 # pragma GCC diagnostic ignored "-Wunsuffixed-float-constants"
 #endif
-	imul *= M_PI;
+	imul = 2 * M_PI * freq / (double)SAMPLE_RATE;
 #ifdef __GNUC__
 # pragma GCC diagnostic pop
 #endif
-	for (i = 0; i < buflen; i++)
-		buffer[i] = (UTYPE)(sin(imul * (double)i) * omul - SMIN);
+	for (i = 0; i < wavelen; i++)
+		buffer[i] = (UTYPE)(sin(imul * (double)i) * omul + SMAX);
+	for (i = wavelen; i < buflen; i += wavelen)
+		memcpy(&buffer[i], &buffer[0], wavelen * sizeof(UTYPE));
 
 	/* Play tone */
 	for (;;) {