From d0edf1adfe67bc11af7aee849004a1acafd0ed4a Mon Sep 17 00:00:00 2001
From: Thomas White <taw@bitwiz.org.uk>
Date: Mon, 20 Jul 2009 00:12:10 +0100
Subject: Some fixes

---
 configure.ac |  3 ++-
 src/audio.c  | 44 ++++++++++++++++++++++++++++++++------------
 src/audio.h  |  6 +++---
 3 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/configure.ac b/configure.ac
index a1898a1..027e451 100644
--- a/configure.ac
+++ b/configure.ac
@@ -41,12 +41,13 @@ else
 fi
 
 AC_MSG_CHECKING([for ALSA])
-if $PKG_CONFIG sdl ; then
+if $PKG_CONFIG alsa ; then
         ALSA_CFLAGS=`$PKG_CONFIG --cflags alsa`
         ALSA_LIBS=`$PKG_CONFIG --libs alsa`
         AC_MSG_RESULT([yes])
 else
         AC_MSG_RESULT([not found])
+        AC_MSG_ERROR([*** ALSA not found.  Do you have 'libasound-dev' or similar installed?])
 fi
 
 CFLAGS="$CFLAGS $GTK_CFLAGS $LIBSDL_CFLAGS $ALSA_CFLAGS"
diff --git a/src/audio.c b/src/audio.c
index 5120f5b..d425384 100644
--- a/src/audio.c
+++ b/src/audio.c
@@ -62,9 +62,14 @@ void audio_trigger_moo()
 		if ( a == NULL ) return;
 	}
 
+	/* Prevent another moo, until we're done */
+	a->mootex = 1;
+
 	printf("Moo!\n");
+
+	/* Switch from "setup" to "prepare" mode, reading for writing data */
 	snd_pcm_prepare(a->alsa_handle);
-	a->mootex = 1;
+	/* Start the moo */
 	a->moo_pos = 0;
 }
 
@@ -76,14 +81,22 @@ static void *audio_alsa_work(void *data)
 	while ( !a->finished ) {
 
 		int ret;
+		snd_pcm_uframes_t tp;
 
 		if ( a->moo_pos >= a->moo_len ) {
 			usleep(1000);
 			continue;
 		}
 
-		ret = snd_pcm_writei(a->alsa_handle, a->moo_buf+a->moo_pos,
-			             a->alsa_frames);
+		/* Play the full number of frames, or the number of frames
+		 * remaining to be played - whichever is the lowest */
+		if ( a->moo_len - a->moo_pos > a->alsa_frames ) {
+			tp = a->alsa_frames;
+		} else {
+			tp = a->moo_len - a->moo_pos;
+		}
+
+		ret = snd_pcm_writei(a->alsa_handle, a->moo_buf+a->moo_pos, tp);
 
 		if (ret == -EPIPE) {
 			fprintf(stderr, "ALSA buffer underrun\n");
@@ -91,20 +104,28 @@ static void *audio_alsa_work(void *data)
 		} else if (ret < 0) {
 			fprintf(stderr, "ALSA write error: %s\n",
 				        snd_strerror(ret));
-		} else if (ret != (int)a->alsa_frames) {
-			fprintf(stderr, "ALSA short write, %d frames\n",
-				        ret);
+		} else if (ret != (int)tp) {
+			fprintf(stderr, "ALSA short write, %d frames\n", ret);
 		} else {
 
 			/* Successful write */
 			a->moo_pos += ret;
 
-			if ( a->moo_pos > a->moo_len ) {
-				while ( snd_pcm_avail(a->alsa_handle) >= 0 ) {
-					usleep(1000);
-				}
+			if ( a->moo_pos == a->moo_len ) {
+
+				/* We have finished writing.  Now sleep
+				 * until the hardware has caught up. */
+				snd_pcm_hwsync(a->alsa_handle);
+				//while ( snd_pcm_avail(a->alsa_handle) >= 0 ) {
+				//	usleep(1000);
+				//}
+
+				/* Drop back to "setup" state */
+				snd_pcm_drop(a->alsa_handle);
+
+				/* Not it's safe to moo again */
 				a->mootex = 0;
-				printf("Done.\n");
+
 			}
 
 		}
@@ -153,7 +174,6 @@ static int audio_open_alsa(AudioContext *a)
 	/* Get the actual period size */
 	snd_pcm_hw_params_get_period_size(params, &frames, &dir);
 	a->alsa_frames = frames;
-	printf("%i frames per period\n", frames);
 
 	a->alsa_handle = handle;
 	a->finished = 0;
diff --git a/src/audio.h b/src/audio.h
index 88ea451..6d336d9 100644
--- a/src/audio.h
+++ b/src/audio.h
@@ -25,9 +25,9 @@
 #ifndef AUDIOH
 #define AUDIO_H
 
-#ifdef HAVE_CONFIG_H
-#include <config.h>
-#endif
+//#ifdef HAVE_CONFIG_H
+//#include <config.h>
+//#endif
 
 #include "types.h"
 
-- 
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