Command-line option for audio debugging

Make clipping sound a little less horrendous (still pretty bad)
Count number of clipped samples


git-svn-id: svn://cook.msm.cam.ac.uk:745/thrust3d/thrust3d@114 84d2e878-0bd5-11dd-ad15-13eda11d74c5

1 files changed, 16 insertions, 4 deletions

diff --git a/src/audio.c b/src/audio.c
index 8e84c5e..6735665 100644
--- a/src/audio.c
+++ b/src/audio.c
@@ -21,7 +21,7 @@
 static void audio_mix(void *data, Uint8 *stream8, int len) {
 
 	AudioContext *a = data;
-	int i, j;
+	int i, j, clip_count;
 	Sint16 *stream = (Sint16 *)stream8;
 	
 	len /= 2;	/* Samples */
@@ -32,6 +32,7 @@ static void audio_mix(void *data, Uint8 *stream8, int len) {
 	}
 	
 	/* For each currently playing sound... */
+	clip_count = 0;
 	for ( i=0; i<AUDIO_MAX_SOUNDS; i++ ) {
 		
 		/* Playing? */
@@ -40,9 +41,18 @@ static void audio_mix(void *data, Uint8 *stream8, int len) {
 		for ( j=0; j<len; j++ ) {
 		
 			Sint16 samp;
+			Sint32 test;
 			
 			samp = a->sounds[i].data[a->sounds[i].dpos++];
-			stream[j] += samp * a->sounds[i].volume;
+			test = stream[j] + samp*a->sounds[i].volume;
+			if ( test > 32767 ) {
+				if ( stream[j] != 32767 ) {
+					clip_count++;
+				}
+				stream[j] = 32767;
+			} else {
+				stream[j] += samp * a->sounds[i].volume;
+			}
 			
 			if ( a->sounds[i].dpos == a->sounds[i].dlen ) {
 				if ( a->sounds[i].repeat ) {
@@ -60,6 +70,8 @@ static void audio_mix(void *data, Uint8 *stream8, int len) {
 		
 	}
 	
+	if ( a->debug && (clip_count > 0) ) printf("AU: Clipped %i samples.\n", clip_count);
+	
 }
 
 void audio_play(AudioContext *a, char *file, float volume, int repeat) {
@@ -108,7 +120,7 @@ void audio_play(AudioContext *a, char *file, float volume, int repeat) {
 }
 
 /* SDL audio initial setup */
-AudioContext *audio_setup() {
+AudioContext *audio_setup(int debug) {
 	
 	AudioContext *a;
 	SDL_AudioSpec fmt;
@@ -119,7 +131,7 @@ AudioContext *audio_setup() {
 	if ( a == NULL ) return NULL;
 	
 	/* Initialise audio context */
-	a->debug = 0;
+	a->debug = debug;
 	for ( i=0; i<AUDIO_MAX_SOUNDS; i++ ) {
 		a->sounds[i].inuse = 0;
 	}