simplify DSoundBuf interface

stepmania/src/arch/Sound/DSoundHelpers.cpp

@@ -257,7 +257,7 @@ DSoundBuf::~DSoundBuf()
 	buf->Release();
 }
 
-bool DSoundBuf::get_output_buf(char **buffer, unsigned *bufsiz, int *play_pos, int chunksize)
+bool DSoundBuf::get_output_buf(char **buffer, unsigned *bufsiz, int chunksize)
 {
 	ASSERT(!buffer_locked);
 
@@ -311,9 +311,11 @@ bool DSoundBuf::get_output_buf(char **buffer, unsigned *bufsiz, int *play_pos, i
 		if(!contained(first_byte_filled, write_cursor, cursorstart) ||
 		   !contained(first_byte_filled, write_cursor, cursorend))
 		{
+			int missed_by = cursorend - write_cursor;
+			wrap( missed_by, buffersize );
 			LOG->Trace("underrun: %i..%i filled but cursor at %i..%i (missed it by %i)",
 				first_byte_filled, write_cursor, cursorstart, cursorend,
-				(cursorend - write_cursor + buffersize) % buffersize);
+				missed_by);
 //				(cursorend - first_byte_filled + buffersize) % buffersize);
 
 			/* Pretend the space between the play and write cursor is filled
@@ -370,9 +372,6 @@ bool DSoundBuf::get_output_buf(char **buffer, unsigned *bufsiz, int *play_pos, i
 
 	buffer_bytes_filled += num_bytes_empty;
 
-	if( play_pos )
-		*play_pos = last_cursor_pos;
-	
 	/* Increment last_cursor_pos to point at where the data we're about to
 	 * ask for will actually be played. */
 	last_cursor_pos += num_bytes_empty / samplesize();

stepmania/src/arch/Sound/DSoundHelpers.h

@@ -49,7 +49,7 @@ public:
 	DSoundBuf(DSound &ds, hw hardware, 
 		int channels, int samplerate, int samplebits, int writeahead);
 
-	bool get_output_buf(char **buffer, unsigned *bufsiz, int *play_pos, int chunksize);
+	bool get_output_buf(char **buffer, unsigned *bufsiz, int chunksize);
 	void release_output_buf(char *buffer, unsigned bufsiz);
 
 	void Reset();
@@ -60,7 +60,7 @@ public:
 
 	~DSoundBuf();
 	int GetPosition() const;
-	int GetMaxPosition() const { return last_cursor_pos; }
+	int GetOutputPosition() const { return last_cursor_pos; }
 };
 
 #endif

stepmania/src/arch/Sound/RageSoundDriver_DSound.cpp

@@ -105,16 +105,16 @@ bool RageSound_DSound::stream::GetData(bool init)
 
 	char *locked_buf;
 	unsigned len;
-	int play_pos;
+	const int play_pos = str_ds->GetOutputPosition();
 
 	if(init) {
 		/* We're initializing; fill the entire buffer. The buffer is supposed to
 		 * be empty, so this should never fail. */
-		if(!str_ds->get_output_buf(&locked_buf, &len, &play_pos, buffersize))
+		if(!str_ds->get_output_buf(&locked_buf, &len, buffersize))
 			ASSERT(0);
 	} else {
 		/* Just fill one chunk. */
-		if(!str_ds->get_output_buf(&locked_buf, &len, &play_pos, chunksize))
+		if(!str_ds->get_output_buf(&locked_buf, &len, chunksize))
 			return false;
 	}
 
@@ -133,7 +133,7 @@ bool RageSound_DSound::stream::GetData(bool init)
 			state = STOPPING;
 
 			/* Flush two buffers worth of data. */
-			flush_pos = str_ds->GetMaxPosition();
+			flush_pos = str_ds->GetOutputPosition();
 		}
 	} else {
 		/* Silence the buffer. */
@@ -280,7 +280,7 @@ void RageSound_DSound::StopMixing(RageSound *snd)
 	stream_pool[i]->state = stream_pool[i]->STOPPING;
 
 	/* Flush two buffers worth of data. */
-	stream_pool[i]->flush_pos = stream_pool[i]->str_ds->GetMaxPosition();
+	stream_pool[i]->flush_pos = stream_pool[i]->str_ds->GetOutputPosition();
 
 	/* This function is called externally (by RageSound) to stop immediately.
 	 * We need to prevent SoundStopped from being called; it should only be

stepmania/src/arch/Sound/RageSoundDriver_DSound_Software.cpp

@@ -63,9 +63,9 @@ bool RageSound_DSound_Software::GetData()
 
 	char *locked_buf;
 	unsigned len;
-	int play_pos;
+	const int play_pos = str_ds->GetOutputPosition();
 
-	if(!str_ds->get_output_buf(&locked_buf, &len, &play_pos, chunksize))
+	if(!str_ds->get_output_buf(&locked_buf, &len, chunksize))
 		return false;
 
 	/* Silence the buffer. */
@@ -96,7 +96,7 @@ bool RageSound_DSound_Software::GetData()
 		{
 			/* This sound is finishing. */
 			sounds[i]->stopping = true;
-			sounds[i]->flush_pos = str_ds->GetMaxPosition();
+			sounds[i]->flush_pos = str_ds->GetOutputPosition();
 		}
 	}