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obscure fixes for large writeaheads

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This commit is contained in:
Glenn Maynard
2004-01-22 23:04:59 +00:00
parent e3c6b2cb34
commit 73e36c6234
1 changed files with 27 additions and 16 deletions
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stepmania/src/arch/Sound/DSoundHelpers.cpp
+27 -16
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@@ -143,7 +143,7 @@ DSoundBuf::DSoundBuf(DSound &ds, DSoundBuf::hw hardware,
/* The size of the actual DSound buffer. This can be large; we generally
* won't fill it completely. */
buffersize = 1024*64;
buffersize = min( buffersize, writeahead );
buffersize = max( buffersize, writeahead );
WAVEFORMATEX waveformat;
memset(&waveformat, 0, sizeof(waveformat));
@@ -302,6 +302,20 @@ bool DSoundBuf::get_output_buf(char **buffer, unsigned *bufsiz, int chunksize)
}
#endif
/* Update buffer_bytes_filled. */
{
int first_byte_filled = write_cursor-buffer_bytes_filled;
if( first_byte_filled < 0 )
first_byte_filled += buffersize; /* unwrap */
int current_cursor = cursorstart;
if( current_cursor < first_byte_filled )
current_cursor += buffersize;
/* The number of bytes that have been played since the last time we got here: */
int bytes_played = current_cursor - first_byte_filled;
buffer_bytes_filled -= bytes_played;
}
/* XXX We can figure out if we've underrun, and increase the write-ahead
* when it happens. Two problems:
@@ -320,25 +334,22 @@ bool DSoundBuf::get_output_buf(char **buffer, unsigned *bufsiz, int chunksize)
{
int first_byte_filled = write_cursor-buffer_bytes_filled;
if(first_byte_filled < 0) first_byte_filled += buffersize; /* unwrap */
int current_cursor = cursorstart;
if(current_cursor < first_byte_filled) current_cursor += buffersize;
/* The number of bytes that have been played since the last time we got here: */
int bytes_played = current_cursor - first_byte_filled;
buffer_bytes_filled -= bytes_played;
if( first_byte_filled < 0 )
first_byte_filled += buffersize; /* unwrap */
/* Data between the play cursor and the write cursor is committed to be
* played. If we don't actually have data there, we've underrun. */
if(!contained(first_byte_filled, write_cursor, cursorstart) ||
!contained(first_byte_filled, write_cursor, cursorend))
* played. If we don't actually have data there, we've underrun.
* (If buffer_bytes_filled == buffersize, then it's full, and can't be
* an underrun.) */
if( buffer_bytes_filled < writeahead &&
(!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,
missed_by);
LOG->Trace("underrun %p: %i..%i filled but cursor at %i..%i (missed it by %i) %i/%i",
this, first_byte_filled, write_cursor, cursorstart, cursorend,
missed_by, buffer_bytes_filled, buffersize);
// (cursorend - first_byte_filled + buffersize) % buffersize);
/* Pretend the space between the play and write cursor is filled
@@ -359,7 +370,7 @@ bool DSoundBuf::get_output_buf(char **buffer, unsigned *bufsiz, int chunksize)
if(buffer_bytes_filled > writeahead)
return false;
int num_bytes_empty = buffersize-buffer_bytes_filled;
int num_bytes_empty = writeahead-buffer_bytes_filled;
/* num_bytes_empty is the amount of free buffer space. If it's
* too small, come back later. */