mixer.c

winNT技术操作系统,国外开放的原代码和LIUX一样

	if (len % dsb->dsound->device->pwfx->nBlockAlign) {
		INT nBlockAlign = dsb->dsound->device->pwfx->nBlockAlign;
		ERR("length not a multiple of block size, len = %d, block size = %d\n", len, nBlockAlign);
		len = (len / nBlockAlign) * nBlockAlign;	/* data alignment */
	}

	if ((buf = ibuf = DSOUND_tmpbuffer(dsb->dsound->device, len)) == NULL)
		return 0;

	TRACE("MixInBuffer (%p) len = %d, dest = %ld\n", dsb, len, writepos);

	ilen = DSOUND_MixerNorm(dsb, ibuf, len);
	if ((dsb->dsbd.dwFlags & DSBCAPS_CTRLPAN) ||
	    (dsb->dsbd.dwFlags & DSBCAPS_CTRLVOLUME) ||
	    (dsb->dsbd.dwFlags & DSBCAPS_CTRL3D))
		DSOUND_MixerVol(dsb, ibuf, len);

	if (dsb->dsound->device->pwfx->wBitsPerSample == 8) {
		BYTE	*obuf = dsb->dsound->device->buffer + writepos;

		if ((writepos + len) <= dsb->dsound->device->buflen)
			todo = len;
		else
			todo = dsb->dsound->device->buflen - writepos;

		for (i = 0; i < todo; i++) {
			/* 8-bit WAV is unsigned */
			field = (*ibuf++ - 128);
			field += (*obuf - 128);
			if (field > 127) field = 127;
			else if (field < -128) field = -128;
			*obuf++ = field + 128;
		}
 
		if (todo < len) {
			todo = len - todo;
			obuf = dsb->dsound->device->buffer;

			for (i = 0; i < todo; i++) {
				/* 8-bit WAV is unsigned */
				field = (*ibuf++ - 128);
				field += (*obuf - 128);
				if (field > 127) field = 127;
				else if (field < -128) field = -128;
				*obuf++ = field + 128;
			}
		}
        } else {
		INT16	*ibufs, *obufs;

		ibufs = (INT16 *) ibuf;
		obufs = (INT16 *)(dsb->dsound->device->buffer + writepos);

		if ((writepos + len) <= dsb->dsound->device->buflen)
			todo = len / 2;
		else
			todo = (dsb->dsound->device->buflen - writepos) / 2;

		for (i = 0; i < todo; i++) {
			/* 16-bit WAV is signed */
			field = *ibufs++;
			field += *obufs;
			if (field > 32767) field = 32767;
			else if (field < -32768) field = -32768;
			*obufs++ = field;
		}

		if (todo < (len / 2)) {
			todo = (len / 2) - todo;
			obufs = (INT16 *)dsb->dsound->device->buffer;

			for (i = 0; i < todo; i++) {
				/* 16-bit WAV is signed */
				field = *ibufs++;
				field += *obufs;
				if (field > 32767) field = 32767;
				else if (field < -32768) field = -32768;
				*obufs++ = field;
			}
		}
        }

	if (dsb->leadin && (dsb->startpos > dsb->buf_mixpos) && (dsb->startpos <= dsb->buf_mixpos + ilen)) {
		/* HACK... leadin should be reset when the PLAY position reaches the startpos,
		 * not the MIX position... but if the sound buffer is bigger than our prebuffering
		 * (which must be the case for the streaming buffers that need this hack anyway)
		 * plus DS_HEL_MARGIN or equivalent, then this ought to work anyway. */
		dsb->leadin = FALSE;
	}

	dsb->buf_mixpos += ilen;

	if (dsb->buf_mixpos >= dsb->buflen) {
		if (dsb->playflags & DSBPLAY_LOOPING) {
			/* wrap */
			dsb->buf_mixpos %= dsb->buflen;
			if (dsb->leadin && (dsb->startpos <= dsb->buf_mixpos))
				dsb->leadin = FALSE; /* HACK: see above */
		} else if (dsb->buf_mixpos > dsb->buflen) {
			ERR("Mixpos (%lu) past buflen (%lu), capping...\n", dsb->buf_mixpos, dsb->buflen);
			dsb->buf_mixpos = dsb->buflen;
		}
	}

	return len;
}

static void DSOUND_PhaseCancel(IDirectSoundBufferImpl *dsb, DWORD writepos, DWORD len)
{
	INT     ilen, field;
	UINT    i, todo;
	BYTE	*buf, *ibuf;

	TRACE("(%p,%ld,%ld)\n",dsb,writepos,len);

	if (len % dsb->dsound->device->pwfx->nBlockAlign) {
		INT nBlockAlign = dsb->dsound->device->pwfx->nBlockAlign;
		ERR("length not a multiple of block size, len = %ld, block size = %d\n", len, nBlockAlign);
		len = (len / nBlockAlign) * nBlockAlign;	/* data alignment */
	}

	if ((buf = ibuf = DSOUND_tmpbuffer(dsb->dsound->device, len)) == NULL)
		return;

	TRACE("PhaseCancel (%p) len = %ld, dest = %ld\n", dsb, len, writepos);

	ilen = DSOUND_MixerNorm(dsb, ibuf, len);
	if ((dsb->dsbd.dwFlags & DSBCAPS_CTRLPAN) ||
	    (dsb->dsbd.dwFlags & DSBCAPS_CTRLVOLUME) ||
	    (dsb->dsbd.dwFlags & DSBCAPS_CTRL3D))
		DSOUND_MixerVol(dsb, ibuf, len);

	/* subtract instead of add, to phase out premixed data */
	if (dsb->dsound->device->pwfx->wBitsPerSample == 8) {
		BYTE	*obuf = dsb->dsound->device->buffer + writepos;

		if ((writepos + len) <= dsb->dsound->device->buflen)
			todo = len;
		else
			todo = dsb->dsound->device->buflen - writepos;

		for (i = 0; i < todo; i++) {
			/* 8-bit WAV is unsigned */
			field = (*ibuf++ - 128);
			field -= (*obuf - 128);
			if (field > 127) field = 127;
			else if (field < -128) field = -128;
			*obuf++ = field + 128;
		}
 
		if (todo < len) {
			todo = len - todo;
			obuf = dsb->dsound->device->buffer;

			for (i = 0; i < todo; i++) {
				/* 8-bit WAV is unsigned */
				field = (*ibuf++ - 128);
				field -= (*obuf - 128);
				if (field > 127) field = 127;
				else if (field < -128) field = -128;
				*obuf++ = field + 128;
			}
		}
        } else {
		INT16	*ibufs, *obufs;

		ibufs = (INT16 *) ibuf;
		obufs = (INT16 *)(dsb->dsound->device->buffer + writepos);

		if ((writepos + len) <= dsb->dsound->device->buflen)
			todo = len / 2;
		else
			todo = (dsb->dsound->device->buflen - writepos) / 2;

		for (i = 0; i < todo; i++) {
			/* 16-bit WAV is signed */
			field = *ibufs++;
			field -= *obufs;
			if (field > 32767) field = 32767;
			else if (field < -32768) field = -32768;
			*obufs++ = field;
		}

		if (todo < (len / 2)) {
			todo = (len / 2) - todo;
			obufs = (INT16 *)dsb->dsound->device->buffer;

			for (i = 0; i < todo; i++) {
				/* 16-bit WAV is signed */
				field = *ibufs++;
				field -= *obufs;
				if (field > 32767) field = 32767;
				else if (field < -32768) field = -32768;
				*obufs++ = field;
			}
		}
        }
}

static void DSOUND_MixCancel(IDirectSoundBufferImpl *dsb, DWORD writepos, BOOL cancel)
{
	DWORD   size, flen, len, npos, nlen;
	INT	iAdvance = dsb->pwfx->nBlockAlign;
	INT	oAdvance = dsb->dsound->device->pwfx->nBlockAlign;
	/* determine amount of premixed data to cancel */
	DWORD primary_done =
		((dsb->primary_mixpos < writepos) ? dsb->dsound->device->buflen : 0) +
		dsb->primary_mixpos - writepos;

	TRACE("(%p, %ld), buf_mixpos=%ld\n", dsb, writepos, dsb->buf_mixpos);

	/* backtrack the mix position */
	size = primary_done / oAdvance;
	flen = size * dsb->freqAdjust;
	len = (flen >> DSOUND_FREQSHIFT) * iAdvance;
	flen &= (1<<DSOUND_FREQSHIFT)-1;
	while (dsb->freqAcc < flen) {
		len += iAdvance;
		dsb->freqAcc += 1<<DSOUND_FREQSHIFT;
	}
	len %= dsb->buflen;
	npos = ((dsb->buf_mixpos < len) ? dsb->buflen : 0) +
		dsb->buf_mixpos - len;
	if (dsb->leadin && (dsb->startpos > npos) && (dsb->startpos <= npos + len)) {
		/* stop backtracking at startpos */
		npos = dsb->startpos;
		len = ((dsb->buf_mixpos < npos) ? dsb->buflen : 0) +
			dsb->buf_mixpos - npos;
		flen = dsb->freqAcc;
		nlen = len / dsb->pwfx->nBlockAlign;
		nlen = ((nlen << DSOUND_FREQSHIFT) + flen) / dsb->freqAdjust;
		nlen *= dsb->dsound->device->pwfx->nBlockAlign;
		writepos =
			((dsb->primary_mixpos < nlen) ? dsb->dsound->device->buflen : 0) +
			dsb->primary_mixpos - nlen;
	}

	dsb->freqAcc -= flen;
	dsb->buf_mixpos = npos;
	dsb->primary_mixpos = writepos;

	TRACE("new buf_mixpos=%ld, primary_mixpos=%ld (len=%ld)\n",
	      dsb->buf_mixpos, dsb->primary_mixpos, len);

	if (cancel) DSOUND_PhaseCancel(dsb, writepos, len);
}

void DSOUND_MixCancelAt(IDirectSoundBufferImpl *dsb, DWORD buf_writepos)
{
#if 0
	DWORD   i, size, flen, len, npos, nlen;
	INT	iAdvance = dsb->pwfx->nBlockAlign;
	INT	oAdvance = dsb->dsound->device->pwfx->nBlockAlign;
	/* determine amount of premixed data to cancel */
	DWORD buf_done =
		((dsb->buf_mixpos < buf_writepos) ? dsb->buflen : 0) +
		dsb->buf_mixpos - buf_writepos;
#endif

	WARN("(%p, %ld), buf_mixpos=%ld\n", dsb, buf_writepos, dsb->buf_mixpos);
	/* since this is not implemented yet, just cancel *ALL* prebuffering for now
	 * (which is faster anyway when there's only a single secondary buffer) */
	dsb->dsound->device->need_remix = TRUE;
}

void DSOUND_ForceRemix(IDirectSoundBufferImpl *dsb)
{
	TRACE("(%p)\n",dsb);
	EnterCriticalSection(&dsb->lock);
	if (dsb->state == STATE_PLAYING)
		dsb->dsound->device->need_remix = TRUE;
	LeaveCriticalSection(&dsb->lock);
}

static DWORD DSOUND_MixOne(IDirectSoundBufferImpl *dsb, DWORD playpos, DWORD writepos, DWORD mixlen)
{
	DWORD len, slen;
	/* determine this buffer's write position */
	DWORD buf_writepos = DSOUND_CalcPlayPosition(dsb, writepos, writepos);
	/* determine how much already-mixed data exists */
	DWORD buf_done =
		((dsb->buf_mixpos < buf_writepos) ? dsb->buflen : 0) +
		dsb->buf_mixpos - buf_writepos;
	DWORD primary_done =
		((dsb->primary_mixpos < writepos) ? dsb->dsound->device->buflen : 0) +
		dsb->primary_mixpos - writepos;
	DWORD adv_done =
		((dsb->dsound->device->mixpos < writepos) ? dsb->dsound->device->buflen : 0) +
		dsb->dsound->device->mixpos - writepos;
	DWORD played =
		((buf_writepos < dsb->playpos) ? dsb->buflen : 0) +
		buf_writepos - dsb->playpos;
	DWORD buf_left = dsb->buflen - buf_writepos;
	int still_behind;

	TRACE("(%p,%ld,%ld,%ld)\n",dsb,playpos,writepos,mixlen);
	TRACE("buf_writepos=%ld, primary_writepos=%ld\n", buf_writepos, writepos);
	TRACE("buf_done=%ld, primary_done=%ld\n", buf_done, primary_done);
	TRACE("buf_mixpos=%ld, primary_mixpos=%ld, mixlen=%ld\n", dsb->buf_mixpos, dsb->primary_mixpos,
	      mixlen);
	TRACE("looping=%ld, startpos=%ld, leadin=%ld\n", dsb->playflags, dsb->startpos, dsb->leadin);

	/* check for notification positions */
	if (dsb->dsbd.dwFlags & DSBCAPS_CTRLPOSITIONNOTIFY &&
	    dsb->state != STATE_STARTING) {
		DSOUND_CheckEvent(dsb, played);
	}

	/* save write position for non-GETCURRENTPOSITION2... */
	dsb->playpos = buf_writepos;

	/* check whether CalcPlayPosition detected a mixing underrun */
	if ((buf_done == 0) && (dsb->primary_mixpos != writepos)) {
		/* it did, but did we have more to play? */
		if ((dsb->playflags & DSBPLAY_LOOPING) ||
		    (dsb->buf_mixpos < dsb->buflen)) {
			/* yes, have to recover */
			ERR("underrun on sound buffer %p\n", dsb);
			TRACE("recovering from underrun: primary_mixpos=%ld\n", writepos);
		}
		dsb->primary_mixpos = writepos;
		primary_done = 0;
	}
	/* determine how far ahead we should mix */
	if (((dsb->playflags & DSBPLAY_LOOPING) ||
	     (dsb->leadin && (dsb->probably_valid_to != 0))) &&
	    !(dsb->dsbd.dwFlags & DSBCAPS_STATIC)) {
		/* if this is a streaming buffer, it typically means that
		 * we should defer mixing past probably_valid_to as long
		 * as we can, to avoid unnecessary remixing */
		/* the heavy-looking calculations shouldn't be that bad,
		 * as any game isn't likely to be have more than 1 or 2
		 * streaming buffers in use at any time anyway... */
		DWORD probably_valid_left =
			(dsb->probably_valid_to == (DWORD)-1) ? dsb->buflen :
			((dsb->probably_valid_to < buf_writepos) ? dsb->buflen : 0) +
			dsb->probably_valid_to - buf_writepos;
		/* check for leadin condition */
		if ((probably_valid_left == 0) &&
		    (dsb->probably_valid_to == dsb->startpos) &&
		    dsb->leadin)
			probably_valid_left = dsb->buflen;
		TRACE("streaming buffer probably_valid_to=%ld, probably_valid_left=%ld\n",
		      dsb->probably_valid_to, probably_valid_left);
		/* check whether the app's time is already up */
		if (probably_valid_left < dsb->writelead) {
			WARN("probably_valid_to now within writelead, possible streaming underrun\n");
			/* once we pass the point of no return,
			 * no reason to hold back anymore */
			dsb->probably_valid_to = (DWORD)-1;
			/* we just have to go ahead and mix what we have,
			 * there's no telling what the app is thinking anyway */
		} else {
			/* adjust for our frequency and our sample size */
			probably_valid_left = MulDiv(probably_valid_left,
						     1 << DSOUND_FREQSHIFT,
						     dsb->pwfx->nBlockAlign * dsb->freqAdjust) *
				              dsb->dsound->device->pwfx->nBlockAlign;
			/* check whether to clip mix_len */
			if (probably_valid_left < mixlen) {
				TRACE("clipping to probably_valid_left=%ld\n", probably_valid_left);
				mixlen = probably_valid_left;
			}
		}
	}
	/* cut mixlen with what's already been mixed */
	if (mixlen < primary_done) {
		/* huh? and still CalcPlayPosition didn't
		 * detect an underrun? */
		FIXME("problem with underrun detection (mixlen=%ld < primary_done=%ld)\n", mixlen, primary_done);
		return 0;
	}
	len = mixlen - primary_done;
	TRACE("remaining mixlen=%ld\n", len);

	if (len < dsb->dsound->device->fraglen) {
		/* smaller than a fragment, wait until it gets larger
		 * before we take the mixing overhead */
		TRACE("mixlen not worth it, deferring mixing\n");
		still_behind = 1;
		goto post_mix;
	}

	/* ok, we know how much to mix, let's go */
	still_behind = (adv_done > primary_done);
	while (len) {
		slen = dsb->dsound->device->buflen - dsb->primary_mixpos;
		if (slen > len) slen = len;
		slen = DSOUND_MixInBuffer(dsb, dsb->primary_mixpos, slen);

		if ((dsb->primary_mixpos < dsb->dsound->device->mixpos) &&
		    (dsb->primary_mixpos + slen >= dsb->dsound->device->mixpos))