dsound: Don't use IAudioClock::GetPosition to determine buffer fullness.

dlls/dsound/dsound_private.h

@@ -83,7 +83,6 @@ struct DirectSoundDevice
     DWORD                       priolevel;
     PWAVEFORMATEX               pwfx;
     UINT                        timerID, playing_offs_bytes, in_mmdev_bytes, prebuf, helfrags;
-    UINT64                      last_pos_bytes;
     DWORD                       fraglen;
     LPBYTE                      buffer;
     DWORD                       writelead, buflen, state, playpos, mixpos;

dlls/dsound/mixer.c

@@ -667,8 +667,7 @@ static void DSOUND_WaveQueue(DirectSoundDevice *device, BOOL force)
  */
 static void DSOUND_PerformMix(DirectSoundDevice *device)
 {
-	UINT64 clock_pos, clock_freq, pos_bytes;
-	UINT delta_frags;
+	UINT32 pad, to_mix_frags, to_mix_bytes;
 	HRESULT hr;
 
 	TRACE("(%p)\n", device);
@@ -676,28 +675,28 @@ static void DSOUND_PerformMix(DirectSoundDevice *device)
 	/* **** */
 	EnterCriticalSection(&device->mixlock);
 
-	hr = IAudioClock_GetFrequency(device->clock, &clock_freq);
+	hr = IAudioClient_GetCurrentPadding(device->client, &pad);
 	if(FAILED(hr)){
-		WARN("GetFrequency failed: %08x\n", hr);
-        LeaveCriticalSection(&device->mixlock);
+		WARN("GetCurrentPadding failed: %08x\n", hr);
+		LeaveCriticalSection(&device->mixlock);
 		return;
 	}
 
-	hr = IAudioClock_GetPosition(device->clock, &clock_pos, NULL);
-	if(FAILED(hr)){
-		WARN("GetCurrentPadding failed: %08x\n", hr);
-        LeaveCriticalSection(&device->mixlock);
+	to_mix_frags = device->prebuf - (pad * device->pwfx->nBlockAlign + device->fraglen - 1) / device->fraglen;
+
+	if(to_mix_frags == 0){
+		/* nothing to do! */
+		LeaveCriticalSection(&device->mixlock);
 		return;
 	}
 
-	pos_bytes = (clock_pos * device->pwfx->nSamplesPerSec * device->pwfx->nBlockAlign) / clock_freq;
+	to_mix_bytes = to_mix_frags * device->fraglen;
 
-	delta_frags = (pos_bytes - device->last_pos_bytes) / device->fraglen;
-	if(delta_frags > 0){
-		device->playing_offs_bytes += delta_frags * device->fraglen;
+	if(device->in_mmdev_bytes > 0){
+		DWORD delta_bytes = min(to_mix_bytes, device->in_mmdev_bytes);
+		device->in_mmdev_bytes -= delta_bytes;
+		device->playing_offs_bytes += delta_bytes;
 		device->playing_offs_bytes %= device->buflen;
-		device->in_mmdev_bytes -= delta_frags * device->fraglen;
-		device->last_pos_bytes = pos_bytes - (pos_bytes % device->fraglen);
 	}
 
 	if (device->priolevel != DSSCL_WRITEPRIMARY) {

dlls/dsound/primary.c

@@ -196,7 +196,7 @@ static HRESULT DSOUND_PrimaryOpen(DirectSoundDevice *device)
 
 	FillMemory(device->buffer, device->buflen, (device->pwfx->wBitsPerSample == 8) ? 128 : 0);
 	FillMemory(device->mix_buffer, device->mix_buffer_len, 0);
-	device->last_pos_bytes = device->playing_offs_bytes = device->in_mmdev_bytes = device->playpos = device->mixpos = 0;
+	device->playing_offs_bytes = device->in_mmdev_bytes = device->playpos = device->mixpos = 0;
 	return DS_OK;
 }