Fix an issue with the DirectSound backend where there'd be some leftover...

Fix an issue with the DirectSound backend where there'd be some leftover samples that are not sent to the application when a capture device is stopped.

mini_al.h

@@ -198,6 +198,7 @@ struct mal_device
             /*HANDLE*/ mal_handle pNotifyEvents[MAL_MAX_FRAGMENTS_DSOUND];  // One event handle for each fragment.
             /*HANDLE*/ mal_handle hStopEvent;
             mal_uint32 ignoredFragmentCounter;  // <-- This is used for a cheap hack to skip over some initial notifications when the device is first played.
+            mal_uint32 lastProcessedFragment;
 		} dsound;
 	#endif
 		
@@ -1394,18 +1395,41 @@ static mal_result mal_device__main_loop__dsound(mal_device* pDevice)
 
         // Has the device been stopped? If so, need to get out of this loop.
         if (hEvent == pDevice->dsound.hStopEvent) {
+            // If it's a capture device there will be some leftover samples that need to be sent to the client. To
+            // calculate this we just look at the previously processed fragment and compare it to the current read
+            // position
+            if (pDevice->type == mal_device_type_capture) {
+                DWORD dwOffset = (((pDevice->dsound.lastProcessedFragment+1) * pDevice->fragmentSizeInFrames) % (pDevice->fragmentSizeInFrames*pDevice->fragmentCount)) * pDevice->channels * mal_get_sample_size_in_bytes(pDevice->format);
+                DWORD dwBytes = mal_device_get_fragment_size_in_bytes(pDevice);
+            
+                DWORD dwPlayPosition;
+                if (IDirectSoundCaptureBuffer8_GetCurrentPosition((LPDIRECTSOUNDCAPTUREBUFFER8)pDevice->dsound.pCaptureBuffer, &dwPlayPosition, NULL) == DS_OK) {
+                    DWORD sampleCount = (dwPlayPosition - dwOffset) / mal_get_sample_size_in_bytes(pDevice->format);
+                    if (sampleCount > 0) {
+                        void* pLockPtr;
+                        DWORD lockSize;
+                        if (IDirectSoundCaptureBuffer8_Lock((LPDIRECTSOUNDCAPTUREBUFFER8)pDevice->dsound.pCaptureBuffer, dwOffset, dwBytes, &pLockPtr, &lockSize, NULL, NULL, 0) == DS_OK) {
+                            mal_device__send_samples_to_client(pDevice, sampleCount, pLockPtr);
+                            IDirectSoundCaptureBuffer8_Unlock((LPDIRECTSOUNDCAPTUREBUFFER8)pDevice->dsound.pCaptureBuffer, pLockPtr, lockSize, NULL, 0);
+                        }
+                    }
+                }
+            }
+
             break;
         }
 
+        // If we get here it means the event that's been signaled represents a fragment.
+        unsigned int fragmentIndex = eventIndex;    // <-- Just for clarity.
+        mal_assert(fragmentIndex < pDevice->fragmentCount);
+
+        pDevice->dsound.lastProcessedFragment = fragmentIndex;
+
         // Some initial fragments need to be skipped over.
         if (pDevice->dsound.ignoredFragmentCounter > 0) {
             pDevice->dsound.ignoredFragmentCounter -= 1;
             continue;
         }
-
-        // If we get here it means the event that's been signaled represents a fragment.
-        unsigned int fragmentIndex = eventIndex;    // <-- Just for clarity.
-        mal_assert(fragmentIndex < pDevice->fragmentCount);
             
         if (pDevice->type == mal_device_type_playback) {
             mal_device__read_fragment_from_client__dsound(pDevice, (fragmentIndex + 1) % pDevice->fragmentCount);
@@ -2284,7 +2308,6 @@ mal_uint32 mal_get_sample_size_in_bytes(mal_format format)
 // - Make device initialization more robust for ALSA
 //   - Clamp period sizes to their min/max.
 // - Support rewinding. This will enable applications to employ better anti-latency.
-// - [DirectSound] When a device is stopped, none of the samples in the current fragment are sent to the client.
 // - Implement the null device.