Openal loopback patch.

openal_loopback.diff

diff --git a/Alc/ALc.c b/Alc/ALc.c
index baf7f01..586cfb7 100644
--- a/Alc/ALc.c
+++ b/Alc/ALc.c
@@ -2221,6 +2221,8 @@ static ALCvoid FreeDevice(ALCdevice *device)
     al_free(device->DryBuffer);
     device->DryBuffer = NULL;
 
+    DestroyRingBuffer(device->loopback_ring);
+
     al_free(device);
 }
 
@@ -2829,6 +2831,10 @@ static ALCsizei GetIntegerv(ALCdevice *device, ALCenum param, ALCsizei size, ALC
             values[0] = (device->Hrtf ? ALC_TRUE : ALC_FALSE);
             return 1;
 
+        case ALC_LOOPBACK_CAPTURE_SAMPLES:
+            values[0] = (RingBufferSize(device->loopback_ring) / 2);
+            return 1;
+
         default:
             alcSetError(device, ALC_INVALID_ENUM);
             return 0;
@@ -3300,6 +3306,8 @@ ALC_API ALCdevice* ALC_APIENTRY alcOpenDevice(const ALCchar *deviceName)
     device->NumUpdates = 4;
     device->UpdateSize = 1024;
 
+    device->loopback_ring = CreateRingBuffer(1, BUFFERSIZE * 4);
+
     if(!PlaybackBackend.getFactory)
         device->Backend = create_backend_wrapper(device, &PlaybackBackend.Funcs,
                                                  ALCbackend_Playback);
@@ -3687,6 +3695,18 @@ ALC_API void ALC_APIENTRY alcCaptureSamples(ALCdevice *device, ALCvoid *buffer,
     if(device) ALCdevice_DecRef(device);
 }
 
+ALC_API void ALC_APIENTRY alcCaptureSamplesLoopback(ALCdevice *device, ALCvoid *buffer, ALCsizei samples)
+{
+    if(!(device=VerifyDevice(device)) || device->Type != Playback)
+        alcSetError(device, ALC_INVALID_DEVICE);
+    else
+    {
+        if(samples >= 0 && RingBufferSize(device->loopback_ring) >= ((ALCuint)samples * 2)) {
+            ReadRingBuffer(device->loopback_ring, buffer, samples * 2);
+        }
+    }
+    if(device) ALCdevice_DecRef(device);
+}
 
 /************************************************
  * ALC loopback functions
diff --git a/Alc/ALu.c b/Alc/ALu.c
index 33a9c41..5a39af1 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -1357,6 +1357,9 @@ ALvoid aluMixData(ALCdevice *device, ALvoid *buffer, ALsizei size)
 #undef WRITE
         }
 
+        int16_t loopback_out_array[SamplesToDo];
+        Write_ALshort(OutBuffer, loopback_out_array, SamplesToDo, 1);
+        WriteRingBuffer(device->loopback_ring, loopback_out_array, sizeof(loopback_out_array));
         size -= SamplesToDo;
         IncrementRef(&device->MixCount);
     }
diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index 3a79a91..088aa32 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -620,6 +620,7 @@ typedef struct HrtfParams {
     ALint DelayStep[2];
 } HrtfParams;
 
+typedef struct RingBuffer RingBuffer;
 
 /* Size for temporary storage of buffer data, in ALfloats. Larger values need
  * more memory, while smaller values may need more iterations. The value needs
@@ -725,6 +726,8 @@ struct ALCdevice_struct
 
     ALCdevice *volatile next;
 
+    RingBuffer *loopback_ring;
+
     /* Memory space used by the default slot (Playback devices only) */
     alignas(16) ALCbyte _slot_mem[];
 };
@@ -833,7 +836,6 @@ void SetMixerFPUMode(FPUCtl *ctl);
 void RestoreFPUMode(const FPUCtl *ctl);
 
 
-typedef struct RingBuffer RingBuffer;
 RingBuffer *CreateRingBuffer(ALsizei frame_size, ALsizei length);
 void DestroyRingBuffer(RingBuffer *ring);
 ALsizei RingBufferSize(RingBuffer *ring);
diff --git a/include/AL/alext.h b/include/AL/alext.h
index cb498b4..a5ea8c2 100644
--- a/include/AL/alext.h
+++ b/include/AL/alext.h
@@ -409,6 +409,9 @@ ALC_API void ALC_APIENTRY alcDeviceResumeSOFT(ALCdevice *device);
 #define AL_FORMAT_BFORMAT3D_MULAW                0x10032
 #endif
 
+#define ALC_LOOPBACK_CAPTURE_SAMPLES 0x1004
+ALC_API void ALC_APIENTRY alcCaptureSamplesLoopback(ALCdevice *device, ALCvoid *buffer, ALCsizei samples);
+
 #ifdef __cplusplus
 }
 #endif