Add a source property to skip channel virtualization for multi-channel buffers

With virtualization disabled, channels are mapped directly from input to output
and any input channel that is missing an output is dropped. Any virtualization
effects (such as HRTF filters) for positional cues are also skipped.

The idea is to allow applications a way to play pre-filtered audio that channel
vitualization effects could interfere with.

1 files changed, 17 insertions, 0 deletions

diff --git a/OpenAL32/alSource.c b/OpenAL32/alSource.c
index e91206eb..a1319005 100644
--- a/OpenAL32/alSource.c
+++ b/OpenAL32/alSource.c
@@ -680,6 +680,16 @@ AL_API ALvoid AL_APIENTRY alSourcei(ALuint source,ALenum eParam,ALint lValue)
                     alSetError(pContext, AL_INVALID_VALUE);
                 break;
 
+            case AL_VIRTUAL_CHANNELS_SOFT:
+                if(lValue == AL_TRUE || lValue == AL_FALSE)
+                {
+                    Source->VirtualChannels = lValue;
+                    Source->NeedsUpdate = AL_TRUE;
+                }
+                else
+                    alSetError(pContext, AL_INVALID_VALUE);
+                break;
+
             case AL_DISTANCE_MODEL:
                 if(lValue == AL_NONE ||
                    lValue == AL_INVERSE_DISTANCE ||
@@ -801,6 +811,7 @@ AL_API void AL_APIENTRY alSourceiv(ALuint source, ALenum eParam, const ALint* pl
             case AL_AUXILIARY_SEND_FILTER_GAIN_AUTO:
             case AL_AUXILIARY_SEND_FILTER_GAINHF_AUTO:
             case AL_DISTANCE_MODEL:
+            case AL_VIRTUAL_CHANNELS_SOFT:
                 alSourcei(source, eParam, plValues[0]);
                 return;
 
@@ -1149,6 +1160,10 @@ AL_API ALvoid AL_APIENTRY alGetSourcei(ALuint source, ALenum eParam, ALint *plVa
                     *plValue = (ALint)Source->DopplerFactor;
                     break;
 
+                case AL_VIRTUAL_CHANNELS_SOFT:
+                    *plValue = Source->VirtualChannels;
+                    break;
+
                 case AL_DISTANCE_MODEL:
                     *plValue = Source->DistanceModel;
                     break;
@@ -1245,6 +1260,7 @@ AL_API void AL_APIENTRY alGetSourceiv(ALuint source, ALenum eParam, ALint* plVal
         case AL_AUXILIARY_SEND_FILTER_GAIN_AUTO:
         case AL_AUXILIARY_SEND_FILTER_GAINHF_AUTO:
         case AL_DISTANCE_MODEL:
+        case AL_VIRTUAL_CHANNELS_SOFT:
             alGetSourcei(source, eParam, plValues);
             return;
 
@@ -1807,6 +1823,7 @@ static ALvoid InitSourceParams(ALsource *Source)
     Source->AirAbsorptionFactor = 0.0f;
     Source->RoomRolloffFactor = 0.0f;
     Source->DopplerFactor = 1.0f;
+    Source->VirtualChannels = AL_TRUE;
 
     Source->DistanceModel = AL_INVERSE_DISTANCE_CLAMPED;