Re-enable duplication for stereo sounds

2 files changed, 26 insertions, 8 deletions

diff --git a/Alc/ALu.c b/Alc/ALu.c
index f5e585ed..7d1805fc 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -213,6 +213,25 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
                 }
             }
         }
+        else if((ALContext->Device->Flags&DEVICE_DUPLICATE_STEREO))
+        {
+            static const ALfloat angles_StereoDup[4] = { -30.0f, -150.0f,
+                                                          30.0f,  150.0f };
+            DryGain *= aluSqrt(2.0f/4.0f);
+            for(c = 0;c < 4;c++)
+            {
+                pos = aluCart2LUTpos(cos(angles_StereoDup[c] * (M_PI/180.0)),
+                                     sin(angles_StereoDup[c] * (M_PI/180.0)));
+                SpeakerGain = &Device->PanningLUT[MAXCHANNELS * pos];
+
+                for(i = 0;i < (ALint)Device->NumChan;i++)
+                {
+                    Channel chan = Device->Speaker2Chan[i];
+                    SrcMatrix[c>>1][chan] += DryGain * ListenerGain *
+                                             SpeakerGain[chan];
+                }
+            }
+        }
         else
         {
             for(c = 0;c < 2;c++)
diff --git a/alsoftrc.sample b/alsoftrc.sample
index 87ac2198..c1ec67f7 100644
--- a/alsoftrc.sample
+++ b/alsoftrc.sample
@@ -93,14 +93,13 @@
 #sources = 256
 
 ## stereodup:
-#  Sets whether to duplicate stereo sounds on the rear and side speakers for 4+
-#  channel output. This provides a "fuller" playback quality for 4+ channel
-#  output modes, although each individual speaker will have a slight reduction
-#  in volume to compensate for the extra output speakers. True, yes, on, and
-#  non-0 values will duplicate stereo sources. 0 and anything else will cause
-#  stereo sounds to only play out the front speakers. This only has an effect
-#  when a suitable output format is used (ie. those that contain side and/or
-#  rear speakers).
+#  Sets whether to duplicate stereo sounds behind the listener for 4+ channel
+#  output. This provides a "fuller" playback quality for surround sound output
+#  modes, although each individual speaker will have a slight reduction in
+#  volume to compensate for the extra output speakers. True, yes, on, and non-0
+#  values will duplicate stereo sources. 0 and anything else will cause stereo
+#  sounds to only play in front. This only has an effect when a suitable output
+#  format is used (ie. those that contain side and/or rear speakers).
 #stereodup = true
 
 ## scalemix: