Remove the stereodup option

There's better ways to do it now with "wide" sound sources.

Alc/ALc.c

@@ -1562,23 +1562,6 @@ static ALCenum UpdateDeviceParams(ALCdevice *device, const ALCint *attrList)
         TRACE("BS2B disabled\n");
     }
 
-    device->Flags &= ~DEVICE_DUPLICATE_STEREO;
-    switch(device->FmtChans)
-    {
-        case DevFmtMono:
-        case DevFmtStereo:
-            break;
-        case DevFmtQuad:
-        case DevFmtX51:
-        case DevFmtX51Side:
-        case DevFmtX61:
-        case DevFmtX71:
-            if(GetConfigValueBool(NULL, "stereodup", AL_TRUE))
-                device->Flags |= DEVICE_DUPLICATE_STEREO;
-            break;
-    }
-    TRACE("Stereo duplication %s\n", (device->Flags&DEVICE_DUPLICATE_STEREO)?"enabled":"disabled");
-
     oldMode = SetMixerFPUMode();
     LockDevice(device);
     context = device->ContextList;

Alc/ALu.c

@@ -200,23 +200,8 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
         chans = MonoMap;
         num_channels = 1;
         break;
-    case FmtStereo:
-        if(!DirectChannels && (Device->Flags&DEVICE_DUPLICATE_STEREO))
-        {
-            DryGain *= aluSqrt(2.0f/4.0f);
-            for(c = 0;c < 2;c++)
-            {
-                pos = aluCart2LUTpos(aluSin(RearMap[c].angle),
-                                     aluCos(RearMap[c].angle));
-                ChannelGain = Device->PanningLUT[pos];
 
-                for(i = 0;i < (ALint)Device->NumChan;i++)
-                {
-                    enum Channel chan = Device->Speaker2Chan[i];
-                    SrcMatrix[c][chan] += DryGain * ChannelGain[chan];
-                }
-            }
-        }
+    case FmtStereo:
         chans = StereoMap;
         num_channels = 2;
         break;

OpenAL32/Include/alMain.h

@@ -609,8 +609,6 @@ struct ALCdevice_struct
 #define ALCdevice_CaptureSamples(a,b,c)  ((a)->Funcs->CaptureSamples((a), (b), (c)))
 #define ALCdevice_AvailableSamples(a)    ((a)->Funcs->AvailableSamples((a)))
 
-// Duplicate stereo sources on the side/rear channels
-#define DEVICE_DUPLICATE_STEREO                  (1<<0)
 // Frequency was requested by the app or config file
 #define DEVICE_FREQUENCY_REQUEST                 (1<<1)
 // Channel configuration was requested by the config file

alsoftrc.sample

@@ -93,16 +93,6 @@
 #  systems with apps that try to play more sounds than the CPU can handle.
 #sources = 256
 
-## stereodup:
-#  Sets whether to duplicate stereo sounds behind the listener. 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
-
 ## drivers:
 #  Sets the backend driver list order, comma-seperated. Unknown backends and
 #  duplicated names are ignored. Unlisted backends won't be considered for use