Add an option for wide stereo sources

Replaces the old stereodup option

4 files changed, 29 insertions, 2 deletions

diff --git a/Alc/ALc.c b/Alc/ALc.c
index 54eb5ecf..7b757a87 100644
--- a/Alc/ALc.c
+++ b/Alc/ALc.c
@@ -1562,6 +1562,10 @@ static ALCenum UpdateDeviceParams(ALCdevice *device, const ALCint *attrList)
         TRACE("BS2B disabled\n");
     }
 
+    device->Flags &= ~DEVICE_WIDE_STEREO;
+    if(device->Type != Loopback && !device->Hrtf && GetConfigValueBool(NULL, "wide-stereo", AL_FALSE))
+        device->Flags |= DEVICE_WIDE_STEREO;
+
     oldMode = SetMixerFPUMode();
     LockDevice(device);
     context = device->ContextList;
diff --git a/Alc/ALu.c b/Alc/ALu.c
index 5ee170a0..c13a5262 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -68,6 +68,10 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
         { FrontLeft, -30.0f * F_PI/180.0f },
         { FrontRight, 30.0f * F_PI/180.0f }
     };
+    static const struct ChanMap StereoWideMap[2] = {
+        { FrontLeft, -90.0f * F_PI/180.0f },
+        { FrontRight, 90.0f * F_PI/180.0f }
+    };
     static const struct ChanMap RearMap[2] = {
         { BackLeft, -150.0f * F_PI/180.0f },
         { BackRight, 150.0f * F_PI/180.0f }
@@ -119,6 +123,7 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
     enum Resampler Resampler;
     ALint num_channels = 0;
     ALboolean DirectChannels;
+    ALfloat hwidth = 0.0f;
     ALfloat Pitch;
     ALfloat cw;
     ALint i, c;
@@ -200,7 +205,13 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
         break;
 
     case FmtStereo:
-        chans = StereoMap;
+        if(!(Device->Flags&DEVICE_WIDE_STEREO))
+            chans = StereoMap;
+        else
+        {
+            chans = StereoWideMap;
+            hwidth = 60.0f * F_PI/180.0f;
+        }
         num_channels = 2;
         break;
 
@@ -274,6 +285,7 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
     }
     else
     {
+        DryGain *= lerp(1.0f, 1.0f/sqrtf(Device->NumChan), hwidth/(F_PI*2.0f));
         for(c = 0;c < num_channels;c++)
         {
             /* Special-case LFE */
@@ -282,7 +294,7 @@ ALvoid CalcNonAttnSourceParams(ALsource *ALSource, const ALCcontext *ALContext)
                 SrcMatrix[c][chans[c].channel] = DryGain;
                 continue;
             }
-            ComputeAngleGains(Device, chans[c].angle, 0.0f, DryGain,
+            ComputeAngleGains(Device, chans[c].angle, hwidth, DryGain,
                               SrcMatrix[c]);
         }
     }
diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index f5d76b10..296461c0 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -612,6 +612,9 @@ struct ALCdevice_struct
 // Sample type was requested by the config file
 #define DEVICE_SAMPLE_TYPE_REQUEST               (1<<3)
 
+// Stereo sources cover 120-degree angles around +/-90
+#define DEVICE_WIDE_STEREO                       (1<<16)
+
 // Specifies if the device is currently running
 #define DEVICE_RUNNING                           (1<<31)
 
diff --git a/alsoftrc.sample b/alsoftrc.sample
index bbb9815e..58746c8f 100644
--- a/alsoftrc.sample
+++ b/alsoftrc.sample
@@ -55,6 +55,14 @@
 #  stereo modes.
 #cf_level = 0
 
+## wide-stereo:
+#  Specifies that stereo sources are given a width of about 120 degrees on each
+#  channel, centering on -90 (left) and +90 (right), as opposed to being points
+#  placed at -30 (left) and +30 (right). This can be useful for surround-sound
+#  to give stereo sources a more encompassing sound. Note that the sound's
+#  overall volume will be slightly reduced to account for the extra output.
+#wide-stereo = false
+
 ## frequency:
 #  Sets the output frequency.
 #frequency = 44100