Add an option to specify the ambisonic output configuration

Alc/ALc.c

@@ -3427,6 +3427,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcOpenDevice(const ALCchar *deviceName)
     device->FmtType = DevFmtTypeDefault;
     device->Frequency = DEFAULT_OUTPUT_RATE;
     device->IsHeadphones = AL_FALSE;
+    device->AmbiFmt = AmbiFormat_Default;
     device->NumUpdates = 4;
     device->UpdateSize = 1024;
 
@@ -3544,6 +3545,18 @@ ALC_API ALCdevice* ALC_APIENTRY alcOpenDevice(const ALCchar *deviceName)
     }
     almtx_init(&device->BackendLock, almtx_plain);
 
+    if(ConfigValueStr(al_string_get_cstr(device->DeviceName), NULL, "ambi-format", &fmt))
+    {
+        if(strcasecmp(fmt, "fuma") == 0)
+            device->AmbiFmt = AmbiFormat_FuMa;
+        else if(strcasecmp(fmt, "acn+sn3d") == 0)
+            device->AmbiFmt = AmbiFormat_ACN_SN3D;
+        else if(strcasecmp(fmt, "acn+n3d") == 0)
+            device->AmbiFmt = AmbiFormat_ACN_N3D;
+        else
+            ERR("Unsupported ambi-format: %s\n", fmt);
+    }
+
     if(DefaultEffect.type != AL_EFFECT_NULL)
     {
         device->DefaultSlot = (ALeffectslot*)device->_slot_mem;
@@ -3706,6 +3719,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcCaptureOpenDevice(const ALCchar *deviceName,
         return NULL;
     }
     device->IsHeadphones = AL_FALSE;
+    device->AmbiFmt = AmbiFormat_Default;
 
     device->UpdateSize = samples;
     device->NumUpdates = 1;
@@ -3903,6 +3917,7 @@ ALC_API ALCdevice* ALC_APIENTRY alcLoopbackOpenDeviceSOFT(const ALCchar *deviceN
     device->FmtChans = DevFmtChannelsDefault;
     device->FmtType = DevFmtTypeDefault;
     device->IsHeadphones = AL_FALSE;
+    device->AmbiFmt = AmbiFormat_Default;
 
     ConfigValueUInt(NULL, NULL, "sources", &device->SourcesMax);
     if(device->SourcesMax == 0) device->SourcesMax = 256;

Alc/panning.c

@@ -63,6 +63,10 @@ static const ALuint FuMa2ACN[MAX_AMBI_COEFFS] = {
     15, /* P */
     9,  /* Q */
 };
+static const ALuint ACN2ACN[MAX_AMBI_COEFFS] = {
+    0,  1,  2,  3,  4,  5,  6,  7,
+    8,  9, 10, 11, 12, 13, 14, 15
+};
 
 /* NOTE: These are scale factors as applied to Ambisonics content. Decoder
  * coefficients should be divided by these values to get proper N3D scalings.
@@ -596,44 +600,45 @@ static void InitPanning(ALCdevice *device)
         device->FOAOut.Ambi = device->Dry.Ambi;
         device->FOAOut.CoeffCount = device->Dry.CoeffCount;
     }
-    else if(device->FmtChans == DevFmtAmbi1)
+    else if(device->FmtChans >= DevFmtAmbi1 && device->FmtChans <= DevFmtAmbi3)
     {
-        count = 4;
-        for(i = 0;i < count;i++)
-        {
-            device->Dry.Ambi.Map[i].Scale = 1.0f/SN3D2N3DScale[i];
-            device->Dry.Ambi.Map[i].Index = i;
-        }
-        device->Dry.CoeffCount = 0;
-        device->Dry.NumChannels = count;
+        const ALuint *acnmap = (device->AmbiFmt == AmbiFormat_FuMa) ? FuMa2ACN : ACN2ACN;
+        const ALfloat *n3dcale = (device->AmbiFmt == AmbiFormat_FuMa) ? FuMa2N3DScale :
+                                 (device->AmbiFmt == AmbiFormat_ACN_SN3D) ? SN3D2N3DScale :
+                                 /*(device->AmbiFmt == AmbiFormat_ACN_N3D) ?*/ UnitScale;
 
-        device->FOAOut.Ambi = device->Dry.Ambi;
-        device->FOAOut.CoeffCount = device->Dry.CoeffCount;
-    }
-    else if(device->FmtChans == DevFmtAmbi2 || device->FmtChans == DevFmtAmbi3)
-    {
         count = (device->FmtChans == DevFmtAmbi3) ? 16 :
-                (device->FmtChans == DevFmtAmbi2) ? 9 : 1;
+                (device->FmtChans == DevFmtAmbi2) ? 9 :
+                (device->FmtChans == DevFmtAmbi1) ? 4 : 1;
         for(i = 0;i < count;i++)
         {
-            device->Dry.Ambi.Map[i].Scale = 1.0f/SN3D2N3DScale[i];
-            device->Dry.Ambi.Map[i].Index = i;
+            ALuint acn = acnmap[i];
+            device->Dry.Ambi.Map[i].Scale = 1.0f/n3dcale[acn];
+            device->Dry.Ambi.Map[i].Index = acn;
         }
         device->Dry.CoeffCount = 0;
         device->Dry.NumChannels = count;
 
-        /* FOA output is always ACN+N3D for higher-order ambisonic output. The
-         * upsampler expects this and will convert it for output.
-         */
-        memset(&device->FOAOut.Ambi, 0, sizeof(device->FOAOut.Ambi));
-        for(i = 0;i < 4;i++)
+        if(device->FmtChans == DevFmtAmbi1)
         {
-            device->FOAOut.Ambi.Map[i].Scale = 1.0f;
-            device->FOAOut.Ambi.Map[i].Index = i;
+            device->FOAOut.Ambi = device->Dry.Ambi;
+            device->FOAOut.CoeffCount = device->Dry.CoeffCount;
         }
-        device->FOAOut.CoeffCount = 0;
+        else
+        {
+            /* FOA output is always ACN+N3D for higher-order ambisonic output.
+             * The upsampler expects this and will convert it for output.
+             */
+            memset(&device->FOAOut.Ambi, 0, sizeof(device->FOAOut.Ambi));
+            for(i = 0;i < 4;i++)
+            {
+                device->FOAOut.Ambi.Map[i].Scale = 1.0f;
+                device->FOAOut.Ambi.Map[i].Index = i;
+            }
+            device->FOAOut.CoeffCount = 0;
 
-        ambiup_reset(device->AmbiUp, device);
+            ambiup_reset(device->AmbiUp, device);
+        }
     }
     else
     {

OpenAL32/Include/alMain.h

@@ -463,6 +463,14 @@ inline ALuint FrameSizeFromDevFmt(enum DevFmtChannels chans, enum DevFmtType typ
     return ChannelsFromDevFmt(chans) * BytesFromDevFmt(type);
 }
 
+enum AmbiFormat {
+    AmbiFormat_FuMa,     /* FuMa channel order and normalization */
+    AmbiFormat_ACN_SN3D, /* ACN channel order and SN3D normalization */
+    AmbiFormat_ACN_N3D,  /* ACN channel order and N3D normalization */
+
+    AmbiFormat_Default = AmbiFormat_ACN_SN3D
+};
+
 
 extern const struct EffectList {
     const char *name;
@@ -557,6 +565,10 @@ struct ALCdevice_struct
     enum DevFmtChannels FmtChans;
     enum DevFmtType     FmtType;
     ALboolean IsHeadphones;
+    /* For DevFmtAmbi* output only, specifies the channel order and
+     * normalization.
+     */
+    enum AmbiFormat AmbiFmt;
 
     al_string DeviceName;
 

alsoftrc.sample

@@ -97,6 +97,11 @@
 #  disabled.
 #stereo-panning = uhj
 
+## ambi-format:
+#  Specifies the channel order and normalization for the "ambi*" set of channel
+#  configurations. Valid settings are: fuma, acn+sn3d, acn+n3d
+#ambi-format = acn+sn3d
+
 ## hrtf:
 #  Controls HRTF processing. These filters provide better spatialization of
 #  sounds while using headphones, but do require a bit more CPU power. The