sndio: Support more than 2 channels

So far the sndio backend only supports Mono and Stereo, but sndio
supports up to 16 channels (64 in their current git code).
This adds support for all the openal-soft formats (DevFmt*).
I tested this on Linux with 5.1 surround speakers.

1 files changed, 32 insertions, 2 deletions

diff --git a/alc/backends/sndio.cpp b/alc/backends/sndio.cpp
index d34a0144..f51f508f 100644
--- a/alc/backends/sndio.cpp
+++ b/alc/backends/sndio.cpp
@@ -127,7 +127,21 @@ bool SndioPlayback::reset()
     sio_initpar(&par);
 
     par.rate = mDevice->Frequency;
-    par.pchan = ((mDevice->FmtChans != DevFmtMono) ? 2 : 1);
+    switch(mDevice->FmtChans)
+    {
+        case DevFmtMono   : par.pchan = 1; break;
+        case DevFmtQuad   : par.pchan = 4; break;
+        case DevFmtX51Rear: // fall-through - "Similar to 5.1, except using rear channels instead of sides"
+        case DevFmtX51    : par.pchan = 6; break;
+        case DevFmtX61    : par.pchan = 7; break;
+        case DevFmtX71    : par.pchan = 8; break;
+
+        case DevFmtStereo : // fall-through
+        default: // fall back to stereo for all unknown formats and Ambi3D
+            mDevice->FmtChans = DevFmtStereo;
+            par.pchan = 2;
+            break;
+    }
 
     switch(mDevice->FmtType)
     {
@@ -176,7 +190,23 @@ bool SndioPlayback::reset()
     }
 
     mDevice->Frequency = par.rate;
-    mDevice->FmtChans = ((par.pchan==1) ? DevFmtMono : DevFmtStereo);
+
+    switch(par.pchan)
+    {
+        case 1: mDevice->FmtChans = DevFmtMono; break;
+        case 2: mDevice->FmtChans = DevFmtStereo; break;
+        case 4: mDevice->FmtChans = DevFmtQuad; break;
+        case 6:
+            if(mDevice->FmtChans != DevFmtX51Rear) // if it's already DevFmtX51Rear no change is needed
+                mDevice->FmtChans = DevFmtX51;
+            break;
+        case 7: mDevice->FmtChans = DevFmtX61; break;
+        case 8: mDevice->FmtChans = DevFmtX71; break;
+        
+        default:
+            ERR("Unexpected number of channels: %d\n", par.pchan);
+            return ALC_FALSE;
+    }
 
     if(par.bits == 8 && par.sig == 1)
         mDevice->FmtType = DevFmtByte;