Use an array to specify the offset for each channel of the device buffer

This effectively inverts the DevChannels array

3 files changed, 78 insertions, 61 deletions

diff --git a/Alc/ALc.c b/Alc/ALc.c
index c93d6758..39296eb5 100644
--- a/Alc/ALc.c
+++ b/Alc/ALc.c
@@ -1287,48 +1287,54 @@ ALint64 ALCdevice_GetLatencyDefault(ALCdevice *device)
  */
 void SetDefaultWFXChannelOrder(ALCdevice *device)
 {
+    ALuint i;
+
+    for(i = 0;i < MaxChannels;i++)
+        device->ChannelOffsets[i] = INVALID_OFFSET;
+
     switch(device->FmtChans)
     {
-    case DevFmtMono: device->DevChannels[0] = FrontCenter; break;
-
-    case DevFmtStereo: device->DevChannels[0] = FrontLeft;
-                       device->DevChannels[1] = FrontRight; break;
-
-    case DevFmtQuad: device->DevChannels[0] = FrontLeft;
-                     device->DevChannels[1] = FrontRight;
-                     device->DevChannels[2] = BackLeft;
-                     device->DevChannels[3] = BackRight; break;
-
-    case DevFmtX51: device->DevChannels[0] = FrontLeft;
-                    device->DevChannels[1] = FrontRight;
-                    device->DevChannels[2] = FrontCenter;
-                    device->DevChannels[3] = LFE;
-                    device->DevChannels[4] = BackLeft;
-                    device->DevChannels[5] = BackRight; break;
-
-    case DevFmtX51Side: device->DevChannels[0] = FrontLeft;
-                        device->DevChannels[1] = FrontRight;
-                        device->DevChannels[2] = FrontCenter;
-                        device->DevChannels[3] = LFE;
-                        device->DevChannels[4] = SideLeft;
-                        device->DevChannels[5] = SideRight; break;
-
-    case DevFmtX61: device->DevChannels[0] = FrontLeft;
-                    device->DevChannels[1] = FrontRight;
-                    device->DevChannels[2] = FrontCenter;
-                    device->DevChannels[3] = LFE;
-                    device->DevChannels[4] = BackCenter;
-                    device->DevChannels[5] = SideLeft;
-                    device->DevChannels[6] = SideRight; break;
-
-    case DevFmtX71: device->DevChannels[0] = FrontLeft;
-                    device->DevChannels[1] = FrontRight;
-                    device->DevChannels[2] = FrontCenter;
-                    device->DevChannels[3] = LFE;
-                    device->DevChannels[4] = BackLeft;
-                    device->DevChannels[5] = BackRight;
-                    device->DevChannels[6] = SideLeft;
-                    device->DevChannels[7] = SideRight; break;
+    case DevFmtMono: device->ChannelOffsets[FrontCenter] = 0;
+                     break;
+    case DevFmtStereo: device->ChannelOffsets[FrontLeft]  = 0;
+                       device->ChannelOffsets[FrontRight] = 1;
+                       break;
+    case DevFmtQuad: device->ChannelOffsets[FrontLeft]  = 0;
+                     device->ChannelOffsets[FrontRight] = 1;
+                     device->ChannelOffsets[BackLeft]   = 2;
+                     device->ChannelOffsets[BackRight]  = 3;
+                     break;
+    case DevFmtX51: device->ChannelOffsets[FrontLeft]   = 0;
+                    device->ChannelOffsets[FrontRight]  = 1;
+                    device->ChannelOffsets[FrontCenter] = 2;
+                    device->ChannelOffsets[LFE]         = 3;
+                    device->ChannelOffsets[BackLeft]    = 4;
+                    device->ChannelOffsets[BackRight]   = 5;
+                    break;
+    case DevFmtX51Side: device->ChannelOffsets[FrontLeft]   = 0;
+                        device->ChannelOffsets[FrontRight]  = 1;
+                        device->ChannelOffsets[FrontCenter] = 2;
+                        device->ChannelOffsets[LFE]         = 3;
+                        device->ChannelOffsets[SideLeft]    = 4;
+                        device->ChannelOffsets[SideRight]   = 5;
+                        break;
+    case DevFmtX61: device->ChannelOffsets[FrontLeft]   = 0;
+                    device->ChannelOffsets[FrontRight]  = 1;
+                    device->ChannelOffsets[FrontCenter] = 2;
+                    device->ChannelOffsets[LFE]         = 3;
+                    device->ChannelOffsets[BackCenter]  = 4;
+                    device->ChannelOffsets[SideLeft]    = 5;
+                    device->ChannelOffsets[SideRight]   = 6;
+                    break;
+    case DevFmtX71: device->ChannelOffsets[FrontLeft]   = 0;
+                    device->ChannelOffsets[FrontRight]  = 1;
+                    device->ChannelOffsets[FrontCenter] = 2;
+                    device->ChannelOffsets[LFE]         = 3;
+                    device->ChannelOffsets[BackLeft]    = 4;
+                    device->ChannelOffsets[BackRight]   = 5;
+                    device->ChannelOffsets[SideLeft]    = 6;
+                    device->ChannelOffsets[SideRight]   = 7;
+                    break;
     }
 }
 
@@ -1338,24 +1344,28 @@ void SetDefaultWFXChannelOrder(ALCdevice *device)
  */
 void SetDefaultChannelOrder(ALCdevice *device)
 {
+    ALuint i;
+
+    for(i = 0;i < MaxChannels;i++)
+        device->ChannelOffsets[i] = INVALID_OFFSET;
+
     switch(device->FmtChans)
     {
-    case DevFmtX51: device->DevChannels[0] = FrontLeft;
-                    device->DevChannels[1] = FrontRight;
-                    device->DevChannels[2] = BackLeft;
-                    device->DevChannels[3] = BackRight;
-                    device->DevChannels[4] = FrontCenter;
-                    device->DevChannels[5] = LFE;
+    case DevFmtX51: device->ChannelOffsets[FrontLeft]   = 0;
+                    device->ChannelOffsets[FrontRight]  = 1;
+                    device->ChannelOffsets[BackLeft]    = 2;
+                    device->ChannelOffsets[BackRight]   = 3;
+                    device->ChannelOffsets[FrontCenter] = 4;
+                    device->ChannelOffsets[LFE]         = 5;
                     return;
-
-    case DevFmtX71: device->DevChannels[0] = FrontLeft;
-                    device->DevChannels[1] = FrontRight;
-                    device->DevChannels[2] = BackLeft;
-                    device->DevChannels[3] = BackRight;
-                    device->DevChannels[4] = FrontCenter;
-                    device->DevChannels[5] = LFE;
-                    device->DevChannels[6] = SideLeft;
-                    device->DevChannels[7] = SideRight;
+    case DevFmtX71: device->ChannelOffsets[FrontLeft]   = 0;
+                    device->ChannelOffsets[FrontRight]  = 1;
+                    device->ChannelOffsets[BackLeft]    = 2;
+                    device->ChannelOffsets[BackRight]   = 3;
+                    device->ChannelOffsets[FrontCenter] = 4;
+                    device->ChannelOffsets[LFE]         = 5;
+                    device->ChannelOffsets[SideLeft]    = 6;
+                    device->ChannelOffsets[SideRight]   = 7;
                     return;
 
     /* Same as WFX order */
diff --git a/Alc/ALu.c b/Alc/ALu.c
index e0e5f8a3..a44c04b3 100644
--- a/Alc/ALu.c
+++ b/Alc/ALu.c
@@ -931,16 +931,19 @@ static int Write_##T(ALCdevice *device, T *RESTRICT buffer,                   \
 {                                                                             \
     ALfloat (*RESTRICT DryBuffer)[BUFFERSIZE] = device->DryBuffer;            \
     ALuint numchans = ChannelsFromDevFmt(device->FmtChans);                   \
-    const enum Channel *ChanMap = device->DevChannels;                        \
+    const ALuint *offsets = device->ChannelOffsets;                           \
     ALuint i, j;                                                              \
                                                                               \
-    for(j = 0;j < numchans;j++)                                               \
+    for(j = 0;j < MaxChannels;j++)                                            \
     {                                                                         \
-        T *RESTRICT out = buffer + j;                                         \
-        enum Channel chan = ChanMap[j];                                       \
+        T *RESTRICT out;                                                      \
                                                                               \
+        if(offsets[j] == INVALID_OFFSET)                                      \
+            continue;                                                         \
+                                                                              \
+        out = buffer + offsets[j];                                            \
         for(i = 0;i < SamplesToDo;i++)                                        \
-            out[i*numchans] = func(DryBuffer[chan][i]);                       \
+            out[i*numchans] = func(DryBuffer[j][i]);                          \
     }                                                                         \
     return SamplesToDo*numchans*sizeof(T);                                    \
 }
diff --git a/OpenAL32/Include/alMain.h b/OpenAL32/Include/alMain.h
index b0f0135f..00512997 100644
--- a/OpenAL32/Include/alMain.h
+++ b/OpenAL32/Include/alMain.h
@@ -603,7 +603,7 @@ struct ALCdevice_struct
     // Device flags
     ALuint       Flags;
 
-    enum Channel DevChannels[MaxChannels];
+    ALuint ChannelOffsets[MaxChannels];
 
     enum Channel Speaker2Chan[MaxChannels];
     ALfloat SpeakerAngle[MaxChannels];
@@ -659,6 +659,10 @@ struct ALCdevice_struct
 // Specifies if the device is currently running
 #define DEVICE_RUNNING                           (1<<31)
 
+/* Invalid channel offset */
+#define INVALID_OFFSET                           (~0u)
+
+
 #define LookupBuffer(m, k) ((struct ALbuffer*)LookupUIntMapKey(&(m)->BufferMap, (k)))
 #define LookupEffect(m, k) ((struct ALeffect*)LookupUIntMapKey(&(m)->EffectMap, (k)))
 #define LookupFilter(m, k) ((struct ALfilter*)LookupUIntMapKey(&(m)->FilterMap, (k)))