Add an internal Super Stereo format

It's not available as an AL buffer format (yet) since I'm not sure how to
expose it. Internally it seems fine as a separate channel configuration, but
because OpenAL combines the channel configuration and sample type, a flag may
work better there.

1 files changed, 26 insertions, 2 deletions

diff --git a/core/buffer_storage.h b/core/buffer_storage.h
index 64943453..091882f9 100644
--- a/core/buffer_storage.h
+++ b/core/buffer_storage.h
@@ -4,6 +4,8 @@
 #include <atomic>
 
 #include "albyte.h"
+#include "alnumeric.h"
+#include "ambidefs.h"
 
 
 using uint = unsigned int;
@@ -30,6 +32,7 @@ enum FmtChannels : unsigned char {
     FmtUHJ2, /* 2-channel UHJ, aka "BHJ", stereo-compatible */
     FmtUHJ3, /* 3-channel UHJ, aka "THJ" */
     FmtUHJ4, /* 4-channel UHJ, aka "PHJ" */
+    FmtSuperStereo, /* Stereo processed with Super Stereo. */
 };
 
 enum class AmbiLayout : unsigned char {
@@ -48,6 +51,21 @@ uint ChannelsFromFmt(FmtChannels chans, uint ambiorder) noexcept;
 inline uint FrameSizeFromFmt(FmtChannels chans, FmtType type, uint ambiorder) noexcept
 { return ChannelsFromFmt(chans, ambiorder) * BytesFromFmt(type); }
 
+constexpr bool IsBFormat(FmtChannels chans) noexcept
+{ return chans == FmtBFormat2D || chans == FmtBFormat3D; }
+
+/* Super Stereo is considered part of the UHJ family here, since it goes
+ * through similar processing as UHJ, both result in a B-Format signal, and
+ * needs the same consideration as BHJ (three channel result with only two
+ * channel input).
+ */
+constexpr bool IsUHJ(FmtChannels chans) noexcept
+{ return chans == FmtUHJ2 || chans == FmtUHJ3 || chans == FmtUHJ4 || chans == FmtSuperStereo; }
+
+/** Ambisonic formats are either B-Format or UHJ formats. */
+constexpr bool IsAmbisonic(FmtChannels chans) noexcept
+{ return IsBFormat(chans) || IsUHJ(chans); }
+
 
 using CallbackType = int(*)(void*, void*, int);
 
@@ -69,8 +87,14 @@ struct BufferStorage {
     { return ChannelsFromFmt(mChannels, mAmbiOrder); }
     inline uint frameSizeFromFmt() const noexcept { return channelsFromFmt() * bytesFromFmt(); }
 
-    inline bool isBFormat() const noexcept
-    { return mChannels == FmtBFormat2D || mChannels == FmtBFormat3D; }
+    inline uint mixerChannelsFromFmt() const noexcept
+    {
+        if(mChannels == FmtUHJ2 || mChannels == FmtSuperStereo) return 3;
+        return ChannelsFromFmt(mChannels, minu(mAmbiOrder, MaxAmbiOrder));
+    }
+
+    inline bool isBFormat() const noexcept { return IsBFormat(mChannels); }
+    inline bool isUhj() const noexcept { return IsUHJ(mChannels); }
 };
 
 #endif /* CORE_BUFFER_STORAGE_H */