Handle padding between device sample frames

The padding must be constant and sample type aligned (e.g. some fixed multiple
of two bytes between the start of two consecutive frames for 16-bit output).
The intent is to always have the ability for stereo output with WASAPI even if
the device has some other unsupported configuration, as long as front-left and
front-right exist.

1 files changed, 17 insertions, 17 deletions

diff --git a/alc/alu.cpp b/alc/alu.cpp
index ef6b2ed7..fc3555bf 100644
--- a/alc/alu.cpp
+++ b/alc/alu.cpp
@@ -1861,22 +1861,21 @@ template<> inline uint8_t SampleConv(float val) noexcept
 
 template<DevFmtType T>
 void Write(const al::span<const FloatBufferLine> InBuffer, void *OutBuffer, const size_t Offset,
-    const ALuint SamplesToDo)
+    const ALuint SamplesToDo, const size_t FrameStep)
 {
     using SampleType = typename DevFmtTypeTraits<T>::Type;
 
-    const size_t numchans{InBuffer.size()};
-    ASSUME(numchans > 0);
+    ASSUME(FrameStep > 0);
 
-    SampleType *outbase = static_cast<SampleType*>(OutBuffer) + Offset*numchans;
-    auto conv_channel = [&outbase,SamplesToDo,numchans](const FloatBufferLine &inbuf) -> void
+    SampleType *outbase = static_cast<SampleType*>(OutBuffer) + Offset*FrameStep;
+    auto conv_channel = [&outbase,SamplesToDo,FrameStep](const FloatBufferLine &inbuf) -> void
     {
         ASSUME(SamplesToDo > 0);
         SampleType *out{outbase++};
-        auto conv_sample = [numchans,&out](const float s) noexcept -> void
+        auto conv_sample = [FrameStep,&out](const float s) noexcept -> void
         {
             *out = SampleConv<SampleType>(s);
-            out += numchans;
+            out += FrameStep;
         };
         std::for_each(inbuf.begin(), inbuf.begin()+SamplesToDo, conv_sample);
     };
@@ -1885,7 +1884,8 @@ void Write(const al::span<const FloatBufferLine> InBuffer, void *OutBuffer, cons
 
 } // namespace
 
-void aluMixData(ALCdevice *device, ALvoid *OutBuffer, const ALuint NumSamples)
+void aluMixData(ALCdevice *device, void *OutBuffer, const ALuint NumSamples,
+    const size_t FrameStep)
 {
     FPUCtl mixer_mode{};
     for(ALuint SamplesDone{0u};SamplesDone < NumSamples;)
@@ -1956,15 +1956,15 @@ void aluMixData(ALCdevice *device, ALvoid *OutBuffer, const ALuint NumSamples)
              */
             switch(device->FmtType)
             {
-#define HANDLE_WRITE(T) case T:                                            \
-    Write<T>(RealOut, OutBuffer, SamplesDone, SamplesToDo); break;
-                HANDLE_WRITE(DevFmtByte)
-                HANDLE_WRITE(DevFmtUByte)
-                HANDLE_WRITE(DevFmtShort)
-                HANDLE_WRITE(DevFmtUShort)
-                HANDLE_WRITE(DevFmtInt)
-                HANDLE_WRITE(DevFmtUInt)
-                HANDLE_WRITE(DevFmtFloat)
+#define HANDLE_WRITE(T) case T:                                               \
+    Write<T>(RealOut, OutBuffer, SamplesDone, SamplesToDo, FrameStep); break;
+            HANDLE_WRITE(DevFmtByte)
+            HANDLE_WRITE(DevFmtUByte)
+            HANDLE_WRITE(DevFmtShort)
+            HANDLE_WRITE(DevFmtUShort)
+            HANDLE_WRITE(DevFmtInt)
+            HANDLE_WRITE(DevFmtUInt)
+            HANDLE_WRITE(DevFmtFloat)
 #undef HANDLE_WRITE
             }
         }