Merge pull request #279 from jpcima/fft-odd-fix

Ensure to pass FFT an even-sized buffer

src/sfizz/AudioBuffer.h

@@ -28,7 +28,7 @@ namespace sfz
  */
 template <class Type, size_t MaxChannels = sfz::config::numChannels,
           unsigned int Alignment = SIMDConfig::defaultAlignment,
-          size_t PaddingLeft_ = 0, size_t PaddingRight = 0>
+          size_t PaddingLeft_ = 0, size_t PaddingRight_ = 0>
 class AudioBuffer {
 public:
     using value_type = typename std::remove_cv<Type>::type;
@@ -40,6 +40,8 @@ public:
     enum {
         //! Increased left padding to preserve required alignment
         PaddingLeft = PaddingLeft_ + (Alignment - (PaddingLeft_ % Alignment)) % Alignment,
+        //! Padding to the right
+        PaddingRight = PaddingRight_,
         //! Total padding left and right
         PaddingTotal = PaddingLeft + PaddingRight,
     };

src/sfizz/Wavetables.cpp

@@ -7,6 +7,7 @@
 #include "Wavetables.h"
 #include "FilePool.h"
 #include "MathHelpers.h"
+#include "absl/meta/type_traits.h"
 #include <kiss_fftr.h>
 
 namespace sfz {
@@ -373,6 +374,13 @@ bool WavetablePool::createFileWave(FilePool& filePool, const std::string& filena
         DBG("[sfizz] Only the first channel of " << filename << " will be used to create the wavetable");
 
     auto audioData = fileHandle->preloadedData->getConstSpan(0);
+
+    // an even size is required for FFT
+    static_assert(absl::remove_reference_t<decltype(*fileHandle->preloadedData)>::PaddingRight > 0,
+                  "Right padding is required on the audio file buffer");
+    if (audioData.size() & 1)
+        audioData = absl::MakeConstSpan(audioData.data(), audioData.size() + 1);
+
     size_t fftSize = audioData.size();
     size_t specSize = fftSize / 2 + 1;