From 2b9737bcfb2d4c51eb9f2499d700ddd3bff6f1c5 Mon Sep 17 00:00:00 2001
From: Paul Ferrand <paulfd@outlook.fr>
Date: Wed, 20 Nov 2019 22:35:51 +0100
Subject: [PATCH] Added a dynamic number of voices

---
 sfizz/Synth.cpp | 31 +++++++++++++++++++++++++++----
 sfizz/Synth.h   |  8 +++++++-
 sfizz/sfizz.cpp | 14 ++++++++++++++
 sfizz/sfizz.h   | 15 +++++++++++++++
 4 files changed, 63 insertions(+), 5 deletions(-)

diff --git a/sfizz/Synth.cpp b/sfizz/Synth.cpp
index d9157e14..d966ed8c 100644
--- a/sfizz/Synth.cpp
+++ b/sfizz/Synth.cpp
@@ -35,11 +35,9 @@
 #include <utility>
 using namespace std::literals;
 
-sfz::Synth::Synth()
+sfz::Synth::Synth(int numVoices)
 {
-    for (int i = 0; i < config::numVoices; ++i)
-        voices.push_back(std::make_unique<Voice>(midiState));
-    voiceViewArray.reserve(config::numVoices);
+    resetVoices(numVoices);
 }
 
 void sfz::Synth::callback(absl::string_view header, const std::vector<Opcode>& members)
@@ -506,4 +504,29 @@ float sfz::Synth::getVolume() const noexcept
 void sfz::Synth::setVolume(float volume) noexcept
 {
     this->volume = Default::volumeRange.clamp(volume);
+}
+
+int sfz::Synth::getNumVoices() const noexcept
+{
+    return numVoices;
+}
+
+void sfz::Synth::setNumVoices(int numVoices) noexcept
+{
+    ASSERT(numVoices > 0);
+    resetVoices(numVoices);
+}
+
+void sfz::Synth::resetVoices(int numVoices)
+{
+    AtomicDisabler callbackDisabler{ canEnterCallback };
+    while (inCallback) {
+        std::this_thread::sleep_for(1ms);
+    }
+
+    voices.clear();
+    for (int i = 0; i < numVoices; ++i)
+        voices.push_back(std::make_unique<Voice>(midiState));
+    voiceViewArray.reserve(numVoices);
+    this->numVoices = numVoices;
 }
\ No newline at end of file
diff --git a/sfizz/Synth.h b/sfizz/Synth.h
index 19242ffb..527771f2 100644
--- a/sfizz/Synth.h
+++ b/sfizz/Synth.h
@@ -39,7 +39,8 @@ namespace sfz {
 
 class Synth : public Parser {
 public:
-    Synth();
+    Synth() {}
+    Synth(int numVoices);
     bool loadSfzFile(const fs::path& file) final;
     int getNumRegions() const noexcept;
     int getNumGroups() const noexcept;
@@ -63,6 +64,8 @@ public:
     void tempo(int delay, float secondsPerQuarter) noexcept;
 
     int getNumActiveVoices() const noexcept;
+    int getNumVoices() const noexcept;
+    void setNumVoices(int numVoices) noexcept;
     void garbageCollect() noexcept;
 protected:
     void callback(absl::string_view header, const std::vector<Opcode>& members) final;
@@ -74,6 +77,7 @@ private:
     int numMasters { 0 };
     int numCurves { 0 };
     void clear();
+    void resetVoices(int numVoices);
     void handleGlobalOpcodes(const std::vector<Opcode>& members);
     void handleControlOpcodes(const std::vector<Opcode>& members);
     void buildRegion(const std::vector<Opcode>& regionOpcodes);
@@ -107,6 +111,8 @@ private:
     std::atomic<bool> canEnterCallback { true };
     std::atomic<bool> inCallback { false };
 
+    int numVoices { config::numVoices };
+
     LEAK_DETECTOR(Synth);
 };
 
diff --git a/sfizz/sfizz.cpp b/sfizz/sfizz.cpp
index 0e0e63dd..7b3a4a01 100644
--- a/sfizz/sfizz.cpp
+++ b/sfizz/sfizz.cpp
@@ -24,6 +24,7 @@
 #include "Synth.h"
 #include "sfizz.h"
 
+#define UNUSED(x) (void)(x)
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -122,6 +123,7 @@ void sfizz_render_block(sfizz_synth_t* synth, float** channels, int num_channels
     auto self = reinterpret_cast<sfz::Synth*>(synth);
     // Only stereo output is supported for now
     ASSERT(num_channels == 2);
+    UNUSED(num_channels);
     self->renderBlock({{channels[0], channels[1]}, static_cast<size_t>(num_frames)});
 }
 
@@ -143,6 +145,18 @@ float sfizz_get_volume(sfizz_synth_t* synth)
     return self->getVolume();
 }
 
+void sfizz_set_num_voices(sfizz_synth_t* synth, int num_voices)
+{
+    auto self = reinterpret_cast<sfz::Synth*>(synth);
+    self->setNumVoices(num_voices);
+}
+
+int sfizz_get_num_voices(sfizz_synth_t* synth)
+{
+    auto self = reinterpret_cast<sfz::Synth*>(synth);
+    return self->getNumVoices();
+}
+
 #ifdef __cplusplus
 }
 #endif
\ No newline at end of file
diff --git a/sfizz/sfizz.h b/sfizz/sfizz.h
index c5537bcd..86f578c4 100644
--- a/sfizz/sfizz.h
+++ b/sfizz/sfizz.h
@@ -232,6 +232,21 @@ void sfizz_set_volume(sfizz_synth_t* synth, float volume);
  */
 float sfizz_get_volume(sfizz_synth_t* synth);
 
+/**
+ * @brief Sets the number of voices used by the synth
+ * 
+ * @param synth 
+ * @param num_voices 
+ */
+void sfizz_set_num_voices(sfizz_synth_t* synth, int num_voices);
+/**
+ * @brief Returns the number of voices
+ * 
+ * @param synth 
+ * @return num_voices 
+ */
+int sfizz_get_num_voices(sfizz_synth_t* synth);
+
 #ifdef __cplusplus
 }
 #endif
\ No newline at end of file