STK support

README.md

@@ -135,6 +135,7 @@ Dependent on the example you might need to install some of the following librari
 - [SAM](https://github.com/pschatzmann/arduino-SAM) A Text to Speach Engine
 - [TTS](https://github.com/pschatzmann/TTS) A Text to Speach Engine
 - [flite](https://github.com/pschatzmann/arduino-flite) A Text to Speach Engine
+- [arduino-stk](https://github.com/pschatzmann/Arduino-STK) Synthesis ToolKit in C++ (STK) 
 - [Mozzi](https://github.com/pschatzmann/Mozzi) A sound synthesis library for Arduino
 - [ESP8266Audio](https://github.com/earlephilhower/ESP8266Audio) to play different audio Formats
 

src/AudioSTK.h

@@ -0,0 +1,71 @@
+#pragma once
+#include "Arduino.h"
+#include <Voicer.h>
+
+
+namespace audio_tools {
+
+/**
+ * @brief Stream Source which provides the audio data using the STK framework: https://github.com/pschatzmann/Arduino-STK
+ * @author Phil Schatzmann
+ * @copyright GPLv3
+ */
+class AudioSTK : public BufferedStream<int16_t> {
+
+    public:
+        /// provides the audio from a Voicer
+        void begin(stk::Voicer &voicer) {
+            p_voicer = &voicer;
+            p_instrument = nullptr;
+            active = true;
+        }
+
+        /// provides the audio from an Instrument
+        void begin(stk::Instrument &instrument) {
+            p_instrument = &instrument;
+            p_voicer = nullptr;
+            active = true;
+        }
+
+        /// stops the generation of sound
+        void end() {
+            active = false;
+        }
+
+    protected:
+        stk::Voicer *p_voicer;
+        stk::Instrument *p_instrument;
+        bool active = false;
+
+        // not supported
+        virtual size_t writeExt(const uint8_t* data, size_t len) {    
+            LOGE("not supported");
+            return 0;
+        }
+
+        virtual size_t readExt( uint8_t *data, size_t len) { 
+            // generate samples
+            size_t result = 0;
+            if (active){
+                result = len;
+                size_t sample_count = len / sizeof(int16_t);
+                int16_t* samples = (int16_t*)data;
+
+                if (p_voicer!=nullptr){
+                    for (int j=0;j<sample_count;j++){
+                        // scale ticks to int16 values
+                        samples[j] = p_voicer->tick() * 32768;
+                    }
+                } else if (p_instrument!=nullptr){
+                    for (int j=0;j<sample_count;j++){
+                        // scale ticks to int16 values
+                        samples[j] = p_instrument->tick() * 32768;
+                    }
+                }
+            }
+            return result;
+        }
+};
+
+
+}

src/AudioTools/AudioCopy.h

@@ -13,6 +13,8 @@ namespace audio_tools {
  * @brief Typed Stream Copy which supports the conversion from channel to 2 channels. We make sure that we
  * allways copy full samples
  * @tparam T 
+ * @author Phil Schatzmann
+ * @copyright GPLv3
  */
 template <class T>
 class StreamCopyT {
@@ -205,7 +207,8 @@ class StreamCopyT {
 
 /**
  * @brief We provide the typeless StreamCopy as a subclass of StreamCopyT
- * 
+ * @author Phil Schatzmann
+ * @copyright GPLv3
  */
 class StreamCopy : public StreamCopyT<uint8_t> {
     public: