Diff: Synthesizer.h

Revision:

6:688698f814c0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Synthesizer.h	Tue Apr 12 20:37:08 2016 +0000
@@ -0,0 +1,116 @@
+/**
+ * The class representing a single monophonic voice.
+ * This class holds and processes its own buffer and play state.
+ *
+ * Note: This class also holds implementations for each of the different instruments.
+ * In a perfect OOP world this would be extracted out into an interface with a
+ *   concrete class for each instrument, but in order to keep overhead low, I
+ *   went for an array of member function pointers instead.
+ *
+ * @author Austin Suszek
+ */
+
+#ifndef AS_SYNTHESIZER_H
+#define AS_SYNTHESIZER_H
+
+#include "Constants.h"
+#include "mbed.h"
+
+/**
+ * An enum representing the possible states of the synthesizer.
+ */
+enum SynthState {
+    OFF,
+    FILL,
+    SUSTAIN,
+    RELEASE  
+};
+
+class Synthesizer {
+public:
+    
+    /**
+     * Constructor
+     */
+    Synthesizer();
+    
+    /**
+     * Signal the beginning of a note being pressed.
+     *
+     * @param key The integer representation of the note
+     * @param velocity (optional) The note velocity in the range of 0-127
+     */
+    void midiNoteOn(int key, int velocity);
+    
+    /**
+     * Signal the end of a note being pressed.
+     */
+    void midiNoteOff();
+    
+    /**
+     * Get the next sample to output.
+     */
+    float getSample();
+     
+    /**
+     * Process the current buffer.
+     */
+    void processBuffer();
+    
+    /**
+     * Returns false for SynthState OFF and true for all other states.
+     */
+    bool isPlaying();
+    
+    /**
+     * Getter for the voiceIndex variable.
+     */
+     int64_t getVoiceIndex(); 
+    
+    /**
+     * Switch to a new synth instrument.
+     *
+     * @param direction 1 for next, -1 for previous.
+     */
+    void nextSynth(int direction);
+    
+    /**
+     * A getter for the current key.
+     * It is always overwritten to the most recent key.
+     */
+    int getCurrentKey();
+    
+    /**
+     * Processor functions. These are responsible for all procesing of the buffer based on their instrument.
+     */
+    void processSine();
+    void processTriangle();
+    void processSquare();
+    void processSaw();
+
+private:
+
+    float buffer[(C::SAMPLE_RATE / C::MIN_FREQUENCY) + 1];
+    int bufferIndex;
+
+    SynthState currentState;
+    
+    int currentKey;
+    int bufferSize;
+    float velocity;
+    
+    int nextBufferSize;
+    float nextVelocity;
+    
+    int64_t voiceIndex;
+    static int64_t nextVoiceIndex;
+    bool fromDisabled;
+    
+    // A process that just outputs input.
+    void identityProcess();
+    
+    volatile int processorIndex;
+    
+};
+
+#endif
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