diff audio/ContinuousSynth.h @ 468:56acd9368532 bqaudioio

Initial work toward switching to bqaudioio library (so as to get I/O, not just O)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/audio/ContinuousSynth.h	Tue Aug 04 13:27:42 2015 +0100
@@ -0,0 +1,65 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef CONTINUOUS_SYNTH_H
+#define CONTINUOUS_SYNTH_H
+
+#include "base/BaseTypes.h"
+
+/**
+ * Mix into a target buffer a signal synthesised so as to sound at a
+ * specific frequency. The frequency may change with each processing
+ * block, or may be switched on or off.
+ */
+
+class ContinuousSynth
+{
+public:
+    ContinuousSynth(int channels, sv_samplerate_t sampleRate, sv_frame_t blockSize, int waveType);
+    ~ContinuousSynth();
+    
+    void setChannelCount(int channels);
+
+    void reset();
+
+    /**
+     * Mix in a signal to be heard at the given fundamental
+     * frequency. Any oscillator state will be maintained between
+     * process calls so as to provide a continuous sound. The f0 value
+     * may vary between calls.
+     *
+     * Supply f0 equal to 0 if you want to maintain the f0 from the
+     * previous block (without having to remember what it was).
+     *
+     * Supply f0 less than 0 for silence. You should continue to call
+     * this even when the signal is silent if you want to ensure the
+     * sound switches on and off cleanly.
+     */
+    void mix(float **toBuffers,
+             float gain,
+             float pan,
+             float f0);
+
+private:
+    int m_channels;
+    sv_samplerate_t m_sampleRate;
+    sv_frame_t m_blockSize;
+
+    double m_prevF0;
+    double m_phase;
+
+    int m_wavetype;
+};
+
+#endif