Initial commit - basic sine generator

CMakeLists.txt

@@ -0,0 +1,18 @@
+cmake_minimum_required(VERSION 2.6)
+project(sinesynth)
+
+set(CMAKE_CXX_STANDARD 11)
+
+include_directories(include)
+
+find_package(PulseAudio)
+if(PULSEAUDIO_FOUND)
+    include_directories(${PULSEAUDIO_INCLUDE_DIR})
+endif()
+
+set(SINESYNTH_LIBS ${PULSEAUDIO_LIBRARY} pulse-simple)
+
+file(GLOB SOURCES "src/*.cpp")
+
+add_executable(sinesynth ${SOURCES})
+target_link_libraries(sinesynth LINK_PUBLIC ${SINESYNTH_LIBS})

include/SineSynth.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <cstdint>
+#include <vector>
+#include <iterator>
+#include <cmath>
+
+using std::vector;
+using std::iterator_traits;
+
+using std::sin;
+using std::cos;
+
+class Generator
+{
+public:
+    virtual void getSamples(const uint16_t nSamples, float *buf) = 0;
+    virtual ~Generator();
+
+    // disallow copy of virtual interface
+    Generator(Generator const &) = delete;
+    Generator &operator=(Generator const &) = delete;
+
+protected:
+    Generator(uint32_t _sampleRate, float _frequency, float _amplitude);
+    uint32_t sampleRate;
+    float frequency;
+    float amplitude;
+
+private:
+};
+
+class SineGenerator : public Generator
+{
+public:
+    SineGenerator(uint32_t _sampleRate, float _frequency, float _amplitude);
+    void getSamples(uint16_t nSamples, float *buf) final;
+    virtual ~SineGenerator();
+
+private:
+    uint32_t tick;
+    float phaseIncr;
+};
+
+class SineSynth
+{
+private:
+    vector<SineGenerator> generators;
+};

src/SineSynth.cpp

@@ -0,0 +1,28 @@
+#include "SineSynth.h"
+
+#include <iostream>
+
+Generator::Generator(uint32_t _sampleRate, float _frequency, float _amplitude) : sampleRate(_sampleRate), frequency(_frequency), amplitude(_amplitude)
+{
+}
+
+Generator::~Generator()
+{
+}
+
+SineGenerator::SineGenerator(uint32_t _sampleRate, float _frequency, float _amplitude = 1) : Generator(_sampleRate, _frequency, _amplitude), tick(0) {
+    phaseIncr = 2 * M_PI * frequency / sampleRate;
+
+    std::cout << "Constructed SineGenerator with freq " << frequency << " phaseIncr " << phaseIncr << std::endl;
+}
+
+SineGenerator::~SineGenerator() {
+
+}
+
+void SineGenerator::getSamples(uint16_t nSamples, float *buf) {
+    for (;nSamples>0;nSamples--) {
+        std::cout << "Generating tick " << tick << std::endl;
+        *buf++ = cos(phaseIncr * tick++) * amplitude;
+    }
+}

src/main.cpp

@@ -0,0 +1,23 @@
+#include <iostream>
+#include <pulse/simple.h>
+
+#include "SineSynth.h"
+
+int main(int argc, char *argv[]) {
+    SineGenerator sg(44100, 440.0f, 0.1);
+    static const pa_sample_spec ss = {
+        .format = PA_SAMPLE_FLOAT32,
+        .rate = 44100,
+        .channels = 1
+    };
+
+    pa_simple *s = NULL;
+    int error;
+    s = pa_simple_new(NULL, argv[0], PA_STREAM_PLAYBACK, NULL, "playback", &ss, NULL, NULL, &error);
+
+    float buf[1024];
+    for (;;) {
+        sg.getSamples(1024, buf);
+        pa_simple_write(s, buf, sizeof(buf), &error);
+    }
+}