public void BasicOperations()
{
using (var buf = new RingBuffer()) {
Assert.Equal(0, buf.BytesAvailable());
Assert.Equal(8191, buf.WriteBytesAvailable()); // implementation dependent.
using (var synth = new SynthUnit(buf)) {
var bytes = new byte [] { 0x90, 0x30, 0 }; // note on at 0x30, but with no velocity = no sound.
buf.Write(bytes, 0, bytes.Length);
var results = new short [1024];
Assert.Equal(3, buf.BytesAvailable());
synth.Init(44100);
synth.GetSamples(results, 0, results.Length);
Assert.All(results, r => Assert.Equal(0, r));
bytes = new byte [] { 0x90, 0x30, 100 }; // now give vel = 100
buf.Write(bytes, 0, bytes.Length);
synth.GetSamples(results, 0, results.Length);
Assert.Contains(results, r => r != 0);
// to see what's being generated, enable these lines.
//var str = string.Concat (results.Select (s => s.ToString ("X04")));
//Console.WriteLine (str);
}
}
}
void WriteCallback(SoundIOOutStream outStream, int min, int max)
{
if (!play_audio)
{
return;
}
Console.WriteLine($"WriteCallback invoked: {min} / {max}");
double float_sample_rate = outStream.SampleRate;
double seconds_per_frame = 1.0 / float_sample_rate;
//if (max - min > samples.Length)
// samples = new short [max - min];
#if test_with_sine
//double seconds_offset = 0;
#else
synth.GetSamples(samples, 0, samples.Length);
#endif
//if (samples.Any (s => s != 0))
// Console.WriteLine (string.Concat (samples.Take (50).Select (s => s.ToString ("X04"))));
int frameRemaining = max;
int frameCount = frameRemaining;
while (play_audio && frameRemaining > 0)
{
var results = outStream.BeginWrite(ref frameCount);
if (frameCount == 0)
{
break;
}
#if test_with_sine
double pitch = 440.0;
double radians_per_second = pitch * 2.0 * Math.PI;
for (int frame = 0; frame < frameCount; frame += 1)
{
double sample = Math.Sin((seconds_offset + frame * seconds_per_frame) * radians_per_second);
for (int channel = 0; channel < outStream.Layout.ChannelCount; channel += 1)
{
var area = results.GetArea(channel);
double range = (double)short.MaxValue - (double)short.MinValue;
double val = sample * range / 2.0;
unsafe { *((short *)area.Pointer) = (short)val; }
area.Pointer += area.Step;
}
}
seconds_offset = Math.IEEERemainder(seconds_offset + seconds_per_frame * frameCount, 1.0);
#else
for (int i = 0; i < outStream.Layout.ChannelCount; i++)
{
var area = results.GetArea(i);
unsafe {
Marshal.Copy(samples, 0, area.Pointer, samples.Length);
area.Pointer += area.Step * samples.Length;
}
}
#endif
outStream.EndWrite();
frameRemaining -= frameCount;
}
}