DACSound16S.cc

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#include "DACSound16S.hh"
#include "DeviceConfig.hh"
#include "MSXMotherBoard.hh"
#include "DynamicClock.hh"
#include "serialize.hh"
 
namespace openmsx {
 
constexpr unsigned DUMMY_INPUT_RATE = 44100; // actual rate depends on frequency setting
 
DACSound16S::DACSound16S(std::string_view name_, static_string_view desc,
                         const DeviceConfig& config)
        : SoundDevice(config.getMotherBoard().getMSXMixer(), name_, desc, 1, DUMMY_INPUT_RATE, false)
        , lastWrittenValue(0)
{
        registerSound(config);
}
 
DACSound16S::~DACSound16S()
{
        unregisterSound();
}
 
void DACSound16S::setOutputRate(unsigned hostSampleRate, double /*speed*/)
{
        setInputRate(hostSampleRate);
}
 
void DACSound16S::reset(EmuTime::param time)
{
        writeDAC(0, time);
}
 
void DACSound16S::writeDAC(int16_t value, EmuTime::param time)
{
        int delta = value - lastWrittenValue;
        if (delta == 0) return;
        lastWrittenValue = value;
 
        BlipBuffer::TimeIndex t;
        getHostSampleClock().getTicksTill(time, t);
        blip.addDelta(t, delta);
}
 
void DACSound16S::generateChannels(float** bufs, unsigned num)
{
        // Note: readSamples() replaces the values in the buffer (it doesn't
        // add the new values to the existing values in the buffer). That's OK
        // because this is a single-channel SoundDevice.
        if (!blip.readSamples<1>(bufs[0], num)) {
                bufs[0] = nullptr;
        }
}
 
bool DACSound16S::updateBuffer(unsigned length, float* buffer,
                               EmuTime::param /*time*/)
{
        return mixChannels(buffer, length);
}
 
template<typename Archive>
void DACSound16S::serialize(Archive& ar, unsigned /*version*/)
{
        // Note: It's ok to NOT serialize a DAC object if you call the
        //       writeDAC() method in some other way during de-serialization.
        //       This is for example done in MSXPPI/KeyClick.
        int16_t lastValue = lastWrittenValue;
        ar.serialize("lastValue", lastValue);
        if constexpr (Archive::IS_LOADER) {
                writeDAC(lastValue, getHostSampleClock().getTime());
        }
}
INSTANTIATE_SERIALIZE_METHODS(DACSound16S);
 
} // namespace openmsx