bsnes/higan/pce/psg/psg.cpp

71 lines
2.0 KiB
C++

#include <pce/pce.hpp>
namespace PCEngine {
PSG psg;
#include "io.cpp"
#include "channel.cpp"
#include "serialization.cpp"
auto PSG::Enter() -> void {
while(true) scheduler.synchronize(), psg.main();
}
auto PSG::main() -> void {
static const uint5 volumeScale[16] = {
0x00, 0x03, 0x05, 0x07, 0x09, 0x0b, 0x0d, 0x0f,
0x10, 0x13, 0x15, 0x17, 0x19, 0x1b, 0x1d, 0x1f,
};
uint5 lmal = volumeScale[io.volumeLeft];
uint5 rmal = volumeScale[io.volumeRight];
double outputLeft = 0.0;
double outputRight = 0.0;
for(auto C : range(6)) {
uint5 al = channel[C].io.volume;
uint5 lal = volumeScale[channel[C].io.volumeLeft];
uint5 ral = volumeScale[channel[C].io.volumeRight];
uint5 volumeLeft = min(0x1f, (0x1f - lmal) + (0x1f - lal) + (0x1f - al));
uint5 volumeRight = min(0x1f, (0x1f - rmal) + (0x1f - ral) + (0x1f - al));
channel[C].run();
if(C == 1 && io.lfoEnable) {
//todo: frequency modulation of channel 0 using channel 1's output
} else {
outputLeft += channel[C].io.output * volumeScalar[volumeLeft];
outputRight += channel[C].io.output * volumeScalar[volumeRight];
}
}
stream->sample(sclamp<16>(outputLeft) / 32768.0, sclamp<16>(outputRight) / 32768.0);
step(1);
}
auto PSG::step(uint clocks) -> void {
Thread::step(clocks);
synchronize(cpu);
}
auto PSG::power() -> void {
create(PSG::Enter, system.colorburst());
stream = Emulator::audio.createStream(2, frequency());
stream->addFilter(Emulator::Filter::Order::First, Emulator::Filter::Type::HighPass, 20.0);
stream->addFilter(Emulator::Filter::Order::Second, Emulator::Filter::Type::LowPass, 20000.0, 3);
memory::fill(&io, sizeof(IO));
for(auto C : range(6)) channel[C].power(C);
double level = 32767.0 / 6.0 / 32.0; //max volume / channels / steps
double step = 48.0 / 32.0; //48dB volume range spread over 32 steps
for(uint n : range(31)) {
volumeScalar[n] = level;
level /= pow(10.0, step / 20.0);
}
volumeScalar[31] = 0.0;
}
}