bsnes/asnes/audio/audio.cpp

86 lines
2.0 KiB
C++
Executable File

#ifdef SYSTEM_CPP
Audio audio;
void Audio::coprocessor_enable(bool state) {
coprocessor = state;
dsp_rdoffset = cop_rdoffset = 0;
dsp_wroffset = cop_wroffset = 0;
dsp_length = cop_length = 0;
r_sum_l = r_sum_r = 0;
}
void Audio::coprocessor_frequency(double input_frequency) {
double output_frequency;
output_frequency = system.apu_frequency() / 768.0;
r_step = input_frequency / output_frequency;
r_frac = 0;
}
void Audio::sample(int16 left, int16 right) {
if(coprocessor == false) {
system.interface->audio_sample(left, right);
} else {
dsp_buffer[dsp_wroffset] = ((uint16)left << 0) + ((uint16)right << 16);
dsp_wroffset = (dsp_wroffset + 1) & 32767;
dsp_length = (dsp_length + 1) & 32767;
flush();
}
}
void Audio::coprocessor_sample(int16 left, int16 right) {
if(r_frac >= 1.0) {
r_frac -= 1.0;
r_sum_l += left;
r_sum_r += right;
return;
}
r_sum_l += left * r_frac;
r_sum_r += right * r_frac;
uint16 output_left = sclamp<16>(int(r_sum_l / r_step));
uint16 output_right = sclamp<16>(int(r_sum_r / r_step));
double first = 1.0 - r_frac;
r_sum_l = left * first;
r_sum_r = right * first;
r_frac = r_step - first;
cop_buffer[cop_wroffset] = (output_left << 0) + (output_right << 16);
cop_wroffset = (cop_wroffset + 1) & 32767;
cop_length = (cop_length + 1) & 32767;
flush();
}
void Audio::init() {
}
void Audio::flush() {
while(dsp_length > 0 && cop_length > 0) {
uint32 dsp_sample = dsp_buffer[dsp_rdoffset];
uint32 cop_sample = cop_buffer[cop_rdoffset];
dsp_rdoffset = (dsp_rdoffset + 1) & 32767;
cop_rdoffset = (cop_rdoffset + 1) & 32767;
dsp_length--;
cop_length--;
int dsp_left = (int16)(dsp_sample >> 0);
int dsp_right = (int16)(dsp_sample >> 16);
int cop_left = (int16)(cop_sample >> 0);
int cop_right = (int16)(cop_sample >> 16);
system.interface->audio_sample(
sclamp<16>((dsp_left + cop_left ) / 2),
sclamp<16>((dsp_right + cop_right) / 2)
);
}
}
#endif