Zelda64Recomp/ultramodern/audio.cpp

68 lines
2.3 KiB
C++

#include "ultra64.h"
#include "ultramodern.hpp"
#include <cassert>
static uint32_t sample_rate = 48000;
static ultramodern::audio_callbacks_t audio_callbacks;
void set_audio_callbacks(const ultramodern::audio_callbacks_t& callbacks) {
audio_callbacks = callbacks;
}
void ultramodern::init_audio() {
// Pick an initial dummy sample rate; this will be set by the game later to the true sample rate.
set_audio_frequency(48000);
}
void ultramodern::set_audio_frequency(uint32_t freq) {
if (audio_callbacks.set_frequency) {
audio_callbacks.set_frequency(freq);
}
sample_rate = freq;
}
void ultramodern::queue_audio_buffer(RDRAM_ARG PTR(int16_t) audio_data_, uint32_t byte_count) {
// Ensure that the byte count is an integer multiple of samples.
assert((byte_count & 1) == 0);
// Calculate the number of samples from the number of bytes.
uint32_t sample_count = byte_count / sizeof(int16_t);
// Queue the swapped audio data.
if (audio_callbacks.queue_samples) {
audio_callbacks.queue_samples(TO_PTR(int16_t, audio_data_), sample_count);
}
}
// For SDL2
//uint32_t buffer_offset_frames = 1;
// For Godot
float buffer_offset_frames = 0.5f;
// If there's ever any audio popping, check here first. Some games are very sensitive to
// the remaining sample count and reporting a number that's too high here can lead to issues.
// Reporting a number that's too low can lead to audio lag in some games.
uint32_t ultramodern::get_remaining_audio_bytes() {
// Get the number of remaining buffered audio bytes.
uint32_t buffered_byte_count;
if (audio_callbacks.get_frames_remaining != nullptr) {
buffered_byte_count = audio_callbacks.get_frames_remaining() * 2 * sizeof(int16_t);
}
else {
buffered_byte_count = 100;
}
// Adjust the reported count to be some number of refreshes in the future, which helps ensure that
// there are enough samples even if the audio thread experiences a small amount of lag. This prevents
// audio popping on games that use the buffered audio byte count to determine how many samples
// to generate.
uint32_t samples_per_vi = (sample_rate / 60);
if (buffered_byte_count > static_cast<uint32_t>(buffer_offset_frames * sizeof(int16_t) * samples_per_vi)) {
buffered_byte_count -= static_cast<uint32_t>(buffer_offset_frames * sizeof(int16_t) * samples_per_vi);
}
else {
buffered_byte_count = 0;
}
return buffered_byte_count;
}