Raimon Zamora
8fc576cda2
- [FIX] si el canal està desactivat, no fer el envelope sweep - [FIX] Se miraba el bit incorrecte per a determinar si el envelope sweep anava amunt o avall
251 lines
7.7 KiB
C++
251 lines
7.7 KiB
C++
#include "APU.h"
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#include <SDL2/SDL.h>
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namespace APU
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{
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#define AUDIO_BUFFER_SIZE 2048
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const float cycles_per_sample = 4194304.0f / 11025.0f;
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SDL_AudioDeviceID sdlAudioDevice;
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uint8_t sound_buffer[AUDIO_BUFFER_SIZE];
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uint16_t sound_pos=0;
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uint16_t sound_start=0;
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float t_sound = 0.0f;
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uint32_t samples_generated=0;
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uint32_t samples_time =0;
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uint32_t samples_t=0;
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#define CH1 channels[0]
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#define CH2 channels[1]
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#define CH3 channels[2]
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#define CH4 channels[3]
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#define apu_enabled (NR52&0x80)
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#define DAC1_enabled ((NR12&0xf8)!=0)
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uint8_t duty_cycles[4][8] = {
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{1, 1, 1, 1, 1, 1, 1, 0},
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{1, 1, 1, 1, 1, 1, 0, 0},
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{1, 1, 1, 1, 0, 0, 0, 0},
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{1, 1, 0, 0, 0, 0, 0, 0},
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};
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struct channel_t
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{
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bool enabled = false;
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uint8_t length_timer = 0;
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bool length_enable = false;
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uint16_t period_divider = 0;
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uint8_t duty_cycle=0;
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uint8_t duty_step = 0;
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uint8_t volume = 0;
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uint8_t envelope_sweep_timer=0;
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};
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channel_t channels[4];
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uint8_t DIVAPU = 0;
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uint8_t NR10 = 0; // 0xff10 - Sound channel 1 sweep
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uint8_t NR11 = 0; // 0xff11 - Sound channel 1 length timer & duty cycle
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uint8_t NR12 = 0; // 0xff12 - Sound channel 1 volume & envelope
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uint8_t NR13 = 0; // 0xff13 - Sound channel 1 period low
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uint8_t NR14 = 0; // 0xff14 - Sound channel 1 period high & control
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// 0xff15 - Not used?
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uint8_t NR21 = 0; // 0xff16 - Sound channel 2 length timer & duty cycle
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uint8_t NR22 = 0; // 0xff17 - Sound channel 2 volume & envelope
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uint8_t NR23 = 0; // 0xff18 - Sound channel 2 period low
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uint8_t NR24 = 0; // 0xff19 - Sound channel 2 period high & control
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uint8_t NR30 = 0; // 0xff1a - Sound channel 3 DAC enable
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uint8_t NR31 = 0; // 0xff1b - Sound channel 3 length timer
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uint8_t NR32 = 0; // 0xff1c - Sound channel 3 output level
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uint8_t NR33 = 0; // 0xff1d - Sound channel 3 period low
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uint8_t NR34 = 0; // 0xff1e - Sound channel 3 period high & control
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// 0xff1f - Not used?
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uint8_t NR41 = 0; // 0xff20 - Sound channel 4 length timer
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uint8_t NR42 = 0; // 0xff21 - Sound channel 4 volume & envelope
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uint8_t NR43 = 0; // 0xff22 - Sound channel 4 frequency & randomness
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uint8_t NR44 = 0; // 0xff23 - Sound channel 4 control
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uint8_t NR50 = 0; // 0xff24 - Master volume & VIN panning
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uint8_t NR51 = 0; // 0xff25 - Sound panning
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uint8_t NR52 = 0; // 0xff26 - Sound on/off
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// 0xff27-0xff2f - Not used?
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uint8_t WaveRAM[16]; // 0xff30-0xff3f
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void audioCallback(void * userdata, uint8_t * stream, int len)
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{
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for (int i=0;i<len;++i)
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{
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stream[i] = sound_buffer[(sound_start++)&(AUDIO_BUFFER_SIZE-1)];
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}
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}
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void silence()
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{
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SDL_PauseAudioDevice(sdlAudioDevice, 1);
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}
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void resume()
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{
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SDL_PauseAudioDevice(sdlAudioDevice, 0);
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}
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void init()
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{
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SDL_AudioSpec audioSpec{11025, AUDIO_U8, 1, 0, AUDIO_BUFFER_SIZE>>2, 0, 0, &audioCallback, NULL};
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sdlAudioDevice = SDL_OpenAudioDevice(NULL, 0, &audioSpec, NULL, 0);
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resume();
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//samples_time=SDL_GetTicks();
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}
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void reset()
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{
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NR10 = 0;
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NR11 = 0;
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NR12 = 0;
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NR13 = 0;
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NR14 = 0;
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NR21 = 0;
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NR22 = 0;
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NR23 = 0;
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NR24 = 0;
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NR30 = 0;
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NR31 = 0;
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NR32 = 0;
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NR33 = 0;
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NR34 = 0;
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NR41 = 0;
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NR42 = 0;
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NR43 = 0;
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NR44 = 0;
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NR50 = 0;
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NR51 = 0;
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NR52 = 0;
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CH1.duty_cycle = 0;
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}
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void triggerCH1()
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{
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CH1.enabled = true;
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CH1.length_timer=NR11&0x3f;
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CH1.period_divider = NR13 | ((NR14 &0x7)<<8);
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// envelope timer is reset
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CH1.volume = NR12>>4;
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// sweep does several things (check documentation)
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}
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uint8_t readRegister(uint16_t address)
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{
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switch(address)
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{
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case 0xff10: return NR10; break;
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case 0xff11: return NR11 & 0xc0; break;
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case 0xff12: return NR12; break;
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case 0xff13: return 0x00; break;
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case 0xff14: return NR14 & 0x40; break;
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case 0xff24: return NR50; break;
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case 0xff25: return NR51; break;
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case 0xff26: return NR52; break;
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}
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return 0x00;
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}
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void writeRegister(uint16_t address, uint8_t value)
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{
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if (!apu_enabled && (address!=0xff26)) return;
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switch(address)
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{
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case 0xff10: NR10 = value; break;
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case 0xff11: NR11 = value; CH1.length_timer=NR11&0x3f; CH1.duty_cycle = NR11>>6; break;
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case 0xff12: NR12 = value; break;
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case 0xff13: NR13 = value; break;
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case 0xff14: NR14 = value; CH1.length_enable=(value&0x40); if (value&0x80) triggerCH1(); break;
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case 0xff24: NR50 = value; break;
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case 0xff25: NR51 = value; break;
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case 0xff26: if (value&0x80) reset(); NR52 = (value&0x80) | (NR52 & 0x0f); break;
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}
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}
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uint8_t DIVAPU_envelope_sweep = 0;
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uint8_t DIVAPU_length = 0;
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uint8_t DIVAPU_CH1_freq_sweep = 0;
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void incDIVAPU()
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{
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DIVAPU++;
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DIVAPU_length++;
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if (DIVAPU_length==2) {
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DIVAPU_length=0;
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if (CH1.enabled && CH1.length_enable) {
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CH1.length_timer++;
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if (CH1.length_timer==0) {
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CH1.enabled = false;
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}
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}
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}
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DIVAPU_CH1_freq_sweep++;
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if (DIVAPU_CH1_freq_sweep==4) {
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DIVAPU_CH1_freq_sweep=0;
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// Do the freq sweep thing
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}
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DIVAPU_envelope_sweep++;
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if (DIVAPU_envelope_sweep==8) {
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DIVAPU_envelope_sweep=0;
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if ( CH1.enabled && (NR12&0x7) ) { // If sweep pace != 0, envelope sweep is enabled
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CH1.envelope_sweep_timer++;
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if ( CH1.envelope_sweep_timer == (NR12&0x07) ) { // if timer == envelope sweep, increase or decrease volume
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CH1.envelope_sweep_timer=0;
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if (NR12&0x8) { // bit set increases, reset decreases
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if (CH1.volume<0x0f) CH1.volume++;
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} else {
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if (CH1.volume>0) CH1.volume--;
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}
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}
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}
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// Do the envelope sweep thing
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}
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}
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uint32_t dots = 0;
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void update(uint32_t dt)
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{
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dots += dt;
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while (dots>=4) {
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dots -= 4;
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CH1.period_divider++;
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if (CH1.period_divider==2048) {
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CH1.period_divider = NR13 | ((NR14 &0x7)<<8);
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CH1.duty_step++;
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if (CH1.duty_step==8) CH1.duty_step=0;
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}
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}
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t_sound += dt;
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samples_t += dt;
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if (t_sound>=cycles_per_sample) {
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t_sound-=cycles_per_sample;
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//samples_generated++;
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/*if (samples_t >=z80::getClock()) {
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//printf("%i\n", samples_generated);
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samples_generated=0;
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samples_t = 0;
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}*/
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/*if (SDL_GetTicks()>=samples_time+1000) {
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printf("%i\n", samples_generated);
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samples_generated=0;
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samples_time = SDL_GetTicks();
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}*/
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//sound_pos = (sound_pos+1) & 0x3ff;
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//sound_buffer[sound_pos] = ear*128;
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//if (sound_pos>=AUDIO_BUFFER_SIZE) sound_pos = last_1 = 0;
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uint8_t sample = 0;
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if (apu_enabled && DAC1_enabled) sample = (duty_cycles[CH1.duty_cycle][CH1.duty_step]*CH1.volume)<<2;
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sound_buffer[(sound_pos++)&(AUDIO_BUFFER_SIZE-1)] = sample;
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//if (ear) last_1 = sound_pos;
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}
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}
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} |