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Unify API for 3 channel types #2

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Unify API for 3 channel types #2

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3019133
Unify access to several common channel fields
S11001001 Apr 28, 2017
b2b3431
Propagate apu channel property changes to cpu
S11001001 Apr 28, 2017
9a44d5d
Avoid duplicate borrow in step_envelope.go; compiles
S11001001 Apr 28, 2017
65a837f
Merge remote-tracking branch 'origin/master' into apu-fields
S11001001 Apr 30, 2017
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218 changes: 118 additions & 100 deletions src/apu.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,28 +11,94 @@ pub struct WaveChannel {
}

pub struct SquareChannel {
pub counter: u16,
pub enabled: bool,
pub wave_channel: WaveChannel,
pub envelope_pos: u8,
pub envelope_period: u8,
pub freq_pos: u32,
pub incr_vol: bool,
pub volume: u8,
pub wave_pos: usize,
pub duty_table: [u8; 32],
}

pub struct NoiseChannel {
pub counter: u16,
pub enabled: bool,
pub wave_channel: WaveChannel,
pub envelope_pos: u8,
pub volume: u8,
pub lfsr: u16,
pub freq_pos: u32,
pub incr_vol: bool,
pub envelope_period: u8,
}

pub trait HasWaveChannel {
fn wave_channel(&mut self) -> &mut WaveChannel;

fn counter(&mut self) -> &mut u16 {
&mut self.wave_channel().counter
}

fn enabled(&mut self) -> &mut bool {
&mut self.wave_channel().enabled
}

fn freq_pos(&mut self) -> &mut u32 {
&mut self.wave_channel().freq_pos
}

fn volume(&mut self) -> &mut u8 {
&mut self.wave_channel().volume
}
}

impl HasWaveChannel for WaveChannel {
fn wave_channel(&mut self) -> &mut WaveChannel {
self
}
}

impl HasWaveChannel for SquareChannel {
fn wave_channel(&mut self) -> &mut WaveChannel {
&mut self.wave_channel
}
}

impl HasWaveChannel for NoiseChannel {
fn wave_channel(&mut self) -> &mut WaveChannel {
&mut self.wave_channel
}
}

trait HasEnvelope {
fn envelope_pos(&mut self) -> &mut u8;
fn envelope_period(&mut self) -> &mut u8;
fn incr_vol(&mut self) -> &mut bool;
}

impl HasEnvelope for SquareChannel {
fn envelope_pos(&mut self) -> &mut u8 {
&mut self.envelope_pos
}

fn envelope_period(&mut self) -> &mut u8 {
&mut self.envelope_period
}

fn incr_vol(&mut self) -> &mut bool {
&mut self.incr_vol
}
}

impl HasEnvelope for NoiseChannel {
fn envelope_pos(&mut self) -> &mut u8 {
&mut self.envelope_pos
}

fn envelope_period(&mut self) -> &mut u8 {
&mut self.envelope_period
}

fn incr_vol(&mut self) -> &mut bool {
&mut self.incr_vol
}
}

pub struct Apu {
pub master_clock: u32,
pub length_clock: u32,
Expand Down Expand Up @@ -60,11 +126,8 @@ pub struct Apu {
impl Default for NoiseChannel {
fn default() -> NoiseChannel {
NoiseChannel {
counter: 0,
enabled: false,
wave_channel: Default::default(),
envelope_pos: 0,
volume: 0,
freq_pos: 0,
lfsr: 0x7FFF,
incr_vol: false,
envelope_period: 0,
Expand All @@ -75,11 +138,8 @@ impl Default for NoiseChannel {
impl Default for SquareChannel {
fn default() -> SquareChannel {
SquareChannel {
counter: 0,
enabled: false,
wave_channel: Default::default(),
envelope_pos: 0,
freq_pos: 0,
volume: 0,
incr_vol: false,
envelope_period: 0,
wave_pos: 0,
Expand Down Expand Up @@ -139,13 +199,13 @@ impl Apu {
pub fn gen_samples(sample_len: u8, cpu: &mut Cpu) {
let mut result = vec![0; sample_len as usize];
let nr51 = cpu.memory[0xFF25];
if cpu.apu.channel_1.enabled {
if *cpu.apu.channel_1.enabled() {
let registers = read_channel_1_addresses(cpu);
let mut channel = &mut cpu.apu.channel_1;
let sound = ((nr51 >> 4) & 1, nr51 & 1);
mix_channel_square(&mut result, channel, registers, sound);
}
if cpu.apu.channel_2.enabled {
if *cpu.apu.channel_2.enabled() {
let registers = read_channel_2_addresses(cpu);
let mut channel = &mut cpu.apu.channel_2;
let sound = ((nr51 >> 5) & 1, (nr51 >> 1) & 1);
Expand All @@ -162,7 +222,7 @@ pub fn gen_samples(sample_len: u8, cpu: &mut Cpu) {
channel_3_registers,
sound);
}
if cpu.apu.channel_4.enabled {
if *cpu.apu.channel_4.enabled() {
let channel_4_registers = cpu.memory[0xFF22];
let mut channel_4 = &mut cpu.apu.channel_4;
mix_channel_4(&mut result, &mut channel_4, channel_4_registers, nr51);
Expand All @@ -187,32 +247,19 @@ pub fn step_length(cpu: &mut Cpu) {
let channel_2_length_enable = read_address(0xFF19, cpu) & 0x40 != 0;
let channel_3_length_enable = read_address(0xFF1E, cpu) & 0x40 != 0;
let channel_4_length_enable = read_address(0xFF23, cpu) & 0x40 != 0;
if cpu.apu.channel_1.enabled && channel_1_length_enable {
if cpu.apu.channel_1.counter == 0 {
cpu.apu.channel_1.enabled = false;
}
cpu.apu.channel_1.counter -= 1;
}
if cpu.apu.channel_2.enabled && channel_2_length_enable {
if cpu.apu.channel_2.counter == 0 {
cpu.apu.channel_2.enabled = false;
}
cpu.apu.channel_2.counter -= 1;
}

if cpu.apu.channel_3.enabled && channel_3_length_enable {
if cpu.apu.channel_3.counter == 0 {
cpu.apu.channel_3.enabled = false;
}
cpu.apu.channel_3.counter -= 1;
}

if cpu.apu.channel_4.enabled && channel_4_length_enable {
if cpu.apu.channel_4.counter == 0 {
cpu.apu.channel_4.enabled = false;
fn go(channel: &mut WaveChannel, length_enable: bool) {
if channel.enabled && length_enable {
if channel.counter == 0 {
channel.enabled = false;
}
channel.counter -= 1;
}
cpu.apu.channel_4.counter -= 1;
}
go(&mut cpu.apu.channel_1.wave_channel, channel_1_length_enable);
go(&mut cpu.apu.channel_2.wave_channel, channel_2_length_enable);
go(&mut cpu.apu.channel_3, channel_3_length_enable);
go(&mut cpu.apu.channel_4.wave_channel, channel_4_length_enable);
}

#[allow(non_snake_case)]
Expand All @@ -223,18 +270,18 @@ pub fn mix_channel_square(result: &mut Vec<i16>,
let time_freq = (freq_hi as u16 & 0b111) << 8 | freq_lo as u16;
let duty = (duty_reg >> 6) as usize;
let not_time_freq = 4 * (2048 - time_freq as u32);
let init_volume = channel.volume as i16;
let init_volume = *channel.volume() as i16;
let volume = match left_out + right_out {
2 => (1 << 9) * init_volume,
1 => (1 << 8) * init_volume,
0 => 0,
_ => unreachable!(),
};
let init_freq = *channel.freq_pos();
let init_wave = channel.wave_pos;
let duty_start = duty * 8;
let duty_table = &channel.duty_table[duty_start..];
let downsample = 1 + 8192 / result.len();
let init_freq = channel.freq_pos;
let init_wave = channel.wave_pos;
let volume_on = volume != 0;
if volume_on {
for x in 0..result.len() {
Expand All @@ -253,9 +300,9 @@ pub fn mix_channel_square(result: &mut Vec<i16>,
(init_wave +
((8191 + not_time_freq as usize - init_freq as usize) /
not_time_freq as usize) as usize) % 8);
channel.freq_pos = cond!(init_freq < 8192,
(not_time_freq - (8192 - init_freq) % not_time_freq) % not_time_freq,
init_freq - 8192);
channel.wave_channel.freq_pos = cond!(init_freq < 8192,
(not_time_freq - (8192 - init_freq) % not_time_freq) % not_time_freq,
init_freq - 8192);
}

#[allow(non_snake_case)]
Expand Down Expand Up @@ -319,12 +366,12 @@ pub fn mix_channel_4(result: &mut Vec<i16>, channel: &mut NoiseChannel, nr43: u8
0 => 0,
_ => unreachable!(),
} as i16;
let volume_init = channel.volume as i16;
let volume_init = *channel.volume() as i16;
let volume = volume_step * volume_init;
let half_width = nr43 & 0x08 != 0; // whether the shift register is 15bits of 7 bits
if shift_clock_freq < 14 && timer_freq as u32 != 0 {
let downsample = 1 + 8192 / result.len();
let mut freq = channel.freq_pos;
let mut freq = *channel.freq_pos();
let mut sample_idx = 0;
for x in 0..8192 {
// cycles
Expand All @@ -347,7 +394,7 @@ pub fn mix_channel_4(result: &mut Vec<i16>, channel: &mut NoiseChannel, nr43: u8
sample_idx += 1;
}
}
channel.freq_pos = freq;
*channel.freq_pos() = freq;
}
}

Expand All @@ -368,7 +415,7 @@ pub fn step_sweep(cpu: &mut Cpu) {
// check again
let sweep_check = cpu.apu.freq_sweep(shift, negate);
if sweep_check > 2047 {
cpu.apu.channel_1.enabled = false;
*cpu.apu.channel_1.enabled() = false;
}
}
} else {
Expand All @@ -378,57 +425,28 @@ pub fn step_sweep(cpu: &mut Cpu) {
}

pub fn step_envelope(cpu: &mut Cpu) {
if cpu.apu.channel_1.enabled && cpu.apu.channel_1.envelope_period != 0 {
if cpu.apu.channel_1.incr_vol && cpu.apu.channel_1.volume < 15 {
if cpu.apu.channel_1.envelope_pos == 0 {
cpu.apu.channel_1.volume += 1;
cpu.apu.channel_1.envelope_pos = cpu.apu.channel_1.envelope_period;
} else {
cpu.apu.channel_1.envelope_pos -= 1;
}
} else if !cpu.apu.channel_1.incr_vol && cpu.apu.channel_1.volume > 0 {
if cpu.apu.channel_1.envelope_pos == 0 {
cpu.apu.channel_1.volume -= 1;
cpu.apu.channel_1.envelope_pos = cpu.apu.channel_1.envelope_period;
} else {
cpu.apu.channel_1.envelope_pos -= 1;
}
}
}
if cpu.apu.channel_2.enabled && cpu.apu.channel_2.envelope_period != 0 {
if cpu.apu.channel_2.incr_vol && cpu.apu.channel_2.volume < 15 {
if cpu.apu.channel_2.envelope_pos == 0 {
cpu.apu.channel_2.volume += 1;
cpu.apu.channel_2.envelope_pos = cpu.apu.channel_2.envelope_period;
} else {
cpu.apu.channel_2.envelope_pos -= 1;
}
} else if !cpu.apu.channel_2.incr_vol && cpu.apu.channel_2.volume > 0 {
if cpu.apu.channel_2.envelope_pos == 0 {
cpu.apu.channel_2.volume -= 1;
cpu.apu.channel_2.envelope_pos = cpu.apu.channel_2.envelope_period;
} else {
cpu.apu.channel_2.envelope_pos -= 1;
}
}
}
if cpu.apu.channel_4.enabled && cpu.apu.channel_4.envelope_period != 0 {
if cpu.apu.channel_4.incr_vol && cpu.apu.channel_4.volume < 15 {
if cpu.apu.channel_4.envelope_pos == 0 {
cpu.apu.channel_4.volume += 1;
cpu.apu.channel_4.envelope_pos = cpu.apu.channel_4.envelope_period;
} else {
cpu.apu.channel_4.envelope_pos -= 1;
}
} else if !cpu.apu.channel_4.incr_vol && cpu.apu.channel_4.volume > 0 {
if cpu.apu.channel_4.envelope_pos == 0 {
cpu.apu.channel_4.volume -= 1;
cpu.apu.channel_4.envelope_pos = cpu.apu.channel_4.envelope_period;
} else {
cpu.apu.channel_4.envelope_pos -= 1;
fn go<T: HasWaveChannel + HasEnvelope>(channel: &mut T) {
if *channel.enabled() && *channel.envelope_period() != 0 {
if *channel.incr_vol() && *channel.volume() < 15 {
if *channel.envelope_pos() == 0 {
*channel.volume() += 1;
*channel.envelope_pos() = *channel.envelope_period();
} else {
*channel.envelope_pos() -= 1;
}
} else if !*channel.incr_vol() && *channel.volume() > 0 {
if *channel.envelope_pos() == 0 {
*channel.volume() -= 1;
*channel.envelope_pos() = *channel.envelope_period();
} else {
*channel.envelope_pos() -= 1;
}
}
}
}
go(&mut cpu.apu.channel_1);
go(&mut cpu.apu.channel_2);
go(&mut cpu.apu.channel_4);
}

pub fn step(cpu: &mut Cpu) {
Expand Down
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