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Refactor PPU interrupt requests and fix Scroll X

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This commit is contained in:
Franco Colmenarez
2021-11-03 22:24:31 -05:00
parent 60fd55abca
commit c5ff92c0ab
5 changed files with 58 additions and 43 deletions
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src/ppu.rs
+47 -30
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@@ -91,6 +91,7 @@ pub enum LCDStatus {
}
pub struct PPU {
prev_state: bool,
cycles: Cycles,
rgba_frame: [[u8; 4]; FRAME_BUFFER_LENGTH as usize],
}
@@ -103,6 +104,7 @@ enum TileNumber {
impl PPU {
pub fn new() -> Self {
Self {
prev_state: false,
cycles: Cycles(0),
rgba_frame: [[0xFF, 0xFF, 0xFF, 0]; FRAME_BUFFER_LENGTH as usize],
}
@@ -134,9 +136,7 @@ impl PPU {
if self.cycles.0 == 0 {
// Mode 2 OAM scan
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::SearchingOAM), true);
if PPU::get_lcd_status(bus, LCDStatus::Mode2OAMInterrupt) {
PPU::request_interrupt(bus, Interrupt::LCDSTAT);
}
self.stat_interrupt(bus);
} else if self.cycles.0 == 80 + 1 {
// Mode 3 drawing pixel line. This could also last 289 cycles
self.draw_line(bus, frame_buffer);
@@ -144,16 +144,13 @@ impl PPU {
} else if self.cycles.0 == 80 + 172 + 1 {
// Mode 0 Horizontal blank. This could last 87 or 204 cycles depending on the mode 3
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::HBlank), true);
if PPU::get_lcd_status(bus, LCDStatus::Mode0HBlankInterrupt) {
PPU::request_interrupt(bus, Interrupt::LCDSTAT);
}
self.stat_interrupt(bus);
}
} else if PPU::get_lcd_y(bus) == 144 && self.cycles.0 == 0 {
// Mode 1 Vertical blank
bus.set_interrupt_flag(Interrupt::VBlank, true);
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank), true);
if PPU::get_lcd_status(bus, LCDStatus::Mode1VBlankInterrupt) {
PPU::request_interrupt(bus, Interrupt::VBlank);
}
self.stat_interrupt(bus);
}
self.increment_cycles(Cycles(1));
@@ -167,21 +164,28 @@ impl PPU {
if PPU::get_lcd_y(bus) > 153 {
PPU::set_lcd_y(bus, 0);
}
PPU::check_lyc(bus);
self.check_lyc(bus);
}
}
fn check_lyc(bus: &mut Bus) {
fn stat_interrupt(&mut self, bus: &mut Bus) {
let state = self.prev_state;
self.prev_state = (
(PPU::get_lcd_status(bus, LCDStatus::Mode2OAMInterrupt) && PPU::get_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::SearchingOAM))) ||
(PPU::get_lcd_status(bus, LCDStatus::Mode0HBlankInterrupt) && PPU::get_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::HBlank))) ||
(PPU::get_lcd_status(bus, LCDStatus::Mode1VBlankInterrupt) && PPU::get_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank)))
);
if self.prev_state && !state {
bus.set_interrupt_flag(Interrupt::LCDSTAT, true);
}
}
fn check_lyc(&mut self, bus: &mut Bus) {
let lyc_compare = PPU::get_lcd_y(bus) == bus.read(LCD_Y_COMPARE_ADDRESS);
if PPU::get_lcd_status(bus, LCDStatus::LYCInterrupt) && lyc_compare {
PPU::set_lcd_status(bus, LCDStatus::LYCFlag, lyc_compare);
PPU::request_interrupt(bus, Interrupt::LCDSTAT);
}
}
fn request_interrupt(bus: &mut Bus, interrupt: Interrupt) {
if PPU::get_lcd_control(bus, LCDControl::LCDEnable) {
bus.set_interrupt_flag(interrupt, true);
PPU::set_lcd_status(bus, LCDStatus::LYCFlag, lyc_compare);
if lyc_compare && PPU::get_lcd_status(bus, LCDStatus::LYCInterrupt) {
bus.set_interrupt_flag(Interrupt::LCDSTAT, true);
self.prev_state = true;
}
}
@@ -216,7 +220,7 @@ impl PPU {
fn set_lcd_control(bus: &mut Bus, control: LCDControl, val: bool) {
let mut byte = bus.read(LCD_CONTROL_ADDRESS);
bus.write(LCD_CONTROL_ADDRESS, control.set(byte, val));
bus.force_write(LCD_CONTROL_ADDRESS, control.set(byte, val));
}
pub fn get_lcd_status(bus: &Bus, status: LCDStatus) -> bool {
@@ -251,7 +255,7 @@ impl PPU {
LCDStatusModeFlag::TransferringToLCD => (byte & 0b11111100) | 3,
},
};
bus.write(LCD_STATUS_ADDRESS, byte);
bus.force_write(LCD_STATUS_ADDRESS, byte);
}
fn get_tile_bytes(x: u8, y: u8, tile_number_type: TileNumber, default_method: bool, bus: &Bus) -> (u8, u8) {
@@ -277,15 +281,15 @@ impl PPU {
fn get_window_pixel(lcd_x: u8, bus: &Bus) -> Option<Pixel> {
let lcd_y = PPU::get_lcd_y(bus);
let window_x = (PPU::get_window_x(bus) as i8 - 7) as u8;
let window_x = PPU::get_window_x(bus);
let window_y = PPU::get_window_y(bus);
if !PPU::get_lcd_control(bus, LCDControl::WindowEnable) || window_x != lcd_x || window_y != lcd_y {
if !PPU::get_lcd_control(bus, LCDControl::WindowEnable) || lcd_x < (window_x.saturating_sub(7)) || window_y != lcd_y {
return None;
}
let x = lcd_x - window_x;
let y = lcd_y - window_x;
let x = lcd_x.wrapping_sub(window_x.saturating_sub(7));
let y = lcd_y.wrapping_sub(window_y);
let default_mode = PPU::get_lcd_control(bus, LCDControl::TileAddressMode);
let tilemap_area = match PPU::get_lcd_control(bus, LCDControl::WindowTileMapAddress) {
@@ -320,23 +324,36 @@ impl PPU {
let bg_pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2, palette);
for pixel in bg_pixels {
let idx = (lcd_x as usize + (lcd_y as usize * LCD_WIDTH as usize)) * 4;
let pixel = bg_pixels[x.rem_euclid(8) as usize];
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
if let Some(window_pixel) = PPU::get_window_pixel(lcd_x, bus) {
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
}
lcd_x += 1;
/* for pixel in bg_pixels {
let idx = (lcd_x as usize + (lcd_y as usize * LCD_WIDTH as usize)) * 4;
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
frame_buffer[idx + 3] = rgba[3];
if let Some(window_pixel) = PPU::get_window_pixel(lcd_x, bus) {
let rgba = PPU::get_rgba(pixel);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
frame_buffer[idx + 3] = rgba[3];
}
lcd_x += 1;
}
} */
}
}