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Per pixel rendering PPU

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This commit is contained in:
Franco Colmenarez 2021-11-22 20:38:01 -05:00
parent d619c653f5
commit 23e7607319
1 changed files with 51 additions and 42 deletions
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93
src/ppu.rs
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@ -134,7 +134,6 @@ struct Sprite {
x_flip: bool,
y_flip: bool,
over_bg: bool,
is_long: bool,
bit_pixels: Option<[u8; 8]>,
}
@ -143,7 +142,11 @@ impl Sprite {
self.x
}
pub fn get_pixel(&mut self, lcd_x: u8, lcd_y: u8, vram: &[u8], last_bg_index: u8) -> Option<(Pixel, bool)> {
pub fn get_pixel(&mut self, lcd_x: u8, lcd_y: u8, vram: &[u8], last_bg_index: u8, lcd_control: u8) -> Option<(Pixel, bool)> {
if !LCDControl::ObjectEnable.get(lcd_control) {
return None;
}
if lcd_x < self.x.saturating_sub(8) || lcd_x >= self.x {
return None;
}
@ -152,7 +155,9 @@ impl Sprite {
return None;
}
let height: u8 = match self.is_long {
let is_long = LCDControl::ObjectSize.get(lcd_control);
let height: u8 = match is_long {
true => 16,
false => 8,
};
@ -176,9 +181,9 @@ impl Sprite {
None => {
let mut tile_number = self.tile_number;
if self.is_long && x <= 7 {
if is_long && x <= 7 {
tile_number = tile_number & 0xFE;
} else if self.is_long && x > 7 {
} else if is_long && x > 7 {
tile_number = tile_number | 0x01;
}
@ -210,6 +215,7 @@ pub struct PPU {
background_priority: bool,
window_enable: bool,
lcd_enable: bool,
window_drawn: bool,
cycles: Cycles,
sprite_buffer: Vec<Sprite>,
window_y_counter: u8,
@ -219,6 +225,7 @@ pub struct PPU {
current_background_pixels: Option<[u8; 8]>,
current_window_pixels: Option<[u8; 8]>,
lcd_y: u8,
lcd_x: u8,
scroll_x: u8,
scroll_y: u8,
window_x: u8,
@ -236,6 +243,7 @@ impl PPU {
lcdstat_request: false,
background_priority: false,
window_enable: false,
window_drawn: false,
lcd_enable: false,
cycles: Cycles(0),
sprite_buffer: Vec::new(),
@ -246,6 +254,7 @@ impl PPU {
current_background_pixels: None,
current_window_pixels: None,
lcd_y: 0,
lcd_x: 0,
scroll_x: 0,
scroll_y: 0,
window_x: 0,
@ -295,6 +304,8 @@ impl PPU {
pub fn get_register(&self, address: u16) -> u8 {
if address == LCD_CONTROL_ADDRESS {
return self.lcd_control;
} else if address == LCD_Y_ADDRESS {
return self.lcd_y;
}
self.io_registers[(address - 0xFF40) as usize]
}
@ -307,7 +318,7 @@ impl PPU {
// Check if LCD is being turned on or off
self.lcd_enable = get_bit(data, BitIndex::I7);
if !get_bit(data, BitIndex::I7) || (get_bit(data, BitIndex::I7) && !get_bit(self.lcd_control, BitIndex::I7)) {
self.io_registers[LCD_Y_ADDRESS as usize - 0xFF40] = 0x00;
self.lcd_y = 0x00;
// Set Hblank
let byte = self.io_registers[LCD_STATUS_ADDRESS as usize - 0xFF40];
self.io_registers[LCD_STATUS_ADDRESS as usize - 0xFF40] = byte & 0b11111100;
@ -339,7 +350,6 @@ impl PPU {
self.increment_cycles(cycles);
return;
}
self.lcd_y = self.get_register(LCD_Y_ADDRESS);
if self.lcd_y < 144 {
if self.cycles.0 <= 80 && !self.get_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::SearchingOAM)) {
@ -347,16 +357,13 @@ impl PPU {
self.set_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::SearchingOAM), true);
self.stat_interrupt();
self.oam_search();
} else if self.cycles.0 > 80 && self.cycles.0 <= 80 + 172 && !self.get_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::TransferringToLCD)) {
} else if self.cycles.0 > 80 && self.cycles.0 <= 80 + 172 {
// Mode 3 drawing pixel line. This could also last 289 cycles
self.scroll_x = self.get_register(SCROLL_X_ADDRESS);
self.scroll_y = self.get_register(SCROLL_Y_ADDRESS);
self.window_x = self.get_register(WINDOW_X_ADDRESS);
self.window_y = self.get_register(WINDOW_Y_ADDRESS);
self.window_enable = self.get_lcd_control(LCDControl::WindowEnable);
self.background_priority = self.get_lcd_control(LCDControl::BackgroundPriority);
self.set_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::TransferringToLCD), true);
self.draw_line(frame_buffer);
if !self.get_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::TransferringToLCD)) {
self.window_drawn = false;
self.set_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::TransferringToLCD), true);
}
self.draw_line(cycles, frame_buffer);
} else if self.cycles.0 > 80 + 172 && self.cycles.0 <= 80 + 172 + 204 && !self.get_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::HBlank)) {
// Mode 0 Horizontal blank. This could last 87 or 204 cycles depending on the mode 3
self.set_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::HBlank), true);
@ -364,7 +371,6 @@ impl PPU {
}
} else if self.lcd_y >= 144 && !self.get_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank)) {
// Mode 1 Vertical blank
self.window_y_counter = 0;
self.set_lcd_status(LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank), true);
self.set_interrupt(Interrupt::VBlank, true);
self.stat_interrupt();
@ -377,12 +383,16 @@ impl PPU {
self.reset_cycles();
self.lcd_y = self.lcd_y.wrapping_add(1);
self.lcd_x = 0;
if self.window_drawn {
self.window_y_counter += 1;
}
// Frame completed
if self.lcd_y > 153 {
self.window_y_counter = 0;
self.lcd_y = 0;
}
self.force_set_register(LCD_Y_ADDRESS, self.lcd_y);
self.stat_interrupt();
}
}
@ -421,10 +431,7 @@ impl PPU {
let long_sprites = self.get_lcd_control(LCDControl::ObjectSize);
let mut addr = SPRITE_ATTRIBUTE_TABLE.min().unwrap();
while addr <= SPRITE_ATTRIBUTE_TABLE.max().unwrap() {
// The gameboy only supports 10 sprites per line,
// but since we are on an emulator we can avoud that limitation
if self.sprite_buffer.len() >= 10 {
// todo!("Make a setting for the 10 sprites per scanline");
break;
}
let y = self.read_oam(addr);
@ -469,7 +476,6 @@ impl PPU {
y,
tile_number,
palette_zero,
is_long: long_sprites,
palette: match palette_zero {
true => palette_0,
false => palette_1,
@ -485,10 +491,10 @@ impl PPU {
self.sprite_buffer.sort_by(|a, b| a.x().cmp(&b.x()));
}
fn find_sprite_pixel(&mut self, lcd_x: u8) -> Option<(Pixel, bool)> {
fn find_sprite_pixel(&mut self) -> Option<(Pixel, bool)> {
let lcd_y = self.lcd_y;
for sprite in &mut self.sprite_buffer {
if let Some(pixel) = sprite.get_pixel(lcd_x, lcd_y, &self.vram, self.last_bg_index) {
if let Some(pixel) = sprite.get_pixel(self.lcd_x, lcd_y, &self.vram, self.last_bg_index, self.lcd_control) {
return Some(pixel);
}
}
@ -553,12 +559,13 @@ impl PPU {
(self.read_vram(addr), self.read_vram(addr + 1))
}
fn get_window_pixel(&mut self, lcd_x: u8) -> Option<Pixel> {
fn get_window_pixel(&mut self) -> Option<Pixel> {
if !self.window_enable {
return None;
}
let lcd_y = self.lcd_y;
let lcd_x = self.lcd_x;
let window_x = self.window_x;
let window_y = self.window_y;
@ -602,11 +609,12 @@ impl PPU {
Some(PPU::get_pixel(PPU::get_palette(bit_pixel, self.bg_palette)))
}
fn get_background_pixel(&mut self, lcd_x: u8) -> Option<Pixel> {
fn get_background_pixel(&mut self) -> Option<Pixel> {
if !self.background_priority {
return None;
}
let lcd_y = self.lcd_y;
let lcd_x = self.lcd_x;
let y = lcd_y.wrapping_add(self.scroll_y);
let x = lcd_x.wrapping_add(self.scroll_x);
let bit_pixel_index = x.rem_euclid(8) as usize;
@ -637,34 +645,37 @@ impl PPU {
Some(PPU::get_pixel(PPU::get_palette(bit_pixel, self.bg_palette)))
}
fn draw_line(&mut self, frame_buffer: &mut [u8]) {
let lcd_y = self.lcd_y;
if lcd_y as u32 >= LCD_HEIGHT {
fn draw_line(&mut self, cycles: Cycles, frame_buffer: &mut [u8]) {
if self.lcd_y as u32 >= LCD_HEIGHT {
return;
}
self.scroll_x = self.get_register(SCROLL_X_ADDRESS);
self.scroll_y = self.get_register(SCROLL_Y_ADDRESS);
self.window_x = self.get_register(WINDOW_X_ADDRESS);
self.window_y = self.get_register(WINDOW_Y_ADDRESS);
self.window_enable = self.get_lcd_control(LCDControl::WindowEnable);
self.background_priority = self.get_lcd_control(LCDControl::BackgroundPriority);
self.current_background_pixels = None;
self.current_window_pixels = None;
self.bg_palette = self.get_register(BACKGROUND_PALETTE_ADDRESS);
let mut lcd_x: u8 = 0;
let mut window_drawn = false;
while (lcd_x as u32) < LCD_WIDTH {
let idx = (lcd_x as usize + (lcd_y as usize * LCD_WIDTH as usize)) * 4;
let mut count = 0;
while count < cycles.0 && (self.lcd_x as u32) < LCD_WIDTH {
let idx = (self.lcd_x as usize + (self.lcd_y as usize * LCD_WIDTH as usize)) * 4;
if let Some(window_pixel) = self.get_window_pixel(lcd_x) {
window_drawn = true;
if let Some(window_pixel) = self.get_window_pixel() {
self.window_drawn = true;
let rgba = PPU::get_rgba(window_pixel, WINDOW_COLORS);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
} else if let Some(background_pixel) = self.get_background_pixel(lcd_x) {
} else if let Some(background_pixel) = self.get_background_pixel() {
let rgba = PPU::get_rgba(background_pixel, BACKGROUND_COLORS);
frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2];
}
if self.get_lcd_control(LCDControl::ObjectEnable) {
if let Some((sprite_pixel, palette_zero)) = self.find_sprite_pixel(lcd_x) {
if let Some((sprite_pixel, palette_zero)) = self.find_sprite_pixel() {
let rgba = PPU::get_rgba(sprite_pixel, match palette_zero {
true => SPRITE_0_COLORS,
false => SPRITE_1_COLORS,
@ -675,10 +686,8 @@ impl PPU {
}
}
lcd_x += 1;
}
if window_drawn {
self.window_y_counter += 1;
self.lcd_x += 1;
count += 1;
}
}