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Fix window and implement sprite over background

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This commit is contained in:
Franco Colmenarez 2021-11-09 15:34:37 -05:00
parent 2474cd72b7
commit aa30b98679
1 changed files with 50 additions and 44 deletions
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94
src/ppu.rs
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@ -23,8 +23,8 @@ pub const DMA_ADDRESS: u16 = 0xFF46;
pub const BACKGROUND_PALETTE_ADDRESS: u16 = 0xFF47; pub const BACKGROUND_PALETTE_ADDRESS: u16 = 0xFF47;
pub const OBJECT_PALETTE_0_ADDRESS: u16 = 0xFF48; pub const OBJECT_PALETTE_0_ADDRESS: u16 = 0xFF48;
pub const OBJECT_PALETTE_1_ADDRESS: u16 = 0xFF49; pub const OBJECT_PALETTE_1_ADDRESS: u16 = 0xFF49;
pub const WINDOW_X_ADDRESS: u16 = 0xFF4A; pub const WINDOW_X_ADDRESS: u16 = 0xFF4B;
pub const WINDOW_Y_ADDRESS: u16 = 0xFF4B; pub const WINDOW_Y_ADDRESS: u16 = 0xFF4A;
pub const TILE_MAP_ADDRESS: u16 = 0x9800; pub const TILE_MAP_ADDRESS: u16 = 0x9800;
#[derive(Debug, Copy, Clone)] #[derive(Debug, Copy, Clone)]
@ -89,12 +89,6 @@ pub enum LCDStatus {
ModeFlag(LCDStatusModeFlag), ModeFlag(LCDStatusModeFlag),
} }
pub struct PPU {
state: bool,
cycles: Cycles,
sprite_buffer: Vec<Sprite>,
}
struct Sprite { struct Sprite {
x: u8, x: u8,
y: u8, y: u8,
@ -111,13 +105,13 @@ impl Sprite {
self.x self.x
} }
pub fn get_pixel(&self, lcd_x: u8, lcd_y: u8, bus: &Bus) -> Option<Pixel> { pub fn get_pixel(&self, lcd_x: u8, lcd_y: u8, bus: &Bus, last_bg_index: u8) -> Option<Pixel> {
if lcd_x < self.x.saturating_sub(8) || lcd_x >= self.x { if lcd_x < self.x.saturating_sub(8) || lcd_x >= self.x {
return None; return None;
} }
if self.over_bg { if self.over_bg && (last_bg_index & 0b11) != 0 {
// todo!("Implement over_bg sprite property"); return None;
} }
let height: u8 = match self.is_long { let height: u8 = match self.is_long {
@ -151,9 +145,11 @@ impl Sprite {
let tile_byte_1 = bus.read(addr); let tile_byte_1 = bus.read(addr);
let tile_byte_2 = bus.read(addr + 1); let tile_byte_2 = bus.read(addr + 1);
let pixel_index = (x as usize).rem_euclid(8); let pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2);
if PPU::get_two_bit_byte_pixels(tile_byte_1, tile_byte_2)[pixel_index] == 0 { let index = (x as usize).rem_euclid(8);
if pixels[index] == 0 {
return None; return None;
} }
@ -161,18 +157,26 @@ impl Sprite {
true => bus.read(OBJECT_PALETTE_1_ADDRESS), true => bus.read(OBJECT_PALETTE_1_ADDRESS),
false => bus.read(OBJECT_PALETTE_0_ADDRESS), false => bus.read(OBJECT_PALETTE_0_ADDRESS),
}; };
let pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2, palette); Some(PPU::get_pixel(PPU::get_palette(pixels[index], palette)))
Some(pixels[pixel_index])
} }
} }
pub struct PPU {
state: bool,
cycles: Cycles,
sprite_buffer: Vec<Sprite>,
window_y_counter: u8,
last_bg_index: u8,
}
impl PPU { impl PPU {
pub fn new() -> Self { pub fn new() -> Self {
Self { Self {
state: false, state: false,
cycles: Cycles(0), cycles: Cycles(0),
sprite_buffer: Vec::new(), sprite_buffer: Vec::new(),
window_y_counter: 0,
last_bg_index: 0,
} }
} }
@ -219,9 +223,11 @@ impl PPU {
self.reset_cycles(); self.reset_cycles();
PPU::set_lcd_y(bus, PPU::get_lcd_y(bus).wrapping_add(1)); PPU::set_lcd_y(bus, PPU::get_lcd_y(bus).wrapping_add(1));
// Frame completed // Frame completed
if PPU::get_lcd_y(bus) > 153 { if PPU::get_lcd_y(bus) > 153 {
PPU::set_lcd_y(bus, 0); PPU::set_lcd_y(bus, 0);
self.window_y_counter = 0;
} }
// self.check_lyc(bus); // self.check_lyc(bus);
self.stat_interrupt(bus); self.stat_interrupt(bus);
@ -273,7 +279,7 @@ impl PPU {
// but since we are on an emulator we can avoud that limitation // but since we are on an emulator we can avoud that limitation
if self.sprite_buffer.len() >= 10 { if self.sprite_buffer.len() >= 10 {
// todo!("Make a setting for the 10 sprites per scanline"); // todo!("Make a setting for the 10 sprites per scanline");
// break; break;
} }
let y = bus.read(addr); let y = bus.read(addr);
let x = bus.read(addr + 1); let x = bus.read(addr + 1);
@ -318,7 +324,7 @@ impl PPU {
fn find_sprite_pixel(&self, lcd_x: u8, bus: &Bus) -> Option<Pixel> { fn find_sprite_pixel(&self, lcd_x: u8, bus: &Bus) -> Option<Pixel> {
let lcd_y = PPU::get_lcd_y(bus); let lcd_y = PPU::get_lcd_y(bus);
for sprite in &self.sprite_buffer { for sprite in &self.sprite_buffer {
if let Some(pixel) = sprite.get_pixel(lcd_x, lcd_y, bus) { if let Some(pixel) = sprite.get_pixel(lcd_x, lcd_y, bus, self.last_bg_index) {
return Some(pixel); return Some(pixel);
} }
} }
@ -408,17 +414,23 @@ impl PPU {
(bus.read(addr), bus.read(addr + 1)) (bus.read(addr), bus.read(addr + 1))
} }
fn get_window_pixel(lcd_x: u8, bus: &Bus) -> Option<Pixel> { fn get_window_pixel(&mut self, lcd_x: u8, bus: &Bus) -> Option<Pixel> {
let lcd_y = PPU::get_lcd_y(bus); let lcd_y = PPU::get_lcd_y(bus);
let window_x = PPU::get_window_x(bus); let window_x = PPU::get_window_x(bus);
let window_y = PPU::get_window_y(bus); let window_y = PPU::get_window_y(bus);
if !PPU::get_lcd_control(bus, LCDControl::WindowEnable) || lcd_x < (window_x.saturating_sub(7)) || window_y != lcd_y { if
!PPU::get_lcd_control(bus, LCDControl::WindowEnable) ||
lcd_x < window_x.saturating_sub(7) ||
lcd_y < window_y ||
window_y >= 144 ||
window_x.saturating_sub(7) >= 160
{
return None; return None;
} }
let x = lcd_x.wrapping_sub(window_x.saturating_sub(7)); let x = lcd_x.wrapping_sub(window_x.saturating_sub(7));
let y = lcd_y.wrapping_sub(window_y); let y = self.window_y_counter;
let default_mode = PPU::get_lcd_control(bus, LCDControl::TileAddressMode); let default_mode = PPU::get_lcd_control(bus, LCDControl::TileAddressMode);
let tilemap_area = match PPU::get_lcd_control(bus, LCDControl::WindowTileMapAddress) { let tilemap_area = match PPU::get_lcd_control(bus, LCDControl::WindowTileMapAddress) {
@ -428,12 +440,14 @@ impl PPU {
let (tile_byte_1, tile_byte_2) = PPU::get_tile_bytes(x, y, tilemap_area, default_mode, bus); let (tile_byte_1, tile_byte_2) = PPU::get_tile_bytes(x, y, tilemap_area, default_mode, bus);
let palette = bus.read(BACKGROUND_PALETTE_ADDRESS); let palette = bus.read(BACKGROUND_PALETTE_ADDRESS);
let pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2, palette); let pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2);
let index = pixels[(x as usize).rem_euclid(8)];
self.last_bg_index = index & 0b11;
Some(pixels[(x as usize).rem_euclid(8)]) Some(PPU::get_pixel(PPU::get_palette(index, palette)))
} }
fn get_background_pixel(lcd_x: u8, bus: &Bus) -> Option<Pixel> { fn get_background_pixel(&mut self, lcd_x: u8, bus: &Bus) -> Option<Pixel> {
if !PPU::get_lcd_control(bus, LCDControl::BackgroundPriority) { if !PPU::get_lcd_control(bus, LCDControl::BackgroundPriority) {
return None; return None;
} }
@ -449,10 +463,11 @@ impl PPU {
}; };
let (tile_byte_1, tile_byte_2) = PPU::get_tile_bytes(x, y, tilemap_area, default_mode, bus); let (tile_byte_1, tile_byte_2) = PPU::get_tile_bytes(x, y, tilemap_area, default_mode, bus);
let bg_pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2, palette); let bg_pixels = PPU::get_byte_pixels(tile_byte_1, tile_byte_2);
let pixel = bg_pixels[x.rem_euclid(8) as usize]; let index = bg_pixels[x.rem_euclid(8) as usize];
self.last_bg_index = index & 0b11;
Some(pixel) Some(PPU::get_pixel(PPU::get_palette(index, palette)))
} }
fn draw_line(&mut self, bus: &Bus, frame_buffer: &mut [u8]) { fn draw_line(&mut self, bus: &Bus, frame_buffer: &mut [u8]) {
@ -461,22 +476,23 @@ impl PPU {
return; return;
} }
let mut lcd_x: u8 = 0; let mut lcd_x: u8 = 0;
let mut window_drawn = false;
while (lcd_x as u32) < LCD_WIDTH { while (lcd_x as u32) < LCD_WIDTH {
let idx = (lcd_x as usize + (lcd_y as usize * LCD_WIDTH as usize)) * 4; let idx = (lcd_x as usize + (lcd_y as usize * LCD_WIDTH as usize)) * 4;
if let Some(background_pixel) = PPU::get_background_pixel(lcd_x, bus) { if let Some(background_pixel) = self.get_background_pixel(lcd_x, bus) {
let rgba = PPU::get_rgba(background_pixel); let rgba = PPU::get_rgba(background_pixel);
frame_buffer[idx] = rgba[0]; frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1]; frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2]; frame_buffer[idx + 2] = rgba[2];
} }
if let Some(window_pixel) = PPU::get_window_pixel(lcd_x, bus) { if let Some(window_pixel) = self.get_window_pixel(lcd_x, bus) {
window_drawn = true;
let rgba = PPU::get_rgba(window_pixel); let rgba = PPU::get_rgba(window_pixel);
frame_buffer[idx] = rgba[0]; frame_buffer[idx] = rgba[0];
frame_buffer[idx + 1] = rgba[1]; frame_buffer[idx + 1] = rgba[1];
frame_buffer[idx + 2] = rgba[2]; frame_buffer[idx + 2] = rgba[2];
} }
if let Some(sprite_pixel) = self.find_sprite_pixel(lcd_x, bus) { if let Some(sprite_pixel) = self.find_sprite_pixel(lcd_x, bus) {
let rgba = PPU::get_rgba(sprite_pixel); let rgba = PPU::get_rgba(sprite_pixel);
frame_buffer[idx] = rgba[0]; frame_buffer[idx] = rgba[0];
@ -486,6 +502,9 @@ impl PPU {
lcd_x += 1; lcd_x += 1;
} }
if window_drawn {
self.window_y_counter += 1;
}
} }
fn get_palette(index: u8, palette_byte: u8) -> u8 { fn get_palette(index: u8, palette_byte: u8) -> u8 {
@ -517,7 +536,7 @@ impl PPU {
} }
} }
fn get_two_bit_byte_pixels(byte1: u8, byte2: u8) -> [u8; 8] { fn get_byte_pixels(byte1: u8, byte2: u8) -> [u8; 8] {
[ [
((byte1 >> 7) & 0b01) | ((byte2 >> 6) & 0b10), ((byte1 >> 7) & 0b01) | ((byte2 >> 6) & 0b10),
((byte1 >> 6) & 0b01) | ((byte2 >> 5) & 0b10), ((byte1 >> 6) & 0b01) | ((byte2 >> 5) & 0b10),
@ -529,17 +548,4 @@ impl PPU {
(byte1 & 0b01) | ((byte2 << 1) & 0b10), (byte1 & 0b01) | ((byte2 << 1) & 0b10),
] ]
} }
fn get_byte_pixels(byte1: u8, byte2: u8, palette: u8) -> [Pixel; 8] {
[
PPU::get_pixel(PPU::get_palette(((byte1 >> 7) & 0b01) | ((byte2 >> 6) & 0b10), palette)),
PPU::get_pixel(PPU::get_palette(((byte1 >> 6) & 0b01) | ((byte2 >> 5) & 0b10), palette)),
PPU::get_pixel(PPU::get_palette(((byte1 >> 5) & 0b01) | ((byte2 >> 4) & 0b10), palette)),
PPU::get_pixel(PPU::get_palette(((byte1 >> 4) & 0b01) | ((byte2 >> 3) & 0b10), palette)),
PPU::get_pixel(PPU::get_palette(((byte1 >> 3) & 0b01) | ((byte2 >> 2) & 0b10), palette)),
PPU::get_pixel(PPU::get_palette(((byte1 >> 2) & 0b01) | ((byte2 >> 1) & 0b10), palette)),
PPU::get_pixel(PPU::get_palette(((byte1 >> 1) & 0b01) | (byte2 & 0b10), palette)),
PPU::get_pixel(PPU::get_palette((byte1 & 0b01) | ((byte2 << 1) & 0b10), palette)),
]
}
} }