1045 lines
28 KiB
Rust
1045 lines
28 KiB
Rust
use crate::bus::BusIo;
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use crate::instruction::Cycle;
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use crate::GB_HEIGHT;
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use crate::GB_WIDTH;
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use dma::DirectMemoryAccess;
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use std::collections::VecDeque;
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use std::convert::TryInto;
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pub(crate) use types::PpuMode;
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use types::{
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BackgroundPalette, GrayShade, LCDControl, LCDStatus, ObjectFlags, ObjectPalette,
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ObjectPaletteId, ObjectSize, Pixels, RenderPriority, TileDataAddress,
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};
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mod dma;
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mod types;
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const VRAM_SIZE: usize = 0x2000;
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const OAM_SIZE: usize = 0xA0;
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const PPU_START_ADDRESS: usize = 0x8000;
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// OAM Scan
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const OBJECT_LIMIT: usize = 10;
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// // White
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// const WHITE: [u8; 4] = 0xFFFFFFFFu32.to_be_bytes();
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// const LIGHT_GRAY: [u8; 4] = 0xB6B6B6FFu32.to_be_bytes();
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// const DARK_GRAY: [u8; 4] = 0x676767FFu32.to_be_bytes();
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// const BLACK: [u8; 4] = 0x000000FFu32.to_be_bytes();
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// Green
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const WHITE: [u8; 4] = 0xE3EEC0FFu32.to_be_bytes();
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const LIGHT_GRAY: [u8; 4] = 0xAEBA89FFu32.to_be_bytes();
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const DARK_GRAY: [u8; 4] = 0x5E6745FFu32.to_be_bytes();
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const BLACK: [u8; 4] = 0x202020FFu32.to_be_bytes();
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#[derive(Debug, Clone)]
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pub struct Ppu {
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pub(crate) int: Interrupt,
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/// 0xFF40 | LCDC - LCD Control
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pub(crate) ctrl: LCDControl,
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/// 0xFF41 | STAT - LCD Status
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pub(crate) stat: LCDStatus,
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pub(crate) monochrome: Monochrome,
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pub(crate) pos: ScreenPosition,
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vram: Box<[u8; VRAM_SIZE]>,
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pub(crate) oam: ObjectAttributeTable,
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pub(crate) dma: DirectMemoryAccess,
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scan_state: OamScanState,
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fetch: PixelFetcher,
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fifo: FifoRenderer,
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obj_buffer: ObjectBuffer,
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frame_buf: Box<[u8; GB_WIDTH * GB_HEIGHT * 4]>,
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window_stat: WindowStatus,
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x_pos: u8,
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cycle: Cycle,
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}
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impl BusIo for Ppu {
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fn read_byte(&self, addr: u16) -> u8 {
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self.vram[addr as usize - PPU_START_ADDRESS]
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}
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fn write_byte(&mut self, addr: u16, byte: u8) {
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self.vram[addr as usize - PPU_START_ADDRESS] = byte;
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}
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}
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impl Ppu {
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pub(crate) fn clock(&mut self) {
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if !self.ctrl.lcd_enabled() {
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return;
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}
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self.cycle += 1;
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match self.stat.mode() {
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PpuMode::OamScan => {
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if self.cycle >= 80.into() {
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self.stat.set_mode(PpuMode::Drawing);
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}
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self.scan_oam();
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}
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PpuMode::Drawing => {
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if self.ctrl.lcd_enabled() {
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// Only Draw when the LCD Is Enabled
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self.draw(self.cycle.into());
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} else {
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self.reset();
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}
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if self.x_pos == 160 {
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if self.stat.hblank_int() {
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// Enable HBlank LCDStat Interrupt
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self.int.set_lcd_stat(true);
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}
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// Done with rendering this frame,
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// we can reset the ppu x_pos and fetcher state now
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// Increment Window line counter if scanline had any window pixels on it
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// only increment once per scanline though
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if self.window_stat.should_draw() {
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self.fetch.back.window_line.increment();
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}
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self.x_pos = 0;
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self.fetch.hblank_reset();
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self.window_stat.hblank_reset();
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self.obj_buffer.clear();
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self.fifo.back.clear();
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self.fifo.obj.clear();
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self.stat.set_mode(PpuMode::HBlank);
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}
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}
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PpuMode::HBlank => {
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// This mode will always end at 456 cycles
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if self.cycle >= 456.into() {
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self.cycle %= 456;
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self.pos.line_y += 1;
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// Update LY==LYC bit
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let are_equal = self.pos.line_y == self.pos.ly_compare;
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self.stat.set_coincidence(are_equal);
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// Request LCD STAT interrupt if conditions met
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if self.stat.coincidence_int() && are_equal {
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self.int.set_lcd_stat(true);
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}
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let next_mode = if self.pos.line_y >= 144 {
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// Request VBlank Interrupt
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self.int.set_vblank(true);
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// Reset Window Line Counter in Fetcher
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self.fetch.vblank_reset();
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// Reset WY=LY coincidence flag
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self.window_stat.vblank_reset();
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if self.stat.vblank_int() {
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// Enable Vblank LCDStat Interrupt
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self.int.set_lcd_stat(true);
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}
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PpuMode::VBlank
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} else {
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if self.stat.oam_int() {
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// Enable OAM LCDStat Interrupt
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self.int.set_lcd_stat(true);
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}
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self.scan_state.reset();
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PpuMode::OamScan
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};
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self.stat.set_mode(next_mode);
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}
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}
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PpuMode::VBlank => {
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if self.cycle > 456.into() {
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self.cycle %= 456;
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self.pos.line_y += 1;
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// Update LY==LYC bit
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let are_equal = self.pos.line_y == self.pos.ly_compare;
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self.stat.set_coincidence(are_equal);
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// Request LCD STAT interrupt if conditions met
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if self.stat.coincidence_int() && are_equal {
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self.int.set_lcd_stat(true);
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}
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if self.pos.line_y == 154 {
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self.pos.line_y = 0;
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if self.stat.oam_int() {
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// Enable OAM LCDStat Interrupt
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self.int.set_lcd_stat(true);
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}
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self.scan_state.reset();
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self.stat.set_mode(PpuMode::OamScan);
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}
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}
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}
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}
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}
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fn scan_oam(&mut self) {
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match self.scan_state.mode() {
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OamScanMode::Scan if !self.dma.is_active() => {
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if !self.window_stat.coincidence() && self.scan_state.count() == 0 {
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// Determine whether we should draw the window next frame
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self.window_stat
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.set_coincidence(self.pos.line_y == self.pos.window_y);
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}
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let sprite_height = self.ctrl.obj_size().as_u8();
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let index = self.scan_state.count();
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let attr = self.oam.attribute(index as usize);
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let line_y = self.pos.line_y + 16;
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if attr.x > 0
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&& line_y >= attr.y
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&& line_y < (attr.y + sprite_height)
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&& !self.obj_buffer.is_full()
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{
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self.obj_buffer.add(attr);
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}
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self.scan_state.increase();
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}
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_ => {}
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}
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self.scan_state.next();
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}
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fn draw(&mut self, _cycle: u32) {
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use FetcherState::*;
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let iter = &mut self.obj_buffer.iter();
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let obj_attr = loop {
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match iter.flatten().next() {
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Some(attr) => {
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if attr.x <= (self.x_pos + 8) {
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self.fetch.back.reset();
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self.fetch.back.pause();
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self.fifo.pause();
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break Some(*attr);
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}
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}
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None => break None,
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}
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};
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if let Some(attr) = obj_attr {
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match self.fetch.obj.state {
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TileNumber => {
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self.fetch.obj.tile.with_id(attr.tile_index);
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self.fetch.obj.next(ToLowByteSleep);
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}
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ToLowByteSleep => self.fetch.obj.next(TileLowByte),
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TileLowByte => {
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let obj_size = self.ctrl.obj_size();
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let addr = PixelFetcher::get_obj_addr(&attr, &self.pos, obj_size);
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let byte = self.read_byte(addr);
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self.fetch.obj.tile.with_low_byte(byte);
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self.fetch.obj.next(ToHighByteSleep);
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}
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ToHighByteSleep => self.fetch.obj.next(TileHighByte),
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TileHighByte => {
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let obj_size = self.ctrl.obj_size();
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let addr = PixelFetcher::get_obj_addr(&attr, &self.pos, obj_size);
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let byte = self.read_byte(addr + 1);
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self.fetch.obj.tile.with_high_byte(byte);
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self.fetch.obj.next(ToFifoSleep);
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}
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ToFifoSleep => self.fetch.obj.next(SendToFifoOne),
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SendToFifoOne => {
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// Load into Fifo
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let (high, low) = self
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.fetch
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.obj
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.tile
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.bytes()
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.expect("Tile high & low bytes are present");
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let tbpp = Pixels::from_bytes(high, low);
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let palette = match attr.flags.palette() {
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ObjectPaletteId::Zero => self.monochrome.obj_palette_0,
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ObjectPaletteId::One => self.monochrome.obj_palette_1,
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};
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let end = Pixels::PIXEL_COUNT - self.fifo.obj.len();
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let start = Pixels::PIXEL_COUNT - end;
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let x_flip = attr.flags.x_flip();
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for i in start..Pixels::PIXEL_COUNT {
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let x = if x_flip { 7 - i } else { i };
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let priority = attr.flags.priority();
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let shade = palette.shade(tbpp.shade_id(x));
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let fifo_info = ObjectFifoInfo {
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shade,
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palette,
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priority,
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};
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self.fifo.obj.push_back(fifo_info);
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}
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self.fetch.back.resume();
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self.fifo.resume();
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self.obj_buffer.remove(&attr);
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self.fetch.obj.next(SendToFifoTwo);
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}
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SendToFifoTwo => self.fetch.obj.reset(),
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}
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}
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if self.ctrl.window_enabled()
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&& !self.window_stat.should_draw()
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&& self.window_stat.coincidence()
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&& self.x_pos as i16 >= self.pos.window_x as i16 - 7
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{
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self.window_stat.set_should_draw(true);
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self.fetch.back.reset();
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self.fetch.x_pos = 0;
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self.fifo.back.clear();
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}
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if self.fetch.back.is_enabled() {
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match self.fetch.back.state {
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TileNumber => {
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let x_pos = self.fetch.x_pos;
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self.fetch
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.back
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.should_render_window(self.window_stat.should_draw());
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let addr = self.fetch.bg_tile_num_addr(&self.ctrl, &self.pos, x_pos);
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let id = self.read_byte(addr);
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self.fetch.back.tile.with_id(id);
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// Move on to the Next state in 2 T-cycles
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self.fetch.back.next(ToLowByteSleep);
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}
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ToLowByteSleep => self.fetch.back.next(TileLowByte),
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TileLowByte => {
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let addr = self.fetch.bg_byte_addr(&self.ctrl, &self.pos);
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let low = self.read_byte(addr);
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self.fetch.back.tile.with_low_byte(low);
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self.fetch.back.next(ToHighByteSleep);
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}
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ToHighByteSleep => self.fetch.back.next(TileHighByte),
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TileHighByte => {
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let addr = self.fetch.bg_byte_addr(&self.ctrl, &self.pos);
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let high = self.read_byte(addr + 1);
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self.fetch.back.tile.with_high_byte(high);
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self.fetch.back.next(ToFifoSleep);
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}
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ToFifoSleep => self.fetch.back.next(SendToFifoOne),
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SendToFifoOne => {
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self.fetch.back.next(SendToFifoTwo);
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}
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SendToFifoTwo => {
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let palette = &self.monochrome.bg_palette;
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self.fetch.send_to_fifo(&mut self.fifo, palette);
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self.fetch.x_pos += 1;
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self.fetch.back.next(TileNumber);
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self.fetch.back.tile = Default::default();
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}
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}
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}
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if self.fifo.is_enabled() {
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use RenderPriority::*;
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if self.x_pos == 0 && !self.fifo.back.is_empty() {
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let to_discard = self.pos.scroll_x % 8;
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for _ in 0..to_discard {
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let _ = self.fifo.back.pop_front();
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}
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}
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// Handle Background Pixel and Sprite FIFO
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let bg_enabled = self.ctrl.bg_win_enabled();
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let obj_enabled = self.ctrl.obj_enabled();
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let i0_colour = self.monochrome.bg_palette.i0_colour();
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// FIXME: Is this the correct behaviour
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let rgba_opt = self.fifo.back.pop_front().map(|bg_info| {
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let bg_shade = if bg_enabled { bg_info.shade } else { i0_colour };
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match self.fifo.obj.pop_front() {
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Some(obj_info) => {
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if obj_enabled {
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match (obj_info.shade, obj_info.priority) {
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(Some(obj_shade), BackgroundAndWindow) => match bg_info.shade {
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GrayShade::White => obj_shade.into_rgba(),
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_ => bg_shade.into_rgba(),
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},
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(Some(obj_shade), Object) => obj_shade.into_rgba(),
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(None, _) => bg_shade.into_rgba(),
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}
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} else {
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bg_shade.into_rgba()
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}
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}
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None => bg_shade.into_rgba(),
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}
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});
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if let Some(rgba) = rgba_opt.as_ref() {
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let y = self.pos.line_y as usize;
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let x = self.x_pos as usize;
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let i = (GB_WIDTH * 4) * y + (x * 4);
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self.frame_buf[i..(i + rgba.len())].copy_from_slice(rgba);
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self.x_pos += 1;
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}
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}
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}
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fn reset(&mut self) {
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self.pos.line_y = 0;
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self.stat.set_mode(PpuMode::HBlank);
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// TODO: Is this an unnecessary performance hit?
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let mut blank = WHITE.repeat(self.frame_buf.len() / 4);
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self.frame_buf.swap_with_slice(&mut blank);
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}
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pub fn copy_to_gui(&self, frame: &mut [u8]) {
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frame.copy_from_slice(self.frame_buf.as_ref());
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}
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}
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impl Default for Ppu {
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fn default() -> Self {
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Self {
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vram: Box::new([0u8; VRAM_SIZE]),
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cycle: Cycle::new(0),
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frame_buf: Box::new([0; GB_WIDTH * GB_HEIGHT * 4]),
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int: Default::default(),
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ctrl: Default::default(),
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monochrome: Default::default(),
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pos: Default::default(),
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stat: Default::default(),
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oam: Default::default(),
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scan_state: Default::default(),
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fetch: Default::default(),
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fifo: Default::default(),
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obj_buffer: Default::default(),
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window_stat: Default::default(),
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dma: Default::default(),
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x_pos: 0,
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}
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}
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}
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#[derive(Debug, Clone, Copy, Default)]
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pub(crate) struct Interrupt {
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_vblank: bool,
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_lcd_stat: bool,
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}
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impl Interrupt {
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pub(crate) fn vblank(&self) -> bool {
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self._vblank
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}
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pub(crate) fn set_vblank(&mut self, enabled: bool) {
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self._vblank = enabled;
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}
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pub(crate) fn lcd_stat(&self) -> bool {
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self._lcd_stat
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}
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pub(crate) fn set_lcd_stat(&mut self, enabled: bool) {
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self._lcd_stat = enabled;
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}
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}
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#[derive(Debug, Clone, Copy, Default)]
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pub(crate) struct ScreenPosition {
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/// 0xFF42 | SCY - Scroll Y
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pub(crate) scroll_y: u8,
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/// 0xFF43 | SCX - Scroll X
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pub(crate) scroll_x: u8,
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/// 0xFF44 | LY - LCD Y Coordinate
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pub(crate) line_y: u8,
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/// 0xFF45 | LYC - LY Compare
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pub(crate) ly_compare: u8,
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/// 0xFF4A | WY - Window Y Position
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pub(crate) window_y: u8,
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/// 0xFF4B | WX - Window X Position
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pub(crate) window_x: u8,
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}
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|
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#[derive(Debug, Clone, Copy, Default)]
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pub(crate) struct Monochrome {
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/// 0xFF47 | BGP - Background Palette Data
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pub(crate) bg_palette: BackgroundPalette,
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/// 0xFF48 | OBP0 - Object Palette 0 Data
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pub(crate) obj_palette_0: ObjectPalette,
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/// 0xFF49 | OBP1 - Object Palette 1 Data
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pub(crate) obj_palette_1: ObjectPalette,
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}
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|
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#[derive(Debug, Clone)]
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pub(crate) struct ObjectAttributeTable {
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buf: Box<[u8; OAM_SIZE]>,
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}
|
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|
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impl BusIo for ObjectAttributeTable {
|
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fn read_byte(&self, addr: u16) -> u8 {
|
|
let index = (addr - 0xFE00) as usize;
|
|
self.buf[index]
|
|
}
|
|
|
|
fn write_byte(&mut self, addr: u16, byte: u8) {
|
|
let index = (addr - 0xFE00) as usize;
|
|
self.buf[index] = byte;
|
|
}
|
|
}
|
|
|
|
impl ObjectAttributeTable {
|
|
fn attribute(&self, index: usize) -> ObjectAttribute {
|
|
let start = index * 4;
|
|
|
|
let slice: &[u8; 4] = self.buf[start..(start + 4)]
|
|
.try_into()
|
|
.expect("TryInto trait called on a &[u8; 4]");
|
|
|
|
slice.into()
|
|
}
|
|
}
|
|
|
|
impl Default for ObjectAttributeTable {
|
|
fn default() -> Self {
|
|
Self {
|
|
buf: Box::new([0; OAM_SIZE]),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq)]
|
|
struct ObjectAttribute {
|
|
y: u8,
|
|
x: u8,
|
|
tile_index: u8,
|
|
flags: ObjectFlags,
|
|
}
|
|
|
|
impl From<[u8; 4]> for ObjectAttribute {
|
|
fn from(bytes: [u8; 4]) -> Self {
|
|
Self {
|
|
y: bytes[0],
|
|
x: bytes[1],
|
|
tile_index: bytes[2],
|
|
flags: bytes[3].into(),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a> From<&'a [u8; 4]> for ObjectAttribute {
|
|
fn from(bytes: &'a [u8; 4]) -> Self {
|
|
Self {
|
|
y: bytes[0],
|
|
x: bytes[1],
|
|
tile_index: bytes[2],
|
|
flags: bytes[3].into(),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy)]
|
|
struct ObjectBuffer {
|
|
buf: [Option<ObjectAttribute>; OBJECT_LIMIT],
|
|
len: usize,
|
|
}
|
|
|
|
impl ObjectBuffer {
|
|
fn iter(&self) -> std::slice::Iter<'_, Option<ObjectAttribute>> {
|
|
self.into_iter()
|
|
}
|
|
}
|
|
|
|
impl<'a> IntoIterator for &'a ObjectBuffer {
|
|
type Item = &'a Option<ObjectAttribute>;
|
|
|
|
type IntoIter = std::slice::Iter<'a, Option<ObjectAttribute>>;
|
|
|
|
fn into_iter(self) -> Self::IntoIter {
|
|
self.buf.iter()
|
|
}
|
|
}
|
|
|
|
impl<'a> IntoIterator for &'a mut ObjectBuffer {
|
|
type Item = &'a Option<ObjectAttribute>;
|
|
|
|
type IntoIter = std::slice::Iter<'a, Option<ObjectAttribute>>;
|
|
|
|
fn into_iter(self) -> Self::IntoIter {
|
|
self.buf.iter()
|
|
}
|
|
}
|
|
|
|
impl ObjectBuffer {
|
|
fn is_full(&self) -> bool {
|
|
self.len == OBJECT_LIMIT
|
|
}
|
|
|
|
fn clear(&mut self) {
|
|
self.buf = [Default::default(); 10];
|
|
self.len = 0;
|
|
}
|
|
|
|
fn add(&mut self, attr: ObjectAttribute) {
|
|
self.buf[self.len] = Some(attr);
|
|
self.len += 1;
|
|
}
|
|
|
|
fn remove(&mut self, attr: &ObjectAttribute) {
|
|
let maybe_index = self.buf.iter().position(|maybe_attr| match maybe_attr {
|
|
Some(other_attr) => attr == other_attr,
|
|
None => false,
|
|
});
|
|
|
|
if let Some(i) = maybe_index {
|
|
self.buf[i] = None;
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Default for ObjectBuffer {
|
|
fn default() -> Self {
|
|
Self {
|
|
buf: [Default::default(); OBJECT_LIMIT],
|
|
len: Default::default(),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct PixelFetcher {
|
|
x_pos: u8,
|
|
back: BackgroundFetcher,
|
|
obj: ObjectFetcher,
|
|
}
|
|
|
|
impl PixelFetcher {
|
|
fn hblank_reset(&mut self) {
|
|
self.back.hblank_reset();
|
|
self.obj.hblank_reset();
|
|
self.x_pos = 0;
|
|
}
|
|
|
|
fn vblank_reset(&mut self) {
|
|
self.back.vblank_reset();
|
|
}
|
|
|
|
fn bg_tile_num_addr(&self, control: &LCDControl, pos: &ScreenPosition, x_pos: u8) -> u16 {
|
|
let line_y = pos.line_y;
|
|
let scroll_y = pos.scroll_y;
|
|
let scroll_x = pos.scroll_x;
|
|
let is_window = self.back.is_window_tile();
|
|
|
|
// Determine which tile map is being used
|
|
let tile_map = if is_window {
|
|
control.win_tile_map_addr()
|
|
} else {
|
|
control.bg_tile_map_addr()
|
|
};
|
|
let tile_map_addr = tile_map.into_address();
|
|
|
|
// Both Offsets are used to offset the tile map address we found above
|
|
// Offsets are ANDed wih 0x3FF so that we stay in bounds of tile map memory
|
|
|
|
let scx_offset = if is_window { 0 } else { scroll_x / 8 };
|
|
let y_offset = if is_window {
|
|
self.back.window_line.count() as u16 / 8
|
|
} else {
|
|
((line_y as u16 + scroll_y as u16) & 0xFF) / 8
|
|
};
|
|
|
|
let x_offset = (scx_offset + x_pos) & 0x1F;
|
|
let offset = (32 * y_offset) + (x_offset as u16);
|
|
|
|
tile_map_addr + (offset & 0x3FF)
|
|
}
|
|
|
|
fn bg_byte_addr(&mut self, control: &LCDControl, pos: &ScreenPosition) -> u16 {
|
|
let line_y = pos.line_y;
|
|
let scroll_y = pos.scroll_y;
|
|
let is_window = self.back.is_window_tile();
|
|
|
|
let id = self.back.tile.id.expect("Tile Number is present");
|
|
|
|
let tile_data_addr = match control.tile_data_addr() {
|
|
TileDataAddress::X8800 => 0x9000u16.wrapping_add(((id as i8) as i16 * 16) as u16),
|
|
TileDataAddress::X8000 => 0x8000 + (id as u16 * 16),
|
|
};
|
|
|
|
let offset = if is_window {
|
|
self.back.window_line.count() as u16 % 8
|
|
} else {
|
|
(line_y as u16 + scroll_y as u16) % 8
|
|
};
|
|
|
|
tile_data_addr + (offset * 2)
|
|
}
|
|
|
|
fn send_to_fifo(&self, fifo: &mut FifoRenderer, palette: &BackgroundPalette) {
|
|
let (high, low) = self
|
|
.back
|
|
.tile
|
|
.bytes()
|
|
.expect("Tile high & low bytes are present");
|
|
|
|
let tbpp = Pixels::from_bytes(high, low);
|
|
|
|
if fifo.back.is_empty() {
|
|
for x in 0..Pixels::PIXEL_COUNT {
|
|
let shade = palette.shade(tbpp.shade_id(x));
|
|
|
|
let fifo_info = BackgroundFifoInfo { shade };
|
|
fifo.back.push_back(fifo_info);
|
|
}
|
|
}
|
|
}
|
|
|
|
fn get_obj_addr(attr: &ObjectAttribute, pos: &ScreenPosition, size: ObjectSize) -> u16 {
|
|
let line_y = pos.line_y;
|
|
|
|
// TODO: Why is the offset 14 and 30 respectively?
|
|
let (id, flip_offset) = match size {
|
|
ObjectSize::Eight => (attr.tile_index, 14),
|
|
ObjectSize::Sixteen => (attr.tile_index & !0x01, 30),
|
|
};
|
|
|
|
let offset = 2 * (line_y - (attr.y - 16));
|
|
|
|
let final_offset = if attr.flags.y_flip() {
|
|
flip_offset - offset
|
|
} else {
|
|
offset
|
|
};
|
|
|
|
0x8000 + (id as u16 * 16) + final_offset as u16
|
|
}
|
|
}
|
|
|
|
trait Fetcher {
|
|
fn next(&mut self, state: FetcherState);
|
|
fn reset(&mut self);
|
|
fn hblank_reset(&mut self);
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy)]
|
|
struct BackgroundFetcher {
|
|
state: FetcherState,
|
|
tile: TileBuilder,
|
|
window_line: WindowLineCounter,
|
|
is_window_tile: bool,
|
|
enabled: bool,
|
|
}
|
|
|
|
impl BackgroundFetcher {
|
|
fn should_render_window(&mut self, value: bool) {
|
|
self.is_window_tile = value;
|
|
}
|
|
|
|
fn is_window_tile(&self) -> bool {
|
|
self.is_window_tile
|
|
}
|
|
|
|
fn pause(&mut self) {
|
|
self.enabled = false;
|
|
}
|
|
|
|
fn resume(&mut self) {
|
|
self.enabled = true;
|
|
}
|
|
|
|
fn is_enabled(&self) -> bool {
|
|
self.enabled
|
|
}
|
|
|
|
fn vblank_reset(&mut self) {
|
|
self.window_line.vblank_reset();
|
|
}
|
|
}
|
|
|
|
impl Fetcher for BackgroundFetcher {
|
|
fn next(&mut self, state: FetcherState) {
|
|
self.state = state
|
|
}
|
|
|
|
fn reset(&mut self) {
|
|
self.state = Default::default();
|
|
self.tile = Default::default();
|
|
}
|
|
|
|
fn hblank_reset(&mut self) {
|
|
self.reset();
|
|
|
|
self.is_window_tile = false;
|
|
|
|
self.enabled = true;
|
|
}
|
|
}
|
|
|
|
impl Default for BackgroundFetcher {
|
|
fn default() -> Self {
|
|
Self {
|
|
state: Default::default(),
|
|
tile: Default::default(),
|
|
is_window_tile: Default::default(),
|
|
window_line: Default::default(),
|
|
enabled: true,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct ObjectFetcher {
|
|
state: FetcherState,
|
|
tile: TileBuilder,
|
|
}
|
|
|
|
impl Fetcher for ObjectFetcher {
|
|
fn next(&mut self, state: FetcherState) {
|
|
self.state = state
|
|
}
|
|
|
|
fn reset(&mut self) {
|
|
self.state = Default::default();
|
|
self.tile = Default::default();
|
|
}
|
|
|
|
fn hblank_reset(&mut self) {
|
|
self.state = Default::default();
|
|
self.tile = Default::default();
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct WindowLineCounter {
|
|
count: u8,
|
|
}
|
|
|
|
impl WindowLineCounter {
|
|
fn increment(&mut self) {
|
|
self.count += 1;
|
|
}
|
|
|
|
fn vblank_reset(&mut self) {
|
|
self.count = 0;
|
|
}
|
|
|
|
fn count(&self) -> u8 {
|
|
self.count
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy)]
|
|
enum FetcherState {
|
|
TileNumber,
|
|
ToLowByteSleep,
|
|
TileLowByte,
|
|
ToHighByteSleep,
|
|
TileHighByte,
|
|
ToFifoSleep,
|
|
SendToFifoOne,
|
|
SendToFifoTwo,
|
|
}
|
|
|
|
impl Default for FetcherState {
|
|
fn default() -> Self {
|
|
Self::TileNumber
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct BackgroundFifoInfo {
|
|
shade: GrayShade,
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct ObjectFifoInfo {
|
|
shade: Option<GrayShade>,
|
|
palette: ObjectPalette,
|
|
priority: RenderPriority,
|
|
}
|
|
|
|
// FIXME: Fifo Registers have a known size. Are heap allocations
|
|
// really necessary here?
|
|
#[derive(Debug, Clone)]
|
|
struct FifoRenderer {
|
|
back: VecDeque<BackgroundFifoInfo>,
|
|
obj: VecDeque<ObjectFifoInfo>,
|
|
enabled: bool,
|
|
}
|
|
|
|
impl FifoRenderer {
|
|
fn is_enabled(&self) -> bool {
|
|
self.enabled
|
|
}
|
|
|
|
fn pause(&mut self) {
|
|
self.enabled = false;
|
|
}
|
|
|
|
fn resume(&mut self) {
|
|
self.enabled = true;
|
|
}
|
|
}
|
|
|
|
impl Default for FifoRenderer {
|
|
fn default() -> Self {
|
|
Self {
|
|
back: VecDeque::with_capacity(8),
|
|
obj: VecDeque::with_capacity(8),
|
|
enabled: true,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct TileBuilder {
|
|
id: Option<u8>,
|
|
low: Option<u8>,
|
|
high: Option<u8>,
|
|
}
|
|
|
|
impl TileBuilder {
|
|
fn with_id(&mut self, id: u8) {
|
|
self.id = Some(id);
|
|
}
|
|
|
|
fn with_low_byte(&mut self, data: u8) {
|
|
self.low = Some(data);
|
|
}
|
|
|
|
fn with_high_byte(&mut self, data: u8) {
|
|
self.high = Some(data);
|
|
}
|
|
|
|
fn bytes(&self) -> Option<(u8, u8)> {
|
|
self.high.zip(self.low)
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct OamScanState {
|
|
count: u8,
|
|
mode: OamScanMode,
|
|
}
|
|
|
|
impl OamScanState {
|
|
fn increase(&mut self) {
|
|
self.count += 1;
|
|
self.count %= 40;
|
|
}
|
|
|
|
fn reset(&mut self) {
|
|
self.count = Default::default();
|
|
self.mode = Default::default();
|
|
}
|
|
|
|
fn count(&self) -> u8 {
|
|
self.count
|
|
}
|
|
|
|
fn mode(&self) -> OamScanMode {
|
|
self.mode
|
|
}
|
|
|
|
fn next(&mut self) {
|
|
use OamScanMode::*;
|
|
|
|
self.mode = match self.mode {
|
|
Scan => Sleep,
|
|
Sleep => Scan,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, PartialEq)]
|
|
enum OamScanMode {
|
|
Scan,
|
|
Sleep,
|
|
}
|
|
|
|
impl Default for OamScanMode {
|
|
fn default() -> Self {
|
|
Self::Scan
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Clone, Copy, Default)]
|
|
struct WindowStatus {
|
|
/// This will be true if WY == LY at any point in the frame thus far
|
|
coincidence: bool,
|
|
/// This will be true if the conditions which tell the PPU to start
|
|
/// drawing from the window tile map is true
|
|
should_draw: bool,
|
|
}
|
|
|
|
impl WindowStatus {
|
|
fn should_draw(&self) -> bool {
|
|
self.should_draw
|
|
}
|
|
|
|
fn coincidence(&self) -> bool {
|
|
self.coincidence
|
|
}
|
|
|
|
fn set_should_draw(&mut self, value: bool) {
|
|
self.should_draw = value;
|
|
}
|
|
|
|
fn set_coincidence(&mut self, value: bool) {
|
|
self.coincidence = value;
|
|
}
|
|
|
|
fn hblank_reset(&mut self) {
|
|
self.should_draw = false;
|
|
}
|
|
|
|
fn vblank_reset(&mut self) {
|
|
self.coincidence = false;
|
|
}
|
|
}
|