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chore(ppu): rearrange/reimplement some behaviour

This commit is contained in:
Rekai Nyangadzayi Musuka 2021-05-05 17:47:06 -05:00
parent abdff1251e
commit af3edde2ab
1 changed files with 15 additions and 15 deletions
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30
src/ppu.rs
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@ -292,13 +292,6 @@ impl Ppu {
if self.fetcher.bg.is_enabled() {
match self.fetcher.bg.state {
TileNumber => {
// Increment Window line counter if scanline had any window pixels on it
// only increment once per scanline though
if self.window_stat.should_draw() {
self.fetcher.bg.window_line.increment();
}
let x_pos = self.fetcher.x_pos;
let addr = self.fetcher.bg_tile_num_addr(
@ -388,6 +381,13 @@ impl Ppu {
self.x_pos += 1;
// Increment Window line counter if scanline had any window pixels on it
// only increment once per scanline though
if self.window_stat.should_draw() && !self.fetcher.bg.window_line.checked() {
self.fetcher.bg.window_line.increment();
}
// Determine whether we should draw the window next frame
if self.pos.line_y == self.pos.window_y {
self.window_stat.set_coincidence(true);
@ -396,6 +396,7 @@ impl Ppu {
if self.window_stat.coincidence()
&& self.control.window_enabled()
&& self.x_pos >= self.pos.window_x - 7
&& !self.window_stat.should_draw()
{
self.window_stat.set_should_draw(true);
self.fetcher.bg.reset();
@ -670,15 +671,14 @@ impl PixelFetcher {
let scx_offset = if window { 0u16 } else { scroll_x as u16 / 8 } & 0x1F;
let y_offset = if window {
32 * (self.bg.window_line.count() as u16 / 8)
self.bg.window_line.count() as u16 / 8
} else {
(32 * (((line_y as u16 + scroll_y as u16) & 0xFF) / 8)) & 0x3FF
};
((line_y as u16 + scroll_y as u16) & 0xFF) / 8
} * 32;
let x_offset = (x_pos as u16 + scx_offset) & 0x3FF;
let y_offset = y_offset;
let x_offset = x_pos as u16 + scx_offset;
tile_map_addr + x_offset + y_offset
tile_map_addr + ((x_offset + y_offset) & 0x3FF)
}
fn bg_byte_low_addr(
@ -697,11 +697,11 @@ impl PixelFetcher {
TileDataAddress::X8000 => 0x8000 + (id as u16).wrapping_mul(16),
};
let offset = 2 * if window {
let offset = if window {
self.bg.window_line.count() % 8
} else {
(line_y + scroll_y) % 8
};
} * 2;
tile_data_addr + offset as u16
}