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chore(ppu): reimplement WindowLineCounter behaviour

This commit is contained in:
Rekai Nyangadzayi Musuka 2021-06-03 00:13:51 -05:00
parent 112454aa59
commit be39c249e1
1 changed files with 24 additions and 41 deletions
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65
src/ppu.rs
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@ -84,6 +84,13 @@ impl Ppu {
// Done with rendering this frame,
// we can reset the ppu x_pos and fetcher state now
// 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.fetch.back.window_line.increment();
}
self.x_pos = 0;
self.fetch.hblank_reset();
@ -179,8 +186,13 @@ impl Ppu {
fn scan_oam(&mut self) {
if self.scan_state.mode() == OamScanMode::Scan {
let sprite_height = self.control.obj_size().as_u8();
if !self.window_stat.coincidence() && self.scan_state.count() == 0 {
// Determine whether we should draw the window next frame
self.window_stat
.set_coincidence(self.pos.line_y == self.pos.window_y);
}
let sprite_height = self.control.obj_size().as_u8();
let index = self.scan_state.count();
let attr = self.oam.attribute(index as usize);
@ -295,6 +307,17 @@ impl Ppu {
}
}
if self.control.window_enabled()
&& !self.window_stat.should_draw()
&& self.window_stat.coincidence()
&& self.x_pos >= self.pos.window_x - 7
{
self.window_stat.set_should_draw(true);
self.fetch.back.reset();
self.fetch.x_pos = 0;
self.fifo.back.clear();
}
if self.fetch.back.is_enabled() {
match self.fetch.back.state {
TileNumber => {
@ -377,34 +400,6 @@ impl Ppu {
self.frame_buf[i..(i + rgba.len())].copy_from_slice(rgba);
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.fetch.back.window_line.checked() {
self.fetch.back.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);
}
if self.window_stat.coincidence()
&& self.control.window_enabled()
&& self.x_pos >= self.pos.window_x - 7
{
if !self.window_stat.should_draw() {
self.window_stat.set_should_draw(true);
self.fetch.back.reset();
self.fetch.x_pos = 0;
self.fifo.back.clear();
}
} else {
if self.window_stat.should_draw() {
self.window_stat.set_should_draw(false);
}
}
}
}
}
@ -784,7 +779,6 @@ impl Fetcher for BackgroundFetcher {
self.reset();
self.is_window_title = false;
self.window_line.hblank_reset();
self.enabled = true;
}
@ -827,26 +821,15 @@ impl Fetcher for ObjectFetcher {
#[derive(Debug, Clone, Copy, Default)]
struct WindowLineCounter {
count: u8,
checked: bool,
}
impl WindowLineCounter {
pub fn checked(&self) -> bool {
self.checked
}
pub fn increment(&mut self) {
self.count += 1;
self.checked = true;
}
pub fn hblank_reset(&mut self) {
self.checked = false;
}
pub fn vblank_reset(&mut self) {
self.count = 0;
self.checked = false;
}
pub fn count(&self) -> u8 {