chore(ppu): improve accuracy of pixel fifo

This commit is contained in:
Rekai Nyangadzayi Musuka 2021-08-14 23:47:16 -05:00
parent d68257bb29
commit c2f2e2194b
1 changed files with 23 additions and 54 deletions

View File

@ -231,20 +231,23 @@ impl Ppu {
fn draw(&mut self, _cycle: u32) {
use FetcherState::*;
let iter = &mut self.obj_buffer.iter();
let mut iter = self.obj_buffer.iter_mut();
let default = &mut None;
let obj_attr = loop {
match iter.flatten().next() {
Some(attr) => {
if attr.x <= (self.x_pos + 8) {
self.fetch.back.reset();
self.fetch.back.pause();
self.fifo.pause();
match iter.next() {
Some(attr_opt) => {
if let Some(attr) = attr_opt {
if attr.x <= (self.x_pos + 8) {
self.fetch.back.reset();
self.fetch.back.pause();
self.fifo.pause();
break Some(*attr);
break attr_opt;
}
}
}
None => break None,
None => break default,
}
};
@ -289,13 +292,12 @@ impl Ppu {
let tbpp = Pixels::from_bytes(high, low);
let palette_kind = attr.flags.palette();
let end = Pixels::PIXEL_COUNT - self.fifo.obj.len();
let start = Pixels::PIXEL_COUNT - end;
let x_flip = attr.flags.x_flip();
for i in start..Pixels::PIXEL_COUNT {
let pixel_count = (attr.x - self.x_pos) as usize;
let start = self.fifo.obj.len();
for i in start..pixel_count {
let x = if x_flip { 7 - i } else { i };
let priority = attr.flags.priority();
@ -312,7 +314,7 @@ impl Ppu {
self.fetch.back.resume();
self.fifo.resume();
self.obj_buffer.remove(&attr);
let _ = std::mem::take(obj_attr);
self.fetch.obj.next(ToFifoTwo);
}
@ -608,67 +610,34 @@ impl<'a> From<&'a [u8; 4]> for ObjectAttribute {
#[derive(Debug)]
struct ObjectBuffer {
buf: [Option<ObjectAttribute>; OBJECT_LIMIT],
inner: [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.inner = [Default::default(); 10];
self.len = 0;
}
fn add(&mut self, attr: ObjectAttribute) {
self.buf[self.len] = Some(attr);
self.inner[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;
}
fn iter_mut(&mut self) -> std::slice::IterMut<'_, Option<ObjectAttribute>> {
self.inner.iter_mut()
}
}
impl Default for ObjectBuffer {
fn default() -> Self {
Self {
buf: [Default::default(); OBJECT_LIMIT],
inner: [Default::default(); OBJECT_LIMIT],
len: Default::default(),
}
}