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|
use std::marker::PhantomData;
use crate::{
config::CHUNK_SIZE,
sim::{cell::Cell, chunk::Chunk, materials::MaterialDef, world::World},
};
struct ChunkAccess<'a> {
ptr: *mut Chunk,
len: usize,
_marker: PhantomData<&'a mut [Chunk]>,
}
impl<'a> ChunkAccess<'a> {
pub fn new(chunks: &'a mut [Chunk]) -> Self {
Self {
ptr: chunks.as_mut_ptr(),
len: chunks.len(),
_marker: PhantomData,
}
}
unsafe fn get(&self, i: usize) -> &'a mut Chunk {
debug_assert!(i < self.len);
unsafe { &mut *self.ptr.add(i) }
}
}
pub struct UpdateCtx<'a, 'b, 'c> {
pub chunks: &'a mut [Option<&'b mut Chunk>; 9],
pub seqno: u64,
pub seqno_parity: u8,
pub x: i32,
pub y: i32,
pub cell: &'c mut Cell,
pub material: &'c MaterialDef,
}
fn get_cell(chunks: &[Option<&mut Chunk>; 9], x: i32, y: i32) -> Option<Cell> {
let dcx = x.div_euclid(CHUNK_SIZE as i32);
let dcy = y.div_euclid(CHUNK_SIZE as i32);
if dcx != 0 || dcy != 0 {
// in a different chunk
let nc_x = x.rem_euclid(CHUNK_SIZE as i32) as u8;
let nc_y = y.rem_euclid(CHUNK_SIZE as i32) as u8;
return if let Some(chunk) = &chunks[(dcx + 1 + (dcy + 1) * 3) as usize] {
Some(chunk.get_cell_at_local_position(nc_x, nc_y))
} else {
None
};
} else {
if let Some(target) = &chunks[4] {
Some(target.get_cell_at_local_position(x as u8, y as u8))
} else {
None
}
}
}
pub fn set_cell(chunks: &mut [Option<&mut Chunk>; 9], x: i32, y: i32, cell: Cell) {
let dcx = x.div_euclid(CHUNK_SIZE as i32);
let dcy = y.div_euclid(CHUNK_SIZE as i32);
if dcx != 0 || dcy != 0 {
// in a different chunk
let nc_x = x.rem_euclid(CHUNK_SIZE as i32) as u8;
let nc_y = y.rem_euclid(CHUNK_SIZE as i32) as u8;
if let Some(chunk) = &mut chunks[(dcx + 1 + (dcy + 1) * 3) as usize] {
chunk.set_cell_at_local_position(nc_x, nc_y, cell);
}
} else {
if let Some(target) = &mut chunks[4] {
target.set_cell_at_local_position(x as u8, y as u8, cell);
}
}
}
impl UpdateCtx<'_, '_, '_> {
pub fn get_cell(&self, dx: i32, dy: i32) -> Option<Cell> {
let x = self.x + dx;
let y = self.y + dy;
get_cell(self.chunks, x, y)
}
fn set_cell(&mut self, dx: i32, dy: i32, cell: Cell) {
let x = self.x + dx;
let y = self.y + dy;
set_cell(self.chunks, x, y, cell);
}
pub fn candidates_swap(&mut self, candidates: &[(i32, i32)]) -> bool {
for &(dx, dy) in candidates {
let candidate_cell = self.get_cell(dx, dy);
if candidate_cell.is_some_and(|c| c.material.def().density < self.material.density) {
self.set_cell(0, 0, candidate_cell.unwrap());
self.set_cell(dx, dy, *self.cell);
return true;
}
}
false
}
}
pub fn sim_tick_chunk(chunks: &mut [Option<&mut Chunk>; 9], seqno: u64) {
puffin::profile_function!();
// scan bottom to top to enable contiguous falling
let seqno_parity = (seqno as u8) & 0b1;
if chunks[4].is_some() {
for y in (0..CHUNK_SIZE as i32).rev() {
for i in 0..CHUNK_SIZE as i32 {
let x = if seqno_parity == 0 {
i
} else {
(CHUNK_SIZE as i32) - i - 1
};
let mut cell = get_cell(chunks, x, y).unwrap();
if cell.flags & 0b1 == seqno_parity {
// flip the parity bit
// TODO if the cell doesn't move this doesn't stay
cell.flags = cell.flags ^ 0b1;
let material = cell.material.def();
let mut update_ctx = UpdateCtx {
chunks,
seqno,
seqno_parity,
x,
y,
cell: &mut cell,
material,
};
if let Some(update) = material.sim_update {
update(&mut update_ctx);
}
}
}
}
}
}
const NEIGHBORHOOD_OFFSETS: [(i32, i32); 9] = [
(-1, -1),
(0, -1),
(1, -1),
(-1, 0),
(0, 0),
(1, 0),
(-1, 1),
(0, 1),
(1, 1),
];
pub fn sim_tick(world: &mut World, seqno: u64) {
puffin::profile_function!();
let mut update_groups: [Vec<(i32, i32)>; 9] = Default::default();
// assign a color to each chunk s.t. every chunk is surrounded by <= 8 chunks of different colors
// --------------------
// | 0, 1, 2, 0, 1, 2 |
// | 3, 4, 5, 3, 4, 5 |
// | 6, 7, 8, 6, 7, 8 |
// | 0, 1, 2, 0, 1, 2 |
// | 3, 4, 5, 3, 4, 5 |
// | 6, 7, 8, 6, 7, 8 |
// --------------------
for (&(cx, cy), _) in &world.chunk_position_to_chunk_idx {
let color = (cx.rem_euclid(3) * 3 + cy.rem_euclid(3)) as usize;
update_groups[color].push((cx, cy));
}
for group in &update_groups {
let access = ChunkAccess::new(&mut world.chunks);
// TODO this can be parallelized since they will never share neighbours
for &(cx, cy) in group {
let mut chunks: [Option<&mut Chunk>; 9] = NEIGHBORHOOD_OFFSETS.map(|(dx, dy)| {
world
.chunk_position_to_chunk_idx
.get(&(cx + dx, cy + dy))
.map(|&idx| unsafe { access.get(idx) })
});
sim_tick_chunk(&mut chunks, seqno);
}
}
}
|
