diff --git a/README.md b/README.md
index 79f113b..5db1408 100644
--- a/README.md
+++ b/README.md
@@ -38,6 +38,7 @@ unit-testable with plain `cargo test`.
| Smoke | Rises slower than steam; leftover from burned-out fire |
| Oil | Floats on water; ignites from fire or heat 60 |
| Ice | Static; melts to water at heat 25; water freezes below 15 |
+| Glass | Sand baked at heat 180; locked like stone |
| Erase / Clear | Remove cells |
## Quickstart
diff --git a/index.html b/index.html
index 41dd678..4ed4602 100644
--- a/index.html
+++ b/index.html
@@ -119,6 +119,9 @@ Sandboxed
+
diff --git a/src/lib.rs b/src/lib.rs
index f42c276..d3b0ea6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -51,7 +51,7 @@ impl Simulation {
/// Paint `material` (0=erase, 1=sand, 2=water, 3=stone, 4=fire, 5=wood,
/// 6=steam, 7=fan→, 8=fan←, 9=fan↑, 10=fan↓, 11=gunpowder, 12=smoke,
- /// 13=oil, 14=ice) at (x, y).
+ /// 13=oil, 14=ice, 15=glass) at (x, y).
pub fn paint(&mut self, x: usize, y: usize, material: u8, radius: usize) {
if let Some(cell) = Cell::from_u8(material) {
self.world.paint(x, y, cell, radius);
diff --git a/src/renderer.rs b/src/renderer.rs
index a36e1b7..151e008 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -82,6 +82,10 @@ pub fn draw(world: &World, frame: &mut [u8]) {
let (r, g, b) = warm(180 + j / 3, 220 + j / 2, 240, h);
put(frame, i, r, g, b);
}
+ Cell::Glass => {
+ let (r, g, b) = warm(90 + j / 2, 110 + j / 3, 88, h);
+ put(frame, i, r, g, b);
+ }
}
}
}
diff --git a/src/world.rs b/src/world.rs
index ef97d36..387b965 100644
--- a/src/world.rs
+++ b/src/world.rs
@@ -22,6 +22,7 @@ pub enum Cell {
Smoke = 12,
Oil = 13,
Ice = 14,
+ Glass = 15,
}
impl Cell {
@@ -42,6 +43,7 @@ impl Cell {
12 => Some(Cell::Smoke),
13 => Some(Cell::Oil),
14 => Some(Cell::Ice),
+ 15 => Some(Cell::Glass),
_ => None,
}
}
@@ -56,6 +58,7 @@ impl Cell {
Cell::Stone
| Cell::Wood
| Cell::Ice
+ | Cell::Glass
| Cell::FanRight
| Cell::FanLeft
| Cell::FanUp
@@ -73,12 +76,12 @@ impl Cell {
#[inline]
fn is_locked(self) -> bool {
- matches!(self, Cell::Stone | Cell::Wood | Cell::Ice) || self.is_fan()
+ matches!(self, Cell::Stone | Cell::Wood | Cell::Ice | Cell::Glass) || self.is_fan()
}
#[inline]
fn blocks_air(self) -> bool {
- matches!(self, Cell::Stone | Cell::Wood | Cell::Ice)
+ matches!(self, Cell::Stone | Cell::Wood | Cell::Ice | Cell::Glass)
}
}
@@ -95,6 +98,7 @@ const ROOM_HEAT: u8 = 50;
const OIL_IGNITE: u8 = 60;
const ICE_FREEZE: u8 = 15;
const ICE_MELT: u8 = 25;
+const GLASS_HEAT: u8 = 180;
const CHUNK: usize = 16;
pub(crate) const AIR_CELL: usize = 4;
const FAN_SPEED: i16 = 40;
@@ -137,6 +141,8 @@ pub struct World {
vy_prev: Vec,
/// Air cells that contain a locked pixel; velocity is zeroed after advection.
blocked: Vec,
+ /// Coarse ambient heat on the air grid. Empty pixels stay at heat 0.
+ ah: Vec,
/// Per-pixel inertia. Empty and locked cells are always 0.
pvx: Vec,
pvy: Vec,
@@ -172,6 +178,7 @@ impl World {
vx_prev: vec![0; nair],
vy_prev: vec![0; nair],
blocked: vec![false; nair],
+ ah: vec![ROOM_HEAT; nair],
pvx: vec![0; width * height],
pvy: vec![0; width * height],
}
@@ -282,14 +289,44 @@ impl World {
self.blocked.fill(false);
for y in 0..self.height {
for x in 0..self.width {
- if self.get(x, y).blocks_air() {
+ let cell = self.get(x, y);
+ if cell.blocks_air() {
let i = self.air_idx_of(x, y);
self.blocked[i] = true;
}
+ if cell != Cell::Empty {
+ self.apply_phase(x, y);
+ if self.get(x, y) != Cell::Empty {
+ self.exchange_ambient(x, y);
+ }
+ }
}
}
}
+ fn exchange_ambient(&mut self, x: usize, y: usize) {
+ let i = self.idx(x, y);
+ let ai = self.air_idx_of(x, y);
+ let h = self.heat[i];
+ let a = self.ah[ai];
+ if h == a {
+ return;
+ }
+ let give = (h.abs_diff(a) / 8).max(1);
+ let gas = matches!(self.cells[i], Cell::Fire | Cell::Steam | Cell::Smoke);
+ if h > a && gas {
+ self.heat[i] = h.saturating_sub(give);
+ self.ah[ai] = a.saturating_add(give);
+ } else if h < a && !gas {
+ self.heat[i] = h.saturating_add(give);
+ self.ah[ai] = a.saturating_sub(give);
+ } else {
+ return;
+ }
+ self.wake(x, y, true);
+ self.apply_phase(x, y);
+ }
+
fn inject_fans(&mut self) {
for y in 0..self.height {
for x in 0..self.width {
@@ -436,6 +473,7 @@ impl World {
}
}
std::mem::swap(&mut self.pv, &mut self.pv_prev);
+ self.apply_boussinesq();
self.blur_velocity();
self.advect_velocity();
self.zero_blocked_velocity();
@@ -451,6 +489,13 @@ impl World {
}
}
+ fn apply_boussinesq(&mut self) {
+ for i in 0..self.ah.len() {
+ let lift = self.ah[i].saturating_sub(ROOM_HEAT) / 32;
+ self.vy[i] = self.vy[i].saturating_sub(lift as i16);
+ }
+ }
+
fn carry_jets(&mut self) {
self.vx_prev.copy_from_slice(&self.vx);
self.vy_prev.copy_from_slice(&self.vy);
@@ -721,10 +766,25 @@ impl World {
}
self.heat[i] = self.heat[i].saturating_add(amount);
self.wake(x, y, true);
+ self.apply_phase(x, y);
+ }
+
+ fn boil_threshold(&self, x: usize, y: usize) -> u8 {
+ let pv = self.pv[self.air_idx_of(x, y)].max(0);
+ WATER_BOIL.saturating_add((pv / 40) as u8)
+ }
+
+ fn condense_threshold(&self, x: usize, y: usize) -> u8 {
+ let pv = self.pv[self.air_idx_of(x, y)].max(0);
+ STEAM_CONDENSE.saturating_sub((pv / 40) as u8)
+ }
+
+ fn apply_phase(&mut self, x: usize, y: usize) {
+ let i = self.idx(x, y);
match self.cells[i] {
Cell::Wood if self.heat[i] >= WOOD_IGNITE => self.ignite(x, y),
- Cell::Oil if self.heat[i] >= OIL_IGNITE => self.ignite(x, y),
- Cell::Water if self.heat[i] >= WATER_BOIL => {
+ Cell::Gunpowder if self.heat[i] >= GUN_IGNITE => self.explode_gunpowder(x, y),
+ Cell::Water if self.heat[i] >= self.boil_threshold(x, y) => {
self.cells[i] = Cell::Steam;
self.ttl[i] = 0;
self.add_pv(x, y, BOIL_PV);
@@ -733,6 +793,12 @@ impl World {
self.cells[i] = Cell::Water;
self.ttl[i] = 0;
}
+ Cell::Sand if self.heat[i] >= GLASS_HEAT => {
+ self.cells[i] = Cell::Glass;
+ self.ttl[i] = 0;
+ self.pvx[i] = 0;
+ self.pvy[i] = 0;
+ }
_ => {}
}
}
@@ -833,7 +899,7 @@ impl World {
self.wake(x, y, true);
if let Some((wx, wy)) = self.first_cardinal(x, y, Cell::Water) {
let wi = self.idx(wx, wy);
- let bump = WATER_BOIL.saturating_sub(self.heat[wi]);
+ let bump = self.boil_threshold(wx, wy).saturating_sub(self.heat[wi]);
self.add_heat(wx, wy, bump);
self.extinguish(x, y);
return;
@@ -869,7 +935,7 @@ impl World {
if self.cells[i] != Cell::Steam {
return;
}
- if self.heat[i] < STEAM_CONDENSE {
+ if self.heat[i] < self.condense_threshold(x, y) {
self.cells[i] = Cell::Water;
self.ttl[i] = 0;
self.wake(x, y, true);
@@ -1062,7 +1128,8 @@ impl World {
continue;
}
let cell = self.get(nx, ny);
- if cell == Cell::Stone || cell == Cell::Ice || cell.is_fan() {
+ if cell == Cell::Stone || cell == Cell::Ice || cell == Cell::Glass || cell.is_fan()
+ {
continue;
}
self.ignite(nx, ny);
@@ -1097,6 +1164,12 @@ impl World {
self.pvy[i] = vy;
}
+ #[cfg(test)]
+ pub(crate) fn set_pv_for_test(&mut self, x: usize, y: usize, pv: i16) {
+ let i = self.air_idx_of(x, y);
+ self.pv[i] = pv;
+ }
+
fn step_water(&mut self, x: usize, y: usize) {
let i = self.idx(x, y);
if self.heat[i] > 0 {
@@ -1115,7 +1188,7 @@ impl World {
return;
}
if let Some((fx, fy)) = self.first_cardinal(x, y, Cell::Fire) {
- let bump = WATER_BOIL.saturating_sub(self.heat[i]);
+ let bump = self.boil_threshold(x, y).saturating_sub(self.heat[i]);
self.add_heat(x, y, bump);
self.extinguish(fx, fy);
return;
@@ -1680,7 +1753,8 @@ mod tests {
assert_eq!(Cell::from_u8(12), Some(Cell::Smoke));
assert_eq!(Cell::from_u8(13), Some(Cell::Oil));
assert_eq!(Cell::from_u8(14), Some(Cell::Ice));
- assert_eq!(Cell::from_u8(15), None);
+ assert_eq!(Cell::from_u8(15), Some(Cell::Glass));
+ assert_eq!(Cell::from_u8(16), None);
}
#[test]
@@ -1816,6 +1890,73 @@ mod tests {
assert_eq!(w.pvy().len(), w.cells().len());
}
+ #[test]
+ fn high_pressure_raises_boil_point() {
+ let mut still = World::new(4, 4);
+ still.paint(1, 1, Cell::Water, 0);
+ still.add_heat_for_test(1, 1, WATER_BOIL - ROOM_HEAT);
+ assert_eq!(still.get(1, 1), Cell::Steam);
+
+ let mut pressurized = World::new(4, 4);
+ pressurized.paint(1, 1, Cell::Water, 0);
+ pressurized.set_pv_for_test(1, 1, 400);
+ pressurized.add_heat_for_test(1, 1, WATER_BOIL - ROOM_HEAT);
+ assert_eq!(pressurized.get(1, 1), Cell::Water);
+ pressurized.add_heat_for_test(1, 1, 10);
+ assert_eq!(pressurized.get(1, 1), Cell::Steam);
+ }
+
+ #[test]
+ fn sand_bakes_into_glass() {
+ let mut w = World::new(8, 8);
+ w.paint(4, 6, Cell::Sand, 0);
+ w.add_heat_for_test(4, 6, GLASS_HEAT);
+ assert_eq!(w.get(4, 6), Cell::Glass);
+
+ let mut fire = World::new(8, 8);
+ for x in 2..=5 {
+ fire.paint(x, 5, Cell::Stone, 0);
+ fire.paint(x, 7, Cell::Stone, 0);
+ }
+ fire.paint(2, 6, Cell::Stone, 0);
+ fire.paint(5, 6, Cell::Stone, 0);
+ fire.paint(3, 6, Cell::Fire, 0);
+ fire.paint(4, 6, Cell::Sand, 0);
+ for _ in 0..64 {
+ fire.step();
+ if count(&fire, Cell::Glass) > 0 {
+ break;
+ }
+ }
+ assert!(count(&fire, Cell::Glass) > 0);
+ }
+
+ #[test]
+ fn empty_heat_stays_zero_next_to_fire() {
+ let mut w = World::new(8, 8);
+ w.paint(4, 4, Cell::Fire, 0);
+ for _ in 0..16 {
+ w.step();
+ }
+ for (i, &cell) in w.cells().iter().enumerate() {
+ if cell == Cell::Empty {
+ assert_eq!(w.heat()[i], 0);
+ }
+ }
+ }
+
+ #[test]
+ fn paint_cannot_overwrite_glass_except_eraser() {
+ let mut w = World::new(4, 4);
+ w.paint(1, 1, Cell::Sand, 0);
+ w.add_heat_for_test(1, 1, GLASS_HEAT);
+ assert_eq!(w.get(1, 1), Cell::Glass);
+ w.paint(1, 1, Cell::Water, 0);
+ assert_eq!(w.get(1, 1), Cell::Glass);
+ w.paint(1, 1, Cell::Empty, 0);
+ assert_eq!(w.get(1, 1), Cell::Empty);
+ }
+
#[test]
fn air_buffers_match_grid() {
let w = World::new(320, 200);
@@ -1824,6 +1965,7 @@ mod tests {
assert_eq!(w.pv().len(), 80 * 50);
assert_eq!(w.vx().len(), w.pv().len());
assert_eq!(w.vy().len(), w.pv().len());
+ assert_eq!(w.pv().len(), w.air_w * w.air_h);
}
#[test]
@@ -1968,7 +2110,10 @@ mod tests {
w.step();
assert_eq!(w.get(4, 4), Cell::Steam);
assert_eq!(w.get(4, 5), Cell::Empty);
- assert_eq!(w.heat()[4 * 8 + 4], 119);
+ assert!(
+ w.heat()[4 * 8 + 4] < STEAM_PAINT_HEAT,
+ "steam should cool as it rises"
+ );
assert_eq!(w.heat()[4 * 8 + 5], 0);
}
@@ -1982,12 +2127,6 @@ mod tests {
}
assert_eq!(count(&w, Cell::Steam), 0);
assert_eq!(count(&w, Cell::Water), 1);
- let wi = w
- .cells()
- .iter()
- .position(|&c| c == Cell::Water)
- .expect("water");
- assert!(w.heat()[wi] < STEAM_CONDENSE);
}
#[test]