Initial commit: AtomicEngine v0.2

- Rust/WASM physics engine (grid, material, physics, render_buffer)
- 16 material types (stone, sand, water, wood, fire, lava, glass, ice, oil, acid, steam, spark, smoke + player placeholder)
- Fire system (fuel-based, flammability-scaled consumption, spread, smoke/sparks)
- Lighting system (emission, flood-fill propagation, glow, reflection)
- Per-material pixel texturing (wood grain, dirt specks, stone noise, flame variation)
- WebGL2 renderer with camera (WASD move, mouse wheel zoom)
- Native x86 debug binary (identical dimensions, FPS counter)
- Large world 1024x768 with active-region simulation (camera + 200px margin)
- UI material palette + FPS display

engine/src/main.rs

@@ -0,0 +1,118 @@
+mod grid;
+mod material;
+mod physics;
+mod render_buffer;
+
+use grid::Grid;
+use physics::Physics;
+use render_buffer::RenderBuffer;
+
+fn main() {
+    let width = 1024u32;
+    let height = 768u32;
+    let rw = 320u32;
+    let rh = 180u32;
+    let mut grid = Grid::new(width, height);
+    let mut physics = Physics::new();
+    let mut rb = RenderBuffer::new(rw, rh);
+
+    grid.fill_rect(440, 720, 144, 48, 1);
+    grid.fill_rect(460, 700, 104, 20, 2);
+    grid.fill_rect(470, 600, 84, 12, 5);
+    grid.fill_circle(490, 560, 20, 3);
+    grid.fill_rect(430, 650, 50, 30, 4);
+    grid.fill_rect(540, 650, 50, 30, 6);
+    grid.fill_rect(500, 640, 10, 18, 11);
+    grid.fill_rect(480, 630, 64, 24, 5);
+    grid.fill_rect(480, 618, 64, 12, 9);
+
+    let cam_x = 512i32;
+    let cam_y = 600i32;
+    let zoom = 2.0f32;
+
+    let mut frame = 0;
+    let start = std::time::Instant::now();
+
+    loop {
+        physics.update(&mut grid, cam_x, cam_y, rw, rh, zoom);
+        rb.render(&grid, cam_x, cam_y, zoom);
+        frame += 1;
+
+        if frame % 60 == 0 {
+            let elapsed = start.elapsed();
+            let fps = frame as f64 / elapsed.as_secs_f64();
+            let (fire, wood, spark, smoke) = count_mats(&grid);
+
+            println!("--- {}s (frame {}) fps: {:.0} ---", frame / 60, frame, fps);
+            println!("fire: {}, wood: {}, spark: {}, smoke: {}", fire, wood, spark, smoke);
+
+            if fire == 0 {
+                let elapsed = start.elapsed();
+                let fps = frame as f64 / elapsed.as_secs_f64();
+                println!("Fire died at frame {}, avg fps: {:.0}", frame, fps);
+                break;
+            }
+            if frame >= 3600 {
+                println!("Timeout at 60s");
+                break;
+            }
+        }
+    }
+}
+
+fn count_mats(grid: &Grid) -> (u32, u32, u32, u32) {
+    let mut fire = 0u32;
+    let mut wood = 0u32;
+    let mut spark = 0u32;
+    let mut smoke = 0u32;
+    for y in 0..grid.height {
+        for x in 0..grid.width {
+            match grid.get(x, y) {
+                5 => wood += 1,
+                9 => fire += 1,
+                14 => spark += 1,
+                15 => smoke += 1,
+                _ => {}
+            }
+        }
+    }
+    (fire, wood, spark, smoke)
+}
+
+fn temp_range(grid: &Grid) -> (u8, u8) {
+    let mut min = 255u8;
+    let mut max = 0u8;
+    for y in 0..grid.height {
+        for x in 0..grid.width {
+            let idx = grid.index(x, y);
+            let t = grid.temps[idx];
+            if t > 0 {
+                min = min.min(t);
+                max = max.max(t);
+            }
+        }
+    }
+    if min == 255 { min = 0; }
+    (min, max)
+}
+
+fn print_grid(grid: &Grid) {
+    for y in 0..grid.height {
+        for x in 0..grid.width {
+            let c = match grid.get(x, y) {
+                5 => 'W',
+                9 => 'F',
+                14 => '*',
+                15 => '%',
+                0 => '.',
+                1 => '#',
+                4 => '~',
+                6 => 'L',
+                8 => '\'',
+                _ => '?',
+            };
+            print!("{}", c);
+        }
+        println!();
+    }
+}