started debug display

patterns/blowup.txt

@@ -0,0 +1,3 @@
+# #
+# #
+###

src/view.rs

@@ -81,10 +81,12 @@ where
     loop {
         handle_inputs(&receiver, &mut view_origin, &mut delay);
         handle.set_delay(delay);
+        let world = handle.snapshot();
 
         let mut canvas = Canvas::from_screen();
+        dbg_layer(&mut canvas, &world, view_origin);
         grid_layer(&mut canvas, view_origin);
-        world_layer(&mut canvas, handle.snapshot(), view_origin);
+        world_layer(&mut canvas, &world, view_origin);
         title_layer(&mut canvas, handle.delay());
         canvas.display();
     }
@@ -109,7 +111,11 @@ fn handle_inputs(receiver: &mpsc::Receiver<InputCmd>, view_origin: &mut Pos, del
                         Dir::Right => pos!(2 * MOVEMENT_STEP, 0),
                     }
             }
-            InputCmd::Accelerate => *delay -= 100,
+            InputCmd::Accelerate => {
+                if *delay > 0 {
+                    *delay -= 100
+                }
+            }
             InputCmd::Decelerate => *delay += 100,
         }
     }
@@ -127,7 +133,7 @@ fn grid_layer(canvas: &mut Canvas, view_origin: Pos) {
     })
 }
 
-fn world_layer<W>(canvas: &mut Canvas, world: W, view_origin: Pos)
+fn world_layer<W>(canvas: &mut Canvas, world: &W, view_origin: Pos)
 where
     W: World,
 {
@@ -161,3 +167,18 @@ fn title_layer(canvas: &mut Canvas, de: usize) {
             .and_then(|line| line.chars().nth(x as usize))
     })
 }
+
+fn dbg_layer<W>(canvas: &mut Canvas, world: &W, view_origin: Pos)
+where
+    W: World,
+{
+    canvas.layer(|local_pos| {
+        let pos = screen_pos_to_world(local_pos, view_origin);
+        world.dbg_is_loaded(pos).then_some('.')
+    })
+}
+
+fn screen_pos_to_world(mut pos: Pos, screen_origin: Pos) -> Pos {
+    pos.y *= 2;
+    pos + screen_origin
+}

src/world.rs

@@ -23,6 +23,7 @@ pub trait World: Default + Clone + Send + 'static {
     fn get(&self, pos: Pos) -> Cell;
     fn set(&mut self, pos: Pos, cell: Cell);
     fn actives(&self) -> Vec<Pos>;
+    fn dbg_is_loaded(&self, pos: Pos) -> bool;
 }
 
 pub use hashed_world::HashedWorld;

src/world/hashed_world.rs

@@ -109,4 +109,8 @@ impl World for HashedWorld {
             })
             .collect()
     }
+
+    fn dbg_is_loaded(&self, pos: Pos) -> bool {
+        self.get_chunk(pos).is_some()
+    }
 }