redoing bump

kiln-core/src/script.rs

@@ -6,8 +6,8 @@
 //!
 //! - `init(me, state)` — run once after the whole map is loaded (see [`ScriptHost::run_init`]).
 //! - `tick(me, state, dt)` — run every frame with the elapsed seconds (see [`ScriptHost::run_tick`]).
-//! - `bump(me, state, id)` — run when another mover steps into this object's cell, with the
-//!   bumper's object index (`-1` for the player); see [`ScriptHost::run_bump`].
+//! - `bump(me, dir)` — run when a solid (the player, an object, or a pushed crate) presses into this
+//!   object's cell, with the [`Direction`] the bump came *from*; see [`ScriptHost::run_bump`].
 //! - `grab(me, state)` — run when the player walks onto a `grab` object; see [`ScriptHost::run_grab`].
 //!   Typically adds a stat + `die()`s.
 //!
@@ -257,10 +257,12 @@ impl ScriptHost {
         }
     }
 
-    /// Calls `bump(id)` on the object with [`ObjectId`] `object_id`, if it defines
-    /// the hook. After the hook, drains the object's queue with `dt = 0`.
-    pub fn run_bump(&mut self, id: ObjectId, bumper: i64) {
-        self.run_hook_on_one(Hook::Bump, id, Some(Dynamic::from(bumper)), 0.0);
+    /// Calls `bump(dir)` on the object with [`ObjectId`] `id`, if it defines the
+    /// hook. `dir` is the [`Direction`] the bump came *from* (it points from the
+    /// bumped object toward the bumper). After the hook, drains the object's queue
+    /// with `dt = 0`.
+    pub fn run_bump(&mut self, id: ObjectId, dir: Direction) {
+        self.run_hook_on_one(Hook::Bump, id, Some(Dynamic::from(dir)), 0.0);
     }
 
     /// Calls `grab()` on the object with [`ObjectId`] `object_id`, if it defines the
@@ -344,6 +346,23 @@ impl ScriptHost {
 
 fn register_write_api(engine: &mut Engine, board: BoardRef) {
     engine.register_type_with_name::<Direction>("Direction");
+    // Rhai does not auto-derive comparison for custom types, so register `==`/`!=`
+    // to let scripts test the `bump` direction (e.g. `if dir == West { … }`).
+    engine.register_fn("==", |a: Direction, b: Direction| a == b);
+    engine.register_fn("!=", |a: Direction, b: Direction| a != b);
+    // Let a Direction interpolate/print as its name (e.g. in `log(`from ${dir}`)`).
+    let dir_name = |d: Direction| match d {
+        Direction::North => "North",
+        Direction::South => "South",
+        Direction::East => "East",
+        Direction::West => "West",
+    };
+    engine.register_fn("to_string", dir_name);
+    engine.register_fn("to_debug", dir_name);
+    // Expose the unit-step components so scripts can turn a direction into a cell
+    // offset (e.g. the bumper's cell is `(me.x + dir.dx, me.y + dir.dy)`).
+    engine.register_get("dx", |d: &mut Direction| d.dx());
+    engine.register_get("dy", |d: &mut Direction| d.dy());
 
     // move(dir): enqueue a Move followed by a rate-limiting Delay.
     let b = board.clone();