Let flyers path over water and lava everywhere

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/map.rs

@@ -656,7 +656,9 @@ impl Map {
                 let mut step = c * 10;
                 if k >= 4 {
                     // diagonal only if both neighbours are walkable (no corner cutting)
-                    if c > 1 || !self.walk(x + dx, y) || !self.walk(x, y + dy) {
+                    // (judged with the same cost, so flyers may cut corners over water and lava)
+                    let open = |cx: i32, cy: i32| cost(idx(cx, cy)) == Some(1);
+                    if c > 1 || !open(x + dx, y) || !open(x, y + dy) {
                         continue;
                     }
                     step = 14;
@@ -673,9 +675,22 @@ impl Map {
     }
 
     pub fn walk_cost(&self) -> impl Fn(usize) -> Option<u32> + '_ {
+        self.creature_cost(false)
+    }
+
+    // flying creatures also cross water and lava
+    pub fn fly_cost(&self) -> impl Fn(usize) -> Option<u32> + '_ {
+        self.creature_cost(true)
+    }
+
+    // the dungeon's creatures walk on open ground; flyers also cross water and lava
+    pub fn creature_cost(&self, fly: bool) -> impl Fn(usize) -> Option<u32> + '_ {
         move |i| {
             let t = &self.t[i];
-            // a locked door stops the dungeon's own creatures too
+            if fly && t.liquid() {
+                return Some(1);
+            }
+            // a locked door stops the dungeon's own creatures too (flyers included)
             if t.walkable() && !(t.kind == Kind::Door && t.res & 1 == 1) {
                 Some(1)
             } else {
@@ -684,9 +699,9 @@ impl Map {
         }
     }
 
-    // flying creatures also cross water and lava
-    pub fn fly_cost(&self) -> impl Fn(usize) -> Option<u32> + '_ {
-        move |i| if self.t[i].walkable() || self.t[i].liquid() { Some(1) } else { None }
+    // path for a walking or flying creature
+    pub fn creature_path(&self, fly: bool, start: usize, target: usize) -> Option<Vec<usize>> {
+        self.search(start, self.creature_cost(fly), |i| i == target, true)
     }
 
     pub fn fly_path_to(&self, start: usize, target: usize) -> Option<Vec<usize>> {
@@ -694,9 +709,15 @@ impl Map {
     }
 
     pub fn hero_cost(&self) -> impl Fn(usize) -> Option<u32> + '_ {
+        self.hero_cost_as(false)
+    }
+
+    // attackers dig through earth; flying ones also cross water and lava
+    pub fn hero_cost_as(&self, fly: bool) -> impl Fn(usize) -> Option<u32> + '_ {
         move |i| {
             let tl = &self.t[i];
             match tl.kind {
+                Kind::Water | Kind::Lava if fly => Some(1),
                 Kind::Earth if tl.reinforced => Some(70),
                 Kind::Steel => Some(300),
                 Kind::Earth => Some(7),
@@ -720,7 +741,11 @@ impl Map {
     }
 
     pub fn hero_path_to_core(&self, start: usize) -> Option<Vec<usize>> {
-        self.search(start, self.hero_cost(), |i| self.adj_core(i), true)
+        self.hero_path_to_core_as(false, start)
+    }
+
+    pub fn hero_path_to_core_as(&self, fly: bool, start: usize) -> Option<Vec<usize>> {
+        self.search(start, self.hero_cost_as(fly), |i| self.adj_core(i), true)
     }