Aerie and flying creatures: bats, chain gargoyles, arcane owls, ember wyrms

- New room: aerie (key Y, rooms category, campaign from mission 7); flyers sleep there
- Arrivals: aerie 4+ bats; + torture chamber gargoyles; + library owls; big aerie and treasury
  (16+ each) a rare ember wyrm; portal checks free places in lairs and aerie separately
- Flyers cross water and lava (path finding, flag, attacks), are not burnt by lava, patrol far
  when idle, attack single enemies, flee to the aerie below 25% health and rest there up to 75%
- Owls shoot arcane bolts, the wyrm breathes fire with splash damage; shots from the air
- Hovering sprites with flapping, aerie floor, perches, roosts, plinths, twig and ember nests
- Room counts are recounted on load (no longer stored); tests for flying and arrivals

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

src/gfx.rs

@@ -64,6 +64,7 @@ pub const D_RUBY: u32 = 122;
 pub const D_DIAMOND: u32 = 123;
 pub const D_RUBBLE: u32 = 124; // floor decals: pebbles and fragments
 pub const D_CRACK: u32 = 125; // a long crack through several stones
+pub const T_AERIE: u32 = 126; // 4 variants: straw, twigs and feathers
 
 pub struct Gfx {
     pub atlas: Texture2D,
@@ -726,6 +727,23 @@ fn gen_atlas() -> Image {
         let h = hash(cu, cv, seed) % 3;
         Some(if e { lo } else if h == 0 || (u % 4 == 1 && v % 4 == 1) { hi } else if d > 0.65 { lo } else { mid })
     };
+    // aerie: straw and twigs on stone, a few feathers
+    for v in 0..4u32 {
+        cv.cell(T_AERIE + v, |x, y| {
+            let base = stones(x, y, v + 230, (70, 62, 58), (36, 30, 30), 8);
+            let twig = (x * 3 + y * 7 + v as i32 * 5) % 13 == 0 || (x * 5 - y * 2 + v as i32) % 17 == 0;
+            let straw = rnd(x / 2, y, v + 231) > 0.62;
+            if hash(x, y, v + 232) % 41 == 0 {
+                Some(c(235, 232, 225)) // feather
+            } else if twig {
+                Some(c(96, 66, 40))
+            } else if straw {
+                Some(shade((190, 160, 80), (rnd(x, y, v + 233) * 20.0) as i32 - 10))
+            } else {
+                Some(base)
+            }
+        });
+    }
     // floor decals
     cv.cell(D_RUBBLE, |x, y| {
         for k in 0..9 {
@@ -890,6 +908,55 @@ fn sprite_rows(k: EK) -> [&'static str; 10] {
             ".kRRRRRRk.",
             "..kkkkkk..",
         ],
+        // flying creatures
+        EK::Bat => [
+            "..........",
+            "k..k..k..k",
+            "Pk.kPPk.kP",
+            "PPkPPPPkPP",
+            "PPPPrPrPPP",
+            "PPPPPPPPPP",
+            ".PPkPPkPP.",
+            "..k.PP.k..",
+            ".....k....",
+            "..........",
+        ],
+        EK::Gargoyle => [
+            "w........w",
+            "Cw.kkkk.wC",
+            "CCkceeckCC",
+            "CCkcccckCC",
+            "CkcccccckC",
+            "k.kcCCck.k",
+            ".kcccccck.",
+            ".kcCkkCck.",
+            ".kck..kck.",
+            ".kk....kk.",
+        ],
+        EK::Owl => [
+            "..k....k..",
+            ".kBk..kBk.",
+            ".kbbbbbbk.",
+            "kbeebbeebk",
+            "kbekbbekbk",
+            ".kbbyybbk.",
+            "kubbbbbbuk",
+            "kubbwwbbuk",
+            ".kubbbbuk.",
+            "..ky..yk..",
+        ],
+        EK::Wyrm => [
+            "R.......kw",
+            "RR....krrk",
+            "RRR..krekr",
+            "RRRRkrrrrk",
+            ".RRrrrrok.",
+            "..rrooork.",
+            ".krrooorr.",
+            "krrrrrrRk.",
+            "k.rrk.rk..",
+            "..kk..kk..",
+        ],
         // obsidian demon with glowing cracks, broken chains and twin axes
         EK::Chainbreaker => [
             "s.kkkkkk.s",
@@ -947,9 +1014,27 @@ fn pal(ch: char) -> Option<Color> {
     })
 }
 
-pub const SPRITE_KINDS: [EK; 13] = [EK::Worker, EK::Kobold, EK::Spider, EK::Mage, EK::Ogre, EK::Knight, EK::Archer, EK::Priest, EK::Dwarf, EK::Paladin, EK::Jailer, EK::Priestess, EK::Chainbreaker];
+pub const SPRITE_KINDS: [EK; 17] = [
+    EK::Worker,
+    EK::Kobold,
+    EK::Spider,
+    EK::Mage,
+    EK::Ogre,
+    EK::Knight,
+    EK::Archer,
+    EK::Priest,
+    EK::Dwarf,
+    EK::Paladin,
+    EK::Jailer,
+    EK::Priestess,
+    EK::Chainbreaker,
+    EK::Bat,
+    EK::Gargoyle,
+    EK::Owl,
+    EK::Wyrm,
+];
 // width of the sprite texture in pixels
-pub const SPRITE_TEX_W: f32 = (13 * 12) as f32;
+pub const SPRITE_TEX_W: f32 = (17 * 12) as f32;
 pub const SPRITE_TEX_H: f32 = 24.0;
 
 pub fn sprite_index(k: EK) -> u32 {
@@ -1143,6 +1228,7 @@ impl Gfx {
             Kind::Bridge => T_BRIDGE + (v & 1),
             Kind::LavaBridge => T_STONEBRIDGE + (v & 1),
             Kind::Shard => T_HEROFLOOR + v,
+            Kind::Aerie => T_AERIE + v,
         }
     }