Steel walls: plate earth walls next to own ground with steel

- New tool Steel (key O, orders category; campaign from mission 11): 80 gold per earth wall,
  40 for a reinforced wall; riveted iron plate texture
- Heroes dig through steel 20 times slower than through earth and avoid it (path cost 300)
- Selling turns a steel wall back into a reinforced wall and refunds half the plating
- Texts EN/DE, test

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

lang/de.lang

@@ -145,7 +145,7 @@ help.k_slap = Shift+Links      Hand: Rückhand für eigene, Faust für Helden au
 help.k_pan = Rechts ziehen    Karte verschieben (auch WASD/Pfeile, Bildrand)
 help.k_rot = Mitte ziehen     Kamera drehen und neigen (auch Q/E, R/F)
 help.k_zoom = Mausrad          Zoomen
-help.k_tools = 1-9,0,X,V,K,J,B,C,T,U,Y  Werkzeug
+help.k_tools = 1-9,0,X,V,K,J,B,C,T,U,Y,O  Werkzeug
 help.k_misc = P / Leertaste    Pause      M  Ton an/aus   +/-  Lautstärke
 help.k_misc2 = G                Kachel-Umrisse an/aus     H  Diese Hilfe
 help.s1 = 1. Grabe zum Portal und lass es von Grubenwichten erobern.
@@ -529,3 +529,12 @@ unit.wyrm = Glutwyrm
 job.rest = Erholt sich im Horst
 job.torment = Bearbeitet einen Gefangenen
 menu.license = DungeonCraft - MIT-Lizenz - (c) 2026 Richard Zink
+
+# steel walls
+tool.steel.label = Stahl
+tool.steel.name = Stahlwände
+tool.steel.desc = Beschlägt Erdwände an deinem Gebiet mit Stahl. Helden kommen kaum hindurch und nehmen lieber lange Umwege. Verkaufen macht wieder befestigte Wände daraus.
+cost.steel = {0} Gold/Wand, {1} für befestigte Wände
+hint.steel_where = Stahl lässt sich nur an Erdwände neben deinem Gebiet anbringen.
+tile.steel = Stahlwand
+tile.steel_info = Helden brauchen ewig, um hindurchzukommen.

lang/en.lang

@@ -146,7 +146,7 @@ help.k_slap = Shift+Left      Hand: backhand own units, punch heroes on your gro
 help.k_pan = Right drag      Move the map (also WASD/arrows, screen edge)
 help.k_rot = Middle drag     Rotate and tilt the camera (also Q/E, R/F)
 help.k_zoom = Mouse wheel     Zoom
-help.k_tools = 1-9,0,X,V,K,J,B,C,T,U,Y  Select tool
+help.k_tools = 1-9,0,X,V,K,J,B,C,T,U,Y,O  Select tool
 help.k_misc = P / Space       Pause      M  Sound on/off   +/-  Volume
 help.k_misc2 = G               Tile outlines on/off     H  This help
 help.s1 = 1. Dig to the portal and let your Pit Imps claim it.
@@ -530,3 +530,12 @@ unit.wyrm = Ember Wyrm
 job.rest = Recovering in the aerie
 job.torment = Working on a prisoner
 menu.license = DungeonCraft - MIT License - (c) 2026 Richard Zink
+
+# steel walls
+tool.steel.label = Steel
+tool.steel.name = Steel Walls
+tool.steel.desc = Plates earth walls next to your ground with steel. Heroes hardly get through and rather take long detours. Selling turns them back into reinforced walls.
+cost.steel = {0} gold/wall, {1} for reinforced walls
+hint.steel_where = Steel can only be put on earth walls next to your own ground.
+tile.steel = Steel wall
+tile.steel_info = Heroes need ages to get through.

src/campaign.rs

@@ -9,8 +9,8 @@ use serde::{Deserialize, Serialize};
 
 // From which mission (0-based) on each tool is available (same order as ui::TOOLS):
 // dig, hand, treasury, lair, farm, training, library, sell, flag, lightning, heal, imp,
-// torture, temple, arrow tower, cannon tower, magic tower, bridge, aerie
+// torture, temple, arrow tower, cannon tower, magic tower, bridge, aerie, steel
-pub const TOOL_UNLOCK: [usize; 19] = [0, 0, 0, 0, 0, 2, 4, 0, 0, 3, 4, 0, 6, 9, 3, 5, 9, 1, 6];
+pub const TOOL_UNLOCK: [usize; 20] = [0, 0, 0, 0, 0, 2, 4, 0, 0, 3, 4, 0, 6, 9, 3, 5, 9, 1, 6, 10];
 
 pub struct FortDef {
     pub at: (f32, f32), // centre as a fraction of the map size

src/game.rs

@@ -418,6 +418,9 @@ pub const ROOM_NAMES: [&str; 8] = ["room.treasury", "room.lair", "room.farm", "r
 
 // bridge cost per tile: over water, over lava
 pub const BRIDGE_COST: [i32; 2] = [30, 75];
+// steel wall cost per tile: from earth, from a reinforced wall
+pub const STEEL_COST: [i32; 2] = [80, 40];
+pub const STEEL_HP: f32 = 40.0;
 
 pub fn room_index(k: Kind) -> Option<usize> {
     ROOM_KINDS.iter().position(|&r| r == k)
@@ -1399,7 +1402,13 @@ impl Game {
                         EK::Dwarf => 3.0,
                         EK::Paladin => 2.0,
                         _ => 1.0,
-                    } * if tile.reinforced { 0.2 } else { 1.0 };
+                    } * if tile.kind == Kind::Steel {
+                        0.05
+                    } else if tile.reinforced {
+                        0.2
+                    } else {
+                        1.0
+                    };
                     self.fx(6, tx as f32 + 0.5, ty as f32 + 0.5, 0.0, 0.0, 0.4, 0xff3a5a7a);
                     self.sfx(Sfx::Dig, tx as f32 + 0.5, ty as f32 + 0.5);
                     let t = &mut self.map.t[next];
@@ -1780,6 +1789,48 @@ impl Game {
 
     // Bridges grow from own ground into the river: every pass adds the river tiles of the
     // rectangle that touch own walkable ground (including bridges built in the pass before)
+    // Earth walls next to own ground become steel walls
+    pub fn build_steel(&mut self, x0: i32, y0: i32, x1: i32, y1: i32) {
+        let (mut built, mut broke) = (0, false);
+        for y in y0.min(y1)..=y0.max(y1) {
+            for x in x0.min(x1)..=x0.max(x1) {
+                if !inb(x, y) {
+                    continue;
+                }
+                let t = self.map.t[idx(x, y)];
+                if t.kind != Kind::Earth || t.owner == Owner::Hero {
+                    continue;
+                }
+                let own = DIR4.iter().any(|&(dx, dy)| self.map.get(x + dx, y + dy).map_or(false, |n| n.owner == Owner::Player && n.walkable()));
+                if !own {
+                    continue;
+                }
+                let cost = STEEL_COST[t.reinforced as usize] as f32;
+                if self.gold < cost {
+                    broke = true;
+                    continue;
+                }
+                self.gold -= cost;
+                let tl = &mut self.map.t[idx(x, y)];
+                tl.kind = Kind::Steel;
+                tl.reinforced = true;
+                tl.marked = false;
+                tl.hp = STEEL_HP;
+                built += 1;
+                self.fx(8, x as f32 + 0.5, y as f32 + 0.5, 0.0, 0.0, 0.5, 0xffd0d0d0);
+                if built == 1 {
+                    self.sfx(Sfx::Reinforce, x as f32 + 0.5, y as f32 + 0.5);
+                }
+            }
+        }
+        if broke {
+            self.msg("msg.no_gold", vec![]);
+            self.sfx_ui(Sfx::Error);
+        } else if built == 0 {
+            self.hint(23, "hint.steel_where");
+        }
+    }
+
     pub fn build_bridges(&mut self, x0: i32, y0: i32, x1: i32, y1: i32) {
         let (mut built, mut broke, mut any_river) = (0, false, false);
         loop {
@@ -3361,6 +3412,13 @@ impl Game {
                     continue;
                 }
                 let t = &mut self.map.t[i];
+                if t.kind == Kind::Steel {
+                    t.kind = Kind::Earth;
+                    t.reinforced = true;
+                    t.hp = 12.0;
+                    refund += STEEL_COST[1] as f32 * 0.5;
+                    continue;
+                }
                 if t.owner == Owner::Player && t.bridge() {
                     let lava = t.kind == Kind::LavaBridge;
                     t.kind = if lava { Kind::Lava } else { Kind::Water };
@@ -4637,6 +4695,28 @@ mod tests {
         assert!(seen.iter().all(|&k| flies(k)), "no lair: only flyers come ({:?})", seen);
     }
 
+    #[test]
+    fn steel_walls_hold_heroes_back() {
+        let mut g = Game::new(3, 64, 64);
+        let (cx, cy) = g.map.core;
+        let (wx, wy) = (cx + 6, (cy - 3..=cy + 5).find(|&y| g.map.t[idx(cx + 6, y)].kind == Kind::Earth).unwrap());
+        g.gold = 1000.0;
+        g.build_steel(wx, wy, wx, wy);
+        assert_eq!(g.map.t[idx(wx, wy)].kind, Kind::Steel);
+        assert_eq!(g.gold, 1000.0 - STEEL_COST[0] as f32);
+        // far from own ground: nothing happens
+        g.build_steel(wx + 5, wy, wx + 5, wy);
+        assert_ne!(g.map.t[idx(wx + 5, wy)].kind, Kind::Steel);
+        // heroes avoid it and dig 20 times slower than through earth
+        assert_eq!(g.map.hero_cost()(idx(wx, wy)), Some(300));
+        // selling: a reinforced earth wall again, half of the plating back
+        let gold = g.gold;
+        g.sell_rect(wx, wy, wx, wy);
+        assert_eq!(g.map.t[idx(wx, wy)].kind, Kind::Earth);
+        assert!(g.map.t[idx(wx, wy)].reinforced);
+        assert!(g.gold > gold);
+    }
+
     #[test]
     fn imps_reinforce_walls() {
         let mut g = Game::new(3, 64, 64);

src/gfx.rs

@@ -65,6 +65,8 @@ 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 const T_STEEL: u32 = 130; // 4 variants: riveted iron plates
+pub const I_STEEL: u32 = 134;
 
 pub struct Gfx {
     pub atlas: Texture2D,
@@ -744,6 +746,31 @@ fn gen_atlas() -> Image {
             }
         });
     }
+    // steel walls: riveted plates with a little rust
+    for v in 0..4u32 {
+        cv.cell(T_STEEL + v, |x, y| {
+            let seam = x % 8 == 0 || y % 8 == 0;
+            let rivet = (x % 8 == 2 || x % 8 == 6) && (y % 8 == 2 || y % 8 == 6);
+            let rust = rnd(x / 2, y / 2, v + 240) > 0.86;
+            if seam {
+                Some(c(44, 48, 58))
+            } else if rivet {
+                Some(c(170, 176, 190))
+            } else if rust {
+                Some(shade((120, 70, 40), (rnd(x, y, v + 241) * 16.0) as i32))
+            } else {
+                Some(shade((96, 102, 116), (rnd(x, y, v + 242) * 10.0) as i32 - 5 + if y % 8 == 1 { 10 } else { 0 }))
+            }
+        });
+    }
+    cv.cell(I_STEEL, |x, y| {
+        if (2..=13).contains(&x) && (3..=12).contains(&y) {
+            let rivet = (x == 4 || x == 11) && (y == 5 || y == 10);
+            Some(if rivet { c(220, 224, 235) } else if x == 2 || y == 3 || x == 13 || y == 12 { c(60, 64, 76) } else { c(130, 136, 150) })
+        } else {
+            None
+        }
+    });
     // floor decals
     cv.cell(D_RUBBLE, |x, y| {
         for k in 0..9 {
@@ -1229,6 +1256,7 @@ impl Gfx {
             Kind::LavaBridge => T_STONEBRIDGE + (v & 1),
             Kind::Shard => T_HEROFLOOR + v,
             Kind::Aerie => T_AERIE + v,
+            Kind::Steel => T_STEEL + v,
         }
     }
 

src/main.rs

@@ -68,7 +68,7 @@ struct Input {
 // Tile under the pointer for a tool: digging (and the hand) aim at walls too,
 // building and everything else only at the floor below the pointer
 fn tool_tile(cam: &Cam, map: &map::Map, tool: Tool, mx: f32, my: f32) -> Option<(i32, i32)> {
-    if matches!(tool, Tool::Dig | Tool::Hand) {
+    if matches!(tool, Tool::Dig | Tool::Hand | Tool::Steel) {
         return cam.pick_tile(map, mx, my).map(|(x, z, _)| (x, z));
     }
     let p = cam.ground_point(mx, my);
@@ -81,7 +81,7 @@ fn tool_tile(cam: &Cam, map: &map::Map, tool: Tool, mx: f32, my: f32) -> Option<
 }
 
 fn area_tool(t: Tool) -> bool {
-    matches!(t, Tool::Dig | Tool::Room(_) | Tool::Sell | Tool::Bridge)
+    matches!(t, Tool::Dig | Tool::Room(_) | Tool::Sell | Tool::Bridge | Tool::Steel)
 }
 
 // Use the active tool on the world at (mx, my) (CSS pixels): a click, or a tap on touch screens
@@ -94,7 +94,7 @@ fn world_action(app: &mut App, ui: &mut Ui, r3d: &R3d, inp: &mut Input, mx: f32,
     let ground = app.cam.ground_point(mx, my);
     let (wx, wy) = (ground.x, ground.y);
     match (ui.tool, tile) {
-        (Tool::Dig | Tool::Room(_) | Tool::Sell | Tool::Bridge, Some(t)) => inp.ldown = Some(t),
+        (Tool::Dig | Tool::Room(_) | Tool::Sell | Tool::Bridge | Tool::Steel, Some(t)) => inp.ldown = Some(t),
         (Tool::Hand, _) => {
             let j = r3d.pick_ent(&app.game, &app.cam, mx, my, false);
             if slap {
@@ -127,6 +127,7 @@ fn finish_rect(app: &mut App, tool: Tool, start: (i32, i32), mx: f32, my: f32) {
         Tool::Room(r) => app.game.build_rect(r, sx, sy, ex, ey),
         Tool::Sell => app.game.sell_rect(sx, sy, ex, ey),
         Tool::Bridge => app.game.build_bridges(sx, sy, ex, ey),
+        Tool::Steel => app.game.build_steel(sx, sy, ex, ey),
         _ => {}
     }
 }
@@ -900,6 +901,7 @@ fn draw_frame(app: &mut App, gfx: &Gfx, r3d: &mut R3d, ui: &mut Ui, menu: &mut M
         Tool::Heal => (Color::new(0.4, 1.0, 0.5, 1.0), Some((ground.x, ground.y, 2.55))),
         Tool::Summon => (Color::new(0.8, 0.5, 1.0, 1.0), None),
         Tool::Bridge => (Color::new(0.9, 0.7, 0.4, 1.0), None),
+        Tool::Steel => (Color::new(0.75, 0.8, 0.9, 1.0), None),
         Tool::Tower(_) => (Color::new(1.0, 0.6, 0.25, 1.0), None),
     };
     let ov = Overlay {

src/map.rs

@@ -58,6 +58,7 @@ pub enum Kind {
     Ruby,       // ruby vein: rare, valuable
     Diamond,    // diamond vein: very rare, very valuable
     Aerie,      // room for flying creatures (their beds)
+    Steel,      // steel wall: hardly anyone gets through
 }
 
 // options for the map generator (campaign missions)
@@ -86,7 +87,7 @@ pub struct River {
 }
 
 // order matters for the packed savegame codec: only append new kinds
-const KINDS: [Kind; 24] = [
+const KINDS: [Kind; 25] = [
     Kind::Rock,
     Kind::Earth,
     Kind::Gold,
@@ -111,6 +112,7 @@ const KINDS: [Kind; 24] = [
     Kind::Ruby,
     Kind::Diamond,
     Kind::Aerie,
+    Kind::Steel,
 ];
 
 // treasures (veins, treasury content, imp loads): 0 gold, 1 silver, 2 ruby, 3 diamond
@@ -159,10 +161,10 @@ impl Tile {
         Tile { kind, owner: Owner::None, hp: 0.0, gold: 0, marked: false, reserved: 0, food: 0.0, bed: 0, var: 0, reinforced: false, res: 0 }
     }
     pub fn solid(&self) -> bool {
-        matches!(self.kind, Kind::Rock | Kind::Earth | Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond)
+        matches!(self.kind, Kind::Rock | Kind::Earth | Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond | Kind::Steel)
     }
     pub fn diggable(&self) -> bool {
-        matches!(self.kind, Kind::Earth | Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond)
+        matches!(self.kind, Kind::Earth | Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond | Kind::Steel)
     }
     // the treasure of a vein (None for everything else)
     pub fn vein(&self) -> Option<u8> {
@@ -637,6 +639,7 @@ impl Map {
             let tl = &self.t[i];
             match tl.kind {
                 Kind::Earth if tl.reinforced => Some(70),
+                Kind::Steel => Some(300),
                 Kind::Earth => Some(7),
                 Kind::Gold | Kind::Silver | Kind::Ruby | Kind::Diamond => Some(12),
                 Kind::Rock | Kind::Core | Kind::Tower | Kind::Water | Kind::Lava => None,

src/render3d.rs

@@ -1717,6 +1717,7 @@ pub fn minimap_color(tile: &Tile) -> [u8; 4] {
         Kind::LavaBridge => [130, 120, 115, 255],
         Kind::Shard => [255, 60, 120, 255],
         Kind::Aerie => [170, 140, 90, 255],
+        Kind::Steel => [150, 160, 180, 255],
     }
 }
 

src/settings.rs

@@ -7,7 +7,7 @@ use std::collections::BTreeMap;
 // Rebindable keyboard actions. Esc (menu) and the arrow keys (camera) are fixed.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
 pub enum Action {
-    Tool(usize), // 0..19, same order as ui::TOOLS
+    Tool(usize), // 0..20, same order as ui::TOOLS
     CamForward,
     CamBack,
     CamLeft,
@@ -25,7 +25,7 @@ pub enum Action {
 }
 
 pub fn all_actions() -> Vec<Action> {
-    let mut v: Vec<Action> = (0..19).map(Action::Tool).collect();
+    let mut v: Vec<Action> = (0..20).map(Action::Tool).collect();
     v.extend_from_slice(&[
         Action::CamForward,
         Action::CamBack,
@@ -70,7 +70,7 @@ impl Action {
     fn default_key(self) -> KeyCode {
         use KeyCode::*;
         match self {
-            Action::Tool(i) => [Key1, Key2, Key3, Key4, Key5, Key6, Key7, Key8, Key9, Key0, X, V, K, J, B, C, T, U, Y][i.min(18)],
+            Action::Tool(i) => [Key1, Key2, Key3, Key4, Key5, Key6, Key7, Key8, Key9, Key0, X, V, K, J, B, C, T, U, Y, O][i.min(19)],
             Action::CamForward => W,
             Action::CamBack => S,
             Action::CamLeft => A,

src/ui.rs

@@ -156,10 +156,11 @@ pub enum Tool {
     Summon,
     Tower(TowerKind),
     Bridge,
+    Steel,
 }
 
 // New tools are appended so that existing key bindings ("tool<i>") keep their meaning
-pub const TOOLS: [Tool; 19] = [
+pub const TOOLS: [Tool; 20] = [
     Tool::Dig,
     Tool::Hand,
     Tool::Room(0),
@@ -179,6 +180,7 @@ pub const TOOLS: [Tool; 19] = [
     Tool::Tower(TowerKind::Magic),
     Tool::Bridge,
     Tool::Room(7),
+    Tool::Steel,
 ];
 
 
@@ -210,6 +212,7 @@ pub fn tool_info(t: Tool) -> ToolInfo {
         Tool::Heal => ("heal", I_HEAL, None),
         Tool::Summon => ("summon", I_SUMMON, None),
         Tool::Bridge => ("bridge", I_BRIDGE, None),
+        Tool::Steel => ("steel", I_STEEL, None),
     };
     let name = match room {
         Some(r) => tr(ROOM_NAMES[r]),
@@ -225,6 +228,7 @@ pub fn tool_cost(t: Tool, g: &Game) -> String {
         Tool::Heal => trf("cost.mana", &["60".into()]),
         Tool::Summon => trf("cost.mana", &[(g.summon_cost() as i32).to_string()]),
         Tool::Bridge => trf("cost.bridge", &[BRIDGE_COST[0].to_string(), BRIDGE_COST[1].to_string()]),
+        Tool::Steel => trf("cost.steel", &[STEEL_COST[0].to_string(), STEEL_COST[1].to_string()]),
         Tool::Tower(k) => {
             let s = tower_stats(k);
             let mut c = trf("cost.tower", &[s.cost[0].to_string(), s.cost[1].to_string(), s.cost[2].to_string()]);
@@ -244,7 +248,7 @@ pub const CATS: [(&str, &[usize]); 6] = [
     ("cat.rooms", &[2, 3, 4, 5, 6, 12, 13, 18, 17]),
     ("cat.towers", &[14, 15, 16]),
     ("cat.spells", &[9, 10, 11]),
-    ("cat.orders", &[8, 7]),
+    ("cat.orders", &[8, 7, 19]),
 ];
 
 #[derive(Clone, Copy, PartialEq, Debug)]
@@ -1061,6 +1065,10 @@ pub fn hover_info(g: &Game, ent: Option<usize>, tile: Option<(i32, i32)>) -> Vec
     };
     match t.kind {
         Kind::Rock => out.push((tr("tile.rock"), DIM)),
+        Kind::Steel => {
+            out.push((tr("tile.steel"), FRAME_HI));
+            out.push((tr("tile.steel_info"), DIM));
+        }
         Kind::Earth if t.reinforced => {
             out.push((tr("tile.reinforced"), FRAME_HI));
             out.push((tr("tile.reinforced_info"), DIM));