Add dynamic parametric building generation

MODS.md

@@ -1546,7 +1546,7 @@ objects: [
 
 The simulator spawns the glTF at the track pose plus offset, rotation and height,
 floating-origin safe like the signal models; an unknown object name gets a placeholder
-block and a warning. In the route editor the **object tool** (key 5) picks an object kind
+block and a warning. In the route editor the **object tool** (key 3 in the equipment box) picks an object kind
 and drops it on the nearest track; the selection panel edits position, lateral offset,
 rotation and height, and the rule check flags placements outside their track or naming an
 object no installed mod has. **Repeat in a row** stamps copies of the selected instance
@@ -1563,6 +1563,58 @@ editor's selection panel has the checkbox, and both programs resolve the height
 way: an object is placed by the terrain tile it stands on, so it streams in and out with
 that tile and its feet meet the ground the tile actually has.
 
+### Parametric buildings
+
+The route editor's **building tool** places an editable building recipe, not a reference
+to a glTF. Static houses under `objects:` remain supported and are the right choice for a
+specific landmark. A generated building is stored under `buildings:`:
+
+```ron
+buildings: [
+    (
+        edge: 0,
+        s: 540.0,
+        lateral_offset: -18.0,
+        yaw_deg: 90.0,
+        snap_to_terrain: true,
+        spec: (
+            use_kind: Residential,
+            width: 12.0,
+            length: 10.0,
+            floors: 3,
+            floor_height: 2.9,
+            roof_style: Gable,
+            roof_height: 3.2,
+            facade: Plaster,
+            facade_color: (0.82, 0.72, 0.58),
+            roof: ClayTile,
+            window_spacing: 2.6,
+            window_width: 1.25,
+            window_height: 1.45,
+            lit_window_share: 0.38,
+            balconies: true,
+            balcony_every: 2,
+            balcony_depth: 1.4,
+            seed: 1384,
+        ),
+    ),
+],
+```
+
+`use_kind` is `Residential`, `Commercial` or `Industrial`; roofs are `Gable`, `Hip`,
+`Flat`, `Shed` and `Mansard`. Facades use `Plaster`, `RedBrick`, `YellowBrick`,
+`Concrete` or `MetalPanel`, and roofs use `ClayTile`, `Slate`, `StandingSeam` or
+`Bitumen`. The editor constrains dimensions to valid ranges and exposes the same values
+after placement. Copy/paste clones the complete recipe, including `seed`, so the copy has
+the same design and lit-window pattern.
+
+The simulator receives only the normalised, tile-local recipe. It reuses one generated
+three-level mesh set for every identical recipe and global PBR materials for every
+building; it does not carry the editor's selection or authoring state. LOD0 includes
+window surrounds and balconies, LOD1 retains the facade rhythm, and LOD2 is the silhouette.
+The emissive share is selected deterministically from `seed` and switched by the normal
+day/night system, so loading the route never rearranges illuminated apartments.
+
 **Levels of detail** work as for vehicles and signals: nodes named `<name>_LOD0`,
 `_LOD1`, … are shown by camera distance. A model without the suffix is one level, drawn
 up to the cull distance. This matters most for trees: every tree of a wood is drawn as an
@@ -1811,14 +1863,14 @@ can be moved, rescaled or deleted on its own afterwards. Trees stream in and out
 their terrain tile and share meshes per species, so even a big wood renders as instanced
 draws.
 
-In the route editor the **tree tool** (key 6) plants one tree per click. The **forest
-brush** (key 7) outlines an area — Enter or right-click **bakes** it into single trees
+In the route editor the **tree tool** (key 2 in the vegetation box) plants one tree per click. The **forest
+brush** (key 3) outlines an area — Enter or right-click **bakes** it into single trees
 (one per `area per tree` m², species from the tool options, clear of the track strip).
 **File ▸ Import forest…** reads an Overpass JSON extract (`landuse=forest` /
 `natural=wood` ways, same download path as the track import) and bakes each polygon the
 same way — an optional aid: whoever wants every tree hand-set simply never uses it, and
 an imported wood is thinned out or cleared exactly like a painted one. For bulk edits the
-**marking brush** (key 8) sweeps over the map and marks every tree and object under the
+**marking brush** (key 6) sweeps over the map and marks every tree, object or parametric building under the
 circle; Delete (or the panel button) removes them together in one undo step.
 
 ### Fields
@@ -2340,7 +2392,7 @@ deletes the whole layer. Retyping the layer in the selection panel moves a singl
 into another one. Hiding is session state; the markers themselves travel with the line,
 so the next session still has them.
 
-The **marker tool** (key 9) sets one per click into the layer named in the tool options.
+The **marker tool** (key 5 in the equipment box) sets one per click into the layer named in the tool options.
 **File ▸ Import reference markers…** reads an Overpass JSON extract and turns the tags it
 knows into markers, each in the layer of its tag: `level-crossing`, `platform`,
 `station`, `signal`, `switch`, `buffer-stop`, `kilometre-mark`, `bridge`, `tunnel`,

README.md

@@ -530,6 +530,16 @@ builder is shared read-only, the DGM sheets keep their own short lock. Terrain,
 vegetation and track objects live in `world-render` and therefore look the same in the
 simulator and in the route editor.
 
+Parametric buildings use the same streamed terrain path without replacing static scenery.
+Their route entry keeps an editable recipe (residential, commercial or industrial use,
+width, length, floor count and height, five roof shapes, facade/roof material, colour,
+window rhythm, balconies and a stable variation seed). The terrain compiler normalises and
+bakes that recipe into a compact placement; `world-render` caches one three-level LOD mesh
+set per distinct recipe and shares a global PBR library of plaster, red/yellow brick,
+concrete, metal panels, clay tile, slate, standing seam and bitumen. Window illumination is
+chosen deterministically from the seed and appears only at night. Copy/paste preserves the
+whole recipe and seed, while all fields remain editable in the module editor.
+
 **Fields** lie on that ground: the outline and the crop are line content, and what a field
 looks like on the day is a function of the crop, the date and the field's own seed — winter
 wheat is blue-green in April, gold in the last week of July and stubble in August, and no
@@ -781,7 +791,7 @@ be laid, which never touches one already lying there.
 | Tool | What a click does |
 |---|---|
 | **Every category** | |
-| `1` Select | In every category: pick whatever stands on the map and edit its fields; `Delete` removes it. `Ctrl`+click gathers devices, objects, trees and markers into a multi-selection (a second `Ctrl`+click takes one out again); a press on empty ground dragged open selects everything inside the circle — `Ctrl` adds it to what is gathered, `Delete` removes the lot in one step |
+| `1` Select | In every category: pick whatever stands on the map and edit its fields; `Delete` removes it. `Ctrl`+click gathers devices, objects, parametric buildings, trees and markers into a multi-selection (a second `Ctrl`+click takes one out again); a press on empty ground dragged open selects everything inside the circle — `Ctrl` adds it to what is gathered, `Delete` removes the lot in one step |
 | **Track** | |
 | `2` Lay track | Press and drag sets the standing end and its heading — on an open end it continues that track, on a track's middle it starts the branch of a turnout (drag along the track = facing, against it = trailing). Every further click appends the arc that leaves the alignment tangentially and hits the point — G1-continuous by construction — or a straight while `Ctrl` is held; the running end snaps onto open ends and closes the gap with two tangent arcs. The status bar reads out length and radius. `Enter` or right-click finishes, `Esc` cancels. The *Tool* section sets what the piece is laid as: track type, speed, gradient, electrification, parallel tracks at a spacing; the toolbox's toggle box snaps radii onto the standard series, lays easements — a curve then goes down as clothoid – arc – clothoid with the rulebook's cant for the piece's speed, ramped over the transitions — and snaps the piece to the terrain: sampled ground heights become its gradient profile, a free start drops onto the surface, an end joined onto other track keeps that track's height |
 | `3` Split track | Cuts the track at the click — two tracks on one joint |
@@ -793,11 +803,12 @@ be laid, which never touches one already lying there.
 | **Lineside equipment** | |
 | `2` Place device | Puts the chosen device kind (signal, magnet, LZB, platform, …) on the clicked track |
 | `3` Place object | Drops a mod's 3D object at its predefined offset and rotation; the toolbox's terrain-snap toggle bases it on the ground instead of the rail plane |
-| `4` Place marker | A reference marker in a named layer — a drawing aid, nothing in the simulation reads it |
+| `4` Parametric building | Places an editable residential, commercial or industrial building. Its properties panel controls dimensions, floors and total height, facade colour/material, five roof shapes, windows, stable night lighting and balconies; `Ctrl+C` / `Ctrl+V` preserves the complete recipe |
+| `5` Place marker | A reference marker in a named layer — a drawing aid, nothing in the simulation reads it |
 | **Vegetation** | |
 | `2` / `3` Tree / forest | One tree per click, or an outlined area baked into single trees — each one stays editable |
 | `4` Field | Clicks outline a piece of farmland, Enter or right-click closes it, the crop comes from the tool options. The usual way to get fields is **File ▸ Import fields…**, which fetches them from the state agricultural registers |
-| `5` Marking brush | Sweep to mark trees and objects in bulk and delete them together |
+| `6` Marking brush | Sweep to mark trees, objects and parametric buildings in bulk and delete them together |
 | **Terrain** | |
 | `2` Raise ground | One lifting stroke per click, by the set amount and radius. The track keeps its height, cutting and embankment are laid over the strokes afterwards |
 | `3` Lower ground | The same stroke downward — a hollow, a pond bed, a pit |

crates/app/src/main.rs

@@ -36,7 +36,7 @@ use bevy::prelude::*;
 use bevy::render::view::screenshot::{Screenshot, save_to_disk};
 use content::import::dgm::TerrainSource;
 use content::terrain::{
-    Scenery, TerrainBuilder, TerrainEdits, TerrainOptions, TerrainStats, Vegetation,
+    Buildings, Scenery, TerrainBuilder, TerrainEdits, TerrainOptions, TerrainStats, Vegetation,
 };
 use content::vehicles::passenger_coach;
 use mod_runtime::ModRuntime;
@@ -1030,6 +1030,11 @@ fn setup(
             &sim.net,
             terrain_options.zone,
         ))
+        .with_buildings(Buildings::from_line(
+            &line_source,
+            &sim.net,
+            terrain_options.zone,
+        ))
         .with_crowd(crowd)
         .with_fields(farmland)
         .with_waters(waters)

crates/app/src/streaming.rs

@@ -142,6 +142,7 @@ impl TerrainStreamer {
 pub fn stream_terrain(
     mut commands: Commands,
     mut meshes: ResMut<Assets<Mesh>>,
+    mut building_assets: ResMut<world_render::BuildingAssets>,
     mut streamer: ResMut<TerrainStreamer>,
     mut info: ResMut<TerrainInfo>,
     sim: Res<SimResource>,
@@ -255,6 +256,7 @@ pub fn stream_terrain(
         let entity = render::spawn_terrain_tile(
             &mut commands,
             &mut meshes,
+            &mut building_assets,
             &streamer.material,
             &streamer.catalog,
             &tile,