Client rendering, stage 1 — the lattice mesh, sunken cells, mountains, and people standing in water

done priority 1 estimate L

ground-types/003 · created 2026-08-17 · updated 2026-08-18

What to do

Replace the one flat green plane (client_main.gd’s _rebuild_area_geometry) with ground that is built from the cells. This stage uses no shader: transitions are vertex-colour blends, which work on every renderer and are an honest placeholder. Runs in parallel with 002 — it can render from a fake payload.

New game/world/client/ground_mesh.gd — pure logic, no Node dependencies, testable headless: from (ground, width, height) build an inset lattice (lattice lines at cell offsets 0, 0.25, 0.75, 1) and return {vertices, indices, colours, uvs} PackedArrays. One rule for every vertex: it is sunk (y = −0.25·CELL) iff every cell touching it is sunken — interior vertices touch one cell, edge vertices two, corners four. A one-cell-wide river is then a flat-bottomed trough with quarter-cell banks (a centre fan would give a row of dimples). Vertex colour = the average of the touching cells’ base colours. Also mountain_instances() (a Mountain cell → instance; peak when all eight neighbours are Mountain, out-of-bounds counting as not-Mountain; variant tint; kw 56 flagged volcano) and pack_data_image() for task 004. 60×60 → 32,761 vertices, 64,800 triangles, one static mesh.
New game/world/client/area_view.gd — build(grid): the ground MeshInstance3D (SurfaceTool, generate_normals(), StandardMaterial3D with vertex_color_use_as_albedo), a MultiMeshInstance3D of low-poly cones for Mountains (taller scale for a peak; a second small MultiMesh of red crater caps for volcanoes), a BoxMesh only for CELL_WALL / CELL_SOFT_BLOCK, portal rings at their cell’s surface height. client_main.gd’s _rebuild_area_geometry() becomes a thin call into it.
humanoid_node.gd: set_target_cell(cell, y); client_main.gd passes y = −0.5·CELL on a sunken cell (local and remote bodies) — the existing constant-speed glide interpolates the dip and the surface at −0.25 hides the lower part. Unify the three CELL_3D copies (humanoid_node.gd, client_main.gd, portal_node.gd) into one.
client/ui/_shots.gd: LOR_GROUND_FILE → build an AreaGrid from a ground content file → g-ground.png. Write a small deterministic fixture file for it; task 005’s real files replace it.

Definition of done

test_runner.gd: the vertex-sunk rule on a single cell, a 1-wide river and a 2-wide river; the peak rule incl. edges; data packing.
A screenshot from _shots.gd showing grass variants, a river with banks, mountains with a peak, reviewed by eye; the web export boots.
Committed and pushed in land-of-lor.

Where the work lands

land-of-lor/game/world/client/.

What was done (2026-08-17, laptop session)

client/world_units.gd — the one CELL_3D (plus SUNKEN_DEPTH, ENTITY_SINK, mountain sizes); humanoid_node.gd, portal_node.gd, client_main.gd use it.
client/ground_mesh.gd (pure): the inset lattice, vertex_sunk / vertex_colour / build, is_peak / mountain_instances, pack_cells (for 004), standing_height / surface_height. 26 new test_runner.gd checks (169 total) — single cell, 1-wide and 2-wide rivers, edge of the Area, blends, peaks incl. the corner case, volcano, packing.
client/area_view.gd (Node3D): floor mesh via SurfaceTool + vertex_color_use_as_albedo, one MultiMesh of cones (peaks taller, tinted per flavour) + red crater caps for kw 56, walls only for CELL_WALL/SOFT_BLOCK, portal rings on the cell’s surface. client_main.gd _rebuild_area_geometry() builds it; entities get snap_to_cell(cell, y) / set_target_cell(cell, y) from standing_height.
_shots.gd: g-ground, g-ground-top, g-ground-wade from LOR_GROUND_FILE or a built-in showcase; reviewed by eye — the river reads as a channel with banks, patches blend, the mountain block has a taller tinted peak, the wading body’s legs are hidden.
The headless Godot client harness (npm run test-client-godot) still passes every movement/prediction check; its two CLIENT_REMOTE checks fail because they still expect entity-<accountId> ids, which 014 replaced — pre-existing, not touched here.
Not done: the web export itself (task 008 does the export and ships it).

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