# Terrain Foundation Evaluation

Date: 2026-07-12
Branch: `codex/terrain-foundation`
Gitea issue: `#22`

This record captures acceptance for the persistent height-grid terrain schema and deterministic
runtime chunk hydration. The permanent workflow lives in the [terrain guide](../../terrain.md).

## Live Editor Evidence

The native Wayland debug editor loaded the committed
`assets/levels/terrain_authoring_showcase.scn.ron` fixture. The screenshot uses Forward rendering to
isolate mesh/material/light correctness while foundation terrain remains explicitly excluded from
Solari until exact terrain layer/Surface parity lands in `#24`.

![Asymmetric shared-material terrain hill generated from four runtime chunks](terrain-showcase-forward.png)

The 5×5 authored grid renders as the expected asymmetric hill, resolves the committed shared
Material Instance, and is split into four 2×2-quad chunks with generated trimesh colliders. The
authored scene contains no `HydratedTerrainChunk`, `Mesh3d`, or collider-constructor components.

## Acceptance Results

| Area | Result | Evidence |
|------|--------|----------|
| Schema and serialization | Pass | Versioned bounded descriptor, exact height count, finite-value and scale/chunk validation, RON round-trip test |
| Chunk hydration | Pass | Deterministic four-chunk runtime fixture; topology test verifies 25 vertices and 96 indices for a 4×4-quad mesh |
| Runtime-only ownership | Pass | Hydration test verifies children have mesh/collider/owner markers but no `LevelObject`, then verifies removal cleanup |
| Actor/editor integration | Pass | First-class Terrain kind, registry descriptor, hierarchy/viewport icon, reflected Add Component and inspector transaction path |
| Material behavior | Pass with boundary | Shared Material/Instance source resolves for raster; missing source uses visible fallback; Solari submission is explicitly excluded pending `#24` |
| Project validation | Pass | 60 level dependencies, existing 5 non-blocking findings, 0 blocking errors |
| Packaged acceptance | Deferred | Explicitly deferred by project-owner direction; no packaged result is claimed here |

## Automated Verification

| Command/suite | Result |
|---------------|--------|
| Focused terrain descriptor/topology/hydration tests | 4 passed |
| Editor component registry reflection contract | Pass |
| `cargo check --workspace --all-targets` | Pass |
| `cargo validate-levels --project .` | 60 dependencies, 5 findings, 0 blockers |