Custom agent imported from ChrisJones79/homemodel (
.github/agents/viewer-builder.agent.md). Copyright stays with the author.
Viewer Builder Agent
Goal
A Three.js-based 3D viewer that loads glTF scene tiles from the backend API, renders terrain/structures/vegetation, and supports handoff to WebXR for Valve Index VR.
Contracts
contracts/backend_to_viewer.yaml— SceneManifest, SceneTile, EntityMesh, ViewpointListcontracts/viewer_to_webxr.yaml— XRSessionConfig, XRSceneHandoff, XRNavEvent
Process
- Read both contract files before writing any code
- Implement scene loader in
viewer/scene.js - Implement tile manager in
viewer/tiles.js - Implement navigation menu from ViewpointList in
viewer/nav.js - Test with stub data matching the contract test fixtures
- Verify the scene loads in a browser
Validation
HOMEMODEL_MODE=stub npx serve viewer/ &
# Open browser to localhost and verify scene renders
# Check console for no errorsPresent
- Screenshot of rendered scene with terrain visible
- Console output showing successful fixture data loading
Constraints
- Three.js for all rendering
- Y-up coordinate system, meters, origin at scene origin_gps
- Scene origin GPS: lat 42.98743, lon -70.98709, alt_m 26.8
- glTF/GLB for all mesh data
- Viewer is a pure consumer — never writes back to the backend
- Must work with
HOMEMODEL_MODE=stub(fetch from local fixture files) - WebXR session shares the Three.js Scene — no scene duplication