Add distance-based terrain LOD system#78
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brendancol merged 4 commits intomasterfrom Mar 6, 2026
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Implement terrain level-of-detail with per-tile resolution control: - TerrainLODManager divides terrain into tiles, assigns LOD levels based on camera distance, and builds separate GAS per tile - LOD levels: 0 (full res), 1 (2x subsample), 2 (4x), 3 (8x) - Tile edge skirts hide T-junction cracks between different LOD levels - Toggle with Shift+A keybinding in interactive viewer - Integrates with existing R/Shift+R resolution and Z/Shift+Z VE controls - Core LOD utilities (compute_lod_level, simplify_mesh, build_lod_chain) in rtxpy/lod.py for terrain and instanced geometry LOD
28 tests covering: - compute_lod_level distance-to-LOD mapping (boundary, edge cases) - compute_lod_distances threshold generation - simplify_mesh quadric decimation - build_lod_chain progressive simplification - TerrainLODManager tile creation, LOD assignment, VE, cache invalidation - Tile helper functions and skirt geometry
- Add LOD utilities section to api-reference.md - Add Shift+A keybinding to user-guide.md keyboard controls - Add terrain LOD tip to performance section
Script generates synthetic terrain and launches the viewer with instructions to toggle LOD via Shift+A. Supports xarray-spatial Perlin noise or falls back to sine-based terrain.
This was referenced Mar 6, 2026
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Closes #74 (terrain LOD portion)
Summary
Terrain LOD from the roadmap (#74). Splits terrain into tiles, picks resolution per tile based on camera distance. Nearby tiles stay full-res, distant tiles get subsampled.
What's included
rtxpy/lod.py— LOD utilities:compute_lod_level(),compute_lod_distances(),simplify_mesh()(quadric decimation),build_lod_chain()(progressive simplification)rtxpy/viewer/terrain_lod.py—TerrainLODManager: tiles the terrain, assigns LOD per tile (0=full, 1=2x, 2=4x, 3=8x subsample), builds a separate GAS per tile, adds edge skirts to cover T-junction cracksNot included (future work per #74)
Test plan
pytest rtxpy/tests/test_lod.py)examples/terrain_lod_demo.py, press Shift+A, check tiles render at varying resolution