forked from 1b-agent/opencadstudio-upstream
Hakan SevenandClaude Opus 4.7
8c08ae104a
ACIS SAT entities (Solid3D / Region / Body) were tessellated at one
fixed sampling density (CIRC_SEGS=48, GRID_U=32, GRID_V=16) regardless
of how far they were from the camera. Distant solids paid the full
triangle bill for fragments that mostly resolved to sub-pixel size.
Generate three pre-built LODs per entity at load time:
* LOD 0 (HIGH) — 48/32/16 segments. Use above 200 px projected diag.
* LOD 1 (MID) — 24/16/8. Use 50–200 px.
* LOD 2 (LOW) — 12/8/4. Use below 50 px.
Tessellation cost is paid 3× on load (cheap — typical files have few
solids). Render picks per-frame via `compute_mesh_lod` from each mesh's
`world_aabb` projected diagonal. When a level is missing (e.g. a solid
entity that only emits LOD 0), the selector walks down to the nearest
available slot.
API ripples:
* New `LodConfig` (HIGH/MID/LOW) drives `tess_sat`, `tess_cone_face`,
`tess_sphere_face`, `tess_torus_face`.
* `tessellate_solid3d / _region / _body` now return `MeshLodSet`.
* `MeshLodSet { lods: Vec<MeshModel>, world_aabb }` + `from_single`
constructor so interactive truck-based commands (BOX/CYLINDER/etc.)
that only generate one tessellation stay one-line.
* GPU side gets `MeshLodGpu { lods: Vec<MeshGpu>, world_aabb }` and
a `mesh_lod_levels` per-frame index vector.
* STL/STEP export pulls slot 0 explicitly so the on-disk geometry
isn't downgraded by the view-dependent ladder.
Background-thread lazy generation (per the roadmap) is deferred — the
synchronous eager build is fine for typical CAD files. Switch to a
queue + background tessellator when files with hundreds of solids
become a load-time bottleneck.
Co-Authored-By: Claude Opus 4.7 <[email protected]>