feat(importer): ufbx FBX importer + meshoptimizer + Bistro pipeline fixes - #668
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Add FbxImporter backed by ufbx v0.14.3 — a single-file C library that supports FBX binary and ASCII formats from 2010 to 2023 (versions 6100–7700), 2–5× faster than Assimp on large files. FbxImporter: - ufbx auto-converts to Y-up and meters (target_axes + target_unit_meters) - Per-face vertex deduplication via (pos,nrm,uv) hash map - UV V-channel flipped (FBX convention) - Per-mesh material extraction with PBR color + texture UUIDs - ImportOptions respected: scale, normals mode, mat/tex gating, flip UV - Progress callbacks at 0.2 / 0.5 / 0.8 / 1.0 AssimpImporter::CanImport now returns true only for "obj" — FBX handled by FbxImporter which is registered first in Engine::Initialize. CMakePresets: remove ASSIMP_BUILD_FBX_IMPORTER (no longer needed). Assimp stays for OBJ only. Closes #667
This was referenced Aug 24, 2026
meshoptimizer v0.22:
- 3-pass optimization per submesh (vertex cache, overdraw, vertex fetch)
- Temp buffers use malloc/free — no arena accumulation across submeshes
- Integrated in FbxImporter and GltfImporter
FbxImporter arena — use ZGetScratch/ZReleaseScratch:
- Replace CreateSubArena(440) with ZGetScratch(&Arena) in ImportFile
- Replace CreateSubArena(64) with ZGetScratch(&Arena) in Import
- Arena.Clear() at start of ImportFile guards against previous crash state
- ZReleaseScratch at end restores cursor
ReloadFromDisk mesh deserialization:
- Use s_Instance->Arena instead of 64MB caller scratch — prevents
OOM crash when reloading large .zemesh files on cold start
Memory budgets:
- ImportPipeline: 1 GB → 3.5 GB (ufbx×2=1GB, gltf×2=128MB, assimp×2=256MB)
- AssetManager: 512 MB → 1 GB (mesh deserialization scratch)
- GLOBAL_VTX_CAPACITY: 256 MB → 512 MB (Bistro needs ~272 MB)
- GLOBAL_IDX_CAPACITY: 256 MB → 512 MB
- MAX_DRAW_COMMANDS: 512 → 8192 (Bistro has ~8000+ submeshes)
Verified: Amazon Lumberyard Bistro exterior FBX (8.5M verts, 272 MB)
imports and renders in the editor.
JeanPhilippeKernel
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JeanPhilippeKernel
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Summary
Full FBX import pipeline with ufbx, mesh optimization, and all fixes needed to render the Amazon Lumberyard Bistro exterior (8.5M vertices, 272 MB).
ufbx v0.14.3 FBX importer (
FbxImporter)target_axes,target_unit_meters)(pos, nrm, uv)hash mapZGetScratch(&Arena)/ZReleaseScratch— correct engine scratch arena patternmeshoptimizer v0.22 (
MeshOptimizer.h)meshopt_optimizeVertexCache,meshopt_optimizeOverdraw,meshopt_optimizeVertexFetchmalloc/free— no arena accumulation across submeshesFbxImporter::ImportFileandGltfImporter::ImportFilePipeline fixes for large scenes
ReloadFromDiskmesh deserialization usess_Instance->Arena(1 GB) instead of 64 MB caller scratch — prevents cold-start OOM crash on 292 MB .zemesh filesArena.Clear()at start ofImportFileguards against dirty state from previous crashed importAssetState::Loadedrecords inReloadFromDiskto prevent duplicate ingestMemory budgets grown
Verified
Amazon Lumberyard Bistro exterior FBX: 8.5M vertices, 272 MB, 8000+ draw commands — imports and renders in the editor.
Closes #667