XBG Format — GeomParser Decompile Reference

Source: Hex-Rays decompile of GeomParser_r64.dll (Ubisoft leak) — the actual XBG compiler ("DuniaGeometryDeserializer" = XBG WRITER). Reference Importer: import_wdl_xbg.py (READ ONLY, works on real files). Cross-reference: XeNTaX forum knowledge (WD1 vertex strides, UV scaling, WD2 version bump) → XeNTaX Watch Dogs knowledge §3

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1. Header Layout

Offset	Size	Type	Meaning	Source
0x00	4	char[4]	Magic "MOEG"	Importer line 112
0x04	2	u16	Version major (0x95 for WDL)	Importer line 113, 394
0x06	2	u16	Version minor (0x46 for WDL)	Importer line 113, 395
0x08	16	—	Unknown/reserved	Importer line 403
0x18	4	u32	unk_count	Importer line 404
0x1C	4	u32	odd_flag	Importer line 405
0x20	var	—	Odd tables (if odd_flag > 0)	Importer lines 118-122
—	76	—	Unknown/reserved	Importer line 410
—	4	u32	lod_count	Importer line 412
—	8×lod	u32[2]	LOD data pairs	Importer lines 414-416

Note: The compiler's ParseFileBuffer deserializes the asset via GXAsset::Asset::Deserialize but does NOT write the MOEG header — that is likely written by EditorExporter_r64.dll which consumes GeomParser output.

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2. Hierarchy Structure (ParseGeometryAssetHierarchy)

Function: DuniaGeometryDeserializer::ParseGeometryAssetHierarchy

The hierarchy walk:

1. Reads node type, export_tag, export_name
2. Filters node types: BREAKABLE, FACADE, BASIC_ANIMATED, DYNAMIC_ANIMATED, LOFTSHAPE
3. Checks for LOD/OCM suffixes
4. For geometry nodes: calls DeserializePolyMesh
5. For skeleton nodes: calls SkeletonNodeToMeshSkeleton
6. For breakable: calls BreakableNodeHierarchyToBoneHierarchy

Mesh list written per-LOD via GXData::WriteBuffer (vtable offset 16 = GetData, 24 = GetSize).

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3. PolyMesh Write Order (DeserializePolyMesh)

Function: DuniaGeometryDeserializer::DeserializePolyMesh

Field-by-field emission order:

Order	Field	Channel Name	Type/Precision	Decompile Lines	Notes
1	Vertex Count	—	u32	64187, 64191	Position channel element count
2	Positions	"Positions"	3×i16 (quantized)	64196-64242	Transformed by node hierarchy matrix; quantized: i16 / 32768 * bbox_ext + bbox_min
3	Face Indices	"PolyFacesIndices"	u32 (tri-list)	64580-64777	3 indices per face; written per-face with vertex links
4	Normals	"Triangulation"/"TriangulationIndex"	3×f32 (computed)	64595-64770	Computed from face vertices via cross product; normalized
5	Tangents	"Triangulation" (channel 0)	4×f32	64595-64770	Computed per-face, stored in vertex link struct
6	UV Channels (0-6)	"TexCoords"	2×f32 per channel	65033-65371	Up to 7 UV channels; loop j=0..6; channel index = v252 - 1
7	Vertex Colors	"VertexColors"	4×u8 (normalized)	65448-65589	RGBA u8 → f32 / 255.0
8	Vertex Illumination	"VertexIllumination"	3×f32	65372-65466	Only if valid alongside VertexColors
9	Bone Weights	"BoneWeights"	4×f32 (normalized)	64252-64568	Max 8 bones/vertex; sorted by weight descending; weights sum to 1.0
10	Bone Indices	"BoneIDs"	4×u16	64252-64568	Indices into skeleton bone array
11	Smoothing Groups	"SmoothingGroups"	u32	64024	From off_180118080[0]
12	Material IDs	"MaterialIDs"	u32	64024	From off_180118080[1]
13	Custom Faces	"CustomFaces"	—	64024	From off_180118080[2]
14	Vertex Links	—	struct (312 bytes)	64806-64899	Per-vertex face adjacency (max 64 faces/vert)
15	Sub-parts	—	—	114242	Called after main mesh
16	Transform	—	4×4 matrix	64077-64185	Node world transform + parent hierarchy

Key struct offsets in GamExMesh (size 0xC0=192):

Offset	Field	Size
+0x08	Position buffer ptr	8
+0x10	Position count	4
+0x14	Position stride	4
+0x18	Normal/Tangent buffer	8
+0x24	Face index buffer	8
+0x2C	Face count	4
+0x30	UV buffers (7×)	8×7
+0x38	UV counts	4×7
+0x56	Vertex color buffer	8
+0x5E	Skin data (weights/indices)	inline in vertex links
+0x72	Vertex link buffer	8
+0x90	Sub-mesh parts	8
+0x98	Material refs	8
+0xB0	Name string	64
+0xF0	LOD index	4

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4. Discrepancy Analysis: Compiler Write vs Importer Read

#	Aspect	Compiler (GeomParser)	Importer (import_wdl_xbg.py)	Status
1	Header magic	NOT written by GeomParser	Expects "MOEG" at offset 0	Gap — EditorExporter writes header
2	Vertex positions	Quantized i16 in local space	Reads quantized i16, applies bbox	Match
3	Face indices	Tri-list, 3×u32 per face	Reads via quad-split index buffer decode	Partial
4	Normals	Computed per-face, stored in vertex links	NOT directly read — reconstructed from faces	Gap
5	Tangents	Computed per-face (4×f32)	NOT read	Gap
6	UV channels	Up to 7, 2×f32 each	Reads UVFlag (params[3]) but decode unclear	Partial
7	Bone weights/indices	4×f32 + 4×u16, sorted by weight	NOT read — .skel file used instead	Gap
8	Vertex colors	4×u8 RGBA	NOT read	Gap
9	Vertex illumination	3×f32	NOT read	Gap
10	Smoothing groups	u32 per face	NOT read	Gap
11	Material IDs	u32 per face	Read via mesh descriptor matID (params[2])	Partial match
12	Sub-parts / LOD	SplitMeshSubParts called	LOD handled via lod_count + mesh lists	Different approach
13	Skeleton	SkeletonNodeToMeshSkeleton	Reads separate .skel file	Different file
14	Transform hierarchy	Applied to positions during compile	NOT applied — uses bbox for position decode	Gap

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5. Bone/Skeleton Mapping

Function: DuniaGeometryDeserializer::SkeletonNodeToMeshSkeleton

• Maps skeleton hierarchy nodes to mesh bone indices
• Called from ParseGeometryAssetHierarchy for animated nodes (BASIC_ANIMATED, DYNAMIC_ANIMATED)
• Bone IDs from "BoneIDs" channel are indices into this skeleton
• Companion .skel file holds actual bone transforms/names (not in .xbg)

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6. Collision (.col) Generation

Search results in GeomParser_r64.dll.c:

• No CPhys, hkpBvCompressedMeshShape, .col.hkx emission found
• Only Collada parser references: CColladaParser::FindCollisionMeshIDs, COLLISION_PRIMITIVE_LIST
• CGamExUtils::gamExSerializeOcc serializes occlusion mesh (GXOccMesh), NOT physics collision

Conclusion: GeomParser does NOT emit retail-compatible .col.hkx.

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7. Channel Name Reference (from off_1801180xx arrays)

Array	Index 0	Full List
off_180118038	"Positions"	Positions, VertexColors, VertexIllumination, TexCoords, Normals, BoneIDs, BoneWeights, BlendTargets, BlendTarget, SmoothingGroups, MaterialIDs, CustomFaces
off_180118020	"PolyFacesIndices"	PolyFacesIndices, Triangulation, TriangulationIndex, Positions, VertexColors, VertexIllumination, TexCoords, Normals, BoneIDs, BoneWeights, BlendTargets, BlendTarget, SmoothingGroups, MaterialIDs, CustomFaces
off_180118028	"Triangulation"	Triangulation, TriangulationIndex, Positions, VertexColors, VertexIllumination, TexCoords, Normals, BoneIDs, BoneWeights, BlendTargets, BlendTarget, SmoothingGroups, MaterialIDs, CustomFaces
off_180118030	"TriangulationIndex"	TriangulationIndex, Positions, VertexColors, VertexIllumination, TexCoords, Normals, BoneIDs, BoneWeights, BlendTargets, BlendTarget, SmoothingGroups, MaterialIDs, CustomFaces
off_180118060	"BoneIDs"	BoneIDs, BoneWeights, BlendTargets, BlendTarget, SmoothingGroups, MaterialIDs, CustomFaces
off_180118068	"BoneWeights"	BoneWeights, BlendTargets, BlendTarget, SmoothingGroups, MaterialIDs, CustomFaces
off_180118080	"SmoothingGroups"	SmoothingGroups, MaterialIDs, CustomFaces

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Summary

The GeomParser decompile reveals the full compiler-side mesh data preparation (quantization, transform application, normal/tangent computation, skin sorting). The actual XBG binary serialization (MOEG header, mesh descriptor lists, index buffers, position buffers) is handled downstream — likely in EditorExporter_r64.dll which consumes the GeomParser output via WriteBuffer.

Critical gaps for importer enhancement:

1. Explicit normal/tangent reading (currently reconstructed)
2. UV channel mapping (UVFlag in mesh params needs decoding)
3. Skin data in .xbg vs .skel split
4. Vertex color/illumination support
5. Smoothing groups for hard edges