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AssetFormats.md

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Asset Formats

This document describes the data layouts for NcEngine assets and asset file types.

Contents

Nc Asset

An asset can exist on its own in a .nca file, or as an entry in a .ncp package. The data layout is identical in either case. Each nca consists of a header that is common between all asset types and an asset blob, the layout of which is determined by the asset type.

.nca File Format

Name Type Size Note
magic number string 4 non-null-terminated string identifying the asset type
compression string 4 NONE until supported
asset id u64 8
blob size u64 8 size of the asset blob
asset blob - blob size unique layout for each asset type

Nc Asset Package

An asset package is one or more assets bundled together. It consists of a header, lookup table, and one or more .nca files packaged together.

.ncp File Format

Name Type Size Note
magic number string 4 always NCPK
version string 8 semver XX.YY.ZZ
asset count u64 8 number of table/asset entries
look up table lutEntry[] asset count * 24 identifies assets in the package
assets nca[] - list of nca files

LUT Entry Format

Name Type Size
asset id u64 8
offset u64 8
last updated time_t 8

Blob Formats

AudioClip Blob Format

Magic Number: 'CLIP'

Name Type Size
samples per channel u64 8
left channel double[] 8 * samples per channel
right channel double[] 8 * samples per channel

ConcaveCollider Blob Format

Magic Number: 'CONC'

Name Type Size
extents Vector3 12
max extent float 4
triangle count u64 8
triangles Triangle[] triangle count * 36

Cubemap Blob Format

Magic Number: 'CUBE'

Name Type Size Note
face side length u32 4
pixel data unsigned char[] face side length ^ 2 * 4 * 6 6 faces with 4 8-bit channels packed together

CubeMap faces in pixel data array are ordered: front, back, up, down, right, left.

HullCollider Blob Format

Magic number: 'HULL'

Name Type Size
extents Vector3 12
max extent float 4
vertex count u64 8
vertex list Vector3[] vertex count * 12

Mesh Blob Format

Magic Number: 'MESH'

Name Type Size Note
extents Vector3 12
max extent float 4
vertex count u64 8
index count u64 8
vertex list MeshVertex[] vertex count * 88
indices int[] index count * 4
bones data has value bool 1
BonesData BonesData BonesData

Bones Data Blob Format

Name Type Size Note
vertexSpaceToBoneSpace count u64 8
boneSpaceToParentSpace count u64 8
boneMapping (u64 + string + u32) * vertexSpaceToBoneSpace count (12 + sizeof(boneName)) * vertexSpaceToBoneSpace count
vertexSpaceToBoneSpace VertexSpaceToBoneSpace[] (72 + sizeof(boneName)) * vertexSpaceToBoneSpace count
boneSpaceToParentSpace BoneSpaceToParentSpace[] (136 + sizeof(boneName)) * vertexSpaceToBoneSpace count

Shader Blob Format

Magic Number: 'SHAD'

TODO

SkeletalAnimation Blob Format

Magic Number: 'SKEL'

Name Type Size Note
name size u64 8
name string name.size()
durationInTicks u32 4
ticksPerSecond float 4
framesPerBone count u64 8
framesPerBone list FramesPerBone[] FramesPerBone

FramesPerBone Blob Format

Name Type Size Note
name size u64 8
name string name.size()
position frames size u64 8
position frames PositionFrames[] position frames size * 20
rotation frames size u64 8
rotation frames RotationFrames[] rotation frames size * 24
scale frames size u64 8
scale frames ScaleFrames[] scale frames size * 20

Texture Blob Format

Magic Number: 'TEXT'

Name Type Size Note
width u32 4
height u32 4
pixelData unsigned char[] width * height * 4 Always forced to 4 8-bit channels