CGFX

CGFX is a container format used to store graphics resources. It can contain 3D models, textures and animation data.

CGFX

CGFX header :

Offset	Length	Description
0x0	0x4	Magic "CGFX"
0x4	0x2	Byte order mark: FFFE (little endian) or FEFF (big endian)
0x6	0x2	CGFX header size
0x8	0x4	Revision
0xC	0x4	File size (bytes)
0x10	0x4	Number of entries

A typical CGFX file contains two main entries, beginning directly after the CGFX header: DATA and IMAG.

DATA

DATA contains a list of DICT references.

DATA header (for N = 0..15) :

Offset	Length	Description
0x0	0x4	Magic "DATA"
0x4	0x4	DATA Size (in bytes)
0x8 +(N*8)	0x4	Number of entries in DICT N
0xC +(N*8)	0x4	Offset (self-relative) to DICT N

The DATA header contains the entry counts and offsets for each DICT entry. The number of entries can vary (probably based on the version?), but are always in the following order. Any unused entries are zeroed.

Typical entries:

N	Type
0	Models
1	Textures
2	LUTS (Material/Color/Shader look-up tables?)
3	Materials
4	Shaders
5	Cameras
6	Lights
7	Fog
8	Environments
9	Skeleton animations
10	Texture animations
11	Visibility animations
12	Camera animations
13	Light animations
14	Emitters
15	Unknown

DICT

DICTs are generic structures used to store values (and associate them to a key ?). A DICT header is 0x1C bytes long.

DICT header :

Offset	Length	Description
0x0	0x4	Magic "DICT"
0x4	0x4	DICT size (in bytes)
0x8	0x4	Number of entries
0xC	0x4	?
0x10	0x2	Unknown. Seems to be shifted left by 4 bits in the source.
0x12	0xA	?

DICT entry:

Offset	Length	Description
0x0	0x4	?
0x4	0x2	?
0x6	0x2	?
0x8	0x4	Offset (self-relative) to symbol
0xC	0x4	Offset (self-relative) to object

CMDL

CMDL is used to describe a 3D model.

CMDL Header :

Offset	Length	Description
0x0	0x4	Flags (bit 7: hasSkeletonSobj)
0x4	0x4	Magic "CMDL"
0x8	0x4	?
0xC	0x4	Offset (self-relative) to model name
0x10	0x18	?
0x28	0x4	Number of entries in Animation Types DICT
0x2C	0x4	Offset (self-relative) to Animation Types DICT
0x30	0xC	Global scale vector (3 floats : x, y, z)
0x3C	0x18	?
0x54	0x30	Matrix 1
0x84	0x30	Matrix 2
0xB4	0x4	Number of Vertex Info SOBJ entries
0xB8	0x4	Offset (self-relative) to Vertex Info SOBJ list
0xBC	0x4	Number of MTOB DICT entries
0xC0	0x4	Offset (self-relative) to MTOB DICT
0xC4	0x4	Number of Vertex Info SOBJ entries
0xC8	0x4	Offset (self-relative) to Vertex Info SOBJ list
0xCC	0x4	Number of Unknown DICT entries
0xD0	0x4	Offset (self-relative) to Unknown DICT
0xD4	0xC	?
0xE0	0x4	Skeleton Info SOBJ offset (self-relative) [only present if flag bit 7 is set]
0xB8+[0xB8]	0x4*N	Vertex Info SOBJ self-relative offset list

A CMDL section refers to outside data; it can not be considered separately from the rest of the CGFX file. The second DICT in the CMDL section contains offsets to MTOB objects.

SOBJ

SOBJ structures can be used to describe 3D objects that are part of the model. If such is the case then they will follow this structure :

Offset	Length	Description
0x0	0x4	Flags (bit 4: model; bit 1: skeleton)
0x4	0x4	Magic "SOBJ"
0x8	0x4	?
0xC	0x4	Unknown symbol offset (self-relative)
0x10	0xC	?
0x1C	0x4	Offset (self-relative) to Unknown1 (appears to hold array of floats) ?
0x20	0xC	Mesh position offset (X/Y/Z floats)
0x2C	0x4	Face groups count
0x30	0x4	Offset (self-relative) to face groups offset array
0x34	0x4	?
0x38	0x4	Vertex groups count
0x3C	0x4	Offset (self-relative) to vertex groups offset array
0x40	0x4	Unknown offset (self-relative) ?

Face groups:

Offset	Length	Description
0x0	0x4	Bone groups count
0x4	0x4	Offset (self-relative) to UInt32 bone group IDs array
0x8	0x4	?
0xC	0x4	Unknown2 count
0x10	0x4	Offset (self-relative) to Unknown2 offset array

Unknown2:

Offset	Length	Description
0x0	0x4	Face group descriptor count
0x4	0x4	Offset (self-relative) to face array descriptors offset array
0x8	0x4	Unknown3 count
0xC	0x4	Offset (self-relative) to UInt32 Unknown3 array
0x10	0x8	?

Face array descriptor:

Offset	Length	Description
0x0	0x4	Flags (bit 1: vertex index format: 0=byte, 1=short)
0x4	0x4	?
0x8	0x4	Vertex index array size (in bytes)
0xC	0x4	Offset (self-relative) to vertex index array

Vertex groups come in a number of different formats. Typically the first vertex group entry is of format 0x40000002 and contains the actual vertex array.

Vertex group format 0x40000002:

Offset	Length	Description
0x0	0x4	Flags (0x40000002)
0x4	0x4	?
0x8	0x4	?
0xC	0x4	?
0x10	0x4	?
0x14	0x4	Vertex array size (in bytes)
0x18	0x4	Offset (self-relative) to vertex array
0x1C	0x4	?
0x20	0x4	?
0x24	0x4	Vertex stride/size in bytes (see below)
0x28	0x4	Unknown3 count
0x2C	0x4	Offset (self-relative) to component declaration offset array

Each mesh's primary vertex group contains an array of vertex component declaration objects, defining the order and parameters for each of a vertex's components.

Vertex component declaration:

Offset	Length	Description
0x0	0x4	Flags (0x40000001)
0x4	0x4	Vertex component type (see below)
0x8	0x4	?
0xC	0x4	?
0x10	0x4	?
0x14	0x4	?
0x18	0x4	?
0x1C	0x4	?
0x20	0x4	?
0x24	0x1	Component data type (see below)
0x25	0x1	?
0x26	0x1	?
0x27	0x1	?
0x28	0x4	Number of values in this component (e.g. XYZ->3, UV->2)
0x2C	0x4	Multiplier for this component's values (float)
0x30	0x4	Position of this component within vertex stride

Vertex formats with bone data support multiple bone assignment. In this case, the sum of all bone weights is 0x64.

Vertex component types:

Value	Type
0x00	Position
0x01	Normal
0x02	? (unobserved)
0x03	Color
0x04	UV0
0x05	UV1
0x06	? (unobserved, possibly UV2)
0x07	Weight
0x08	Index

Vertex component data types:

Value	Type
0x00	sbyte
0x01	byte
0x02	short
0x03	? (unobserved, possibly ushort)
0x04	? (unobserved, possibly int)
0x05	? (unobserved, possibly uint)
0x06	float

Vertex components are stored as one of the above data types, and the vertex component declaration contains a multiplier that adapts the values to the float version which the game will use. For example, color RGBA values are stored as bytes, and the multiplier converts them from 0-255 to 0-1.0, and position components using short values are normalized via the multiplier to take advantage of the entire short value range.

TXOB

TXOBs are contained within MTOBs. They can describe textures; if such is the case, then their structure is as follows :

Offset	Length	Description
0x0	0x4	Flags
0x4	0x4	Magic "TXOB"
0x8	0x8	?
0xC	0x4	Offset (self-relative) to symbol
0x18	0x4	Texture height
0x1C	0x4	Texture width
0x28	0x4	Mipmap levels
0x34	0x4	Texture format ID (see table below)
0x3C	0x4	Texture height (?)
0x40	0x4	Texture width (?)
0x44	0x4	Texture data size
0x48	0x4	Texture data offset (self-relative)

Texture format ID	Description
0x0	RGBA8
0x1	RGB8
0x2	RGBA5551
0x3	RGB565
0x4	RGBA4
0x5	LA8
0x6	HILO8
0x7	L8
0x8	A8
0x9	LA4
0xA	L4
0xB	A4 ?
0xC	ETC1 (see notes below)
0xD	ETC1A4 ?

Every texture format has its texture data divided into 8x8 tiles. See SMDH for more information. ETC1 is a compressed texture format which compresses blocks of 4x4 pixels into u64s. These u64 are traditionally stored in big endian; however, nintendo's implementation stores them in little endian. ETC1 textures are stored in 8x8 tiles; decompressed 4x4 therefore have to be organized accordingly. See [1] for implementation example.

LUTS

Appears to contain color lookup tables possibly for use with shaders.

LUTS Header:

Offset	Length	Description
0x0	0x4	Magic "LUTS"
0x4	0x2	Seems to adhere to powers of 2 (width/height/flags?)
0x6	0x2	Seems to adhere to powers of 2 (width/height/flags?)
0x8	0x4	?
0xC	0x8	all zeroes ?
0x14	0x4	?
0x18	0x4	Offset to DICT (self-relative) ?

All observed instances have an otherwise unreferenced DICT section immediately afterward (the last LUTS value being a 0x4, which may describe the relative position of that DICT), which appears to describe material specularity.

Skeleton data

Skeleton data is stored in an array. Each entry is 0xE0 bytes in length and organized this way :

Offset	Length	Description
0x0	0x4	Offset (self relative) to name symbol
0x4	0x4	?
0x8	0x4	Joint ID
0xC	0x4	Parent joint ID
0x10	0x4	Signed offset (self-relative) to parent joint
0x2C	0xC	Angle vector (floats, x, y, z)
0x38	0xC	Position vector (floats, x, y, z)
0x44	0x30	Transformation matrix (4x3)
0x74	0x30	Identity matrix ? (4x3)

Each entry stores the joint transformation data twice; once as angle/position vectors and once as a transformation matrix. Each entry also stores a second matrix which appears to always be identity. (?)

CANM

CANMs are used to store skeletal animation data.

Tools

• Every File Explorer
• Ohana3DS and its forks
• SPICA

Links

• Another CGFX Format Description (Archived Page): http://florian.nouwt.com/wiki/index.php/CGFX_(File_Format)