CTPK (File Format)

CTPK (Citra Texture PacKage) is an archive format used in Nintendo 3DS games, used to store texture data.

File Format

The file byte order is always little endian.

Header

Every CTPK file begins with a 0x20 byte header structure.

Offset	Type	Description
0x00	Char[4]	File magic. Always CTPK in ASCII.
0x04	UInt16	Version number.
0x06	UInt16	Number of Texture Entries.
0x08	UInt32	Texture Data offset.
0x0C	UInt32	Size of Texture Data in bytes.
0x10	UInt32	Hash Table offset.
0x14	UInt32	Texture Format Information Table offset.
0x18	Byte[8]	Padding.

Texture Entry

Followed by the header, there is an entry for each texture. They have the following tructure:

Offset	Type	Description
0x00	UInt32	File name offset.
0x04	UInt32	Size of the texture in bytes.
0x08	UInt32	Offset in Texture Data.
0x0C	UInt32	Image format.
0x10	UInt16	Width.
0x12	UInt16	Height.
0x14	Byte	Mip level.
0x15	Byte	Type: 0x0 = Cube map 0x1 = 1D 0x2 = 2D
0x16	UInt16	Cube map flags.
0x18	UInt32	Bitmap size offset, relative to the start of the entry.
0x1C	UInt32	Unix timestamp.

Followed by all entries comes all bitmap sizes (UInt32s) and texture file names (null-terminated strings).

Hash Table

This section contains checksums for each texture entry. Each entry of the table is 8 bytes long and has the following structure:

Offset	Type	Description
0x00	UInt32	CRC32 of the texture file name.
0x04	Int32	Texture index.

Texture Format Information Table

This section contains format and compression information for each texture entry. Each entry of the table is 4 bytes long and has the following structure:

Offset	Type	Description
0x00	Byte	Image format.
0x01	Byte[3]	Unknown flags.

Texture Data

This section contains texture data, aligned by 0x80.

Version List

Version	Found in
0.1	StreetPass Mii Plaza

Tools

The following tools can handle CTPK files:

• (none)