DKRDS Track (File Format)

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DKRDS Track is the nameless file format used in Diddy Kong Racing DS that stores the tracks' section models, collision and textures. Its type identifier in assets.bin is 0x9A.

File Format

The file byte order is always little endian.

Header

The file starts with a header that is 56 bytes long.

Offset	Type	Description
0x00	Int32	Number of sections (N).
0x04	Int32	Track Section Group offset.
0x08	Int32	Unknown Section 1 offset.
0x0C	Byte[4]	Unknown. Always 0xCCCCCCCC.
0x10	Int32	Culling Groups offset.
0x14	Int32	Culling Groups data type: 1 = 4-byte per N group. 2 = 8-byte per N group.
0x18	Int32	Number of textures.
0x1C	Int32	Texture Group offset.
0x20	Int32	Unknown Section 2 offset.
0x24	Int32	Wish Race Unknown Section entry count.
0x28	Int32	Wish Race Unknown Section offset.
0x2C	Byte[4]	Unknown. Seems to be some kind of flags.
0x30	Int32	Unknown.
0x34	Int32	File size.
0x38	End of header

Track Section Group

This group starts with a list of N offsets.

Track Section Header

Offset	Type	Description
0x00	Int32[N]	Track Section Entry offsets. Relative to the start of this group.

Track Section Entry

Every section entry defines model and collision data. The entry starts with a 32-byte header.

Track Section Entry Header

Offset	Type	Description
0x00	Byte	Unknown.
0x01	Byte	Unknown. Always 5?
0x02	UInt16	Unknown.
0x04	UInt16	Number of polygon groups (P).
0x06	UInt16	Number of vertices in Track Section Vertex Data (V).
0x08	UInt16	Number of UVs in Track Section UV Data (U).
0x0A	UInt16	Number of colors in Track Section Color Data (C).
0x0C	Int32	Track Section Triangle Data offset.
0x10	Int32	Track Section Collision Data offset.
0x14	Int32	Track Section Vertex Data offset.
0x18	Int32	Track Section UV Data offset.
0x1C	Int32	Track Section Color Data offset.
0x38	End of header, start of Track Section Data

Track Section Data

This data follows directly after the header of the section entry and starts with a 76-byte header.

Offset	Type	Description
0x00	Int32	Unknown. Seems to be always 0xFFFFFFFF and set to an address when loaded in memory.
0x04	Int32[3]	Collision XYZ offset.
0x10	Int32[3]	Visual model XYZ offset. The units are not the same as the collision offset.
0x1C	UInt16[12][2]	Unknown. Both 24-byte arrays seem to always be the same? They affect collision data.
0x4C	End of header, start of Track Section Polygon Data

Track Section Polygon Data

This section seems to store P polygon groups' attributes.

Offset	Type	Description
0x00	Polygon Group Entry[P]	Polygon group entries.

Polygon Group Entry

Each polygon group entry is 12 bytes long.

Offset	Type	Description
0x00	UInt16	First triangle ID.
0x02	UInt16	Number of triangles.
0x04	Byte	Unknown.
0x05	Byte	Unknown. Seems to affect collision attributes, such as the type of collision and terrain effects.
0x06	UInt16	Unknown.
0x08	Byte[4]	Unknown.

The number of triangles T can be calculated by adding the first triangle ID to the number of triangles of the last polygon group entry.

Track Section Triangle Data

This section stores T triangle entries.

Offset	Type	Description
0x00	Triangle Entry[T]	Triangle entries.

Triangle Entry

Each triangle entry is 20 bytes long.

Offset	Type	Description
0x00	UInt16	Texture ID.
0x02	UInt16[3]	Unknown. Seems to affect the collision only. Perhaps triangle normals?
0x08	Byte[4]	Vertex position indices. The index for each of the 3 vertices is 10 bits long. 2 last bits are unknown.
0x0C	Byte[4]	UV indices. The index for each of the 3 vertices is 10 bits long. 2 last bits are unknown.
0x10	Byte[4]	Color indices. The index for each of the 3 vertices is 10 bits long. 2 last bits are unknown.

Track Section Collision Data

4-byte data per triangle (?). TBD

Track Section Vertex Data

Vertex data is stored as 6-byte groups per entry V.

Offset	Type	Description
0x00	Int16[3][V]	Vertex XYZ position.

Track Section UV Data

UV data is stored as 4-byte groups per entry U.

Offset	Type	Description
0x00	Int16[2][U]	Vertex UV position.

Track Section Color Data

Color data is stored as 2-byte groups per entry C.

Offset	Type	Description
0x00	UInt16[C]	RGBA5551 color.

Unknown Section 1

TBD

Culling Groups

This section includes a 4-byte or 8-byte per track section values that determine which section models are loaded when entering a specific section. Each section is represented as 1 bit.

Offset	Type	Description
0x00	UInt16[N]/UInt32[N]	Culled model sections, represented as N bits, 1 per section, in order from the least to the most significant bit. 0 if culled, 1 if loaded.

Texture Group

See DKRDS Texture Group.

Unknown Section 2

TBD

Wish Race Unknown Section

This section is only used for the Wish Race tracks. TBD

Tools

The following tools can handle DKRDS Track:

• (none)