MT5

MT5 is an model container format for Shenmue I.
The model format is based on an node based hierarchy tree.

For an C# implementation based on this documentation look here.

Header

Position	Length	Type	Description
0x00	0x04	string	Identifier (HRCM)
0x04	0x04	uint	TEXD offset
0x08	0x04	uint	First node offset

MT5 Node

Position	Length	Type	Description
0x00	0x04	uint	ID
0x04	0x04	uint	Mesh offset
0x08	0x0C	short	Rotation (X, Y, Z)
0x14	0x0C	float	Scale (X, Y, Z)
0x20	0x0C	float	Position/Translate (X, Y, Z)
0x2C	0x04	uint	Child offset
0x30	0x04	uint	Sibling offset
0x34	0x04	uint	Parent offset
0x38	0x04	string	Node name
0x3C	0x04	?	Reserved

Mesh Data

Position	Length	Type	Description
0x00	0x04	uint	Polytype?
0x04	0x04	uint	Vertices offset
0x08	0x04	uint	Vertex count
0x0C	0x04	uint	Instructions offset
0x10	0x0C	float	Mesh center (X, Y, Z)
0x1C	0x04	float	Mesh radius

Instructions

These instructions are state machine like. Each instruction changes the state of how to render the strip.
Each instruction identifier is 2 bytes long.

Unused (0x0E00, 0x0F00)

Ignored. Skip 10 bytes.

Unused (0x8000, 0xA000)

Ignored. Skip 2 bytes.

Unknown (0x0B00)

Unknown.

Strip Attributes (0x0200, 0x0300)

First byte holds UV flag for how they are interpreted. Holds information about the texture UV wrap modes.

Texture (0x0900)

Sets the texture to use for the next instructions.

Strip Group (0x1000 - 0x1400, 0x1800 - 0x1C00)

Position	Length	Type	Description
0x00	0x02	ushort	Strip count

These strip groups have the following vertex data based on the identifiers:

Identifier	Vertex Size	Description
0x1000, 0x1300, 0x1800, 0x1B00	2 Bytes (Index)	Vertex index
0x1200, 0x1A00	2 Bytes (Index) + 4 Bytes (BGRA)	Vertex index, Color
0x1100, 0x1900	2 Bytes (Index) + 4 Bytes (UV)	Vertex index, UV
0x1400, 0x1C00	2 Bytes (Index) + 4 Bytes (UV) + 4 Bytes (BGRA)	Vertex index, UV, Color

Strip

Position	Length	Type	Description
0x00	0x02	short	Strip vertex count

Sometimes the vertex count can be negativ, just abs() it.
The reason for this behaviour is unknown.

Strip "Vertex"

Type	Size	Description
short	0x02	Vertex index
short	0x04	(optional) Texture Coordinate (UV)
byte	0x04	(optional) BGRA8888 Color

The vertex structure is based on the strip group identifier.
Often the vertex index can be negativ, this is an optimization and is used to point to the parents vertices.
The UV coordinates are UVH (UV high-resolution) and need to be divided by 1024 to get normalized UV coordnates.

End (0x0080)

Defines the end of instructions.

Vertices

The vertices only hold the position and normal of an vertex.

Vertex

Position	Length	Type	Description
0x00	0x0C	float	Position (X, Y, Z)
0x0C	0x0C	float	Normals (X, Y, Z)

TEXD

This sections holds textures for the model.

Position	Length	Type	Description
0x00	0x04	string	Identifier
0x04	0x04	uint	Header size (or offset to first entry)
0x08	0x04	uint	Texture count

TEXD Entry

Position	Length	Type	Description
0x00	0x04	string	Identifier (TEXN, NAME)
0x04	0x04	uint	Entry size in bytes

TEXN

This entry defines an actual PVRT texture.

Position	Length	Type	Description
0x00	0x04	uint	ID
0x04	0x04	string	Name
0x08	0x0?	PVRT	Texture

NAME

This entry is used to define used textures outside of the MT5.

Position	Length	Type	Description
0x00	0x04	uint	ID
0x04	0x04	string	Name