SHP0 (File Format)
Overview
This page describes the SHP0 file format, as found within BRRES files. They are used for polygon morphing, a smooth transition from one set of vertices to another, commonly used in flags. Another notable usage is the opening and closing of a Chain Chomp's mouth. Other than vertices, SHP0 can also be used to morph normals and vertex colors. For simplicity, this article only references vertices.
File Format
File Header
| Offset | Type | Description |
|---|---|---|
| 0x00 | String | The magic "SHP0" to identify the sub file. See »BRRES Sub Files« for other magics. |
| 0x04 | UInt32 | Length of the sub file. |
| 0x08 | UInt32 | Sub file version number. The number of sections (N) is dependent of this version number. See »BRRES Sub Files« for details. |
| 0x0C | Int32 | Offset to outer BRRES File. |
| 0x10 | Int32[N] | N section offsets. N is implied in the version number (offset 0x08). |
| 0x10+N*4 | Int32 | String offset to the name of this sub file. This name equal to the name of the entry name of the BRRES Index Group pointing to this data. |
| 0x14+N*4 | End of this header | |
- All offsets are relative to the start of the header.
- Mario Kart Wii uses SHP0 v4 with (N=) 3 sections.
- The first section points to a BRRES Index Group structure for the data sections.
The meaning of each section is defined by numbers as below:
| Section | description |
|---|---|
| 0 | Animation data |
| 1 | Vertex data names |
| 2 | Unknown. Not seen in Mario Kart Wii or v4 SHP0's. |
SHP0 header
Following the section offsets, there is a MDL0 header structure.
| Offset | Size | Description |
|---|---|---|
| 0x00 | 0 | String offset to path of file — Unused |
| 0x04 | 2 | Number of animation frames |
| 0x06 | 2 | Size of the vertex data name array |
| 0x08 | 4 | Looping (0x00=disabled 0x01=enabled). |
Section Formats
Section 0 - Animation Data
This section contains controllers for the animations. Each controller can contain multiple animations; generally only one animation is used.
| Offset | Size | Description |
|---|---|---|
| 0x00 | 4 | Four bitflags, add together to enable multiple:
|
| 0x04 | 4 | Name offset. This is the name of the target vertex set. |
| 0x08 | 2 | Index to a section 1 entry |
| 0x0A | 2 | Number of animation entries (N) |
| 0x0C | 4 | Animation flags, if the Xth bit (LSB first) is set, the Xth animation entry is a constant float, otherwise it contains a pointer to the actual animation data. |
| 0x10 | 4 | Offset to an index conversion array, whereby each entry is a 2-byte index to an entry in section 1. The Xth entry is used by the Xth animation entry. This table is used to link an animation entry index to the name of the target set of vertices. |
| 0x14 | N*4 | Offsets to N animation entries, or a float if the corresponding bit in the flags is set. |
| 0x14 + N*4 | End of entry/Start of index conversion array | |
The name offset is relative to the start of the entry, the offsets to the animation entries are relative to the offset address itself.
Animation Entry
Each animation entry contains a collection of key frames that are used to animate an object. It contains a small header, followed by a list of key frames. An animation entry has the following layout:
| Offset | Size | Description |
|---|---|---|
| 0x00 | 2 | Number of key frames (N) |
| 0x02 | 2 | Padding |
| 0x04 | 4 | A float of the inverse of the number of frames this animation is active (1/X). This value is usually derived from the number of frames of the SHP0 file itself, but this is not obligatory. |
| 0x08 | N*12 | N key frame entries |
The key frames have the following layout:
| Offset | Size | Description |
|---|---|---|
| 0x00 | 4 | Frame number |
| 0x04 | 4 | Animation value |
| 0x08 | 4 | Slope (Hermite interpolation) |
All values are stored as float.
The animation value describes how far the target vertices (the name of the controller) have to be morphed into the destination vertices (the name of this entry). This is a value between 0 and 1.
Section 1 - Vertex Data Names
This section contains a list of pointers, and is referenced by the animations in section 0. Each pointer points to the name of a vertex list in the MDL0.
Example of Usage
SHP0 animations are sparsely used in Mario Kart Wii. The most common usage is in waving flags, but a more notable example is the Chain Chomp object making use of SHP0 for opening and closing its mouth. The MDL0 for the Chain Chomp contains two sets of vertices and normals for each polygon to achive this, whereby one of each pair is linked to the polygon itself as default. The pair of vertices belonging to the body have the names wanwan_body (default) and wanwan5_body (mouth open).
To animate the body of the Chain Chomp, a SHP0 is created with an entry (controller) with the name wanwan_body, which references the default set of vertices. An animation with the name wanwan5_body is then added to this entry, which references the set of vertices used for a fully opened mouth. The key frames are used to determine how far the original set of vertices have to be morphed into the target set. A value of 0 equals a closed mouth, 1 equals a fully opened mouth, and 0.5 equals a partly opened mouth. When animated, this leads to the biting animation of the Chain Chomp.
Tools
The following tools can handle SHP0 files:
- BrawlBox, by Kryal and BlackJax.
- BrawlCrate, by soopercool101.