Havok
Havok is a middleware software suite developed by the Irish company Havok. Havok provides a physics engine component and related functions to video games.
On September 14, 2007, Intel announced it had signed a definitive agreement to acquire Havok Inc.[1] In 2008, Havok was honored at the 59th Annual Technology & Engineering Emmy Awards for advancing the development of physics engines in electronic entertainment. On October 2, 2015, Microsoft announced it had acquired Havok.[2]
Products
The Havok middleware suite consists of the following modules:[3]
- Havok Physics: It is designed primarily for video games, and allows for real-time collision and dynamics of rigid bodies in three dimensions. It provides multiple types of dynamic constraints between rigid bodies (e.g. for ragdoll physics), and has a highly optimized collision detection library. By using dynamical simulation, Havok Physics allows for more realistic virtual worlds in games. The company was developing a specialized version of Havok Physics called Havok FX that made use of ATI and NVIDIA GPUs for physics simulations;[4] however, the goal of GPU acceleration did not materialize until several years later.[5]
- Havok AI: In 2009, Havok released Havok AI, which provides advanced pathfinding capabilities for games. Havok AI provides navigation mesh generation, pathfinding and path following for video game environments.
- Havok Cloth: Released in 2008, Havok Cloth deals with efficient simulation of character garments and soft body dynamics.
- Havok Destruction: Also released in 2008, Havok Destruction provides tools for creation of destructible and deformable rigid body environments.
- Havok Animation Studio (discontinued): Havok Animation Studio is formally known as Havok Behavior and Havok Animation. Havok Behavior is a runtime SDK for controlling game character animation at a high level using finite state machines. Havok Animation provides efficient playback and compression of character animations in games, and features such as inverse kinematics.
- Havok Script (discontinued): Havok Script is a Lua-compatible virtual machine designed for video game development. It is shipped as part of the Havok Script Studio.
- Havok Vision Engine (discontinued): On August 8, 2011, Havok announced their acquisition of German game engine development company Trinigy and their Vision Engine and toolset.
Usage
![[icon]](/wiki/File:Wiki_letter_w_cropped.svg){kind=small} | This section needs expansion. You can help by adding to it. |
Breath of the Wild uses the Havok Physics, Havok AI and Havok Cloth.
| Extension | Product | Description | Locations |
|---|---|---|---|
| hknm2 | Havok AI | Navigation meshes (used by AI for path finding) | NavMesh/
|
| hkrb | Havok Physics | Rigid body physics | Physics/RigidBody/
|
| hkcl | Havok Cloth | Cloth physics | Physics/Cloth/
|
| hkrg | Havok Physics | Rag doll physics | Physics/Ragdoll/
|
| hksc | Havok Physics | Static compound physics | Physics/StaticCompound/
|
| hktmrb | Havok Physics | Terrain mesh rigid body physics | Physics/TeraMeshRigidBody/
|
File Types
hknm2
 | This section is empty. You can help by adding to it. |
hkrb
| This section is empty. You can help by adding to it. |
hkcl
| This section is empty. You can help by adding to it. |
hkrg
| This section is empty. You can help by adding to it. |
hksc
| This section is empty. You can help by adding to it. |
hktmrb
| This section is empty. You can help by adding to it. |
Havok File Specification
Havok files serve as a data container for multiple Havok classes per file and sometimes multiple Havok files per file[6]. The class names are defined in each file.
Note that this specification only applies to version 2014.2.0-r1
File Structure
Each file contains a header and three sections: classnames, types and data
classnames
The classnames section (__classnames__ internally) contains a list of Havok classes used by the file to correctly decompile the binary data into a usable data structure.
types
The types section (__types__ internally) does not appear to be used by Breath of the Wild.
data
the data section (__data__ internally) contains binary data to be serialized into Havok data structures for use by the Havok engine.
Header
The header seems to have a 16-byte alignment and can be 64-bytes (short header) or 80-bytes (long header) in length, depending on if Unknown 13 equals 0 (short header) or 16 (long header).
| Offset (h) | Size | Data Type | Description |
|---|---|---|---|
0x00
|
8 | Bytes | Havok file signature (magic) 57 E0 E0 57 10 C0 C0 10
|
0x08
|
4 | Unsigned Int | Unknown 00 (always 0; possibly padding) |
0x0c
|
4 | Unsigned Int | Unknown 01 (always 11) |
0x10
|
1 | Byte | Unknown 02 (always 4) |
0x11
|
1 | Byte | Unknown 03 (always 0) |
0x12
|
1 | Byte | Unknown 04 (always 0) |
0x13
|
1 | Byte | Unknown 05 (always 1) |
0x14
|
4 | Unsigned Int | Unknown 06 (always 3) |
0x18
|
4 | Unsigned Int | Unknown 07 (always 2) |
0x1c
|
4 | Unsigned Int | Unknown 08 (always 0) |
0x20
|
4 | Unsigned Int | Unknown 09 (always 0) |
0x24
|
4 | Unsigned Int | Unknown 10 (always 75) |
0x28
|
16 | String | Havok version hk_2014.2.0-r1 for BotW files
|
0x38
|
4 | Unsigned Int | Unknown 11 (always 0; possibly padding) |
0x3c
|
2 | Short | Unknown 12 (always 21) |
0x3e
|
2 | Short | Unknown 13 (0 or 16; if 16, the header is 16 bytes longer) |
Optional Header Bytes
There are optional header bytes for a long header. If Unknown 13 equals 16, an additional 16 bytes are added to the header for a total of 80 bytes.
| Offset (h) | Size | Data Type | Description |
|---|---|---|---|
| 0x40 | 2 | Short | Unknown 14 (always 20) |
| 0x42 | 2 | Short | Unknown 15 (always 0; possibly padding) |
| 0x44 | 4 | Int | Unknown 16 (always 0; probably padding for alignment) |
| 0x48 | 4 | Int | Unknown 17 (always 0; probably padding for alignment) |
| 0x4c | 4 | Int | Unknown 18 (always 0; probably padding for alignment) |
Section Headers
Each section has a 64-byte header which includes the section name, absolute offset to the section start and six relative offsets to segments within the section. All three section headers follow the file header and are delimited by 16 ff bytes.
| Offset (h) | Size | Data Type | Description |
|---|---|---|---|
0x00
|
20 | String | Section name |
0x14
|
4 | Unsigned Int | Absolute offset |
0x18
|
4 | Unsigned Int | Relative offset 1 |
0x1c
|
4 | Unsigned Int | Relative offset 2 |
0x20
|
4 | Unsigned Int | Relative offset 3 |
0x24
|
4 | Unsigned Int | Relative offset 4 |
0x28
|
4 | Unsigned Int | Relative offset 5 |
0x2c
|
4 | Unsigned Int | Relative offset 6 |
Section Name
There are only three section names: __classnames__, __types__ and __data__. The section name is a null-terminated string with a delimiter byte of FF in byte 20.
Absolute Offset
The absolute offset to the section.
Relative Offsets
The relative offsets point to different large structures within the section. There are usually a few unique offsets and then multiple duplicated offsets. It is unknown if only unique offsets are significant at this time.
For example, given the following section header:
5F 5F 64 61 74 61 5F 5F 00 00 00 00 00 00 00 00 | __data__........
00 00 00 FF 00 00 01 60 00 00 3C 00 00 00 3C 10 | .......`..<...<.
00 00 3C 10 00 00 3C 20 00 00 3C 20 00 00 3C 20 | ..<...< ..< ..<
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF | ................The section name is __data__. The absolute offset is 0x160 with the relative offsets
0x3c000x3c100x3c100x3c200x3c200x3c20
- ↑ Intel To Acquire Havok
- ↑ Havok to join Microsoft
- ↑ Product Overview
- ↑ Havok Intros Havok FX Engine to Compute Physics Effects on GPUs
- ↑ Havok Physics Playstation 4 Demo
- ↑ Static Compound files (hksc) include two Havok file definitions. The first file defines
StaticCompoundInfoand the second defineshkpPhysicsData(which includeshkpRigidBody,hkpStaticCompoundShape,hkpBvCompressedMeshShape,hkpConvexVerticesShape, et. al.).