An object's '''draw distance''' is declared in the [[Item Definition|IDE]] files.

The draw distance value tells the engine how far away any given object should be rendered relative to the player's position (Line of Sight) or viewpoint. Close range normal objects are rendered for a distance no greater then 299.9 [[unit]]s however [[LOD]] objects are rendered from 300 to 3000 [[unit]]s.

In [[GTA 3]] and [[Vice City]], [[collision file|collision data]] for an LOD object (draw distance is greater than 300) is ignored by the engine.

In [[San Andreas]]' LOD models can share the same collision with no mesh or collision spare but the same rule applies where every LOD model or Normal model much have a collision.

Same models can have the collision data stored within where you can link the LOD object to another object. As long as the object has an LOD flag which is -1 in the [[IPL]] file the game searches for a collision.

[[Category:Mapping]][[Category:Documentation]]

Draw distance

2011-12-16T03:51:27Z

X-Seti:

An object's '''draw distance''' is declared in the [[Item Definition|IDE]] files.

The draw distance value tells the engine how far away any given object should be rendered relative to the player's position (Line of Sight) or viewpoint. Close range normal objects are rendered for a distance no greater then 299.9 [[unit]]s however [[LOD]] objects are rendered from 300 to 3000 [[unit]]s.

In [[GTA 3]] and [[Vice City]], [[collision file|collision data]] for an LOD object (draw distance is greater than 300) is ignored by the engine.

In [[San Andreas]]' LOD models can share the same collision with no mesh or collision spare but the same rule applies where every LOD model or Normal model much have a collision.

Same models can have the collision data stored within where you can link the LOD object to another object. As long as the object has an LOD flag which is -1 in the IPL file the game searches for a collision.

[[Category:Mapping]][[Category:Documentation]]

IMG archive

2009-08-07T22:03:36Z

X-Seti: /* Version 1 - GTA III & VC */

GTA's most commonly used [[archive file]]s are known by the extension <code>'''.img'''</code>. They have a very simple format and currently exist in multiple versions.

== Structure ==

=== Version 1 - GTA III & VC ===

Version 1 archives used in GTA III and Vice City, are actually split up into two files: the content directory (<code>.dir</code>) and the actual archive (<code>.img</code>).

The directory is a list of files each with name, offset and size of the file. The values for offset and size have to be ''multiplied by 2048'', since files are aligned to 2 KB boundaries. This means that even a file with only 123 byte content will take up 2 KB in the archive. Files are stored (usually) unsorted, uncompressed and linear (no directory tree).

First you have to find out the number of entries (n).
Just divide the filesize of the <code>.dir</code> file by 32 and you will get it.

There is no Header, like in V2 (San Andreas) Files!

Entry: (repeated n times) 
4 byte - DWORD - offset of file inside archive (in blocks)
4 byte - DWORD - size of file (in blocks)
24 byte - CHAR[24] - name of file

The <code>.img</code> file itself has no special structure or header, just all the files in 2 KB blocks.

=== Version 2 - GTA SA ===

Version 2 archives, introduced with GTA San Andreas, combine <code>.dir</code> and <code>.img</code> files into one <code>.img</code> file. The directory has the same format as in version 1, but is located at the beginning of the archive. Files are again aligned to 2 KB boundaries. File offsets are relative to the start of the whole archive, not to the end of the file list.

Header: 
4 byte - CHAR[4] - FourCC, always "VER2"
4 byte - DWORD - number of entries (n) 
Entry: (repeated n times) 
4 byte - DWORD - offset of file inside archive (in blocks)
4 byte - DWORD - size of file (in blocks)
24 byte - CHAR[24] - name of file

A major drawback of this format is the complicated extendability. If you have to add many files, it might happen that you run out of space for the directory, and have to move the first file(s) to the end.

=== Version 3 - GTA IV ===

GTA IV introduced yet another <code>.img</code> file format. Not only the format is new, also there can be encrypted archive headers (see below). The internal IMG parser of the game works with 2 kb buffers, which means that the 2 kb bounds from earlier versions (blocks) are still present, yet optional.

==== IMG Header ====

The header of an unencrypted file always has a size of '''20 bytes'''.

4 byte - DWORD - Identifier (0xA94E2A52 if the archive is not encrypted)
4 byte - DWORD - Version (always 3, if not the format would be differ)
4 byte - DWORD - Number of Items
4 byte - DWORD - Table Size (in bytes)
2 byte - WORD - Size of Table Items (needs to be always 0x10)
2 byte - WORD - Unknown

==== IMG Table ====

The table holds information about the items. Each item header has a size of '''16 bytes''' .

4 byte - DWORD - Itemsize (in bytes)
4 byte - DWORD - Resource type
4 byte - DWORD - Offset (in blocks)
2 byte - WORD - Used Blocks
2 byte - WORD - Padding

Item Names' length will be calculate as :
Table Size - (Number of Items * Item Size)
Next that string will be split by '\x0'

A [[resource file|resource]] type is identified by the 4b DWORD value:
* 0x01: Generic
* 0x08: Texture archive
* 0x20: Bounds
* 0x6E: Model file
* 0x24: xpfl

==== Encryption ====

The header and directory (table) of IMG archives can be encrypted. This is usually the case if the 4 byte identifier at the start of the file seems invalid. Decryption is done via 16 repetitions of AES-128 in ECB mode, see [[Cryptography#AES]].

== Tools ==
====Version 1 only====
* [[ImgEd]]
====Version 2 only====
* {{GTAF|354093|IMG Manager}}
* [[Spark]]

====Versions 1 and 2====
* [[IMG Tool]]
* [[G-IMG]]
====Version 3 only====
* [[SparkIV]]
* [[OpenIV]]

== Libraries ==
====Version 3 only====
* [[X Archive Poison]]

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[[Category:Other Formats]][[Category:GTA 3]][[Category:GTA VC]]