Incoming .IAN Reader

This is a JavaScript plugin for reading/writing .IAN files - a proprietary 3D model format used by the 1998 video game Incoming.

This format was reverse engineered and as a result there are still values whose meaning are unknown. These values aren't included in the data returned by the plugin, but guesses to what they are/notes can be found in the source code.

Key Features

• File data can be used with three.js to render models in-browser:

• Convert between IAN and OBJ, allowing for custom in-game models and model export to programs such as Blender, Maya, etc.

• OBJ files can be converted to IAN format allowing custom models in-game:

How to Use

Include incoming-reader.js in the page and pass an ArrayBuffer of the .IAN file to the global IncomingReader function:

<input type="file" id="file-input" />

<script src="incoming-reader.js"></script>
<script>
    document.getElementById("file-input").addEventListener("input", function() {
        for (const file of this.files) {
            const fileReader = new FileReader();

            fileReader.onload = function() {
                const incomingReader = new IncomingReader(this.result);
            }

            fileReader.readAsArrayBuffer(file);
        }
    })
</script>

Methods

readIAN() returns Object

Returns an object containing the following:

writeIAN(filename : String)

Converts an OBJ file to IAN format.

Pass an OBJ file ArrayBuffer to the plugin and call incomingReader.writeIAN("my_model"). This will prompt a download from a Blob object URL.

It is recommended to export a default IAN file and keep your model to roughly the same size.

writeOBJ(filename : String)

Converts an IAN file to OBJ format.

Pass an IAN file ArrayBuffer to the plugin and call incomingReader.writeOBJ("my_model"). This will prompt a download from a Blob object URL.

Additional Information

Overview

The game assets are contained in the following folders (typically located at C:\Program Files (x86)\Incoming):

Incoming/
├── asc/
├── pcobject/
├── ppm/
└── wavs/

See the sections below for further details on each folder.

"asc" Folder

Contains several files related to the levels of the game, each contained in its own folder. The folder for the first level, Africa, contains:

Incoming/
└── asc/
    └── africa/
        ├── africa.mdl
        ├── africa.odl
        ├── africa.wdl
        ├── africa_action.mdl
        ├── africa_virus.mdl
        ├── africa_virus.odl
        ├── city2tc.bin
        └── tland1.bin

A brief overview of the file types:

city2tc.bin

These files consist of 128 blocks of 256 bytes. Each block corresponds to one column of the terrain, starting from north west, going across. Two bytes are used to describe the texture information for each square, which means each level is a 128×128 grid.

An excerpt from Africa's file, split into rows of two bytes:

85 00
05 00
86 00
06 00

The first byte contains two values: the texture index, and its position. Levels use eight textures for terrain which are specified inside the .odl file.

The texture index is always the last digit of the first byte, i.e. 5, 5, 6, 6 for the bytes shown above, and can be quickly calculated using the modulus operator:

0x85 % 0x10 // 5
0x05 % 0x10 // 5
0x86 % 0x10 // 6
0x06 % 0x10 // 6

Textures are zero-indexed.

The texture position is determined from the remainder of the modulus operation. Terrain textures are 256×256px, however only a quarter (128×128px) segment is shown per tile. There are 16 possible positions (highlighted by the red square):

Value	Position
0x00
0x10
0x20
0x30
0x40
0x50
0x60
0x70
0x80
0x90
0xA0
0xB0
0xC0
0xD0
0xE0
0xF0

The second byte is a bitmask of texture properties, such as rotation/mirroring:

tland1.bin

As mentioned, this file solely consist of height values for the terrain which is used to modify a flat plane. Each height value is a 16-bit signed integer, resulting in a 513×513 grid of values. Height values seem to be negative in Incoming, so these values would need to be inverted if used for drawing terrain.

An example applying the Moon level's values to a plane using three.js is shown below:

"pcobject" Folder

Contains all model files. Alien models are stored in "cweapons" whereas allied models can be found in "pweapons".

LOD meshes can be found within "low" folders in each directory.

Models displaying different levels of damage are separated into folders corresponding to the amount of damage (ranging from 1-3, with 3 being the most damaged).

"ppm" Folder

Contains all texture files. Textures are encoded as PPM files, an open-source bitmap format.

"wavs" Folder

Contains all sound files. Sounds are stored in WAV format. All sounds appear to be monophonic 22.05 kHz / 16-bit.

Unknown

Yet to be figured out is the purpose of the .ctl files inside the Incoming\asc\pads\ folder. As the name indicates, these may be related to healing pads.