.MTP in IGI 2 -- Model-Texture Packages

1. Architectural Role & Engine Purpose

In I.G.I. 2: Covert Strike (2003), the MTP (Model-Texture Package) format continues to serve as the binary EA IFF-85 container bundling 3D models with their associated textures (same FORM MTP container family as IGI 1).

Clear Distinction from .DAT: In IGI 2, levelN.dat remains a human-readable plain-text asset manifest. .MTP is a binary package format used to deploy self-contained multi-texture weapon systems and multi-part character assets.

2. Binary File Layout & Memory Map Diagram

The IGI 2 MTP binary structure encapsulates models, compressed textures, and instance tables:

3. Direct3D 8 Texture Binding Pipeline Diagram

The IGI 2 runtime resolves MTP bindings directly into Direct3D 8 texture stages:

4. Architectural Mechanics & Specifications

In IGI 2, MTP instance definitions map each model to its texture list from the shared TEXF pool. Because the INST chunk appears before TEXF in file order, parsers read all chunks first and resolve MODS[modelIdx] and TEXF[texIdx] names afterward.

5. C++ Struct Definitions

#pragma pack(push, 1)
struct Igi2MtpInstanceHeader {
    uint32_t model_index;    // Index into MODS array
    uint32_t texture_count;  // Number of assigned texture indices
};
static_assert(sizeof(Igi2MtpInstanceHeader) == 8, "Igi2MtpInstanceHeader must be 8 bytes");
#pragma pack(pop)