MREA (File Format)

The .MREA file format is used to define areas in Metroid Prime and Donkey Kong Country Returns. MREA files are broken up into many sections, and each section serves a specific purpose. However for the sake of brevity this article will only cover each revision of the MREA header.

Universal Header

This header is shared between Metroid Prime and Donkey Kong Country, and is fairly straight forward.

Offset	Size	Description
0x0	4	Magic Number 0xDEADBEEF
0x4	4	File Version See below
0x8	48	Transformation Matrix The position of the area in world-space
0x38	4	Mesh Count
0x3C	4	SCLY Count Note: Not present in Metroid Prime 1
0x40	4	Section Count

Version	Game
15	Metroid Prime 1
25	Metroid Prime 2
30	Metroid Prime 3
32	Donkey Kong Country Returns

Metroid Prime Section Numbers

Immediately following the header each section in an MREA is given it's own number, the following is the order in which they appear:

Description
Materials
SCLY
SCGN Note: Not present in Metroid Prime 1
Collision
Unknown
Lights
VISI
PATH
AROT
PTLA Note: Not present in Metroid Prime 1
EGMC Note: Not present in Metroid Prime 1

Metroid Prime 3 & Donkey Kong Header

Metroid Prime 3 and Donkey Kong Country Returns share the same header, also Metroid Prime 2 contains the Compressed Block Count present in this header as well.

Offset	Size	Description
0x0	4	Compressed Block Count Note: Present in Metroid Prime 2	0x4	Section Number Count Note: see below