EMD (Resident Evil 1997)

Latest revision as of 15:36, 26 August 2023

This content was first retrieved from the Internet Archive's Wayback Machine for the date 2016-08-09 from the following URL: https://web.archive.org/web/20160809012215/http://rewiki.regengedanken.de/wiki/.EMD_(Resident_Evil)

The .EMD file format is used by Resident Evil. It contains the description of 3D models of the game (enemies, player, etc...).

[edit] Structure

The values are stored in Little-Endian order.

[edit] Directory

There is a directory, which is stored at the end of the file, it contains 4 offsets. So its position is filesize-4*4 bytes.

[edit] File/Section 0, skeleton

This section starts with a header:

typedef struct {
	unsigned short relpos_offset;/* Relative offset to emd1_skel_relpos[] array */
	unsigned short length; /* Relative offset to emd1_skel_data[] array, which is also length of relpos+armature+mesh numbers  */
	unsigned short count; /* Number of objects in relpos,data2,mesh arrays? */
	unsigned short size; /* Size of each element in emd1_skel_data[] array */
} emd1_skel_header_t;

If offset is more than 8, there are some extra stuff, namely data1,data2 and mesh arrays.

typedef struct {
	short x;
	short y;
	short z;
} emd1_skel_relpos_t; /* Relative position of each mesh in the object */

typedef struct {
	unsigned short mesh_count; /* Number of meshes linked to this one */
	unsigned short offset; /* Relative offset to mesh numbers (emd1_skel_mesh[] array) */
} emd1_skel_armature_t;

emd1_skel_relpos_t emd1_skel_relpos[count];
emd1_skel_armature_t emd1_skel_armature[count];
unsigned char emd1_skel_mesh[count]; /* Mesh number on which to apply relative position */

Finally an array of elements which have a size of emd1_skel_header.size bytes each.

typedef struct {
	short x_offset;	/* distance from reference point */
	short y_offset;
	short z_offset;

	short x_speed;	/* speed at which moving the model */
	short y_speed;
	short z_speed;

	short angles[3*15];	/* angle for each bone/model around x,y,z axis */

	short unknown;
} emd1_skel_anim_t;

emd1_skel_anim_t emd1_skel_anim[];

[edit] File/Section 1, animation steps

This section starts with this header, a certain number of records composed of count and offsets.

typedef struct {
    unsigned short count;  /* Count of indices to process from emd_sec1_data[] array */
    unsigned short offset; /* Byte offset to first index in emd_sec1_data[] array */
} emd_anim_header_t;

emd_anim_header_t emd_anim_header[];

Following this array, you'll find another array of unsigned long. Each value (animation frame number?) is an index in emd_sec2_data array in the skeleton section.

unsigned long emd_anim_skel_t[];    /* Bits 31-16:   Bitmasks for flags */
                                    /* Bits 15-0:    Number of frame to display ? */

Then you'll finally find the 'unsigned long' byte length of the section.

unsigned long length;

[edit] File/Section 2, meshes

The last object holds the 3D stuff. Maybe the rest of the file is use to store animations, and links between primitives.

[edit] Header

typedef struct {
    unsigned long length; /* Section length in bytes */
    unsigned long unknown;
    unsigned long obj_count; /* Number of objects in model */
} emd_model_header_t;

[edit] Objects

The model is separated in 'obj_count' objects. Following the header is the description of each object, in the form of an array of 'model_object'. Each offset is relative to the first emd_model_object_t.

typedef struct {
    emd_model_triangles_t triangles;
} emd_model_object_t;

typedef struct {
    unsigned long vertex_offset; /* Offset to vertex data, array of emd_vertex_t */
    unsigned long vertex_count;  /* Vertex count */
    unsigned long normal_offset; /* Offset to normal data, array of emd_vertex_t */
    unsigned long normal_count;  /* Normal count */
    unsigned long tri_offset; /* Offset to triangle data, array of emd_triangle_t */
    unsigned long tri_count;  /* Triangle count */
    unsigned long dummy;
} emd_model_triangles_t;

[edit] Index arrays

Normal and vertex coordinates are saved in same format:

typedef struct {
    signed short x; /* Coordinates */
    signed short y;
    signed short z;
    signed short zero;    
} emd_vertex_t; /* Normals have same format */

A triangle is stored in this format:

typedef struct {
    unsigned long unknown; /* id 0x34000609 */

    unsigned char tu0; /* u,v texture coordinates of vertex 0 */
    unsigned char tv0;
    unsigned short clutid; /* Texture clut id, bits 0-5 */
    unsigned char tu1;
    unsigned char tv1;
    unsigned short page;  /* Texture page */
    unsigned char tu2;
    unsigned char tv2;
    unsigned short dummy;

    unsigned short n0; /* Index of normal data for vertex 0 */
    unsigned short v0; /* Index of vertex data for vertex 0 */
    unsigned short n1;
    unsigned short v1;    
    unsigned short n2;
    unsigned short v2;    
} emd_triangle_t; /* Triangle */

[edit] File/Section 3, texture

And finally, an embedded TIM image, which is the texture to apply to the model.