Fight 3D resources

FGT/*.LIB, FGT/*.DAT

Everything that draws a close-combat scene: 3D meshes, scenery lists, palettes, movement and camera tables, and the sine table.

Close-combat scenes in Battle Isle 2 are drawn with small 3D meshes rather than sprites. Everything that draws them lives in the FGT/ directory: the meshes (three archives sharing a 3DOB magic), the scenery and ground lists, the palettes, the backdrops, the movement and camera tables, a sine/tangent table and the sound banks. This page describes each in turn.

Status: resource layouts and documented ordinary-fight playback rules recovered. All 520 mesh records validate against the decoded header, vertices, polygons and moving-part layout. The scene, motion, raster, clock and audio source rules are documented below. Native commands now establish ordinary cross-fight phase retention. No identified algorithm gap remains for the documented parameterized paths. One particle integration input producer remains unbound, as described below; native visual, audio and cadence conformance is also incomplete.

ObjectHeader66 bytes3DOBchar[4]vertex_offsetu16 slot_offsetu16 face_offsetu16 trailing_offsetu16 reserved_0cu16[5]vertex_count_minus_oneu16 face_count_minus_oneu16 part_countu16 lead_1cu8[8]world_positioni16[3]object_rotationi16[3]lead_30u8[18]Polygonsvariable sizePolygonRecord × face_countvariable sizeLayout2 B Vertices4 B Runtime12 B Colour5 B Drawing3 BVertices6 × vertex_count bytesVertex × vertex_count6 bytes eachPosition6 BFace normals6 × face_count bytesFaceNormal × face_count6 bytes eachNormal6 BParts32 × part_count + listsPartRecord × part_count32 bytes eachGeometry8 B Pivot6 B Runtime12 B Reserved6 Bvertex listsu16[]Vertex slots10 × vertex_count bytes010 bytes each

Each box is one table of a 3DOB object, in file order. The polygons start right after the header; the other tables are found by the four offsets in the header, and each line runs from an offset to the table it locates. A stack stands for the records of a table, with its count in the label. Cut blocks are not drawn to scale. Dashed blocks hold the same value in every object.

Archive	Records	Contents
`FGT/UN3D000.LIB`	240	units (`UNIT###`), animations (`ANIT###`)
`FGT/LAND000.LIB`	288	terrain objects (`LAND###`)
`FGT/LAND300.LIB`	288	terrain objects
`FGT/PAL000.LIB`	41	the fight palettes the meshes are coloured from
`FGT/LAYR000.LIB`, `LAYR300.LIB`	96 each	`3DLD` scenery layer lists
`FGT/GRND000.LIB`, `GRND300.LIB`	24 each	`3DLD` ground lists
`FGT/BACK000.LIB`	20	the raster horizon backdrops and their moons - not meshes; see Where the mountains go

Object	Size	Reads as
`AMMO001A`	2 vertices, 1 two-vertex face, steel	a tracer: a bare 320-unit line
`AMMO002A`	7 vertices, 8 faces, steel and olive	a shell, 420 units long and 30 wide
`AMMO005A`	9 vertices, 2 faces, all sky, `y = 0` throughout	a flat water splash
`AMMO006A`	16 vertices, 10 faces, steel and gold	a 110-unit ball with gold octagon caps
`AMMO050A`	12 vertices, 8 faces, entirely gold	a 120-unit ball of flame - a muzzle or impact flash

Object layout

All multi-byte integers are little-endian.

66 bytes13 fields● 10 ◐ 3 ○ 0

0x00char[4]tag ●Literal 3DOB (0x424f4433).

Tables

4 fields · 8 bytes

0x04u16vertex_offset ●byte offset of the vertex table

0x06u16slot_offset ●byte offset of the runtime vertex slots; equals trailing_offset on the 410 objects that have no parts

0x08u16face_offset ●byte offset of the face-normal table

0x0au16trailing_offset ●byte offset of the part table

Counts

3 fields · 6 bytes

0x16u16vertex_count_minus_one ●vertex count is this + 1

0x18u16face_count_minus_one ●face count is this + 1

0x1au16part_count ●first word of the 40-byte object lead; see Moving parts

Runtime

4 fields · 38 bytes

0x1cu8[8]lead_1c ◐Zero on disk; runtime role not established here.

0x24i16[3]world_position ●Zero on disk; transform entry stores caller XYZ here.

0x2ai16[3]object_rotation ●Zero on disk; transform entry stores caller XYZ angles here.

0x30u8[18]lead_30 ◐Zero on disk; runtime role not established here.

Where each slot's values sit: slot k is element k of every array above.
slot	world_position	object_rotation
A	0x24	0x2a
B	0x26	0x2c
C	0x28	0x2e

Reserved

1 field · 10 bytes

0x0cu16[5]reserved_0c ◐0 across the corpus

6 bytes3 fields● 3 ◐ 0 ○ 0

0x00

Point at the bar to name a field; select it to jump to its row.

knownpartly knownunknown: investigatenamed, never setalways one valueunused bits

Position

3 fields · 6 bytes

0x00i16x ●model space

0x02i16y ●+Y is down, so up is -Y

0x04i16z ●model space

6 bytes3 fields● 3 ◐ 0 ○ 0

0x00

Point at the bar to name a field; select it to jump to its row.

knownpartly knownunknown: investigatenamed, never setalways one valueunused bits

Normal

3 fields · 6 bytes

0x00i16x ●one per polygon; a unit normal in 14-bit fixed point (16384 = 1.0)

0x02i16y ●as x

0x04i16z ●as x

variable size14 fields● 9 ◐ 5 ○ 0

Layout

1 field · 2 bytes

0x00u16record_size ●total bytes of this record; also 26 + 2*vertex_count - the fixed fields run +0x00..+0x19, then one word per vertex.

Vertices

3 fields · 4 bytes

0x02u16first_vertex_ptr ●equals the first entry of vertex_ptrs

0x0cu16vertex_count_minus_one ●polygon has this + 1 vertices

tailu16[vertex_count]vertex_ptrs ●the last vertex_count words

Runtime

4 fields · 12 bytes

0x04i16[3]normal_scratch ●Zero on disk; normal XYZ is copied here and rotated at runtime.

0x0au8[2]containing_part_ids ●Cleared per draw; tagged faces record up to two containing part numbers in traversal order for optional part commands.

0x16i16light_term_scratch ●Zero on disk; preparation writes the pre-camera rotated normal term, or the grouped/disabled-normal replacement.

0x18u8[2]anchor_indices ◐Initialization zeros this word; the conditional anchor pass writes two counter bytes consumed as signed anchor indices.

Where each slot's values sit: slot k is element k of every array above.
slot	containing_part_ids	anchor_indices
A	0x0a	0x18
B	0x0b	0x19

Colour

3 fields · 5 bytes

0x0eu16shade ●0, 32, 64, 96, 128, 160 - the polygon's colour: a base index into the fight palette, see Colour

0x13i8lighting_mode ◐Selects ordinary, ambient-only, direct-bias and special normal/material paths.

0x14i16bias ●-8..+8; ordinary shade step, or anchor key/effect-model selector in the special material path.

Drawing

3 fields · 3 bytes

0x10u8raster_mode ◐Selects raster dispatch; mode 1 also participates in anchor preparation.

0x11i8face_group_control ◐Positive reuses the prior lighting term, negative sets it to zero; also controls face-list traversal and culling.

0x12u8normal_control ◐Nonzero bypasses ordinary normal rotation and takes the zero lighting-term path; also bypasses one backface test.

32 bytes10 fields● 9 ◐ 1 ○ 0

0x00

Point at the bar to name a field; select it to jump to its row.

knownpartly knownunknown: investigatenamed, never setalways one valueunused bits

Geometry

4 fields · 8 bytes

0x00u16polygon_ptr ●file offset of the part's first polygon record

0x02u16polygon_count_minus_one ●the part owns this + 1 consecutive polygons

0x04u16vertex_list_ptr ●file offset of the part's vertex-index list

0x06u16vertex_count_minus_one ●the list holds this + 1 entries

Pivot

3 fields · 6 bytes

0x08i16pivot_x ●the axis the part turns about, in model space

0x0ai16pivot_y ●up is -Y, as everywhere else in the format

0x0ci16pivot_z ●

Runtime

2 fields · 12 bytes

0x0ei16[3]translation ●0 on disk; runtime X/Y/Z translation added after pivot rotation

0x14i16[3]angles ●runtime X/Y/Z angles; applied in Z, X, Y order; 0 on disk.

Where each slot's values sit: slot k is element k of every array above.
slot	translation	angles
A	0x0e	0x14
B	0x10	0x16
C	0x12	0x18

Reserved

1 field · 6 bytes

0x1au8[6]reserved_1a ◐0 on disk; runtime role unresolved

variable size7 fields● 6 ◐ 1 ○ 0

0x00char[4]tag ●Literal 3DLD.

Objects

1 field · 12 bytes

0x04u16[6]object_ids ●ids of the LAND objects this record may place; 0xffff/0xfffe mark unused slots

Colour

2 fields · 4 bytes

0x1cu16ground_palette_base ●GRND loader passes this palette base to the continuous-floor renderer.

0x1ei16ground_shade_adjustment ●Added to renderer ambient for that side of the continuous ground.

Placements

2 fields · 2 bytes

0x20u16count ●placements

0x22..Placement[]placements ●16 bytes each

Reserved

1 field · 12 bytes

0x10u8[12]padding ◐Padding or leftover source filename bytes; not the colour words that follow.

16 bytes6 fields● 6 ◐ 0 ○ 0

0x00

Point at the bar to name a field; select it to jump to its row.

knownpartly knownunknown: investigatenamed, never setalways one valueunused bits

Position

4 fields · 8 bytes

0x00u16slot ●index into object_ids

0x04i16x ●always a multiple of 1000

0x06i16z ●always a multiple of 1000

0x08i16y ●Zero on disk; copied as vertical position at submission.

Drawing

1 field · 2 bytes

0x02i16draw_control ●0, -1 or -2 in these files; copied unchanged to staged controls.

Rotation

1 field · 6 bytes

0x0ai16[3]rotations ●Zero on disk; copied as object X/Y/Z rotations.

Still to investigate

Every field marked unknown or partial above, and every bit that is set without a name or named without ever being set.

lead_1c◐Zero on disk; runtime role not established here. ObjectHeader
lead_30◐Zero on disk; runtime role not established here. ObjectHeader
raster_mode◐Selects raster dispatch; mode 1 also participates in anchor preparation. PolygonRecord
face_group_control◐Positive reuses the prior lighting term, negative sets it to zero; also controls face-list traversal and culling. PolygonRecord
normal_control◐Nonzero bypasses ordinary normal rotation and takes the zero lighting-term path; also bypasses one backface test. PolygonRecord
lighting_mode◐Selects ordinary, ambient-only, direct-bias and special normal/material paths. PolygonRecord
anchor_indices◐Initialization zeros this word; the conditional anchor pass writes two counter bytes consumed as signed anchor indices. PolygonRecord

/* Fight 3D Resources (FGT/). All fields little-endian unless the type says otherwise.

* Each comment gives status (● known ◐ partial ○ unknown), values seen, and meaning. */

/* ObjectHeader */

struct ObjectHeader {

/*00*/chartag[4];// ● Literal 3DOB (0x424f4433).

/*04*/uint16_tvertex_offset;// ● byte offset of the vertex table

/*06*/uint16_tslot_offset;// ● byte offset of the runtime vertex slots; equals trailing_offset on the 410 objects that have no parts

/*08*/uint16_tface_offset;// ● byte offset of the face-normal table

/*0a*/uint16_ttrailing_offset;// ● byte offset of the part table

/*0c*/uint16_treserved_0c[5];// ◐ 0 across the corpus

/*16*/uint16_tvertex_count_minus_one;// ● vertex count is this + 1

/*18*/uint16_tface_count_minus_one;// ● face count is this + 1

/*1a*/uint16_tpart_count;// ● first word of the 40-byte object lead; see [Moving parts](#moving-parts)

/*1c*/uint8_tlead_1c[8];// ◐ Zero on disk; runtime role not established here.

/*24*/int16_tworld_position[3];// ● Zero on disk; transform entry stores caller XYZ here.

/*2a*/int16_tobject_rotation[3];// ● Zero on disk; transform entry stores caller XYZ angles here.

/*30*/uint8_tlead_30[18];// ◐ Zero on disk; runtime role not established here.

}; /* 66 bytes */

/* Vertex */

struct Vertex {

/*00*/int16_tx;// ● model space

/*02*/int16_ty;// ● **+Y is down**, so up is -Y

/*04*/int16_tz;// ● model space

}; /* 6 bytes */

/* FaceNormal */

struct FaceNormal {

/*00*/int16_tx;// ● one per polygon; a **unit normal** in 14-bit fixed point (16384 = 1.0)

/*02*/int16_ty;// ● as x

/*04*/int16_tz;// ● as x

}; /* 6 bytes */

/* PolygonRecord */

struct PolygonRecord {

/*00*/uint16_trecord_size;// ● total bytes of this record; also 26 + 2*vertex_count - the fixed fields run +0x00..+0x19, then one word per vertex.

/*02*/uint16_tfirst_vertex_ptr;// ● equals the first entry of vertex_ptrs

/*04*/int16_tnormal_scratch[3];// ● Zero on disk; normal XYZ is copied here and rotated at runtime.

/*0a*/uint8_tcontaining_part_ids[2];// ● Cleared per draw; tagged faces record up to two containing part numbers in traversal order for optional part commands.

/*0c*/uint16_tvertex_count_minus_one;// ● polygon has this + 1 vertices

/*0e*/uint16_tshade;// ● 0, 32, 64, 96, 128, 160 - the polygon's colour: a base index into the fight palette, see [Colour](#colour)

/*10*/uint8_traster_mode;// ◐ Selects raster dispatch; mode 1 also participates in anchor preparation.

/*11*/int8_tface_group_control;// ◐ Positive reuses the prior lighting term, negative sets it to zero; also controls face-list traversal and culling.

/*12*/uint8_tnormal_control;// ◐ Nonzero bypasses ordinary normal rotation and takes the zero lighting-term path; also bypasses one backface test.

/*13*/int8_tlighting_mode;// ◐ Selects ordinary, ambient-only, direct-bias and special normal/material paths.

/*14*/int16_tbias;// ● -8..+8; ordinary shade step, or anchor key/effect-model selector in the special material path.

/*16*/int16_tlight_term_scratch;// ● Zero on disk; preparation writes the pre-camera rotated normal term, or the grouped/disabled-normal replacement.

/*18*/uint8_tanchor_indices[2];// ◐ Initialization zeros this word; the conditional anchor pass writes two counter bytes consumed as signed anchor indices.

/*..*/uint16_tvertex_ptrs[vertex_count];// ● tailthe last vertex_count words

};

/* PartRecord */

struct PartRecord {

/*00*/uint16_tpolygon_ptr;// ● file offset of the part's first polygon record

/*02*/uint16_tpolygon_count_minus_one;// ● the part owns this + 1 consecutive polygons

/*04*/uint16_tvertex_list_ptr;// ● file offset of the part's vertex-index list

/*06*/uint16_tvertex_count_minus_one;// ● the list holds this + 1 entries

/*08*/int16_tpivot_x;// ● the axis the part turns about, in model space

/*0a*/int16_tpivot_y;// ● up is -Y, as everywhere else in the format

/*0c*/int16_tpivot_z;// ●

/*0e*/int16_ttranslation[3];// ● 0 on disk; runtime X/Y/Z translation added after pivot rotation

/*14*/int16_tangles[3];// ● runtime X/Y/Z angles; applied in Z, X, Y order; 0 on disk.

/*1a*/uint8_treserved_1a[6];// ◐ 0 on disk; runtime role unresolved

}; /* 32 bytes */

/* LandRecord */

struct LandRecord {

/*00*/chartag[4];// ● Literal 3DLD.

/*04*/uint16_tobject_ids[6];// ● ids of the LAND objects this record may place; 0xffff/0xfffe mark unused slots

/*10*/uint8_tpadding[12];// ◐ Padding or leftover source filename bytes; not the colour words that follow.

/*1c*/uint16_tground_palette_base;// ● GRND loader passes this palette base to the continuous-floor renderer.

/*1e*/int16_tground_shade_adjustment;// ● Added to renderer ambient for that side of the continuous ground.

/*20*/uint16_tcount;// ● placements

/*..*/uint8_tplacements[];// ● 0x22..16 bytes each

};

/* Placement */

struct Placement {

/*00*/uint16_tslot;// ● index into object_ids

/*02*/int16_tdraw_control;// ● 0, -1 or -2 in these files; copied unchanged to staged controls.

/*04*/int16_tx;// ● always a multiple of 1000

/*06*/int16_tz;// ● always a multiple of 1000

/*08*/int16_ty;// ● Zero on disk; copied as vertical position at submission.

/*0a*/int16_trotations[3];// ● Zero on disk; copied as object X/Y/Z rotations.

}; /* 16 bytes */

Fight 3D resources

Archives

Object layout

Tables

Counts

Runtime

Reserved

Position

Normal

Layout

Vertices

Runtime

Colour

Drawing

Geometry

Pivot

Runtime

Reserved

Objects

Colour

Placements

Reserved

Position

Drawing

Rotation

Still to investigate