K240 Buildings

Construction data

Disassembly of K240 v1.886 using IRA reveals a data structure 400 bytes long, beginning at $1c338 in the main game executable. Analysis reveals that this stores data on the game's buildings, including all 40 Terran buildings but not alien buildings. Ten bytes are used to store each in the following format:

Datatype	Name	Description
WORD	Name	Index of the building name in the game's strings list
WORD	Description	Index of the building's description in the game's strings list
WORD	Cost	Build price of the building
BYTE	Hitpoints	Building hit points
BYTE	Build time	Build time in days
BYTE	Scaffold	Scaffold height
BYTE	Empty	Empty

Name	Description	Cost	Hitpoints	Build time	Scaffold	Actual name
0001	0013	03e8	05	20	00	Living Quarters
0002	0023	05dc	22	20	00	Power Store
0003	0024	05dc	18	14	00	Storage Facility
0004	0025	1b58	10	24	00	Anti-Missile Pod
0005	0026	01f4	05	08	00	Solar Panel
00ba	00bb	1f40	18	20	02	Decontamination Filter
0007	0028	05dc	0a	0a	00	Solar Generator
0008	0029	1130	18	20	00	Weapons Factory
0009	002a	0fa0	14	20	00	Mine
000a	002b	1388	0a	18	00	Satellite Silo
000b	002c	4e20	24	34	00	Screen Generator
000c	002d	afc8	24	30	01	Ore Teleporter
000d	002e	88b8	18	34	01	Gravity Nullifier
000e	002f	157c	14	24	00	Deep Bore Mine
000f	0030	10cc	0f	20	00	Missile Silo
0010	0031	4e20	14	24	01	Repair Facility
0011	0032	0dac	0f	24	03	Sensor Array
00bc	00bd	157c	14	1e	00	Plasma Turret
00be	00bf	1d4c	14	34	00	Photon Turret
0014	0033	32c8	18	30	02	Life Support
0015	0034	1f40	24	28	03	C.P.U
0016	0035	6784	18	2a	02	Seismic Penetrator
0017	0036	afc8	1c	40	01	Asteroid Engines
0018	0037	2710	22	28	02	Powerplant
0019	0038	1f40	24	20	02	Command Centre
001a	0039	1d4c	14	20	02	Construction Yard
001b	003a	012c	05	10	00	Landing Pad
001c	003b	0d48	10	18	00	Laser Turret
001d	003c	1388	0a	20	03	Solar Matrix
001e	003d	0bb8	0a	30	03	Resiblock
001f	003e	0bb8	20	28	02	Storage Tower
0020	003f	1c20	14	30	03	Protected Solar Matrix
0021	003f	2134	14	38	03	Protected Resiblock
0022	003f	1d4c	20	30	02	Protected Storage Tower
00c0	00c1	1388	0f	1e	03	Medical Centre
00c2	00c3	0c80	22	14	02	Environment Control
00c4	00c5	2134	34	20	03	Protected Environment Control
00c6	00c7	1b58	18	10	03	Hydroponics
00c8	00c9	1388	14	14	03	Hydration Plant
00ca	00cb	1194	0f	18	02	Security Centre

The C.P.U. is listed as costing 8000, although it cannot be built except automatically when a new colony is started.

The Decontamination Filter, Plasma Turret and Photon Turret have high numbers in the string list, appear out-of-order, and have their descriptions immediately following. This suggests they were added later in the game's development. They may have taken the place of three deleted buildings.

The Medical Centre, Environment Control, Protected Environment Control, Hydroponics, Hydration Plant and Security Centre all appear at the end of the list, have high numbers in the string list, and have their descriptions immediately follow in the string list. This suggests that they were added even later in the game's development. Early on, Life Support may have supplied all air, food and water.

Except for building hit points, all data in this table is visible in the game or in the game manual. Building hit points in decimal are as follows.

Hitpoints	Building name
5	Landing Pad
5	Living Quarters
5	Solar Panel
10	Resiblock
10	Satellite Silo
10	Solar Generator
10	Solar Matrix
15	Medical Centre
15	Missile Silo
15	Security Centre
15	Sensor Array
16	Anti-Missile Pod
16	Laser Turret
20	Construction Yard
20	Deep Bore Mine
20	Hydration Plant
20	Mine
20	Photon Turret
20	Plasma Turret
20	Protected Resiblock
20	Protected Solar Matrix
20	Repair Facility
24	Decontamination Filter
24	Gravity Nullifier
24	Hydroponics
24	Life Support
24	Seismic Penetrator
24	Storage Facility
24	Weapons Factory
28	Asteroid Engines
32	Protected Storage Tower
32	Storage Tower
34	Environment Control
34	Power Store
34	Powerplant
36	C.P.U
36	Command Centre
36	Ore Teleporter
36	Screen Generator
52	Protected Environment Control

Interestingly, the "protected" buildings are actually tougher than their non-protected equivalents, except for the Protected Storage Tower.

This table does not store sprite reference or whether the building takes up 1 square or 2x2 squares.

Current building data

Disassembly using IRA reveals that nine areas of memory are written to disk in order to form the save game file, which suggests that these nine areas hold the entire game state. Analysis of PART4, which begins 93,658 bytes into the save game file and is 33,600 bytes long, reveals that the game stores building data for 24 asteroids, 100 buildings per asteroid, and 14 bytes per building. The hex editor HxD was useful for this analysis.

The limit of 100 buildings per asteroid explains why attempting to build too many buildings returns the message, "Asteroid structure too weak!" Tests reveal that the size of buildings (1 square or 2x2 squares) is irrelevant, only the number, which cannot exceed 100 due to a limitation of the data structure. Relatedly, it's possible that the reason why Landing Pads can't be built close to the edge of the asteroid is to prevent a ship taking off from a Landing Pad at the very top row of a large asteroid and rising above the top of the screen. Since an asteroid can be rotated, all edges are potentially "top".

The format is as follows:

Datatype	Name	Description
Byte	ID	The building's index in the buildings construction data, not necessarily its string index
Byte	Hitpoints	Current hitpoints
Byte	Time to build?	Last 7 bits seems to be the number of days left to build.
Byte	BYTE03	Empty?
2 Bytes	Coords	Coordinates
6 bytes	Big coords	Additional coordinates for four-square buildings, also used by missile silos for animation frames while firing
Byte	Turret recharge	Seems to be an "initiative count" or time-to-fire for turrets
Byte	BYTE13	??

Save state viewing with WinUAE reveals interesting features.

Building Armour doubles the hit points of new buildings, not existing ones. However, a Repair Facility will repair old buildings up to the Building Armour maximum. It seems as if Building Armour doubles the "maximum" hit points of all buildings, which allows existing buildings to be repaired to the new standard.

Watching the data of a colony under attack reveals that a Screen Generator halves all damage taken by buildings in its range, rounded down.

Detonating buildings

Destroying a building with the green bomb tool appears to deal that building 120 damage. This ensures destruction of any building, even (hypothetically) a 60HP building with Building Armour. The strongest Terran building is a Protected Environment Control with Building Armour at 104 hit points.

As building hit points is a signed integer, it's theoretically possible to have a building with 128 hit points which would survive this hit, but presumably no Terran or alien building can acquire this many hit points. This also implies that the Kll'Kp'Qua cannot acquire Building Armour, as their Queen's Chamber has 100 hit points, and Building Armour would raise this to 200, which the game would read as negative, thus destroying all new Queen's Chamber buildings one day after they are placed.

Observations

The following buildings require eight colonists each: Mine, Deep Bore Mine, Seismic Penetrator, Construction Yard, Command Centre and Missile Silo. No other buildings require workers. Ships do not require colonists for crew.

Wanted

• Alien building data
• Information on the function of alien buildings
• Damage values / to-hit functions for Terran turrets and the turrets of Protected buildings
• Sprite rips
• How the game determines a building's type for the purpose of spy satellite reports
• What determines the order in which buildings disable in event of power loss