Blob Wars : Metal Blob Solid
Copyright Parallel Realities 2004-2011
Licensed under the GNU General Public License

Last Updated: 9th December 2004

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+++ Contents
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1) Introduction
2) The PAK File
3) The FileData Object
4) The Map File
5) Map Entites
6) Other Files
7) FAQ
8) Closing comments


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+++ Introduction
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Contained within are pieces of information to do with the game, the map structure
and the structure of the pak file that is used in BW:MBS. I have created this
document for educational purposes.

This document is completely unsupported.

Thank you in advance for understanding.

To build the game without needing to recreate the PAK file each time to can 
build using the following command,

make USEPAK=0

The binary created will load files from the directory it resides within (so it
will look for data, sound, gfx and music in the local dir). When building the
game without using the PAK file you will get debug information to the console
and an FPS counter. You may also use the following additional command line
options,

-map <filename> Start the game using the specified map

-skill <skill level> Start the game using the specified skill (0, 1, 2, 3)

-showsprites Show the sprites that have been loaded. Use in conjunction with
			 a map file for best results
			 
-hub Jump directory to the hub. Will automatically load the first available game

-randomscreens Takes random screenshots and dumps them into a directory called
			   screenshots. You might not want to use this(!)
			   
-nomonsters	   Does not add monsters to levels (does not affect Boss missions)

-credits	   Show the credits

Stephen Sweeney


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+++ The PAK File
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The PAK file used in BW:MBS differs from the one used in Project: Starfighter where
as it is compressed and contains a lot more metadata making it a lot more effecient.
The format is as follows,

NB: All binary data is little endian

<variable length data> (char)
<varibale number of binary strutures> (FileData)
<offset of FileData structures> (unsigned long)
<number of file data structures in archive> (unsigned long)

BW:MBS will open the pak file, seek to the end, two back two unsigned longs and read
them. It then have information regarding the file structure and can read in all the
FileData objects that exist. These are stored in memory for the duration of the 
program and stepped through when a file needs to be loaded from the PAK.


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+++ The FileData Object 
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The FileData object holds the metadata for each file in the PAK archive. The object
itself has the following format,

NB: All binary data is little endian

char filename[60];
uLongf cSize;
uLongf fSize;
uLongf location;

Filename is the filename of the file (including the path). It is limited to 56 characters
since it is loosely based on the original PAK file spec for Quake. This could obviously
be changed if more characters were required.

cSize is the compressed size of the data. All the data in the PAK file is compressed using
zlib compress at a strength of 9. This number is used to tell uncompress how much data there
is and also used by CPak.cpp when loading the data from the pak file into a buffer in
memory.

fSize is the full uncompressed size of the data. This is used by uncompress and also when
allocating a memory buffer save uncompress the data into.

location is the offset of the data within the PAK archive. When a match for the filename
has been found in stepping through the filedata array, the PAK file is opened and then
seeked to the appropriate location. The appropriate amount of data is then read.

When working with big endian machines it is neccessary to convert the values in the FileData
object o little endian so they may of proper use.


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+++ The Map Files
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The maps are BW:MBS are plain text. They contain the data for the map, the objectives,
enemies, doors, and pretty much everything else you see during the game. Sprites and
new enemies can also be configured within the map data.

The map data beings with a large set of numbers. 400 columns and 300 rows allowing for
very large maps. This, in hindsight, was overkill. But the reason this was because the
map blocks used to be 16 x 16 pixels whilst they are now 32 x 32 pixels. After these
rows the entity data starts.

The map entities take the following format,

<skilllevel> <entityname> <entity arguments>

Skill level is required and should contain a combination of E, M or H to represent
whether that entity should appear on Easy Medium or Hard. Pretty much all the entities
appear on Hard. For example,

MH ENEMY "SpiderBlob V1.0" 1000 1000

This will place a Spider Blob enemy at 1000, 1000 on the map on difficulities Medium
and Hard, but not Easy.

Comments can be represented with C++ still slashes,

// here is a comment

Note: Bosses are hard coded. They do not live in the map data.


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+++ Map Entities
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STAGENAME <"stagename">

The stage name of the map. Must have within quotes.


BACKGROUND <filename>

The filename of the background to be used in this level.


MUSIC <filename>

The music to be used in this level.


TILESET <path>

The path to the tiles to be used in this level.


REQUIRED_MIAS <initial number to rescue>

The initial number of MIAs required to complete the stage.


MIA <"name"> <x> <y> <type>

Defines an MIA for this level. The type of MIA is either MIA_NORMAL or MIA_AQUA


START <x> <y>

Determines where Bob will initially start on this level. Ignored when returning to a
level.


CLIPPING <x1> <x2> <y1> <y2>

Determines the scroll limit for the map. The map will not scroll further than the 
specified coordinates.


AMBIENCE <sound file>

The sound effect that will be played in the background to represent the ambient sound
in the level (like the bubbling sound in the Caves levels).


ALPHATILES <variable length list>

Tile numbers that should be made transparent. Ideally this should have been in the tileset
directory. Numbers should be seperated by spaces with -1 to determine the end of the list.


OBJECTIVE <"description"> <"target"> <requiredAmount> <optional>

Defines an objective for the level.


ITEM <type> <"name"> <x> <y> <sprite>

Creates an item of given type, name and sprite at the given coordinates. Types 0 - 4 are
used for weapons. 5 - 7 for cherries and 8 - 14 for points pods. Types 100 and 101 are items
that can be picked up and carried in the inventory. Items are type 101 are not shown in
the inventory (for example, Crystals and Cherry Plants).


ENEMY <"name"> <x> <y>

Places the specified enemy (via their name) at the specified coordinates.


SPAWN_POINT <name> <x> <y> <type> <subtype> <min wait> <max wait> <active / inactive>

Used to spawn an item / entity at a random interval. For example, the lava balls that jump
out of the lava in Inner Cave Network, Part 1 are spawned by having a type of SPW_HAZARD
and a subtype of HAZARD_LAVABALL. They appear every 1 to 10 seconds. The type and subtype
are dealt with in defines.h and processed in spawnPoints.cpp. x and y coordinates are also
supplied to tell the game where the item should be spawned. The only exception to the rule
are enemies. They have an x and y as -1 and -1 since they simply teleport in around the 
player's location.


TELEPORTER <name> <x> <y> <destination x> <destination y> <on / off>

Simply sets up a teleporter with an origin and a destination. Can be on or off by default.


LINEDEF <"type"> <related object> <"message"> <x> <y> <width> <height> <active / inactive>

Sets up a line that is actived when the player crosses it. Common types can be of "Checkpoint", 
"Message, "Exit". "Exit" will prevent the player from crossing until it is the last required
objective remaining on the level.


SWITCH <"name"> <target object> <required item> <"message"> <switch type> <x> <y> <active / inactive>

Creates a switch that can be triggered by the player (or other entities depending on the type)
to toggle activate an object. Possible switch types are, 

SWT_NORMAL 
SWT_TOGGLE
SWT_TIMED
SWT_PRESSURE
SWT_RESET 
and SWT_WATERLEVEL. 

Note that for switches that reset Obstacles the obstacle name should
be placed into the "message". SWT_RESET switches are timed by default. Also, SWT_NORMALs become SWT_USEDs
when they are activated. This is to aid in the persistence of the level.


TRAIN <name> <start x> <start y> <end x> <end y> <wait time> <start location> <active / inactive>

Creates a train (a moving platform) with start and end locations as specified. The wait time states
how long the platform will wait (in 60ths of a second) at each end before changing direction. Start
location specifies which end the train will start at (either TR_AT_START or TR_AT_END). Note that
end locations must be the same value as or greater values than the start locations.


DOOR <"name"> <type> <open x> <open y> <closed x> <close y> <open / closed>

Creates a door with the specified open and close coordinates. Available door types are,

TR_DOOR
TR_LOCKED_DOOR
TR_GOLD_DOOR
TR_SILVER_DOOR
TR_BRONZE_DOOR
TR_SLIDEDOOR
TR_LOCKED_SLIDEDOOR
TR_GOLD_SLIDEDOOR
TR_SILVER_SLIDEDOOR
TR_BRONZE_SLIDEDOOR

As their names suggest the doors are either normal doors, locked or require a certain key to 
open them. Locked doors can be in conjunction with switches and other triggers in order to make
them open. Like trains, the closed x and y coordinates much be greater than or equal in value to
the open coordinates.


OBSTACLE <"name"> <x> <y> <sprite>

Sets up an obstacle with the given name and sprite than can be pushed. The name of the obstacle
can be used in conjunction with reset type switches to return them to their original location.


TRAP <name> <type> <damage> <speed> <startX> <startY> <endX> <endY> <wait1> <wait2> <sprite> <active>

Creates a trap in the location specified by start X and start Y. For traps such as the swinging ball
and spikes, the end X and end Y specifies the second location to move to. Wait 1 and Wait 2 tell
the trap how long to wait for each state (the energy beams have off and on times for example). Trap
types available are,

TRAP_TYPE_SPIKE
TRAP_TYPE_MINE
TRAP_TYPE_SWING
TRAP_TYPE_CRUSHER
TRAP_TYPE_BARRIER
TRAP_TYPE_FLAME


SPAWNABLE_ENEMY <"name">

Only ten of these may be defined. Used with enemy spawn points this list details which enemies
can be spawned on the map.


SPRITE <name> <frame name> <wait time> * 8

Can be used to define a new sprite to be used specifically on this level. It supports up
to 8 frames and wait times. When there are no more frames to be read, @none@ -1 is used
to denote no more reading it required.


DEFENEMY <"name"> <left sprite> <right sprite> <death sprite> <"weapon name"> <health> <score> <flags>

Create an enemy. Flags should be from the ENT_* flags are defined in defines.h


WATER_LEVEL <level>

Specifies the water level within the level. Use in conjunction with water level switches to 
raise the water level


TIME_LIMIT <minutes> <seconds>

The time limit for this level when playing on Extreme Mode.


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+++ FAQ
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Q. 	Can you give me some help modifying the source?

A. 	Unfortunately I have other commitments, mainly in the real world, that would prevent me
	from setting aside the time the do so. In the time I do have spare I prefer to work on
	new projects.
	

Q.	Why package up all the data into one file instead of leaving it loose?

A.	Three reasons - 1) It takes up less room on disc ; 2) It's easier to deal with one large
	data file rather than lots of file scattered all over the place ; 3) It stops people 
	digging around in the data and potentially spoiling the game for themselves.
	

Q.	How long did the game take to make?

A.	About 18 months from beginning to end.


Q.	Why did so much change during the game, like the saves becoming incompatible around 0.91?

A.	Metal Blob Solid was very much a make-it-up-as-you-go-along game. It was only decided later
	on that the levels should be kept within a persistant state so as to not force the player
	to reopen doors, redo puzzles, etc. This in itself was a bit of a headache and due to a
	small cockup when creating the persistance data the game would crash if you returned to a
	previous level, left, saved, quit the game and reloaded.
	

Q.	Why can't you see all the game or fight the bosses on Easy?

A.	It's easy mode(!) The bosses aren't exactly a walk in the park and bits of the game (such as
	battling Galdov for the Reality Crystal) are part of the game's plot. Because on Easy there
	is nothing to do except rescue MIAs, it was decided that you should get an ending, but not
	*the* ending after finishing the game on Easy. Also, a hell of a lot of work went into the
	bosses, other objectives, cutscenes, etc so it also has to do with appreciation.
	

Q.	Are there any secrets in the game?

A.	No. If you finish the game on Normal or Hard you see everything the game has to offer.
	Although you do unlock Extreme mode which is the whole game again but with a time limit on
	each mission.
	

Q.	Are you going to make any other games?

A.	There are plans, but nothing set in stone. Again, real life commitments can change
	everything.
	

Q.	Will there be a sequel to Metal Blob Solid?

A.	See above.
	

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+++ Closing Comments
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Metal Blob Solid was fun to make more often than not. There was some hair pulling and
frustation involved in making the game, but that's natural in any project. In the end
I grew quite fond of the bandana wearing Blob and decided to give his adventure more
meaning, which was why the plot suddenly appeared, along with the bosses and cutscenes.

I hope you've all enjoyed playing the game and I hope to bring you some more games in the
future.

