added simple math constant folding, but commented it out for now

[gaemu.git] / dox / gmformat7.txt

Binary Format of GameMaker Save Files (gmd, gm6, gmk)
Copyright (c) 2008 IsmAvatar <cmagicj@nni.com>

License:
Redistribution and use of this document, with or without modification,
is permitted provided that redistributions retain the above copyright
notice, this condition, and the following disclaimer.

Disclaimer:
THIS DOCUMENT IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THIS DOCUMENT OR THE USE OR OTHER DEALINGS IN
THIS DOCUMENT.

You may need a hex editor to examine GM files and/or make modifications.
You can use the one I used, XVI32. It can be found at
http://www.chmaas.handshake.de/delphi/freeware/xvi32/xvi32.htm

Note About Legality:

I have thoroughly reviewed the Licence Agreement of GameMaker, and have a
general knowledge of copyrights and such. These activities are legal, as
long as I do not tamper with the compiler and as long as I maintain
credit to Mark Overmars for the original GameMaker, which I will make
sure to revere and worship greatly in this product. A note from Mark
Overmars himself regarding this activity:

"Sorry for not replying earlier. I was first was on holidays and then
trying to catch up. I don;t think this is an important issue. Actually
.gm6 files are not really protected. And even though I prefer people not
to hack them, I cannot see a reason to be worried about this.

Mark"

Note About Version:

From time to time, you'll see some bytes documented as "GM Version needed
for the following info". For resources, first GM version tells when the
resource type was added, while the second GM version tells when the last
update of the resource type was.

We will only focus on versions 530, 600, and 702 although these other
versions may be mentioned elsewhere.

* 702 for GM7.0 (notice, GMK is obfuscated. Please see the GMKrypt Documentation)
* 701 for GM7.0 as well.
* 620 for GM7.0 in some places. This may be because Mark was planning on calling it 6.2
* 600 for GM6.1 and GM6.0 (cross-compatible)
* 530 for GM5.3 and GM5.3a (bug-fix version. cross-compatible)
* 520 for 510 for GM5.1
* 500 for GM5.2 and GM5.0 (forward compatible)
* 430 for GM4.3

and so on. Other numbers may pop up as well, as in-between versions. For
example, 542 means that 530 cannot read it, but 600 can. Software usually
does this for format changes during development. Also see Angle Brackets
below.

Note About Sounds, Images, Data Files, and Game Information
All images, with the exception of Data File images and the Game Icon, are stored as zlib compressed bitmaps.
All sounds are stored in their original format when possible, and then zlib compressed.
Game Information is stored in Rich Text Format (RTF).
You should also see Angle Brackets below.

Note About Longint / Numbers

GM uses primarily 32-bit (4-byte) little-endian signed integers, which I
choose to call "longints", for most of its data. Even basic things like
True/False and Radio Buttons etc. each tend to be stored in their own
4-byte/32-bit set, rather than merging 8 of them to make a single byte or
merging 32 of them to make that same 4-byte.

I will display any dates as Gregorian ISO standard (yyyy-mm-dd).

Dates are stored in 64-bit (8-byte) signed doubles representing the
number of days that have passed since 1899-12-30. Fractional parts are
used to represent fractions of days (hours, minutes, seconds, etc).

Colors are stored in a longint, usually only using the first 3 bytes as R
G B respectively, although sometimes they'll make use of the 4th byte, so
handle carefully. Usually the 4th byte is 0.

Unless otherwise denoted by a preceding (<byte size>-bytes) note, all
data is stored in 32-bit integers or 32-bit preceded 8-bit character
sequences (as denoted by insertions, explained below).

Note About Insertion and Curly Brackets { }

Insertion will take 2 normal forms, and a third special form (see Angle
Brackets). Both normal forms will almost always have a longint before the
insertion to indicate how much information is contained in the insertion.
If this number is 0, no additional data will be inserted. The data is
then surrounded by curly brackets { }.

The first kind of insertion is String Insertion. This is when the data is
a series of 8-bit (1-byte) characters. My documentation will show these
by having all the information (the length longint, the curly brackets,
and the data) on one line.

Example of string insertion:
  Length of Name { Name }
which would turn out as something like 07 Sprites ...
or just 00 ...

The second kind of insertion is Structured Insertion (although you
needn't remember the name - it's stolen from C's struct). For this, the
documentation format will be the length longint, and then the first curly
bracket { on a new line, followed by the data on its own lines separate
from the curly brackets, and then concluded with an end curly bracket on
a new line. See the examples below.

Two common forms will arise. One is the true/false Structured Insertion.
This determines simply whether or not the insertion will appear.

Example of a true/false
  Object exists
  {
   Object ID
  }

The other is the Repitition Structured Insertion. This means that the
first longint will indicate *how many times* the data within will be
inserted. The data itself is not actually repeated - only the structure
format is.

Example of repetition
  Number of Objects
  {
   View ID
  }
In this case, supposing there's 8 views, each with increments of ID
The result would be: 08 00 01 02 03 04 05 06 07 (replacing each of those numbers with the longint equivelent)

Note about Conditional Insertions and Angle Brackets < >

Conditional Insertions are when a certain condition (e.g. the value of a
prior longint) must be met in order for the data to be inserted. This is
set apart from normal insertions because that longint may not be
adjacent, or because the longint value may not be an obvious indicator of
the repetitions (e.g. 0 may indicate that data is indeed inserted, while
1 may indicate that it is not). Angle Brackets are placed around this
conditional expression.

A very common example of Conditional Insertions is the Version Number, as
this weighs heavily on what data appears in which version. Each section
has its own version number - there's 1 for Game Information, 1 for each
resource, and a separate one for the format of each resource. Thus you
should keep an eye on which version number is being used for that section
- and also keep an eye on the scope of that version number.

Example of Version Numbers:
 GM version needed for the following info (542/600)
 <530 only> Load only on Use (0)
 <600 only> Preload (1)

If different versions get grouped together like that, I will try to group
the older versions first and the newer versions later.

Of course, Conditional Insertions aren't solely dependant on a version
number. Here's an example of Special Case insertion (one which does not
denote how often the data is repeated)

 10 or -1
 <if not -1> Size of Image data { Image Data }

This frequently occurs in Sounds and Images. At this time we do not
understand why this odd conditional is there - why use 10 instead of 1,
and -1 instead of 0?

Note about Default Values in Parenthesis

I've also started including default values and value ranges to my format
documentations, for your convenience. When the default value is not
obvious by the format, I will put an asterisk (*) next to it.

Here are a few examples of the formats used;
(<Lower>-<Upper>,<Default>) e.g. (0-100,10)
(Min <Value>,<Default>) e.g. (Min 0, 100)
(<Default>) e.g. (0)
([Range,]<Val1>=Name1,<Val2>=Name2[,<Val3>=Name3[,...]]) e.g. (0-2,0*=Yes,1=No,2=Cancel)

----------------------------
Now to explain the bytes.

Reserved, tells GM that it's a GM file (1234321)
GM Version needed for Game Settings (530/600/701)
<530 only> Reserved (0)
Game ID. (0-100,000,000, Random*)
(16 bytes) These seem to go hand-in-hand with the Game ID, for when they
change. Its purpose is unclear. You may just plug in 0's with no apparent
effects.
GM version needed for the following info (530/542/600/702)
Start in full-screen mode (0)
<600+> Interpolate colors between pixels (0)
Don't draw a border in windowed mode (0)
Display the cursor (1)
<530 only> Scale percentage in windowed mode (1-999, 100*)
<530 only> Scale percentage in fullscreen mode (0=max) (0-999, 100*)
<530 only> Only scale when there is hardware support (1)
<542+> Scaling (-1 to 999, -1* = Keep Aspect Ratio, 0 = Full Scale, 1-999 = Fixed Scale)
<542+> Allow the player to resize the game window (0)
<542+> Let the game window always stay on top (0)
<542+> Color outside the room region (0 or 0x00000000)
Set the resolution of the screen (0)
<530 only> Color Depth (0* = 16-bit, 1 = 32-bit)
<530 only> Use exclusive graphics mode (0)
<530 only> Resolution (0-6, 0=640x480, 1*=800x600, ..., 5=320x240, 6=No Change)
<530 only> Frequency (0-4, 4)
<530 only> Wait for a vertical blank before drawing (0)
<530 only> Display the caption in full-screen mode (1)
<542+> Color Depth (0* = No Change, 1 = 16-bit, 2 = 32-bit)
<542+> Resolution (0-6, 0* = No change, ...)
<542+> Frequency (0-5, 0* = No change, 1 = 60, ...)
Don't show the buttons in the window caption (0)
<542+> Use synchronization to avoid tearing (0)
Let <F4> switch between screen modes (1)
Let <F1> show the game information (1)
Let <Esc> end the game (1)
Let <F5> save the game and <F6> load a game (1)
<702+> Let <F9> take a screenshot of the game (1)
<702+> Treat the close button as <Esc> key (1)
Game Process Priority (0* = Normal, 1 = High, 2 = Highest)
<530 only> Reserved (1)
<530 only> Reserved (1)
Freeze the game when the form looses focus (0)
Loading Progress Bar (LPB) (0 = No LPB, 1* = Default LPB, 2 = Own LPB)
<if LPB = 2> {
 10 or -1
 <if not -1> Size of Back Image data { Back Image Data }
 10 or -1
 <if not -1> Size of Front Image data { Front Image Data }
}
Show your own image while loading (0)
{
 10 or -1
 <if not -1> Size of Front Image data { Front Image Data }
}
Make image partially transparent (0)
Make translucent with alpha value (0-255, 255)
Scale progress bar image (1)
Size of Icon data (2238) { Icon Image Data }
Display error messages (1)
Write error messages to file game_errors.log (0)
Abort on all error messages (0)
Treat uninitialized variables as value 0 (evil!) (0)
Length of Author (0) { Author }
<600 and below> Version (100)
<702 only> Length of Version (3) { Version ("100") }
(double) Last Changed date and time (generated)
Length of Information (0) { Information }
How many Constants there are (0)
{
 Length of Name { Name }
 Length of Value { Value }
}
<702 only> Major (1)
<702 only> Minor (0)
<702 only> Release (0)
<702 only> Build (0)
<702 only> Length of Company (0) { Company }
<702 only> Length of Product (0) { Product }
<702 only> Length of Copyright (0) { Copyright }
<702 only> Length of Description (0) { Description }
<542 and 600> How many Include files there are (0)
{
 Length of Filename { Filename }
}
<542 and 600> Folder to save Include files to (0* = main, 1 = temp)
<542 and 600> Overwrite existing Include files (0)
<542 and 600> Remove Include files at game end (0)

GM version needed for the following info (400)
How many sound ID's there are (0)
{
 Whether sound of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (440/600)
  <440 only> Kind (-1*=None, 0="Wave", 1="Midi", 2="Mp3", 10="Unknown")
  <600 only> Kind (0=Normal, 1=Background, 2=3D, 3=Multimedia)
  Length of Filetype { Filetype (like ".wav") }
  <600 only> Length of Filename { Filename (no directory) }
  <600 only> Music exists
  {
   Size of Music Data { Music Data }
  }
  <440 only and Kind is not -1> Size of Music Data { Music Data }
  <440 only> Allow for sound effects (0)
  <440 only> Buffers (1)
  <440 only> Load only on use (0)
  <600 only> Effects (Chorus=1, Echo=2, Flanger=4, Gargle=8, Reverb=16)
    Notice, Effects is actually merged into 1 longint
    To get the value, simply add active Effect numbers together
  <600 only> (double - 8 bytes) Volume (1)
  <600 only> (double - 8 bytes) Pan (0*=center)
  <600 only> Preload (1)
 }
}

GM version needed for the following info (400)
How many sprite ID's there are (0)
{
 Whether sprite of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (400/542)
  Width
  Height
  Left Bounding Box (can be negative)
  Right Bounding Box (can be negative)
  Bottom Bounding Box (can be negative)
  Top Bounding Box (can be negative)
  Transparent (1)
  <542 only> Smooth Edges (0)
  <542 only> Preload Texture (1)
  Bounding Box (0*=Automatic, 1=Full image, 2=Manual)
  Precise collision checking (1)
  <400 only> Use video memory (1)
  <400 only> Load only on use (0)
  X Origin (0)
  Y Origin (0)
  How many subimages there are
  {
   10 or -1
   <if not -1> Size of Image data { Image Data }
  }
 }
}

GM version needed for the following info (400)
How many background ID's there are (0)
{
 Whether background of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (400/543)
  Width
  Height
  Transparent (0)
  <400 only> Use video memory (1)
  <400 only> Load only on use (1)
  <543 only> Smooth Edges (0)
  <543 only> Preload Texture (0)
  <543 only> Use as tile set (0)
  <543 only> tile width (16)
  <543 only> tile height (16)
  <543 only> horizontal offset (0)
  <543 only> vertical offset (0)
  <543 only> horizontal sep (0)
  <543 only> vertical sep (0)
  Image exists
  {
   10 or -1
   <if not -1> Size of Image data { Image Data }
  }
 }
}

GM version needed for the following info (420)
How many path ID's there are (0)
{
 Whether path of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (530)
  Connection Kind (0* = Straight lines, 1 = Smooth curve)
  Closed (1)
  Precision (1-8, 4)
  Room Index to show as Background (-1* = none)
  Snap X (16)
  Snap Y (16)
  How many Points there are (0)
  {
   (double) X
   (double) Y
   (double) Speed
  }
 }
}

GM version needed for the following info (400)
How many script ID's there are (0)
{
 Whether script of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (400)
  Length of Script { Script }
 }
}

GM version needed for the following info (440/540)
<440 only> How many data file ID's there are
{
 Whether data file of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (440)
  Length of File Name (0) { File Name }
  File Data exists (0)
  {
   Size of File Data { File Data }
  }
  Export (0=Don't, 1=Temp Folder, 2*=Working Folder, 3=As Font)
  Overwrite the File (0)
  Free Data Memory (1)
  Remove at Game End (1)
 }
}
<540 only> How many font ID's there are
{
 Whether font of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (540)
  Length of Font Name { Font Name }
  Size (12)
  Bold (0)
  Italic (0)
  Character Range Begin (32)
  Character Range End (127)
 }
}

GM version needed for the following info (500)
How many timeline ID's there are (0)
{
 Whether timeline of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (500)
  How many Moments there are (0)
  {
   Moment position
Here is where Action information is inserted. This information is exactly
the same as it appears in objects. As such, to understand how these bytes
work, rather than documenting it twice, I shall refer you to see Actions
below, between the **stars**
  }
 }
}

GM version needed for the following info (400)
How many object ID's there are (0)
{
 Whether object of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (430)
  Sprite Index (-1* = none)
  Solid (0)
  Visible (1)
  Depth (0)
  Persistent (0)
  Parent object index (-100* = none)
  Mask sprite index (-1* = none)
  Reserved (10)
Now we have an interesting thing. We have eleven (11) -1's thrown in for
each of the event types. They appear after each event's data (or simply
appear where they are if the event type has no data), but the events may
have -1's in them too, so you can't just count down 11 -1's and hope to
be at the end of the object. No event begins with -1, so if you have a -1
where an event should be, you know that the event has no data. If there
is data, it is documented here. If there are multiple kinds (event kind =
'numb' in the GM manual) of the same event, each kind will be added in
without a -1 appended on the end until the last. The first kind to appear
will actually be the highest kind number, and then it will count down.
Other than that, Events appear in standard order. The stars ** you will
see below relate to Time Lines. See Time Lines for more info.
  {
   Event Numb (see GM Manual)
   **GM version needed for the following info (400)
   How many actions this event has
   {
    The GM version needed for the following info (440)
    Library ID
    Action ID
    Action Kind (Normal, Begin Group, Else, etc. See Lib Builder)
    Action may be Relative
    Action is a Question
    Action Applies to something
    Action Type (0=Nothing, 1=Function, 2=Code)
    Length of Function Name { Function Name }
    Length of Code { Code }
    Argument Count
    How many arguments there are (always 8)
    {
     Argument Kind (See Lib Builder)
    }
    Applies to Object Index (-1 for Self, -2 for Other)
    Relative
    How many arguments there are (always 8)
    {
     Argument Length { Argument Value }
    }
    NOT
   }**
  }
  (Don't forget the -1 after each Primary event)
 }
}

GM version needed for the following info (420)
How many room ID's there are (0)
{
 Whether room of this ID exists or not
 {
  Length of Name { Name }
  The GM version needed for the following info (520/541)
  Length of Room Caption (0) { Room Caption }
  Width (640)
  Height (480)
  Snap Y (16)
  Snap X (16)
  Turn the grid into an isometric grid (0)
  Speed (30)
  Persistent (0)
  Background Color (12632256 or 0xC0C0C000)
  Draw background color (1)
  Length of Creation Code { Creation Code }
  How many Backgrounds there are (always 8)
  {
   Visible when room starts (0)
   Foreground Image (0)
   Background Image index (-1* = none)
   X (0)
   Y (0)
   Tile Hor. (1)
   Tile Vert. (1)
   Hor. Speed (0)
   Vert. Speed (0)
   Stretch (0)
  }
  Enable the use of Views (0)
  How many Vies there are (always 8)
  {
   Visible when room starts (0)
   <520 only> Left
   <520 only> Top
   <520 only> Width
   <520 only> Height
   <520 only> X
   <520 only> Y
   <541 only> View X (min 0, 0)
   <541 only> View Y (min 0, 0)
   <541 only> View W (min 1, 640)
   <541 only> View H (min 1, 480)
   <541 only> Port X (min 0, 0)
   <541 only> Port Y (min 0, 0)
   <541 only> Port W (min 1, )
   <541 only> Port H (min 1)
   Hbor (min 0, 32)
   Vbor (min 0, 32)
   Hsp (min -1*)
   Vsp (min -1*)
   Object following (-1* = none)
  }
  How many Instances are in the room (0)
  {
   X
   Y
   Object Index
   ID (starts with 100001)
   Length of Creation Code { Creation Code }
   Locked
  }
  How many Tiles are in the room (0)
  {
   X
   Y
   Background Index
   TileX
   TileY
   Width
   Height
   Layer/Depth (1000000)
   ID (starts with 10000001dec)
   Locked
  }
  Remember the Room Editor Info (REI if 0. May be 0 if all settings are defaults)
  Room Editor Width (646, 0 if REI)
  Room Editor Height (488, 0 if REI)
  Toggle the showing of the grid (1, 0 if REI)
  Show Objects (1, 0 if REI)
  Show Tiles (1, 0 if REI)
  Show Backgrounds (1, 0 if REI)
  Show Foregrounds (1, 0 if REI)
  Show Views (0, 0 if REI)
  Delete underlying objects (1, 0 if REI)
  Delete underlying tiles (1, 0 if REI)
  <520 only> Tile Width (16)
  <520 only> Tile Height (16)
  <520 only> Tile Hsep (1)
  <520 only> Tile Vsep (1)
  <520 only> Tile Horizontal Offset (0)
  <520 only> Tile Vertical Offset (0)
  Tab (0-4, 0, 0 if REI)
    0* = objects, 1 settings, 2 tiles, 3 backgrounds, 4 views
  X Position of the horizontal scrollbar of the Room Editor (0, 0 if REI)
  Y Position of the vertical scrollbar of the Room Editor (0, 0 if REI)
 }
}
ID of last instance placed (100000)
ID of last tile placed (1000000)

<701 only> GM version needed for Includes (620)
<701 only> How many Includes there are (0)
{
 GM version needed for the following info (620)
 Length of Filename (0) { Filename }
 Length of Filepath (0) { Filepath }
 Whether an Original File is chosen or not
 Original File Size (0)
 Store in editable gmk file (0)
 {
  Length of File Data (0) { File Data }
 }
 Export (0=Don't, 1=Temp Dir, 2=Working Dir*, 3=Following Folder)
 Length of Folder To Export To (0) { Folder To Export To }
 Overwrite the file if it exists (0)
 Free memory after export (1)
 Remove at game end (1)
}

<701 only> GM version needed for Packages (700)
<701 only> How many Packages there are (0)
{
 Length of Package Name { Package Name }
}

GM version needed for the following info (430/600/620)
Background Color of Game Information (-16777192 or 0x180000FF)
Mimic the main game window/main form (0)
<600+> Length of Form Caption (16) { Form Caption ("Game Information") }
<600+> Position Left (-1)
<600+> Position Top (-1)
<600+> Position Width (600)
<600+> Position Height (400)
<600+> Show the window border and caption (1)
<600+> Allow the player to resize the window (1)
<600+> Stay always on top (0)
<600+> Stop the game while showing help (1)
Length of Game Information RTF (147) { Game Information in Rich Text Format }

GM version needed for the following info (500)
How many library dependancies there are (these are stored in the order of
the lib's filenames, in alphabetical order. Likewise, they are executed
in this same order)
{
 Length of Library Creation Code { Library Creation Code }
}

GM version needed for the following info (500/540/700)
How many executable rooms there are (this stores the room indexes in
execution order, so you know which room to summon next via
room_goto_next() etc.)
{
 Room index (in execution order, which is usally the same as the Tree Order)
}


(Following that is the Resource Tree, which concludes the file)

Creating the Resource Tree:

<700 only> There are 12 Root Tree Resources - 9 primary, 3 secondary
<500 and 540> There are 11 Root Tree Resources - 9 primary, 2 secondary

Format:
Status, Grouping, Index, Length, { Name }, Contents
You repeat that for all things on the resource tree, as they appear,
going down, all branches expanded.

Status:
1) Primary Resource
2) Group
3) Secondary Resource

Grouping (in the order they appear in the file):
2) Sprites
3) Sounds
6) Backgrounds
8) Paths
7) Scripts
9) <500> Data Files / <540> Fonts
C) Time Lines
1) Objects
4) Rooms
A) Game Information*
B) <500> Game Options* / <540> Global Game Settings*
D) <700> Extension Packages*
*Considered Secondary Resources that don't belong in a primary resource group.

Index:

All Secondary Resources are given an Index, or a reference number, which
reflects the index of the resource far above, where you set their
properties and options. Primary Resources, Groups, and Game Information
and Game Options / Global Game Settings all use 0 for their Index.
Occasionally you may find that they will actually use a number other than
zero. It is unclear why they would do this, but just keep it in mind.

If the index does not reflect their resource number above, you may either
get invisible resources, or <undefined> resources. Also, make sure that
no two secondary resources under a single Grouping have the same Index.
This may result in Duplicate Complex, in which both are dependant on each
other and anything you do to one is done to the other.

Name Length { Name }:
All have a Name Length. After that, it will count out that many bytes for the name itself.

Contents:

All Primary Resources and Groups have Contents count, which is how many
groups/secondary resources it has within itself, non-recursive. Secondary
Resources always have a content count of 0, since they may never contain
anything.

Non-recursive means that if a folder has several resources, only that
folder is counted. Once it reaches the folder, it will tell how many
resources it contains.

Let's say you have 5 sprites, but all 5 of them are inside a Group, and
that group falls under Sprites. The Sprites Primary Resource has 1
content, which is the Group. The Group has 5 contents - the 5 sprites.


In an empty file, it would look something like this:
1 2 0 7 Sprites 0 1 3 0 6 Sounds 0 etc.
In the pacman example that comes with most distributions of GM, it would look like this:
1 2 0 7 Sprites 6 2 2 0 7 pacmans 5 3 2 0 8 pac_left 0 3 2 1 9 pac_right 0 3 2 2 6 pac_up 0 3 2 3 8 pac_down 0 3 2 4 9 pac_stand 0 2 2 0 8 monsters 2 etc.
This will cause the tree to look like this:
+Sprites
 -pacmans
  []pac_left
  []pac_right
  []pac_up
  []pac_down
  []pac_stand
 -monsters (etc...)

Since Primary Resources are included in the save file, you can change
their names (and their lengths, as long as you update the longint before
their name to reflect the new length) and it will actually display in the
resource tree to the left.

--End--
Additional data may be stored at the end of the file and GM will ignore/discard it.