Getting Started With E02
E02 is built for creating games through the use of its various editing tools. The two basic types are the Data Editors, and the Script Tools. Either type can be used to alter existing games, but proper use of both could yield totally new and unique games. Each editor and tool have their own, more detailed documentation. An easy way to get started would be to focus on a particular aspect of development and browse that portion of the documentation while attempting to modify an existing game. Piece by piece, a major modification, or an entirely new game can be built this way.

The following list is an overview of the available functionality. For a complete list of all documentation files, see the end of this page.

Data Editors:

• Level Editor
  For editing levels
• Tile Editor
  For editing tile art, solidity, and animation, and palette colors and animation
• Level Ripper
  For creating levels and tilesets from PCX/TGA images
• Object Editor
  For moving or deleting objects placed in a level, or changing their properties
• Sprite Editor
  For editing sprite boundaries and properties, and viewing and testing animations

Script Tools:

• Game Listing File
  For making the game available to E02
• Game Def
  For setting up certain properties of a game and loading "global" data
• Zone Def
  For setting up certain properties of "zones" and "acts" and loading their data
• Object Def
  For defining "Game Objects" for use in-play
• Font Def
  For creating fonts for use in E02
• Character Def
  For setting up player properties, art, and sound effects
• Music Def
  For loading music
• Sound Effect Def
  For loading sound effects
• Status Script
  For creating logos, title screens, status displays, level intros/outtros, menus, intermissions, etc
• Functions
  For level init, animations, menu selection events, level events, object/player control, etc

File Setup Information

Certain files are absolutely necesary for a stand-alone game, and must be in certain places. Be sure to pay special attention to where the "Game Listing", "Game Def", and "Zone Def" files belong, and how to use them.

Aside from Game-global data, games built using E02 are made up of "Zones", which themselves are broken up into "Acts". "Zones" are a collection of data that make up any one level, menu screen, intro/ending sequence, etc, depending on how they are used. "Acts" are sub-sets of data within a "Zone" that are generally used to group similar levels together. Both are defined in the Zone Def files that appear in each "Zone" folder.

"Zone" folders are named by their Zone ID number (which must contain at least two digits), such as "zone00" for when the game's "Zone" setting is set to 0. Any number value may be used for Zone IDs, and they do not need to be sequential. Registers 3 and 4 represent the current "Zone" and "Act" respectively, however, they only have an effect when they are tested by scripted game events, or when Register 7, "InLevel" is set to 0, which causes E02 to reload "Zone" and "Act" data. The simplest way to fully switch levels is to use the Func_Set_Level command, which takes care of all three.

Files used with E02 must not use long filenames. Instead, their names must consist only of 8 characters, and 3 characters for the suffix (12345678.123, 8charfil.def). Not all supported platforms allow long filenames.

Files and file references must have consistent casing. Some supported platforms are case-sensitive. Referencing a file named "filename.ext" when the file on disk is "filename.ext" will work. Referencing a file named "FileName.ext" when the file on disk is "filename.ext" will not work. All files and folders expected by E02 itself are assumed to be all lower-case (such as "game.def", "zone00/zone.def", "keymap.def", etc). Files referenced by scripts may use any casing as long as the actual file and all references to it match exactly. E02 cannot enforce this restriction on platforms that are case-insensitive, so a practice such as limiting all files and folders strictly to lower-case names would be an easy way to avoid mistakes that will only cause errors for other users.

For all script file types, please also view previously-created scripts as well as the documentation to get a deeper understanding of how they work.


Level Data and Menu/Gameplay Setup Information

Level, Tile, and Object files that must be made available to any particular level must be loaded by the appropriate Script Commands in that level's "Act Init" function. If none of those commands are called, the level will start with an empty level, blank tiles, and no objects. When files are loaded with those commands, they become the current Level, Tile, and Object files, which will be used for any saving/loading initiated within the editors. These files must be specified by these commands even if they do not exist (blank ones will be created if they do not exist), because this is the only way to supply filenames to the editor. Otherwise, data cannot be saved.

The "Act Init" function must also call any "Object" that is to be used in the current level, whether it is a gameplay level, a menu "level", a title screen/intermission "level", or any other type of screen. Built-in objects are very necesary, such as the tile plane object for displaying planes, the player move and draw objects for making a player character available, and the Script Objects, for displaying Status Scripts. Please see the "Zone Def", Function, and Built-in Object documentation for more information. The "SpawnObject" function will be of particular interest.


ID, Count, Variable, and Constant Value Information

Remember that ID numbers for everything start with the number 0, not the number 1. The very first ID number for anything must be 0, and the very last must be the total number of entries minus 1. The total number of entries in any list will be the ID number of the final entry plus 1, because the 0 entry also counts. (Example: 0, 1, 2, 3 - there are 4 total values listed). This includes entries within scripts, as well as ID numbers for "acts". ("Act 1" has the ID number 0)

"Variables" are areas of memory that are set aside to store number values that can be changed. Variables are used to store temporary values, counters, changeable settings, etc. They are laid out as lists, and each one is referenced by its "ID number" from within that list. When a Script Command requires a "Variable ID" as a Parameter, the number entered for the Parameter is taken as the ID number of a Variable, and the value stored in that Variable is used for the operation. There are three basic types of Variables: Game Variables/Registers, Player Variables, Object Variables

"Constant Values" are essentially the opposite of Variables; they are "Constant", they never change. "Constant Values" are used when a known value must be used in a mathematical expression, to initialize a Variable, or to pass as known Parameters to any other Command. When a Script Command requires a "Constant Value" as a Parameter, the value entered as the parameter is taken literally; that value is used for the operation.

All "Constant Values" are treated as Base 10 (Decimal) by default, however, Base 16 (Hexadecimal) and Base 2 (Binary) values may be entered by prefixing the number value with '$' or '%', respectively (For example, "31" (Decimal), "$1F" (Hex), and "%00011111" (Binary) all represent the same value)

-Advanced- "Constant Value" versions of mathematical Commands may be used to perform math operations on a Variable ID (the Variable's reference number, not the contents of that variable) by using the special Variable reference "Tags" (as described below), entering the ID of that Variable as the "Constant Value". This is also useful for storing Variable IDs in "Registers", for use when a Command that requests a Variable ID allows that ID to be obtained from a "Register". Furthermore, the extra "Tag" "O" may be used in conjunction with the "G", "Z", and "A" "Tags" to reference an Object Type ID (as in "OZ4", to reference "Zone"-specific Object Type 4).



Script Value Tags Information

There are also several "tags" that may be used on certain script lines to change the meaning of a Number Value. They are used to make keeping track of certain IDs easier. When they are to be used, they must come immediately before the value they are meant to alter, without spaces, such as "A2", "r0", "U13", etc. These tags are:

• "G", "Z", "A" (Game/Zone/Act data IDs)
  These tags, standing for "Game", "Zone", and "Act" may be used in certain places in the script to signify that a data ID number represents data that was loaded by a "Game Def" as "global" data, or by a "Zone Def" as either "Zone" data or "Act" data. These tags are useful because when they are available for use, you won't need to keep track of the real data ID of the data as it is understood by the game. These tags allow you to use the ID of the data as it is shown in the script that loads it. If these tags are not available, and the Real data ID of any data must be used, it is simple enough to calculate the ID. "Game Data" IDs are the ID that they are given from the script that loads them. Starting at 0 for the first ID, it is the order in which they appear in that script. For "Zone Data", its script ID is found in the same way as a "Game Data", but its Real ID is found by adding the total number of "Game Data" of the same type to its "Script ID". "Act Data" is found in a similar way, but its Real ID is its "Script ID" plus the total number of "Game Data" of the same type, plus the total number of "Zone Data" of the same type. It may sound complicated at first, but it is actually very simple once you've come to understand it. These tags may only be used where a script's documentation says they are available.
  
  
• "R", "r" (Data stored in "Registers"/"Game Variables")
  These tags are used when the value inside a "Register" should be taken as a Parameter to a function. These can be used so that when a function requires a number value, it can use a value that was stored in memory by another function instead of using a fixed value that was written in the script. This is very useful, although it is only available where the function descriptions in the function documentation say that they may be used. Lower-case r represents a main game "Register", whereas capital R represents a user-created "Register". More information is available in the "Game Variable" documentation.
  
  
• "U" ("Register"/"Game Variable" IDs)
  This tag is used when the ID number of a "Register" (not the value stored inside it) is necesary. This tag is only used in certain functions, such as mathematical and conditional functions. Main game "Registers" are used by simply using their ID, while user-created "Registers" use the tag "U", as in "User". More information is available in the "Game Variable" documentation.
  
  
• "C", "c", "A", "a" (Player Variable IDs)
  Although the tag "A" is also used to signify "Act" data, it does not conflict with its use for Player Variables. This tag is used for Player Variables when the ID number of a player variable is required as a Parameter to a function. Player constants are given to the function by their ID number, but Active Player Variables can be signified by using the "A" tag, for "Active". More information is available in the "Player Variable" documentation.
  
  

Script Setup Information

Each script file, although it uses its own extension, is a plain text file. It is best to work with these files in a fixed-width font viewer, such as Windows' "Notepad". If the file becomes too large, there are other free viewers, such as "Crimson Editor", which is much more powerful and much less resource-intensive. A wide variety of viewers for non-Windows systems are also available from various sources.

The basic format of the script files is very simple. Each line consists of a "Header String" and a "Data String". The header string is NOT interpreted in any way by the program; it is ignored, and is simply used as reference. It can contain any text that describes what is required on that particular line, or even no text at all, but it is generally best to use the text given in the documentation for each script type. The end of the Header String, and the beginning of the Data String is referenced by a colon (:). The colon must not ever be used at any time for any reason other than signifying the start of a Data String. The end of a Data String is signified by an enter keypress. No data is interpreted beyond that point, as the program then disregards everything else until it finds another colon. As an example, an entry in a script file may look like this:

Header String: Data String
Num Of Sound Effects: 32

In the example, the string "Num Of Sound Effects" is ignored entirely, and is used only to tell the person reading the script that the data supplied is used by the program to determine the number of sound effects to be loaded. The Data String will either be regarded as a Text String or a Number Value, which is determined during the processing of the script. Each script type documentation states exactly what data is expected in each part of each script. It is very important to follow the format exactly, because if the format is broken, the program will not be able to recover, and will either act inappropriately, or crash.

The semicolon (;) is used throughout many of the scripts to signify a comment. The script parser will stop interpreting a line if a semicolon is met.

While all other aspects of a script use only the colon (:) as a line identifier, Functions use a few others to identify certain parts of the function itself, which are detailed in their own documentation


Image Setup Information

Image files used to store image data for use in E02 can be any size as long as height and width are both even, but must be 256-color PCX "Version 5", or 256-color RLE-compressed or uncompressed TGA. If the images aren't saved in one of these formats, they will be interpreted wrong, and the data taken will either appear as garbage or cause a crash.

E02 graphics are 256-color palettized, and so, the display colors of graphics loaded from image files depend on the palette settings within E02 at the time they are displayed. The full in-game palette is broken into two parts-

"Level Palette"

This area is controlled by settings in a Tile File, and set up using the Level Ripper and/or the Tile Editor. There are three possible size settings-



	64		One palette section (0-63) is controlled by Tile File data. "Water" overlay is allowed (palette indexes 128-255 are reserved as mirrors of 0-127, modified by the "water color"). Indexes 64-127 are left for the "Global Palette".
	128		Two palette sections (0-63, 128-191) are controlled by Tile File data. "Water" overlay is not allowed. Indexes 64-127 and 192-255 are left for the "Global Palette".
	192		Three palette sections (0-63, 128-191, 129-255) are controlled by Tile File data. "Water" overlay is not allowed. Indexes 64-127 are left for the "Global Palette".


There may be one or more of these palettes stored in a single Tile File, which may be set as the active palette by the Func_Switch_Palette Script Command. Each of these palettes may also contain data to animate/cycle colors both within and between each index, which may be set up using the Palette Animation area of the Palette Editor.

When a Tile File is loaded, that file's "Palette 0" becomes E02's active Level Palette.


"Global Palette"

This area's size is determined by the current "Level Palette" setting, as described above. The colors are loaded from either "globpal.pcx" or "globpal.tga" in the current game's "Art" folder. If the "Art" folder doesn't exist, or neither of these files exist, the file is loaded from E02's "Default/Art" folder. If both a PCX and a TGA file exist, the PCX file will be used. The colors are read from the same indexes of the image file's palette at which they will be used in E02 (64-127, 128-191, 192-255).

Indexes 64-127 will remain the same throughout gameplay, unless modified manually. Indexes 128-255 will be overwritten if a Level Palete of size 64 or 192 is activated.

Both tiles and sprites may use either area of the palette, and either area may be manipulated by the Func_Set_Palette_Range command. If, after that command has been used to modify the palette, the original colors need to be restored, the Func_Switch_Palette and Func_Restore_Global_Palette commands may be used.

Palette entry 0 is reserved for "transparancy", meaning that any area of any graphic that is drawn with that index will not actually be drawn to the screen, and anything that was drawn to the screen before will show through. This entry is also the "Backdrop Color". This is the color that the screen will be filled with if a Backdrop Object was spawned.


Sound and Music Setup Information

E02 uses uncompressed WAV format for sound effects. It will recognize sounds of any frequency, 8- or 16-bit, and stereo or mono, but they will be converted to 8-bit mono durong load. WAV files of similar type may also be loaded as music, as well as XM files with up to 16 channels. XM support is based on the XM standard - special extensions to the format added by various tracker programs are not supported.



Complete Documents Listing
(in alphabetical order)

• Animation.html
• Built-in Objects.html
• Character Def.html
• Command Line.html
• Font Def.html
• Font File.html
• Functions.html
• /Funcs
  • Animation.html
  • Files.html
  • Function Control.html
  • General.html
  • HotSpot.html
  • /If
    • Collision.html
    • Flags.html
    • General.html
    • Variables.html
  • Level Control.html
  • /Math
    • AbsValue.html
    • Add.html
    • AND.html
    • Array.html
    • Divide.html
    • Equal.html
    • Flags.html
    • Modulus.html
    • Multiply.html
    • Negate.html
    • OR.html
    • Power.html
    • Shift.html
    • Subtract.html
    • Vector.html
    • XOR.html
  • Objects.html
  • Palette.html
  • Players.html
  • Random.html
  • Sound.html
  • Status Objects.html
  • Switch.html
  • Table.html
  • While.html
• Game Def.html
• Game Listing File.html
• Game Objects.html
• Game Variables.html
• Getting Started.html
• KeyMap.html
• KeyTable.html
• Levels.html
• Level Editor.html
• Level Looping.html
• Level Ripper.html
• Music Def.html
• Object Collisions.html
• Object Debug Drawing.html
• Object Debug Placement.html
• Object Def.html
• Object Drawers.html
• Object Editor.html
• Object Movers.html
• Object Projectile Collisions.html
• Object Variables.html
• Player Management.html
• Player Variables.html
• ReadMe.html
• Sound Effect Def.html
• Sprite Editor.html
• Sprites.html
• Status Script.html
• Table Def.html
• Table File.html
• Tile Editor.html
• Tile Selector.html
• What's New.html
• XM.html
• Zone Def.html