IRE Developer's Information
Author: jpm

# IRE

IT-HE Roleplaying Game Engine

## Developer Documentation

version 0.6 -11/8/1999

Made with Netscape Composer, DRDOS, Win 3.1, and Win95 when necessary
Written by Joseph P Morris
Proofread by Alan P Keane
(C) 1999 Joseph P Morris
Any trademarks in this document are the property of their respective owners.
This is free software and as such there is no warranty whatsoever. Use at your own risk..

Update history:

0.5.03 - 11/08/99 - Corrected a critical error in the documentation

> - add_quantity and take_quantity had the last 2 parameters the WRONG WAY AROUND: this would cause a crash.

0.5.02 - 23/07/99 - Documented some forgotten functions

> - Documented forgotten function object_set_behaviour
> - Documented new conversation functions [goto] (5.3.2) and [set_behaviour] (5.4.1)
> - Documented new features in flat.gam resource file (chapter 6)

0.5.01 - 22/06/99 - Final checks for R 0.5

> - Documented forgotten functions transfer_to_pocket, force_from_pocket
> - Documented forgotton functions choose_member and choose_leader
> - Documented new function get_number

0.5.0 - 05/6/99 - Release 0.50, totally new conversation engine

> - Inserted a new chapter 5: programming conversations (with the new script system)
> - Updated 1.4.1 so it is not obsolete anymore
> - Updated 3.2.3 to add new flags and keywords
> - Documented new Section:Rooftiles in 3.2.9
> - Added new variables game_minute, game_hour, game_day, game_month, game_year
> - Added undocumented functions transfer_object, get_first_object
> - Added new functions replace_object,move_forward, move_backward, turn_l, turn_r
> - Added new functions add_quantity, take_quantity, wait_for_animation, lightning
> - Added new functions find_object_with_tag, find_container
> - Added new functions get_pflag, set_pflag, get_user_flag, set_user_flag, get_yn
> - Updated screenshots of editor.
> - Added section 2.2.9 - setting an object's owner
> - Added section 2.2.10 - editing an object's statistics
> - Added section 2.2.11 - editing an object's behaviour

0.4.1 - 28/3/99 - Release 0.41, VRM system changed to SeeR

> - Mentioned the graphical script editor in section 3.1.
> - Updated the description of VRMs and how they are compiled in section 4.1
> - Added new description of how you must use flags since 0.041
> - Added new VRM functions get_flag and set_flag, see above

0.4.0 - 18/1/99 - Release 0.4, rewrite of core map system

> - Removed sections 2.2.8 to 2.2.10, about obsolete features of the editor.
> - Added new section 2.2.8, about editing objects inside containers
> - Added new VRM functions redraw_map, line_of_sight, move_to_top and in_pocket
> - Updated create_object and get_top_object, get_best_object etc.
> - Added new vrm function move_object which you must use instead of modifying the X and Y coordinates
> - Added new functions spill_contents and spill_contents_at
> - Added new flags etc to section 3.2.3 and 4.2.4
> - Added NODRIFT command to Section: Sound in section 3.2.7
> - Added Section 3.2.7 and 3.2.8 to the index (oops)
> - Added Part 5, about the .GAM file
> - Described partially-solid objects in section 3.2.3

0.3.1 - 5/9/98

> - Added section 2.1.4, about cut and paste
> - Added section 2.1.5, about the tile randomiser
> - Added section 2.1.6, about bulk replace
> - Added two new .cel files to section 1.4.1
> - set_darkness changed to a single level instead of RGB levels

0.3.0 - 15/6/98

> - Fixed some typos.
> - Added 'light' and 'enemy' to section 4.2.4
> - Added new function 'set_darkness' to section 4.3.4

0.2.8 - 15/6/98

> - Added new function 'delay' to section 4.3.2
> - Added new function 'start_song' to section 4.3.2
> - Updated entry for 'stop_song' in section 4.3.2

0.2.7 - 11/6/98

> - Added new function 'rnd' to section 4.3.2
> - Added new function 'restart' to section 4.3.4

0.2.6 - 10/6/98

> - Added the 'ifHurt' parameter to section 3.2.3
> - Fixed typo in the example of section 4.3.2
> - Added 'object->stats->oldhp' to section 4.2.4

0.2.5 - 9/6/98

> - Sections 1.4.4 and 1.4.5 are re-written because the music is now script-controlled.not loaded incrementally.
> - Added the overlay flag to section 3.2.2
> - Added the post_overlay flag to section 3.2.3
> - Added the wielded flag to section 3.2.3
> - Wrote about the ifDead parameter for objects in section 3.2.3
> - Added Section 3.2.7, about the new sound loaders
> - Added Section 3.2.8 about the new music loaders.
> - Added the new system variable 'victim' to section 4.2.4
> - Described new function set_object_sequence in section 4.3.1
> - Described new printxy function in section 4.3.2

0.2.4 - 21/5/98

> - Wrote about the automatic object placement in section 2.2.8 and 3.2.3
> - How to put objects into containers. Section 2.2.10

0.2.3 - 20/5/98

- Updated screenshots of the editor to latest version.
- Forgot a number of vital things in the pascal-c chart.
- Update tag documentation in the editor.
- Added TRANSLUCENT flag to section 3.2.3 and 4.2.4

0.2.2 - 15/5/98

- Added CONTAINER flag to section 3.2.3 and 4.2.4
- Added is_solid to section 4.3.1
- weight_object is now called weigh_object. This was a typo in the documentation.

Contents

Part 1 : Introduction

> 1.1 What is the IRE?
> 1.2 What do I need to edit the IRE?
> 1.3 File formats

> > 1.3.1 - Graphics
> > 1.3.2 - Sounds
> > 1.3.3 - Music

> 1.4 Where the files should be stored

> > 1.4.1 - RES
> > 1.4.2 - RES\BACKINGS
> > 1.4.3 - RES\CODE
> > 1.4.4 - RES\MUSIC
> > 1.4.5 - RES\SOUND
> > 1.4.6 - RES\SPRITES

> 1.5 How the program searches for files

Part 2 : The IRE map editor

> 2.1 Backgrounds

> > 2.1.1 getting familiar with the editor
> > 2.1.2 placing tiles on the map
> > 2.1.3 selecting tiles
> > 2.1.4 cut and paste
> > 2.1.5 Randomising tiles
> > 2.1.6 Bulk Replacing

> 2.2 Sprites

> > 2.2.1 The editor in sprites mode
> > 2.2.2 Creating sprites
> > 2.2.3 Moving sprites
> > 2.2.4 Changing sprites
> > 2.2.5 Setting the direction
> > 2.2.6 Deleting sprites
> > 2.2.7 Tagging Objects
> > 2.2.8 Editing Containers
> > 2.2.9 Setting a character's individual name
> > 2.2.10 Editing an object's individual statistics
> > 2.2.11 Editing an object's individual behaviour

> 2.3 Rooftops

> > 2.3.1 The editor in rooftops mode
> > 2.3.2 Editing rooftops

Part 3 : The IRE script file

> 3.1 What is the script file and what does it do?
> 3.2 Script file sections

> > 3.2.1 Section: Sprites
> > 3.2.2 Section: Sequences
> > 3.2.3 Section: Characters
> > 3.2.4 Section: Descriptions
> > 3.2.5 Section: Code
> > 3.2.6 Section: Tiles
> > 3.2.7 Section: Sounds
> > 3.2.8 Section: Music
> > 3.2.9 Section: Rooftiles

Part 4 : The IRE VRM system

> 4.1 What are VRM files?

> > 4.1.1 The VRM concept
> > 4.1.2 How VRMs are made
> > 4.1.3 A VRM tutorial
> > 4.1.4 Rules for writing VRMs
> > 4.1.5 How the example works
> > 4.1.6 Data Types

> 4.2 The OBJECT

> > 4.2.1 Introducing the OBJECT
> > 4.2.2 Creating an OBJECT from scratch
> > 4.2.3 Modifying OBJECTs
> > 4.2.4 OBJECT Reference guide
> > 4.2.5 The TILE

> 4.3 Function Reference

> > 4.3.1 Object functions
> > 4.3.2 IO functions
> > 4.3.3 Flow control functions
> > 4.3.4 Miscellaneous functions

> 4.4 System Variables
> 4.5 Keyboard Macros

Part 5 : Programming Conversations

> 5.1 Overview
> 5.2 Page structure and simple commands

> > 5.2.1 Simple Linking
> > 5.2.2 Interactive Linking
> > 5.2.3 Images
> > 5.2.4 Setting the text colour
> > 5.3 Advanced conversations - Conditional branching

> > > 5.3.1 Checking for an object
> > > 5.3.2 Important tips
> > > 5.3.3 Checking for a party member
> > > 5.3.4 Using your own flags
> > > 5.3.5 Personal flags

> 5.4 Manipulating the game world

> > 5.4.1 Calling VRM functions
> > 5.4.2 Creating and destroying objects
> > 5.4.3 The theory of the conservation of money

Part 6 : Game description files

> 6.1 Crucial lines
> 6.2 The text console
> 6.3 Loading screen

Part 7 : Conclusion and Contact info

## Part 1 - Introduction

### 1.1 - What is the IRE?

In 1993 I got hold of a computer roleplaying game called Ultima 6. This game changed my life forever.
Previously I'd seen DCworld, an Ultima 5-type game editor. Ultima 6 was a whole new level above DCworld, like the difference between Wolfenstein and Doom.
When I buy new hardware, the bottom line is, will U6 work? No U6, no sale.

I spent the next few years in Ultima 6, hacking it, twisting it, folding it into new shapes.
I wrote a set of tools which hack the program, and allow you create new worlds, but there is a limit.
Ultima 6 has some pretty strange data structures which I never did figure out completely.

In '94 I started an abortive attempt to make a U6 clone, which was codenamed U6C. I couldn't draw a player and it bombed.

After the failure of Avios to run satisfactorily on the P200 I am using, despite intense optimisation, I decided to stop working on it, and turned instead to making a 'perfect' ultima 6 type game. This is what I have so far.

The IRE is a Computer Role-Playing Game which takes most of its ideas from Ultima 6, and some from Ultima 7.

The main difference between the design of U6 and IRE, is that IRE is designed from the ground up to allow someone to edit it. Ultima 6 was not designed this way.

### 1.2 - What will I need to edit the IRE?

There are many features you can edit, and you will need a variety of programs to edit each different part of the game.
Most editors are provided, but some you will have to acquire yourself.

First, we shall look at all the resources that the game can use.

Map files

The map file is the world in which the player inhabits. At present the engine can only support one map per game, although this will probably change later.

Font

The font is the character set used in the game. The characters are fixed-space 8x8 letters, and are stored in the raw bit-packed format used by Arthur Barr's font editor.

Script file

The script file is central to IRE. It is a description file that describes a game written using IRE.
It tells the program which sprites will be loaded, it binds the sprites into animation sequences and defines the behaviour of all characters and objects in the game.

The script file is described in detail in Chapter 3.

VRM files

Although the script coordinates everything, it is the VRM files which do the actual work.
VRMs (or Virtual Runnable Modules) are written in C (using my library functions) and get loaded into the game as it starts. Each game event is driven by a corresponding VRM.

VRM programming is described in detail in Chapter 4.

Internal graphics

Certain parts of the IRE system have their own sprites, such as the mouse pointer and the volume slider. These graphics are not controlled by the script file (although they might be later), and the program will attempt to load them itself. The internal graphics are 256-colour and stored in the Animator .CEL format. You can also use PCX if you prefer.
If you need to convert between CEL and another format, try using PICTVIEW by Jan Patera.

Sprites and tiles

Sprites and tiles are all defined in the script file, and are loaded in as the script is parsed.
They are stored in .CEL or .PCX format, and may have either 256 colours or 16.7 million.

Backing pictures

At present backing pictures are loaded in by the program, like the internal graphics of the mouse pointer and the volume slider. They must be in PCX format and either 640x400 in size, or 640x480.
They can be 8-bit or 24-bit PCX files.

Game package

Once you have a finished game and you are ready to distribute it, you can pack all the datafiles into one large resource file. IRE uses the .rar files from Eugene Roschal's fine archiver, RAR.
The files must NOT be compressed or the game will be unable to read them.
Set the compression method to STORE (ALT-M) in order to do this.

Summary

Property to edit | Recommended Editor | Comments
Map files | The IRE editor |
Font | Arthur's font editor (supplied) |
Script file | Any text editor | This is covered in part three
VRM files | SEERC is supplied to build them | This is covered in part four
Internal graphics | Autodesk Animator | You can use PICTVIEW by Jan Patera to convert graphics to CEL files
Sprites and Tiles | Any PCX editor |
Backing pictures | Any PCX editor |
Game package | The RAR archiver, shareware |

### 1.3 - File formats

The program uses a fairly narrow selection of file formats, so you may have to use some conversion software to get the data from your favourite package into IRE.

#### 1.3.1 - Graphics formats

The IRE uses two main graphics formats, .CEL and .PCX.
In future releases, all the loaders will be able to take either format, but at present, some will only take one or the other.

PCX files.

PCX files are straightforward, so any package that creates a .PCX should produce something readable by IRE.

Here are some known caveats:

The PCX files must be compressed using the runlength method. This is the standard, but if you do somehow manage to make an uncompressed PCX file, the program will likely choke on it.

The PCX files must be either 8-bit or 24-bit. 1,2,4 or 16-bit PCX files will be rejected and the program will stop with an error.

CEL files.

The .CEL files refer to Autodesk Animator .CEL files. This means Autodesk Animator, not Animator Pro. Animator Pro uses .FLI files and just calls them .CEL files.

If you try and load a .CEL file created by Animator Pro, IRE will go back to DOS with a panic message saying that the .CEL file you gave it "is not a .CEL file".

If you don't have the original Animator, use .PCX files instead of .CEL.

Alternatively, get RSE 2.00, a freeware program which is able to read and write .CEL files compatible with IRE.

Graphics sizes.

- For sprites, any size of PCX file will do.
- CEL files should not exceed 320x200. Files larger than this have not been tested, but might be achievable with PICTVIEW.
- The map tiles must be 32x32 in size, or very interesting things will start to happen.
- Backing pictures must be either 640x400 or 640x480, or the backing appears corrupted.

#### 1.3.2 - Sound formats

The IRE sound engine can load .WAV files produced by most applications.
The .WAV files can be 8 or 16 bit, and any frequency up to 44Khz is allowed.

Stereo .WAV files are not supported however.

I don't know if .WAV files can be compressed, but it they can, that won't work either.

#### 1.3.3 - Music formats

The IRE music player uses MOD files, a digital music system originating from the Commodore Amiga's somewhat creative sound circuits. Lack of any music chips at all gave rise to the .MOD file, a four-channel digital music system.

The IRE's sound engine can support the following types of .MOD file:

File name | Name | Channels | Comments
.MOD | Protracker module | 4 | Generic module format
.MTM | ? | 16 | More obscure format
.S3M | Screamtracker III | 32 | Popular module format
.STM | Screamtracker II | 4 | PC extension to the MOD format
.ULT | Ultratracker | 32 | Originated on the (late) GUS soundcard
.XM | Fastracker | 32 | Rival format to S3M Both FT1 and FT2 variants supported

Before you race off, remember that there is a maximum of 32 channels available to the sound engine.

If you use all 32 for the music there will be none left for the sound effects.

The amount of channels reserved for the music and sound is set in the game's config file, not the script file. By default it is 16+4, i.e. 20 channels in total.

### 1.4 - Where the files should go

It is important to understand how IRE looks for it's resources, so that you know where to put the new files.

Each IRE game will have a directory of its own, and it will look for the files in various subdirectories
in the tree.

By default, IRE will look in the RES directory, so we'll refer to as the RES directory in future.
(RES is shorthand for resources).

Note that it does not have to be RES, and you should call your directory something else when you develop an IRE game.
(It's controlled by your .GAM file, which is described in Part 7)

If you've followed the previous section, you should have some idea of the resources that each IRE game will use.

Unless the file is requested by the system itself, it can go anywhere you like, as the script file will contain the full path of each file.

Internal Graphics and the script file itself, must go in particular places, which will be described in detail later. Where you put the other resources is up to you.

The files are generally organised in this way:

1.4.1 - RES

The RES directory must contain the following files:

main.txt | The script file
arrow00.cel | The mouse pointer image
soundbar.cel | The volume slider backing image
slider1.cel | The slider that has been selected
slider2.cel | The slider that is not selected
font.dat | The typeface used in the game
eyesore.cel | Used by the editor for the 'Random Tile'
warning.cel | Shown if the Random Tile appears in the game
credits.dat | ANSI credits at end, like ENDOOM in Doom
help.txt | A conversation file that is run when F1 is pressed, see Part 5

1.4.2 - RES\BACKINGS

The RES\BACKINGS directory must contain the following file:

panel.pcx | The background image of the game status area

Additionally, I store the map tiles in this directory, but as each sprite's location is defined in the script file, this is just a matter of preference.

1.4.3 - RES\CODE

You need a place to store the VRM files used in the game, I called mine RES\CODE.
Again, the VRMs are defined in the script file, so you can put them anywhere you like,
RES\VRM might be another choice.

You could keep them on another drive, or even just in the RES\ directory, although that would be untidy.

1.4.4 - RES\MUSIC

You need a place to store the music files. I keep them in RES\MUSIC.
As of kernel version 0.025, the music is defined in the script file, so you can put them anywhere you like,
RES\MODS might be another choice.

You could keep them on another drive, or even just in the RES\ directory, although that would be untidy.

1.4.5 - RES\SOUND

You need a place to store the sound effects. I keep them in RES\SOUND.
As of kernel version 0.025, the music is defined in the script file, so you can put them anywhere you like,
RES\WAVS might be another choice.

1.4.6 - RES\SPRITES

You need a place to store the sprites used in the game, I called mine RES\SPRITES.
Again, the sprites and other game images are defined in the script file, so you can put them anywhere you like, maybe RES\OBJECTS.

### 1.5 - The search order

The search order is quite important.

When it tries to load a file, it will look for it in the following order:

1. In the IRE directory, e.g. C:\IRE\
2. In the RES directory, e.g. C:\IRE\RES\
3. In a specified .RAR file, e.g. RES.RAR

So, if a file is found in the IRE directory it will take precedence over a file found in either of the other two places.

NOTE: The map editor will ONLY load maps from the IRE directory, and not from the RES or RAR sources. All other files, the graphics and such can be loaded from other sources.

## Part 2 - The map editor

The IRE map consists of three layers:

A Background
Objects and characters
Rooftops

### 2.1 Editing the background

Backgrounds are made up of tiles, which are 32x32 in size.
These tiles are arranged in a huge grid, which makes up the map.

#### 2.1.1 - getting familiar with the editor

This is a screenshot of the editor in Background mode, we will refer to it as the editor is described.

First, look the main window. This is the map, as it will appear when the game is being played.
You can pan around the map using the cursor keys, or the four arrow buttons to the right of the window.

Also, note the two black panels on the far right-hand side of the screen.

They control the screen display, and allow you to switch off the other layers of the level if you find they get in the way while you are editing.

"SPRITES ON" means that the movable objects in the game, such as the player, other characters and similar things will be displayed. If you click once in the black area, it will read "SPRITES OFF" instead, and any sprites visible on the map will disappear while you are editing the backgrounds.

Similarly, "ROOFTOPS ON" means that the highest-level objects in the game, normally the roofs of buildings, will be displayed. If you click in the black area, it will change to "ROOFTOPS OFF". Rooftops are not displayed by default, as you are mainly going to edit the insides of buildings and that
is generally impossible with the roof in the way.

#### 2.1.2 Placing tiles on the map

At it's most simple, map editing consists of just clicking on the map, and drawing the tiles on it.

Looking to the right of the main map window, are two small squares, marked 'L' and 'R'.
This shows the currently selected tiles, which will appear when you click on the map.

The tile in the 'L' window is the tile that will appear if you click with the left button, and the 'R' tile is the tile that will appear if you click with the right mouse button.

This means that you can use the left mouse button to do most of your drawing, and set the right-button to a common sort of tile and use it to erase mistakes without having to select another tile from the list.

#### 2.1.3 Selecting tiles

Looking back at the editor screenshot, there is a bar at the bottom which contains all the tiles you can use in the map.

The bar has some buttons at either end, allowing you to scroll around the tiles, one at a time or at high speed, through the list of tiles.

To choose a tile, move the mouse over the bar, and click on the tile you want, with the mouse button you wish to contain this tile.

For example, if you click on a wall with the left button, the wall will appear on the 'L' box, and drawing with the left button will draw walls.

Now, you can doodle around on the map with that particular tile.

Adding new kinds of tile is dealt with in Chapter 3.

#### 2.1.4 Prefabs

Support for prefabricated parts is not fully implemented at this stage, so if you use the buttons they work like cut-and-paste.
Clicking on 'Get Prefab' will copy the current screenful of tiles into a 'clipboard', and 'Put Prefab' will put the contents of the clipboard onto the screen.

When it is completed, the Prefab system will support hundreds of clipboards that are stored to disk so you can create a library of commonly-used map sections.

#### 2.1.5 Randomising tiles

Introduced in IRE 0.3, is support for randomising sections of the map, for instance to make grass that does not repeat.

To achieve this, do the following:

1. Click on the 'Random Tile' button at the bottom of the screen. This looks hideous to remind you that the tiles are still on the map.

2. Draw the 'Random Tile' over the section you want to be randomised. If it's a fairly large area, you can use the 'Clear L' or 'Clear R' buttons to fill the screen with the current tile.

3. Now, choose the tiles that you want it to pick from. These must be grouped together on the tile bar: you cannot choose from different tiles scattered everywhere.

4. To do this, Left-Click on the first tile in the group, and Right-Click on the last tile in the group.

(For example, with the grass, left-click on the first tile, and right-click on the seventh), the editor will pick tiles between these two.

5. Click on the Randomise button. All the yellow tiles will be replaced with a selection from the group you chose in step 4.

#### 2.1.6 Bulk Replace

Suppose you wanted to turn all the grass in the map into something else. You can 'reverse' the action of the randomiser above, in a similar manner.

1. Choose the group of tiles that you want to isolate, for example the grass. Like Step 4 in the Randomiser, you must use the Left and Right buttons to choose the first and last tile to be replaced.

2. Click on 'Replace Tiles', and all the tiles in the group you've selected will turn into the Random Tiles!

3. Now you can use the randomiser to turn them into mud or whatever you fancy.

### 2.2 - Editing Sprites

#### 2.2.1 - The editor in Sprites mode

This is a screenshot of the editor in Sprite mode. There are some subtle differences between Background and Sprite mode, so we will look at each item again.

First, look the main window. This is still the map, but note that the character has a white box around him. This is because the player has been selected, and he is the object being edited.

Now, look again at the two black panels on the far right-hand side of the screen.

"ROOFTOPS OFF" has not changed at all, but "SPRITES ON" has changed to "EXCLUDE OFF".

This switch still controls the display of the sprites, but now it will switch off most of the sprites if it is enabled, instead of the whole lot.
Specifically, "EXCLUDE ON" will display only the currently selected object, i.e. the one with the white box. It is used for situations when the other objects get in the way of the one you are positioning.

#### 2.2.2 - Creating a new sprite

To create a new sprite, click on the button marked 'New Item'.

When you do this, a box will appear, showing you a list of all the objects in the game, and displaying a picture of each one.

When you've found the one you want, using the cursor keys to scroll, press ENTER and the object will appear in the middle of the screen.

The object will be highlighted with the white selection box, and you can drag it to the proper place.

To create copies of this object quickly, you can press INS (or INSERT) on the keyboard, and a copy of the object will appear wherever the mouse pointer is on the map. If the mouse pointer is not over the map, no object will be created.

The INS method creates a copy of the selected object. If no object is selected, it will pop up the creation list and the object will appear in the centre of the screen, like 'New Item'.

Individual Names

An object can have its own special name, for example 'Kenny McKormick', which is used when you talk to the person, among other things.

Below the map is the panel marked 'Individual Name:'. You can click on this to enter the object's individual name.

#### 2.2.3 - Selecting and moving objects

To select an object, just left-click on it, and it should become highlighted.
If another object has already been selected first, left-click on an empty space to clear the selection first.

You can move objects by dragging them around the map with the left button, or, you can instantly move an object (without dragging) by right-clicking where you want the object to go. This is often useful if the selected object is off-screen.

#### 2.2.4 - Changing an object's direction

Looking at the screenshot again, there is a second set of arrow-buttons in the middle of the screen, on the right hand side.

When an object is selected, one of these arrows should be depressed.
This is the direction in which the object is facing.

For example, the player can face in any of the four directions. To make the player face left, select the player and click on the left arrow button.
The player should now face left.

Many simple objects only have one direction, in which case the arrow buttons will have no effect. Doors and windows usually have two directions, Up/down for the horizontal position, and Left/Right for the vertical position.

The directions an object has are defined in the script file.

#### 2.2.5 - Changing the object's type

At some stage you will decide that you want to change one object into another.
You can do this by selecting the object, and then clicking on the 'Edit Item' button, (or pressing ENTER).

This will pop up the creation list again, and the object will change to the new type. (By default, it will highlight the type of object it was before in the menu.)

#### 2.2.6 - Deleting an object

To delete and object first select it, and then click on 'Delete Item', or press the 'DEL' key if you prefer.

There will be no warning before the sprite is removed, so take care.

#### 2.2.7 - Tagging objects

On the bottom right hand side of the screen are three buttons, 'Find Tag', an entry box and 'Next Free Tag'.

The entry box is used to assign a control value to certain objects.

What the object does will depend on the script assigned to it in the main script file, but it will often be necessary to mark certain objects with a tag.

One of the main uses of tags will be locked doors.
A door can be open, shut, or locked shut.
There will also be a key to lock or unlock the door.

In these cases, the key and the door must both have the same Tag number for the key to fit the door.

Click on the number in the black entry box to enter a different tag number.

The button marked 'find tag' will ask you for a number, and then search all the objects in the game to find one with the appropriate tag number. It will not be able to show the object if it is inside a container.

The button marked 'Next free tag' will find the first tag number which does not exist in the game.

#### 2.2.8 - Containers

In release 0.4 it is now possible to edit containers.
(Some objects, such as bottles, will contain objects inside as soon as they are created. These are determined by the script file.)

Container editing is done using the new 'Edit Pockets' button.
First, select the object you wish to modify. When it is highlighted, you can click on 'Edit Pockets', which will display a list of the objects which are in the container. You should see this:

There are currently four things you can do with containers:

1. Create a new object inside a container
2. Delete an object inside a container
3. Move an object out of a container
4. Bring an outside object into the container.

Creating and Removing objects

'Create object' is the button used to create an object. Clicking on this will bring up the familiar creation menu.

To remove an object, first click on the object you want to remove in the list. It will turn red, indicating that it has been selected.
Then click on 'Remove object' and the chosen object will disappear.

Moving Objects out of the container.

First, highlight the object you want to move out of the container.
Then click on 'Move Outside' and the object will disappear from the list. When you leave the pocket editing window, you will
find the object on top of the container.

Bringing Objects in to the container.

First, get out of the pocket editor.
Select the container, and place it ON TOP of the object you want to be inside the container.
Now, making sure the object is highlighted, click on 'Edit Pockets', and choose 'Bring Inside'.
Press 'Y' to continue and the object will be there.

CAVEAT: It is not currently possible to edit the properties of an object while it is inside a container. If you wish to adjust the direction or tag number of an object in a container, you will have to move it out of the container first.

#### 2.2.9 - Setting an object's owner

In release 0.5 objects can now have owners, who get angry if their object is stolen.
In order for this to work, you must specify who owns the object.

At the bottom of the panel is a field marked 'Object is property of:'.
If you click on this while an object is selected, you will be asked to click on the person who owns the object.

Here is the screen you will see:

TYou can pan around the map to find the person who owns it, and click on them. They will be highlighted red when an object they own has been selected.

Alternatively you can choose the person from a list (of all objects which are marked as 'Person' and have an individual name).

If you decide that the object should be public property, you can click on 'Make Public Property'.

#### 2.2.10 - Changing an object's statistics

In release 0.5 it is now possible to change the statistics of a single object without using the scriptfile.
This allows you to create special variations of an object by giving it individual properties.
It also allows you to specify the number of objects in a pile if you have a group item, such as a heap of coins.

This is done using the 'Statistics' button.

First, select the object you wish to modify. When it is highlighted, you can click on 'Statistics', which will display the properties you can edit. You should see this:

This should be self-explanatory.

2.2.11 - Changing an object's behavior

In release 0.5 you can also change the way an individual object interacts with the rest of the world, by giving it its own unique set of functions.

This is done using the 'Behaviour' button.

First, select the object you wish to modify. When it is highlighted, you can click on 'Behaviour', which will display the properties you can edit. You should see this:

Each of the boxes (except Speech File) is a VRM function which is called when the event happens. You can choose this from a list.

Speech File is the only one which is not a VRM file: instead you enter the path to the file containing the conversation.
In the current release, there is no list of files. However the program will check if the filename you have entered is correct, and warn you if it does not exist.

### 2.3 - Editing Rooftops

#### 2.3.1 - The editor in Rooftop mode

This is a screenshot of the editor in Rooftop mode.
As you can see, the editor is exactly the same as for Background Tiles, so familiarise yourself with the Background editor first.

#### 2.3.2 - Editing rooftops

Rooftops are similar in concept to Background tiles, except that background tiles will interact with sprites.

Rooftops are completely separate and are for decorative purposes only.

As the name implies, Rooftops are special tiles that are drawn above everything else in the game. They are not always drawn, and the rooftop layer can be shown or removed at will by VRM scripts. By default, they will be removed if the player is underneath a tile.

At the bottom of the screen is the set of tiles that can be used. These are defined in the script file.
Each tile is a single frame, and it may or may not cause the roof to disappear when the player is underneath it.
(You don't want this to happen when the player is standing outside the building and the roof is overhanging.)

Basically you just click and paint the roof tiles. The first tile in the list is blank and can be used to erase bits of roof.

## Part 3 - The Script File

### 3.1 - What is the script file and what does it do?

Although you can use the default objects and their behaviours to good effect, as a 'super-ultima-6' engine, you will at some stage want to add your own graphics and objects to the game.

To do this you must go into the main script file.
You can either do this manually, or you can use the graphical Script editor, SCRIPTER.
Scripter is not documented yet, but if you read this chapter and then play around with it, it should be easy enough to pick up.

The IRE script file is a description file that describes a game written using
IRE. It tells the program which sprites will be loaded, it binds the sprites
into animation sequences and defines the behaviour of characters in the game.

The script file is parsed by the game (and the editor) as it starts up, and any errors it detects will be reported at this stage, with a red and green error report (except in Linux and BeOS which are black-and-white).

If you intend to start playing around with script files, It is a good idea to print this document out for reference.

Here are some rules for writing script files:

- The script file consists of several sections.
- Each section starts with the statement 'SECTION: sprites' for example. The colon is necessary.
- # is used as a comment. Anything following a # will be ignored.
- The compiler will often IGNORE anything it does not understand.
- The case of the letters in the script file does not matter. For instance, 'WORD' is the same as 'word'.
- Spaces, whitespace and commas are all treated as spaces, and will appear as a single space in the error dumps. Comments will not appear in the error dump.

### 3.2 - Script file sections

Let's look at each section in turn.

#### 3.2.1 - Section: sprites

The sprites section is used to declare sprites that will be used in the game.
All moving images and map tiles that appear in the game must be declared here.

The sprites section is basically a list consisting of the following form:

    SECTION: sprites

`name filename`
`name2 filename2`
`name3 filename3`

'name' is the title of the sprite. Every time you want to refer to this image,
you should call it by this name.

'filename' is the file containing the image. Images are stored as autodesk animator .CEL files, or .PCX files.

The list will continue until the next section is reached.

EXAMPLE:

> `SECTION: sprites`

> > `left_frame sprites\left01.cel`
> > `left_frame2 sprites\left02.cel`
> > `left_frame3 sprites\left03.cel`

> > `right_frame sprites\right01.cel`
> > `right_frame2 sprites\right02.cel`
> > `right_frame3 sprites\right03.cel`

> > `up_frame sprites\up01.cel`
> > `up_frame2 sprites\up02.cel`
> > `up_frame3 sprites\up03.cel`

> > `down_frame sprites\down01.cel`
> > `down_frame2 sprites\down02.cel`
> > `down_frame3 sprites\down03.cel`

#### 3.2.2 - Section: sequences

The sequences section is used to declare all animation sequences.
Any animation, character or object that appears in the game must have its
animation declared here.

There are two ways to declare sequences, the 'traditional' way, and the Quick
way.

Traditionally, sequences are declared like this:

`SECTION: sequences`

> `name sequence_name`
> `<options>`
> `framelist:`
> `frame1`
> `frame2`
> `...`
> `END`

'name'
NAME is the title of this animation. Every time you want to refer to this animation, (in other parts of the script, or the Rooftops editor) you will use this name.

'framelist:'
FRAMELIST: marks the start of the list of frames. All frames in the list are entries in the SPRITES section.

'END'
END marks the end of the list of frames.
I.E, everything between framelist: and END will be treated as a frame, and the program will try to find it in the sprite list.

<options>
You don't literally type '<options>'. Instead, this is the part where you can specify some flags to control the animation.

The following flags are understood by the game:

pingpong | This makes the animation play backwards when it finishes. E.g. frame 1, frame 2, frame 3, frame 2, frame 1
loops | This will make the animation repeat endlessly.
stepped | This makes the animation play only after each turn of the game, rather than continuously.
overlay <sprite> | This will make the specified sprite appear on top of the animation. The overlay will be a single frame, not a real animation. For example, the blood on the dead player is an overlay.

'LOOPED' or 'LOOP' can be used as alternatives to 'LOOPS'.

Quick sequences

Although the sequence declarations are OK for most things, it is over-long for simple sequences which only need one frame. For example, map tiles will usually consist of a single frame, and the above declaration is overkill.

To speed this up, I added a quicker, easier way to define simple sequences
for map tiles and other single-frame entities.

These are called QuickNames, and they are a one-line sequence definition.

Suppose you wanted to declare this sequence:

> `name GrassTile`
> `framelist:`
> `grasstile00`
> `END`

Using a QuickName to declare the tile, it would be done this way:

> quickname GrassTile grasstile00

..which is a lot simpler (though much less flexible).

For reference only, it can be noted that the actual declaration of a QuickName
consists of three words.

1. quickname | Start the declaration
2. sequence_name | Identifying name of the sequence being created
3. sprite_name | A sprite from the SPRITES: section

EXAMPLES:

`SECTION: sequences`

`name MoveLeft`
`framelist:`
`left_frame`
`left_frame2`
`left_frame3`
`END`

`name Moveright`
`framelist:`
`right_frame`
`right_frame2`
`right_frame3`
`END`

`name Moveup`
`framelist:`
`up_frame`
`up_frame2`
`up_frame3`
`END`

`name Movedown`
`framelist:`
`down_frame`
`down_frame2`
`down_frame3`
`END`

`name Dead_Guy`
`overlay blood`
`framelist:`
`dead_guy`
`END`

`quickname First_Tile tile_frame_1`
`quickname Second_Tile tile_frame_2`

#### 3.2.3 - Section: Characters

The characters section is probably the most complex section in the script.
It is used to define characters that exist in the game. The editor refers to characters as 'Sprites'. There must be at least one character (the player).

Characters are defined in this way:

> `SECTION: characters`

> > `name charname`
> > `hp 99`
> > `dexterity 99`
> > `weight 99`
> > `damage 99`
> > `description "You see a Thing."`
> > `short "Thing"`

> > `ifDead thing_is_destroyed`
> > `ifUsed thing_is_used`
> > `ifTriggered thing_is_stood_on`
> > `solid`
> > `fixed`

> > `up up_sequence`
> > `down down_sequence`
> > `left left_sequence`
> > `right right_sequence`

'name'
NAME is the description of the character. It is used in the editor, and in VRM files, if a new object is to be created. Name is required.

'hp'
HP is the initial health of the character. If it is not present, the health is assumed to be 100. It has a maximum value of 2 billion health points. If it drops below 0, the object dies. If it drops below -10000 the object is vapourised!

'dexterity'
DEXTERITY is not yet used. It has a maximum value of 2 billion.

'strength'
STRENGTH is used to determine how many objects this character can carry. It is only useful if this really is a character. Strength is implemented in the character's VRM file, not by the actual game itself. It has a maximum value of 2 billion.

'intelligence'
INTELLIGENCE is not yet used, but it will be used by VRM code to do something later on. It has a maximum value of 2 billion.

'weight'
WEIGHT is used in conjunction with Strength. In my default files, a character of strength 30 can carry a total of 30 weight points. Weight is used by the function 'weight_total', in VRM files. It has a maximum value of 2 billion.

'damage'
DAMAGE is used in my VRM files as the amount of damage that the object will do if it is used as a weapon.
In the case of the player or another person, damage is the amount of damage caused by his or her fists. It has a maximum value of 2 billion.

'light'
LIGHT is the amount of light the object casts, it can be either 0, 1 or -1.
0 means it casts no light at all, 1 means it casts light and -1 means it casts darkness instead of light.

'description'
DESCRIPTION is a text description of the object which is displayed when you Look at it. If no description is supplied, the game will say 'you see nothing of interest.'. (This can be modified, looking is done through VRM files).

Descriptions can be done in two ways. Either you specify the text of the description in quotes, or you can put the name of an entry from the Description section.

'short'
SHORT is usually a single-word text description of the object which is displayed when you USE, GET or DROP it. If no description is supplied, the game will say 'no description'. Watch out for this message when testing your game.

'ifUsed'
IFUSED will call a VRM function if the player Uses the object.
The parameter will be a VRM in the Code section.

'ifTriggered'
IFUSED will call a VRM function if the player steps on the object.
The parameter will be a VRM in the Code section.
NOTE! current_object will point to the object that was stood on, and victim will point to the player, or whoever trod on it.

'ifDead' (also 'ifKilled')
IFDEAD will call a VRM function if the object is destroyed. This happens when the health reaches 0.
The parameter will be a VRM in the Code section. If no VRM is specified, nothing will happen until it reaches -10000 when it will disappear and anything in it's pocket will be emptied out on the spot where it stood.

'ifHurt' (also 'ifDamaged')
IFHURT will call a VRM function if the object takes damage. (That is, if the health at the end of the turn is less than it was at the start of the turn).
The parameter will be a VRM in the Code section. If no VRM is specified, nothing will happen.
I use it in my demo to make the people shout when they are hit, and to make the bombs explode in a chain reaction.

'ifLookedAt' (also 'iflook', 'iflooked')
IFLOOKEDAT will call a VRM function when the player looks at the object. This can be used for things like bottles, or allowing the player to know what's in a container without opening it. Or, it could be used to make a Basilisk...
The parameter will be a VRM in the Code section. If no VRM is specified, nothing will happen.

'onInit'
ONINIT will call a VRM function when the object is first created. It has not been tested.

'behaviour' (also 'behavior')
BEHAVIOUR will call a VRM function every turn of the game loop. This is used to make the player work as well as
any other object that moves of it's own accord.
The parameter will be a VRM in the Code section. If no VRM is specified, nothing will happen.

'Conversation'
This is the conversation file that the game will run if the player talks to this object. It is NOT a VRM file, it is an interpreted text file. I keep mine in RES\PEOPLE.
See Part 5 to learn about writing conversations.

'contains'
This is an object which the person will be carrying when they are created (either in the editor or at run-time). For example 'contains knife' will mean that the person will be created with a 'knife', which is another object in the scriptfile.
You can have up to 8 'contains object' lines per character.

'resurrect_as'
If an object is dead, it can be resurrected unless otherwise stated.
Normally the object will change form when it is killed, and will return to its original form when resurrected.
However, you can use 'resurrect_as object' to make the object come back as something else.
NOTE: resurrect_as has only been lightly tested and may not work.

'no_resurrect'
A flag to prevent the object from being able to be resurrected.

'solid'
SOLID is a flag that means this object will be solid and the player cannot walk through it.

'blockslight'
BLOCKSLIGHT is a flag that means this object will block light created by a nearby light source.

'fixed'
FIXED is a flag that means this object is nailed to the ground and the player cannot pick it up. It also prevents the object from being pushed, or even moving by itself.
NOTE! When any object enters a container it will become fixed (to prevent it from trying to move about) and will stop being fixed when it leaves the pocket.

'tabletop'
TABLETOP is a flag that means this object is solid and cannot be walked upon, but objects can be pushed and dropped on top if it.

'invisible'
INVISIBLE is a flag that means this object can only be seen in the editor, not in the game itself. (Useful for tripwires etc)

'container'
CONTAINER is a flag that means that things can be dropped into this object and move into its pocket in the game. (In the map editor, you can move objects into anything.)

'translucent'
TRANSLUCENT is a flag that means this will be drawn using the new translucency code.
You will be able to see other things through the object.

'post_overlay'
POST_OVERLAY. If the current object's sequence has an overlay attached, the overlay will be drawn ABOVE all other sprites. The object will appear below the roof, however.
It is used in the demo to make the door appear above anything else, and also in the chairs, to make the back appear above the player. If the object has no overlay, the flag will have no effect.
NOTE: There can be up to 255 objects which do this onscreen at once. If this limit is exceeded, the rest will not be drawn.

'wielded'
WIELDED is a flag that is used by my default VRMs. If it is set, the object can be wielded as a weapon or shield etc.
Wielded is not used by the engine at all.

'fragile'
FRAGILE is a flag that is used by my default VRMs. If it is set, the object will break if thrown too far.
Fragile is not used by the engine at all.

'SpikeProof'
SPIKEPROOF is a flag that prevents this object from setting off any Triggers.
NOTE: Spikeproof objects cannot be dropped into a container either.

'Person'
PERSON is a flag that is used to determine if an object is intelligent or not. It will also apply to animals and monsters.
At present it is only used in one place: If it is set, the object won't be able to walk onto a tabletop.

'Quantity'
QUANTITY is a flag that means that a single object can actually be a group of objects, like a pile of gold coins.
For example: 'Look at gold coins: You see 1000 gold coins.'
The actual quantity of objects will be set by the map editor, or by VRM code, if the object is created at run-time.

Directions.
The next few entries will be the character's movement frames.
To use these, you must specify the direction, then the animation which is played when the character goes in this direction. The animation will be an entry from the SEQUENCES section.
The following directions are supported internally and MUST be defined:

> up
> down
> left
> right

Partially-Solid Objects

You really want to use the graphical editor for this one!

If you have a large object, you might not want all of it to be solid.
For example, the doors. The door consists of two halves, the door and the adjacent wall. The player must be able to walk through only ONE part of the door.

In order to control this, you need to specify two things: The size of the solid part, and the offset from the top-left hand corner. Because the door can either be horizontal or vertical, we must specify both axes separately.

The vertical door has a width and height of 1x2, but the solid area is just 1x1. And it doesn't start at 0,0 anymore, but 0,1.
So, we have a 1x1 solid area at 0,1.

Here is a helpful diagram:

And here's one for the Horizontal:

You would specify this in the character's description using the SETSOLID command.

SETSOLID has five parameters, the axis, (V or H) the offset (+x,+y) and the size of the solid area (+w,+h)

For the vertical door, which has an offset of 0,1 and a solid area of 1x1 the command is:

SETSOLID V 0 1 1 1

The horizontal door is 2x1, and the solid area is again, 1x1. But it is at an offset of 0,0.
So the command for this is:

SETSOLID H 0 0 1 1

If setsolid is not used for a large object, the game will assume the entire object is solid.

If you don't follow, take a look at the examples in the main.txt file and use the graphical editor instead.

Active Areas

Active areas are just the same as partially-solid objects, but the areas which are not covered do not interact with the game at all,
so looking at that square or using it will have no effect.

These are specified using:

SETACTIVEAREA (axis) (x offset) (y offset) (width) (height)

If no active area is specified, it will assume the entire object is active.
See Partially-solid objects, above.

#### 3.2.4 - Section: Descriptions

Descriptions are not used in the graphical Script Editor! In fact, they will be removed entirely from the script file when it is saved.
But this doesn't matter, since it was just to make life easier before the editor was written :-)
If you don't want to use the editor (why not?), read on....

Descriptions were briefly mentioned in the above section. They are a way of defining a set of commonly-used text strings for descriptions in characters and tiles.
They will be used especially in tiles, as there will be a lot of tiles which need the same description.

Like the Sprites section, the Descriptions section is just a list.

Each entry is in the form:

LABEL String

Where LABEL is a unique identifier for the description, which will be used in the Characters section.
String is just the text of the description, no quotes.

For example:

SECTION: Descriptions

> `grass You see some lush green grass`
> `stonewall You see a thick stone wall`
> `player Hi, Mom!`

#### 3.2.5 - Section: Code

Like the Sprites and Description sections, Code is just a list.

Each entry is a function that is contained in a .VRM file. VRM files are kept in the subdirectory CODE by default, but this just a matter of preference.

Example:

SECTION: CODE

> `mainproc code\mainproc.vrm`
> `follower code\follower.vrm`
> `schedule code\schedule.vrm`

> `player code\player.vrm`
> `opendoor code\opendoor.vrm`
> `closedoor code\closedor.vrm`

The first three code entries are special and must be supplied.
MAINPROC is called once when the game begins. You can set up things at this stage. If you don't need to do this, you can just have an empty function in the file.

FOLLOWER is called each turn of the game, if you have any followers in the game. Followers are created when someone joins your party, and their behaviour is set to call this function each time they move. A reasonable default behaviour is to centre on the player, using a simple tracking algorithm.

SCHEDULE is called each turn of the game. For this reason, it must take up as little time as possible! It can be used to simulate multitasking but most people will use it to run time-based functions. The demo uses it to make the player come out of the acid trips after a certain number of turns.

#### 3.2.6 - Section: tiles

ATTENTION! The current version of the graphical script editor does NOT handle tiles yet!
You will need to read this bit...

The tiles section is used to declare all map tiles that can be used in the game.

Map tiles are declared in a 3 or 4 line declaration like this:

SECTION: tiles

> `name grass`
> `sequence grass_sequence`
> `description "You see some lush green grass"`
> `solid`

'name'
NAME is the title of this tile. It is used by the compiler to tell where each entry begins. The name is not usually used by the game except possibly for debugging.

'sequence'
SEQUENCE is the animation sequence that is used whenever the tile is displayed. Mostly it will be a single-frame animation sequence defined using quickname, but for other things, such as water, it can be a full animating sequence. The name you put here must be in the Sequences section.

'description'
DESCRIPTION is a text description of the object which is displayed when you Look at it. If no description is supplied, the game will say 'you see nothing of interest.'.
Descriptions can be done in two ways. Either you specify the text of the description in quotes, or you can put the name of an entry from the Description section.

'solid'
SOLID is optional. If it is present, the tile will be impassible, like a wall. If it is not present, the player and any NPCs in the game
will be able to move through it.

'blockslight'
BLOCKSLIGHT is optional. If it is present, the tile will block light from a nearby lightsource.

#### 3.2.7 - Section: Sounds

SOUNDS is nearly just a list. Since 0.04, it can also have an optional parameter, NODRIFT.
If NODRIFT is going to be used, it must be the third entry on the line.
It locks the sound to it's original frequency. If NODRIFT is omitted, the sound will be played at a random pitch, close to the original frequency.

Each entry is the name of a sound that is contained in a .WAV file. WAV files are kept in the subdirectory SOUND by default, but this just a matter of preference.

Example:

SECTION: SOUNDS

> ouch sound\ouch.wav NODRIFT # Ouch is always played at a fixed pitch
> close_door sound\closdoor.wav # Close_Door will not necessarily be played at original pitch.

The name will be used in VRM code to play a sound file.
E.g. play_sound("ouch");

#### 3.2.8 - Section: Music

Like the Sounds section, Music is just a list.

Each entry is the name of a song that is contained in a .MOD or .S3M file. The files are kept in the subdirectory MUSIC by default, but this just a matter of preference.
For a full list of the sound formats supported, see section 1.4.?

Example:

SECTION: MUSIC

> intro music\intro.mod
> theme music\theme.xm

The name will be used in VRM code to play a song file.
E.g. play_song("intro");

#### 3.2.9 - Section: rooftiles

ATTENTION! The current version of the graphical script editor does NOT handle tiles yet!
You will need to read this bit...

The rooftiles section is used to declare all tiles that can be used to make a roof.
There can be up to 255. The first one is automatically created by the system (it is blank).

Roof tiles are declared in a completely different manner to anything else.
It is just a list of of files, with a single optional flag, and no name.

The order is important: this is the order they will be presented in the editor, and it cannot be changed without affecting the map.

`SECTION: rooftiles`

> `root/tile1.cel`
> `roof/tile2.cel`
> `roof/tile3.cel stand_under`
> `roof/tile4.cel`
> `roof/tile5.cel stand_under`

By default, the tiles will cause the roof to disappear if the player is standing underneath one.
However, sometimes you can have tiles which overhang the side of the roof, especially on the left and top sides of the building.
In this case you don't want them to disappear if the player is there. For these tiles, add the flag 'stand_under' to the end of the line.

## Part 4 - The VRM System

### 4.1 - What are VRMs?

#### 4.1.1 - The VRM concept

VRMs, or Virtual Runnable Modules, are a system of interpreted files, containing the code necessary to cause events that happen in the game.

In Quake, by Id Software, every event that happens in the game is written in a small chunk of script language, called Quake-C, which is compiled into bytecode and parsed by the game.

IRE uses this same approach.
Each game event is written in C, and compiled using a compiler called SEERC. The compiled code is a .VRM file, which is loaded into the game as it starts up.

#### 4.1.2 - How VRMs are made

The programming is done in C, but you can easily pick it up if you know PASCAL or some dialects of BASIC.
The differences between these languages is very slight, conceptually, but they use different symbols and have varying degrees of 'strictness'.

Of course, it's better if you do have a basic grasp of C.

VRMS are written using my special library of functions, for convenience and for security. You cannot use any other functions than are in this library. A VRM, once compiled, will run on any platform.

However it's a good idea to include the source code for the VRMs, in case the VRM binary format ever changes.

To make a VRM, you must first produce a source file using your favourite text editor, and save it with a .CPP file extension, somewhere inside the res/code directory

Then you type BUILD from the res/code directory, and the system will look for and compile any VRMs that have changed.
You should now have a .VRM file corresponding to the .CPP file you just wrote!

If any errors occurred, you will get some warning messages during compilation.
Any warnings are considered BAD. You might have a .VRM file out the other end, but it probably won't work until all the warnings are gone.

Now, if the script file has an entry for OBJECTS.CPP, and if there is a call to the VRM, you will see the VRM work!

I think it's time for a quick tutorial now.

#### 4.1.3 - A tutorial of a simple VRM

In this tutorial, we'll see how to use most of the information in the guide so far, to create a simple object.

First, go into you chosen paint package, and draw a straight line, or something that looks like a sewing needle.

Save it to RES\SPRITES\needle.PCX (or .CEL)

Next, edit main.txt in the RES\ directory.

Look for SECTION: Sprites
Go to the end of the list, and add a new entry:

        Needle    SPRITES\needle.pcx

(Or, needle.cel, depending on what format you used)

Now, go to SECTION: Sequences
Go to the end of the sequence list, and add a new entry:

        quickname    Needle    Needle

Now, go to SECTION: Characters
Got to the end of the character section, and add a new entry:

`name Needle`
`up Needle`
`down Needle`
`left Needle`
`right Needle`
`weight 3`
`description "You see a sharp sewing needle"`
`ifUsed NeedleCode`

Now, there is one last entry to make to the script file.
Go to SECTION: Code, and add the new entry:

        NeedleCode    CODE\needle.vrm

Now, we should be ready to make the VRM.

Go into the RES\CODE directory, and create a new file, called NEEDLE.CPP.
The file should read as follows:

`// Needle - a sample VRM. This line is a comment, by the way.`
`#include "vrm.hpp"`
`PROC`

`print("Ouch!\n");`

`ENDPROC`
`// Stop typing..`

Now, quit from the editor, and type..

> BUILD

..on the command line. If you typed it correctly, it should chunter for a bit, and you will have a nice NEEDLE.VRM file.

Now, go back to the main IRE directory, and run the editor.

> ED -edit test1

Go into Sprites mode, and you should be able to create a needle.
Place it somewhere near the player, so you can find it easily.

Now, run the game! Find the needle, use it, and the player should be able to prick their thumb on the needle.

#### 4.1.4 - Basic rules for writing VRMs

Now we've made a VRM and compiled it, we'll take a look at how it works.
But first, know the basic rules of VRM-writing.

These are the ground rules. Venerate them and Obey them in All Things.

1. You must have the line #include "vrm.hpp" before the code starts.
2. You must have the lines PROC and ENDPROC, and your code must go between them.
3. Single-line comments begin with // and the rest of that line is ignored.
4. Multi-line comments start with /* and everything is ignored until */
5. When defining variables you should stick to letters and the underbar _ symbol.
6. You can't have spaces in the names of variables.
7. You can have numbers ONLY if there is a letter or an _ in front of the number.
8. C is case-sensitive, so 'CHAR' is not the same as 'char'
9. Blocks start and end with '{' and '}' respectively.

C is like pascal, but the conventions and symbols used are highly abbreviated, and look very strange at first sight.

Simple Pascal to C conversion guide...

PASCAL | C | DESCRIPTION
BEGIN | { | Start a block of code
END | } | End a block of code
(* | /* | Start a comment
*) | */ | End a comment
if a = b then | if (a == b) | If A and B are equal
a AND b | (a && b) | logical AND in an IF statement
a OR b | (a || b) | logical OR in an IF statement
a XOR b | (a ^^ b) | logical XOR in an IF statement
if NOT a then | if (!a) | if a is not true (i.e. a is zero)
a := b; | a = b; | let a = b

#### 4.1.5 - How does the example code work?

Now, with the ground rules in your head, or printed out, let's look at the code line-by-line...

        // Needle - a sample VRM.  This line is a comment, by the way.

        #include "vrm.hpp"

        PROC

            print("Ouch!\n");

        ENDPROC

        // Stop typing..

The first line is just a comment. It is ignored.

The next line, '#include "vrm.hpp"' is needed to set up the compiler.
Don't worry about it, just remember to put it there.

Then we have the PROC line. This tells the compiler that the module is here,
and everything after it will be compiled up until the ENDPROC line.
(It's actually a #define macro to simplify the process of setting up a VRM function)

Now we have the actual code.

print("Ouch!\n");

This will print a string in the standard C way, which might be a bit of a shock to PASCAL or BASIC programmers.

I'll go into detail later, but basically, it prints the text out on the console.
The '\n' at the end is a special code, meaning end-of-line, and the next string or number to be printed will appear on the line below.

After that, we have the ENDPROC line, which tells the compiler that this is the end of the procedure.

And finally we have another comment.

#### 4.1.6 - Data types

The following data types can be used to declare your variables.

C data types. All C data types are supported, but these are the most useful ones:
STRING is a special addition of mine, it maps onto 'char *'

NAME | TYPE | DESCRIPTION
char | a single letter | Can also be a number from -128 to 127
unsigned char | same as char | This is a number from 0 to 255
short | number | A number from -32768 to 32767
unsigned short | number | A number from 0 to 65535
int | number | A number from -2147483647 to 2147483648
unsigned int | number | A number from 0 to 4294967296
char * | text string | A fixed length text string

Notes for advanced users:

- Do not use LONG! It will change to a 64-bit quantity later but has been disabled for now.
- LONG LONG is not supported either.
- Floating point support is not tested, so use it only if you know what you're doing.
- Never try something stupid like adding two strings together.. it won't work!

An example of declaring variables, and assigning values to them.
This has no apparent effect whatsoever, but it demonstrates the logic involved.

`PROC`

> `char character;`
> `short number;`
> `STRING str;`

> `character = 'a';`
> `character = 120; // Pascal goes apeshit if you try to do this.. ..but this is not pascal.`

> `number = 3;`
> `number = 1 + 2;`

> `string = "This is a string";`

`ENDPROC`

### 4.2 - The OBJECT

#### 4.2.1 - Introducing the OBJECT

In addition to the traditional int and char, there is also.. OBJECT!

OBJECT is a pointer to a Thing that appears in the game, that is, a Sprite in the editor, and a Character in the script file.

Each OBJECT is a group of ints, chars and other gubbins that makes up an object in the game.

If you know C, then you'll know what I mean when I say that it is a pointer to a structure, and each member of the OBJECT is accessed using object->member notation. If you don't know C that well, then just do as I say and it will be fine :-)

#### 4.2.2 - Creating an object from scratch

You won't often need to do this, but here goes...

Normally, an OBJECT is declared as follows:

> OBJECT *myobject;

However, you must note that 'myobject' is not yet there!
It exists, but it is 'empty', and the game will exit prematurely if you try to use it at this point.

To actually create the object, you will need to call my function, create_object.
You must have some idea of which object to create at this point.

To create a needle from the tutorial, you would use the code:

> OBJECT *new_needle;
> new_needle = create_object("needle",10,10);

and lo, a needle will appear at coordinates 10,10 on the map.

When using create_object, the name you specify is a name in 'Section: Characters'. If you try to create an object that is not in the section: characters list, the game will exit and display the following error:

...where 'OBJECTPANEL' is the name of the object that it tried to create.

Now, creating objects is extremely useful, but mostly you will be modifying existing objects that are internal to the game.

#### 4.2.3 - Modifying objects

Each OBJECT is a collection of all the properties that the game character has. The character's position, their health, even their appearance and behaviour can all be controlled by fiddling around with the properties of the character's OBJECT.

The object which you are going to spend a lot of time fiddling around with is the player.
The player has a special variable you can use, so you don't have to hunt for them. This is called, surprisingly, player.

I'll use the player to demonstrate the parts you can modify. If you look in vrm.hpp, you will see there are others. But you don't want to mess with those.

Each part of an object is addressed using the form object->part. This may sound confusing, but an example should help.
To set the player's health to 100, you would say:

player->stats->hp = 100;

Where 'player' is the object being modified, and 'stats->hp' is the amount of health, the part of the player we are changing.

#### 4.2.4 - Object reference guide

You can look at and modify the following parts of an object safely:

object->stats->hp | number | The object's health. When this is 0, the object dies, or is destroyed
object->stats->str | number | The object's strength
object->stats->intel | number | The object's intelligence
object->stats->weight | number | The object's weight
object->stats->damage | number | The amount of damage the object can do as a weapon.
object->stats->quantity | number | Quantity of objects in a group or pile, for example 1000 gold coins.
object->tag | number | Unique ID number for events, like the unique ID of a key for a door.
object->light | -1, 0, 1 | If 1 or more, the object emits a circular light pattern of fixed intensity. If -1 or less, the object emits a circular pattern of DARKNESS. Future releases will support varying intensity and patterns.

In addition, there is also object->user[0] through to object->user[9], which is a group of 10 variables set aside for VRM writers to use how they want :-)

The following parts of an object you can look at, but you should not modify unless you know what you're doing.:

Member | Type | Description
object->name | string | The name of the object. Same string as used in create_object(name)
object->desc | string | The description you see when you look at it.
object->personalname | string | The individual name of the object, set in the map editor, or NULL for none.
object->w | number | width of the object in pixels
object->h | number | height of the object in pixels
object->mw | number | width of the object in map squares
object->mh | number | height of the object in map squares
object->curdir | number | Direction the object is facing. 0 = up, 1 = down, 2 = left, 3 = right
object->pocket | OBJECT * | The first entry in a list of objects inside this object's pocket. For bags etc..
object->wield[..] | OBJECT *[ ] | An array of objects that the character is wielding. wield[0] to wield[7] You can wield weapons by modifying this, but don't do anything silly.
object->stats->oldhp | number | The object's health points at the start of the turn. Modifying this may disrupt the operation of 'ifHurt', see section 3.2.3.
object->stats->pFlags | number | Conversation flags specific to this object. You should not use this directly, use get_pflag and set_pflag instead.
object->enemy | OBJECT * | This object is the NPC's enemy, they may relieve their stress on this object.
object->owner | OBJECT * | This is the object which the current object belongs to. If you steal it when they are looking, they will beat the hell out of you. NULL if public property.
object->next | OBJECT * | This is the next object in the map square that the object is in. The objects afterwards will appear above it.

### Warning: Unavoidable Changes in 0.041 Since release 0.041, you can not use the traditional method of getting at the flags! If you try to, the VRM will not compile. You must now use get_flag and set_flag instead! Unavoidable Changes in 0.040 Since release 0.04, you must NEVER modify the object's X and Y positions, or the game will bomb out. Use move_object wherever you want to move an object around the map.

There are three objects that have special purposes..

player

We have already looked at player. Player always points to the object you are currently controlling, whether it is the player themselves, or a follower who you have switched control to.

current_object

This is the 'current object'. Many VRMs are designed to perform a certain action on an object, such as moving it, opening it, closing etc. When the VRM code starts running, current_object will have been set to the object you are supposed to modify.

From the IRE demo, here is an example:

> PROC

> > change_object(current_object,"StoneDoor1_Open");
> > play_sound(0);

> ENDPROC

When you go up to the door and USE it, the game sets current_object to point to the door you are opening.
Then, the VRM that opens the door calls change_object() to change the current object (the door) into an open door.
Then it plays the door opening sound, (which is stolen from the VERGE project, the recently-revived and neat-looking rival to IRE)

victim

Victim is used by the IsTriggered mechanism described in section 3.2.3.
When the VRM code starts running, current_object will have been set to the object that is being triggered, and victim will be the object you are supposed to modify.

From the IRE demo, here is an example:

> PROC

> > victim->stats->hp -= current_object->stats->damage;

> ENDPROC

When you tread on The Death, it becomes the current_object. You become the victim.
The VRM will therefore deduct a certain amount of health from the victim.
(In the demo, The Death does 10000 damage points, slaying you instantly)

#### 4.2.5 - The TILE

TILES are similar to objects, but they deal with the fixed tiles that make up the map.

The only way you will ever see the TILES, is when you use the function get_tile(x,y), which returns the TILE at that position on the map.

The TILE will be declared as, for example, TILE *tilepointer;

You can never create or destroy tiles.

Here is a list of the members of a TILE what you should know about:

Member | Type | Description
tile->name | string | The name of the object. Same string as used in create_object(name)
tile->desc | string | The description you see when you look at the tile

### 4.3 - Functions Reference

When programming VRMs, you will use my functions. You have no choice :-)
They shield all the nasty stuff like creating objects, traversing the lists and shit from you, the VRM developer.
(Of course, if you want to see the nasty stuff, or make your own functions, look in the source code)

This is a list of all the functions currently supported by the engine....

#### 4.3.1 - Object functions

set_flag (new in 0.041)

Format: void set_flag(OBJECT *object, FLAG_TYPE, int ONE_OR_ZERO);

Description: Allows you to set a controlling flag in an object.

Input: The OBJECT which is to be modified, and the flag to change (See below for the list) and the new value it will take.

Flag | Description
IS_ON | If 1, the object is usable. If 0, it has been 'killed' and is not really there. Setting it to 1 again will bring he object 'back to life'.
IS_PARTY | Is the object a party member? If so, you can walk through it and swap places
IS_FIXED | Can the object be picked up, pushed around or move by itself? Fixed to the ground if 1. Objects automatically become fixed when put in a container, and un-fixed when they leave.
IS_SOLID | Can you walk over it or is it solid? Impassible if 1
IS_TABLETOP | If 1, you can drop objects on it, even though it is solid.
IS_CONTAINER | If 1, then you can drop other objects into it, and it will move them into its object->pocket list. Affects move_from_pocket
IS_TRANSLUCENT | If 1, the object is drawn semi-transparently. No other effects.
CAN_WIELD | If 1, the object can be wielded by the player (Not enforced by the engine)
IS_SPIKEPROOF | If 1, the object does not respond to triggers, and cannot be dropped in containers.
IS_FRAGILE | If 1, the object will break if thrown too far. (Not enforced by the engine)
IS_INVISIBLE | If 1, the object cannot be seen on the map and will not always interact.
IS_YOURS | If 1, the object is Your Property (Not enforced by the engine)
DOES_BLOCKLIGHT | If 1, the object will block light from a light source.
IS_PERSON | If 1, the object cannot walk onto a tabletop, other effects will come later too
SEEK_STATE | Reserved for moving NPCs
IS_QUANTITY | If 1, the object can be a group of objects. For example, one object could be a pile of 1000 gold coins, (which could be split into several piles of 250 gold coins or similar).

Returns: nothing.

Since IRE 0.041, you MUST use this function instead of accessing the flags directly.

Example:

> set_flag(player,IS_TRANSLUCENT,1);

get_flag (new in 0.041)

Format: int get_flag(OBJECT *object, FLAG_TYPE);

Description: Allows you to find out whether a controlling flag is set or not.

Input: The OBJECT which is to be modified, and the flag to change (See set_flag for the list)

Returns: 1 if the flag is set, or 0 if it isn't set.

Since IRE 0.041, you MUST use this function instead of accessing the flags directly.

Example:

> if( get_flag(player,IS_TRANSLUCENT))
> print("The player is high as a kite\n");

set_pflag (new in 0.05)

Format: void set_pflag(OBJECT *object, int flag_no, int ONE_OR_ZERO);

Description: Allows you to set a conversation flag in an object. See Part 5 for more detail about this.

Input: The OBJECT which is to be modified, and the flag to change (a number between 0 and 31) and the new value it will take.

Returns: nothing

Example:

> set_pflag(object,31,1); // Set flag 31 to be TRUE for this object

get_pflag (new in 0.05)

Format: int get_pflag(OBJECT *object, int flag_no);

Description: Allows you to examine a conversation flag in an object. See Part 5 for more detail about this.

Input: The OBJECT which is to be scrutinised, and the flag to examine (a number between 0 and 31).

Returns: 0 if the flag is false, or something else if it is true.

Example:

> if(get_pflag(object,2))
> {
> printf("He is angry and will not speak to you.\n");
> return;
> }

set_user_flag (new in 0.05)

Format: void set_user_flag(STRING flag_name, int ONE_OR_ZERO);

Description: Allows you to set a named conversation flag that is accessable throughout the game. If the named flag does not exist, a new one will be created with that name. See Part 5 for more detail about this.

Input: The flag to change (a string) and the new value it will take.

Returns: nothing

Example:

> set_user_flag("killed_the_king",1);

get_user_flag (new in 0.05)

Format: int get_user_flag(STRING flag_name);

Description: Allows you to examine a named conversation flag that is accessable throughout the game. If the named flag does not exist, it returns FALSE. See Part 5 for more detail about this.

Input: The flag to examine (a string)..

Returns: 1 if the flag is true, 0 if the flag is flase or does not exist yet.

Example:

> if(get_user_flag("killed_the_king"))
> printf("TREASON! HIGH TREASON!\n");

move_object (new in 0.04)

Format: int move_object(OBJECT *object, int x, int y);

Description: Moves the object around the map. If you modify the coordinates directly, the game will fall over.

Input: The OBJECT which is to be moved, and the new position it will occupy.

Returns: 1 if the move was successful, 0 if it was blocked by an obstruction.

Since IRE 0.04, you MUST use this function or risk calamity.

Example:

> move_object(player,player->x+1,player->y+1);

transfer_object (new in 0.04 but undocumented)

Format: void transfer_object(OBJECT *object, int x, int y);

Description: Moves the object around the map without checking. Can move through walls or on top of solid objects.

Input: The OBJECT which is to be moved, and the new position it will occupy.

Returns: Nothing. If it fails (unlikely) the game will abort with an error message.

See move_object above.

create_object

Format: OBJECT *create_object(STRING name, int x, int y);

Description: Creates a new object and adds it into the list of Things.

Input: A STRING with the name of the sprite to create, (from CHARACTERS), the coordinates where it will appear.

Returns: The newly-created object.

Since IRE 0.04, the X and Y coordinates must be specified.

Example:

> OBJECT *enemy;
> enemy = create_object("evil_dude",10,10);

remove_object

Format: remove_object(OBJECT *victim);

Description: Destroys an object and frees the resources it is using.

Input: The OBJECT to be removed.

Returns: nothing.

(pointless) Example:

> OBJECT *enemy;
> enemy = create_object("evil_dude");
> remove_object(enemy);

change_object

Format: change_object(OBJECT *object, STRING name);

Description: Changes an existing object into another type of object. Most of the statistics such as health, strength etc remain unchanged.

Input: The OBJECT you are going to change, A STRING with the name of the new object type, (from CHARACTERS).

Returns: nothing.

Example:

> OBJECT *enemy;
> enemy = create_object("evil_dude");
> change_object(enemy, "really_evil_dude");

replace_object (new in 0.05)

Format: replace_object(OBJECT *object, STRING name);

Description: Changes an existing object into another type of object completely, discarding all previous statistics and other info.
Input: The OBJECT you are going to change, A STRING with the name of the new object type, (from CHARACTERS).

Returns: nothing.

Example:

> OBJECT *enemy;
> enemy = create_object("evil_dude");
> replace_object(enemy, "pumpkin");

set_object_direction

Format: set_object_direction(OBJECT *object, long DIRECTION);

Description: Set the direction that the object is facing.

Input: The OBJECT you are going to change, A number 0-3, or preferably, one of the following macros:

> UP
> DOWN
> LEFT
> RIGHT

Returns: nothing.

Example:

> OBJECT *enemy;
> enemy = create_object("evil_dude");
> set_object_direction(enemy, UP); // Face upwards, (North)

set_object_sequence

Format: set_object_sequence(OBJECT *object, STRING sequence);

Description: This will change the appearance of the object, so that a special animation sequence is displayed instead, until the object moves. It has no physical effects on the object, only its appearance.

Input: The OBJECT you are going to change, A string, which must be one of the entries in SECTION: SEQUENCES from the script file.

Returns: nothing.

Example:

> OBJECT *enemy;
> enemy = create_object("evil_dude",10,10);
> if(enemy->user[0] == bored)
> set_object_sequence(enemy, "evil_dude_twiddling_thumbs");

set_object_behaviour

Format: set_object_behaviour(OBJECT *object, STRING new_vrm);

Description: Set the VRM function which will be called for this object each turn.

Input: The OBJECT you are going to change, A string, which must be one of the entries in SECTION: CODE from the script file, or else NULL. If the string is NULL, the object's behaviour will be deactivated and it will do nothing each turn.

Returns: nothing.

Example:

> OBJECT *enemy;
> enemy = create_object("evil_dude",10,10);
> if(enemy->user[0] == hungry)
> set_object_behaviour(enemy, "find_some_food");

get_object

Format: OBJECT * get_object(short x, short y);

Description: Looks at the map square X,Y, and returns the object in this position. If there are more than one object in this space, it will return the one on the top of the pile.

Input: The X and Y coordinates of the map square to be investigated.

Returns: The object it found, or NULL if nothing was found. MAKE SURE you check that this is not NULL, otherwise the game will crash out.

Example:

> OBJECT *it;
> it = get_object(100,100);
> if( it != NULL)
> print("We found something!");

get_top_object

Format: OBJECT * get_top_object(short x, short y);

get_top_object is obsolete. Please use get_object instead.

get_best_object

Format: OBJECT * get_best_object(short x, short y);

get_best_object is obsolete. Please use get_object instead.

get_first_object (new in 0.040 but undocumented)

Format: OBJECT * get_first_object(short x, short y);

Description: Looks at the map square X,Y, and returns the object in this position. If there are more than one object in this space, it will return the one at the bottom of the pile.

Input: The X and Y coordinates of the map square to be investigated.

Returns: The object it found, or NULL if nothing was found. MAKE SURE you check that this is not NULL, otherwise the game will crash out.

Example:

> OBJECT *it;
> it = get_first_object(100,100);
> if( it != NULL)
> print("We found something!");

find_object_with_tag (new in 0.05)

Format: OBJECT * find_object_with_tag(int tag, STRING name);

Description: Looks through the entire map and returns the first object of type 'name' with the matching tag, or NULL if none could be found..

Input: The tag number to search for, and an optional object type to search for, or NULL if any object will do.

Returns: The object it found, or NULL if nothing was found. MAKE SURE you check that this is not NULL, otherwise the game will crash out.

Examples:

> `OBJECT *it;`
> `it = find_object_with_tag(15,NULL); // any type of object will do`
> `if( it != NULL)`
> `print("We found something!");`

> `it = find_object_with_tag(15,"door"); // only a door will do`
> `if( it != NULL)`
> `print("We found a door!");`

find_container (new in 0.05)

Format: OBJECT * find_container(OBJECT *object);

Description: Looks through the entire map and returns the object that contains the specified object.

Input: The object which you want to find the container for.

Returns: The object it found, or NULL if nothing was found. MAKE SURE you check that this is not NULL, otherwise the game will crash out.

Example:

> `it = find_container(object);`
> `if( it != NULL)`
> `print("We found the container which has %s in it.",object->name);`

show_object

Format: show_object(OBJECT *object, int x,int y);

Description: Displays an OBJECT on the screen, without any relation to the map whatsoever. Used for status area and suchlike.

Input: The object to be projected, and the X and Y coordinates on the screen where the object will appear.

Returns: nothing.

Example:

> OBJECT *object = NULL; // Zero to begin with

> PROC

> if(object == NULL)

> > object = create_object("cursor");

> show_object(100,100,object);

> ENDPROC

object_is_called

Format: short object_is_called(OBJECT *object, STRING name);

Description: This returns a non-zero value if the NAME string is the same as the object's name. Returns 0 if no match.

Input: The object being tested, and the name we are looking for.

Returns: non-zero on a success, 0 on error..

Example:

> if( object_is_called(object,"door"))

> > print("it is a door");

move_to_pocket

Format: move_to_pocket(OBJECT *object, OBJECT *pocket);

Description: This moves OBJECT into the pocket of the object POCKET.
To preserve the integrity of the game, certain things are disallowed. You cannot move an object into its own pocket,
or pick up an object marked as a Person. If you need to do either of these, use transfer_to_pocket.
No checking is performed as regards weight!
move_to_pocket correctly handles grouped objects such as a pile of coins.

Input: The object to move, and the object which has the pocket we are interested in.

Returns: none.

Example:

> move_to_pocket(current_object,player);

transfer_to_pocket

Format: transfer_to_pocket(OBJECT *object, OBJECT *pocket);

Description: This moves OBJECT into the pocket of the object POCKET.
It can be used to move people, inclusding the player, into a container, which is illegal when using move_to_pocket.
Use with care, since the game will not work correctly if the player is incapacitated.
transfer_to_pocket correctly handles grouped objects such as a pile of coins.

Input: The object to move, and the object which has the pocket we are interested in.

Returns: none.

Example:

> transfer_to_pocket(player,vehicle);

move_from_pocket

Format: long move_from_pocket(OBJECT *object, OBJECT *pocket, short X, short Y);

Description: This moves OBJECT out of the pocket of the object POCKET, and put it on map square X,Y. If something else is in the way, it will return 0, allowing you to print 'blocked' or such.

Input: The object to move, object which has the pocket we are interested in, nd the X,Y of the place to drop it.

Returns: 0 if the operation failed, because there was something in the way. 1 on success.

Example:

> move_from_pocket(current_object,player,100,100);

force_from_pocket

Format: long force_from_pocket(OBJECT *object, OBJECT *pocket, short X, short Y);

Description: This moves OBJECT out of the pocket of the object POCKET, and put it on map square X,Y. It doesn't check to see whether the object can go into the square or not: it just does it.

Input: The object to move, object which has the pocket we are interested in, nd the X,Y of the place to drop it.

Returns: 0 if the operation failed, because the object didn't exist or the destination was outside the map. 1 on success.

Example:

> force_from_pocket(current_object,player,100,100);

weigh_object

Format: long weigh_object(OBJECT *object);

Description: Returns the total weight of an object, and all within it.

BUG: If you have a bag inside a bag, it will not sum the weight of the inner bag.

Input: The object to weight, and all objects within it.

Returns: Weight of the object and all who sail in her.

Example:

> if( weigh_object(player) > 5000)

> > printf("Sire! He is weighted down with loot!\n");

add_to_party

Format: long add_to_party(OBJECT *new_member);

Description: Adds a character to the party if possible.

Input: The OBJECT (preferably a character but doesn't have to be), which will be added to the party.

Returns: -1 if the operation failed, (too many in party) or the number of the new guy.

Example:

> OBJECT *brick;

> if(add_to_party(brick) < 0 )

> > print("The brick doesn't want to join because the party is too large\n");

choose_member

Format: int choose_member(int member);

Description: Makes the party member 'member' take control and become the player.

Input: The number of the party member who will become the player.

Returns: 0 if the member was not in the party or q if the operation succeeded.

Example:

> int brick_id;

> brick_id = add_to_party(brick);
> choose_member(brick);

choose_leader

Format: int choose_leader(int member);

Description: Makes the party member 'member' take control of the party. All other members will follow him or her.

Input: The number of the party member who will lead the party.

Returns: 0 if the member was not in the party or 1 if the operation succeeded.

Example:

> int brick_id;

> brick_id = add_to_party(brick);
> choose_member(brick);

is_solid

Format: int is_solid(int x; int y);

Description: Checks if the map square at x,y is clear of any obstructions.

Input: The x,y co-ordinates of the map square to examine.

Returns: 1 if there is an obstruction there, 0 if not.

Example:

> if( is_solid(100,100))

> > printf("Map square 100,100 is blocked\n");

in_pocket

Format: int in_pocket(OBJECT *obj);

Description: Scans the entire world, looking for this object. Returns 1 if the object is not where it thinks it is, which normally indicates the object is inside a container.
in_pocket will take a comparatively long time to do, so perform any quicker tests first when possible.

Input: The object to check out.

Returns: 1 if the object is inside a container, 0 if it is lying on the ground.

Example:

> if( in_pocket(player))

> > printf("Holy Gee, this is awful!\n");

line_of_sight (new in 0.041)

Format: int line_of_sight(int xa, int ya, int xb, int yb);

Description: This will draw an imaginary line between the two positions on the map.
If there is an obstruction, it will return 0. If there is a clear path between the points, it will return 1.

Input: The two sets of X,Y coordinates, which it will try to find a line-of-sight between.

Returns: 1 if there is a clear line of sight, 0 if there is an obstruction.

Example:

> if( line_of_sight(player->x,player->y,enemy->x,enemy->y))

> > printf("Time to die!\n");

move_to_top

Format: void move_to_top(OBJECT *object);

Description: This will move the object to the top of the pile for the square it is sitting on.
(It actually works by transferring the object to 0,0 and then back to the previous position, so it is now at the top of the heap).

Input: The object to adjust.

Returns: none.

Example:

> move_to_top(player);

spill_contents

Format: void spill_contents(OBJECT *object);

Description: Removes all the contents of a container, and puts them in a pile above it.

Input: The object to have its contents spilled.

Returns: none.

Example:

> spill_contents(chest);

spill_contents_at

Format: void spill_contents_at(OBJECT *object, int x, int y);

Description: Removes all the contents of a container, and puts them in a pile elsewhere.

Input: The object to have its contents spilled, the position where the spillage will occur.

Returns: none.

Example:

> spill_contents_at(chest,chest->x,chest->y+1);

move_forward (new in 0.05)

Format: int move_forward(OBJECT *object);

Description: Moves the object one step forward in the direction it is facing.

Input: The OBJECT which is to be moved.

Returns: 1 if the move was successful, 0 if it was blocked by an obstruction.

Example:

> move_forward(player);

move_backward (new in 0.05)

Format: int move_backward(OBJECT *object);

Description: Moves the object one step backward in the opposite direction to the one it is facing.

Input: The OBJECT which is to be moved.

Returns: 1 if the move was successful, 0 if it was blocked by an obstruction.

Example:

> move_backward(player);

turn_l (new in 0.05)

Format: int turn_l(OBJECT *object);

Description: Rotates the object 90 degrees anti-clockwise.

Input: The OBJECT which is to be rotated.

Returns: The direction the object is now facing.

Example:

> turn_l(player);

turn_r (new in 0.05)

Format: int turn_r(OBJECT *object);

Description: Rotates the object 90 degrees clockwise.

Input: The OBJECT which is to be rotated.

Returns: The direction the object is now facing.

Example:

> turn_r(player);

add_quantity (new in 0.05)

Format: void add_quantity(OBJECT *container, STRING type, int quantity);

Description: Creates a quantity of a single type of object and places them in another object's pockets.
If the object to be created has its QUANTITY flag set, a single object will be created and its quantity value set to the specified amount. If it does not have the QUANTITY flag, then the requested quantity will be the number of objects created.

Input: The container which will receive these objects, the type of object and the number of objects to create.

Returns: Nothing.

Example:

> printf("The pharoah showers you with gold!\n");
> add_quantity(player,"gold_coins",1000000);

take_quantity (new in 0.05)

Format: int take_quantity(OBJECT *container, STRING type, int quantity);

Description: Destroys a quantity of a single type of object from another object's pockets.
If the requested amount is not in the object's pockets it returns 0.

Input: The container which will lose these objects, the type of object and the number of objects to destroy.

Returns: 1 on success, 0 if there wasn't that many objects there.

Example:

> if(!take_quantity(player,"gold_coins",10000))
> printf("I'm sorry sir, you can't afford it.\n");

#### 4.3.2 - IO functions

print (and printf)

Format: print(STRING text, parameters....);

Description: prints some text on the console. Corresponds to printf in real C.

Input: A string, which may contain control codes, followed by zero or more parameters ..

Control codes:

Control code | Description
\n | Begin new line. Only \n at the end of the string will work correctly, \n in front will have odd results.
\\ | A slash, \ (Single slash is used to start a control code, like \n)
\" | A quote, " (the string is started by quotes. In BASIC you use """ , but in C is is \")
%d | A decimal number appears at this point. E.g. print("found %d things",100); prints 'found 100 things'
%c | A character appears at this point. E.g. print("[%c]",'a'); prints '[a]'
%s | A string appears at this point.
%% | A percentage, % (single % is used to print a parameter, like %d)

Returns: nothing.

Example:

> STRING str1="cow";
> STRING str2="moon";

> printf("This is a string\n");
> printf("%d + %d = %d\n",1,1,2);
> printf("The %s jumped over the %s\n",str1,str2);

Output:

This is a string
1 + 1 = 2
The cow jumped over the moon

printxy

Format: printxy(int x,int y, STRING text, parameters....);

Description: prints some text directlt on the screen, not to the console. The text will not appear until the next redraw.

Input: Two numbers, the X and Y coordinates where the text will appear. The TEXT and PARAMETERS are the same format as print, which is described above.

Returns: nothing.

Example:

> printxy(32,32,"Thiswill appear in the game window");

clear

Format: clear();

Description: clears all text from the game console..

Input: nothing.

Returns: nothing.

Example:

> print("You won't see this\n");
> clear();

play_song

Format: play_song(STRING song_name);

Description: Plays a song.

Input: The song name. This will be one of the entries in 'SECTION: MUSIC' of the script file.

Returns: nothing.

Example:

> play_song("intro");

play_sound

Format: play_sound(STRING sound_name);

Description: Plays a sound.

Input: The sound name. This will be one of the entries in 'SECTION: SOUNDS' of the script file.

Returns: nothing.

Example:

> play_sound("ouch");

stop_song

Format: stop_song();

Description: Dips the volume of the music to 0. Does not stop the actual playing of the music.
You must call start_song() afterwards.

Input: none.

Returns: nothing.

Example:

> stop_song();

start_song

Format: start_song();

Description: Resets the volume to it's original level, before stop_song() was called.
You must have called stop_song() beforehand, or it will have no effect.

Input: none.

Returns: nothing.

Example:

> start_song();

get_input

Format: get_input();

Description: Gets a fresh key from the user, and puts it into the system variable, key.

Input: none.

Returns: nothing.

Example:

> get_input();
> if (key == KEY_UP)

> > print("You pressed UP\n");

get_yn

Format: get_yn(STRING question);

Description: Prints a question (followed by 'are you sure?') and waits for the user to press Y or N.

Input: A string containing the question.

Returns: 1 if the user pressed Y, otherwise 0.

Example:

> if(get_yn("Commit suicide"))
> call_vrm("kill_player");

get_number

Format: get_number(int default);

Description: Prints the number given as a default, and allows the user to edit it.

Input: A number, which is the default if the user just presses Enter.

Returns: The new number, or 0 if the user pressed Escape.

Example:

> int num;
> printf("Enter a number:\n");
> num = get_number(100);
> printf("The user typed %d\n",num);

redraw

Format: redraw();

Description: Updates the entire screen display. This happens in the main loop anyway, but if your VRM has taken control, to choose a spell or something, you'll want to do this.

Input: none.

Returns: nothing.

Example:

> show_object(100,100,object); // Draw the object
> redraw(); // Update the display to make it appear immediately

redraw_map

Format: redraw_map();

Description: Updates the entire screen display, and redraws the map, recalculating the light levels too.
This happens in the main loop anyway, but if your VRM has taken control, to choose a spell or something, you'll want to do this.

Input: none.

Returns: nothing.

Example: (Fades the viewport to black)

> int ctr;
> for(ctr=0;ctr<255;ctr++)
> {
> set_darkness(ctr);
> redraw_map();
> waitfor(2);
> }

lightning (new in 0.05)

Format: lightning(duration);

Description: Flashes the screen blue-white for a number of game ticks. This number is in 35ths of a second and should be at least 2. It will not appear visible until the next update of the screen (e.g.,redraw_map).

Input: Length of the lightning flash in 1/35ths of a second.

Returns: nothing.

Example:

> lightning(2);

#### 4.3.3 - flow control functions

call_vrm

Format: call_vrm(STRING name);

Description: Calls another VRM, using the name from Section: CODE.

Input: The name of the VRM to call.

Returns: nothing.

Example:

> call_vrm("object_vrm");

#### 4.3.4 - miscellaneous functions

get_tile

Format: TILE * get_tile(short x, short y);

Description: Looks at the map square X,Y, and returns the TILE in this position. See 4.2.5 for more info.

Input: The X and Y coordinates of the map square to be investigated.

Returns: A pointer to the tile. Unless the coordinates were off the map, it will always return something.

Example:

> TILE *t;
> t = get_tile(100,100);
> print("The tile at 100,100 is described as.. '%s'\n",t->desc)

restart

Format: restart( );

Description: Reloads the map and sets everything back to it's default state.

Input: None.

Returns: None.

Example:

> if(everyone == dead)
> restart();

set_darkness

Format: set_darkness(int level);

Description: Sets the amount of darkness, 0-255.

Input: Amount of darkness to apply. 0 is daylight, and 255 is total blackness.

Returns: None.

Example:

> set_darkness(192); // Make everything quite dark, but not pitch black.

random

Format: int rnd(int max_number);

Description: rnd returns a random number from 0 up to the number you specify as the maximum, -1.
For example, rnd(3) will return either 0,1 or 2.

Input: The maximum number it should return, plus one.

Returns: The random number.

Example:

> int t;
> t = rnd(4);
> if(t == 0)
> print("It was a zero\n");
> if(t == 1)
> print("It was a one\n");
> if(t == 2)
> print("It was a two\n");
> if(t == 3)
> print("It was a three\n");

waitfor

Format: void waitfor(int time);

Description: waitfor waits for a number of time units, before execution is resumed.
Each time unit is 1/35 of a second (because IRE uses a 35Hz timebase).

For example, waitfor(35) will delay one second.
It does not stop the animation.

Input: The number of 1/35ths of a second to pause.

Returns: None.

Example:

> waitfor(35); // delay one second

wait_for_animation (new in 0.05)

Format: void wait_for_animation(OBJECT *obj);

Description: wait_for_animation waits for an object to finish animating before execution is resumed. It is useful for special effects or plot-critical scenes. It will return immediately if the object has an animation that loops.

Input: The object with the animation to wait on.

Returns: None.

Example:

> set_sequence(arch_villain,"arch_villain_dying");
> wait_for_animation(arch_villain);

#### 4.4 - System Variables

show_roof

show_roof is a CHAR.

show_roof can be set to either 1 or 0.
If show_roof is 1, the ROOFTOP layer is displayed and you cannot see inside buildings.
If show_roof is 0, the ROOFTOP layer is not displayed, and you see the insides of buildings.

storage

storage is an array of LONGs, which you can use to store things. Mainly they are used to communicate between VRMs.
STORAGE is always available at any point. There are up to 1024 elements in the storage array, and future releases will have more.

storage[0] is the first storage item, and storage[1023] is the last. NEVER use storage[1024] because it does not exist!

objectstore

objectstore is an array of unallocated OBJECTS, which you can use to store things. Mainly they are used to communicate between VRMs. For instance, objectstore[0] might point to the player. By using create_object you can add new objects
in the objectstore. The status areas in the demo work this way.

OBJECTSTORE is always available at any point. There are up to 128 elements in the storage array, and future releases will have more.

objectstore[0] is the first storage item, and objectstore[127] is the last. NEVER use objectstore[128] because it does not exist!

key

key is the current keypress. When the user presses a key, the value of the key they have pressed will end up here.
If you need to get a fresh keypress in a VRM, use the function get_input. Otherwise key will contain the last keypress from the main loop.

See also 4.5, the Keyboard List

current_object, victim

See section 4.2.4

game_minute, game_hour, game_day,game_month, game_year

These allow you to examine and control the current time in the game.
The game system follows earth time, with each turn taking one second, and so-on.

It differs from the earth calendar in that each month is always 30 days, although this may be customisable in future releases.

#### 4.5 - Keyboard Macros

Use these whenever you want to see if a key has been pressed.

Example:

> if( key == KEY_UP)

> > print("You pressed UP");

Function Keys

> KEY_F1
> KEY_F2 (Used by the system)
> KEY_F3 (Used by the system)
> KEY_F4
> KEY_F5
> KEY_F6
> KEY_F7
> KEY_F8
> KEY_F9
> KEY_F10 (Used by the system)
> KEY_F11
> KEY_F12

Numeric keyboard keys

> KEY_ESC
> KEY_1
> KEY_2
> KEY_3
> KEY_4
> KEY_5
> KEY_6
> KEY_7
> KEY_8
> KEY_9
> KEY_0

Main keyboard section

> KEY_TAB
> KEY_Q
> KEY_W
> KEY_E
> KEY_R
> KEY_T
> KEY_Y
> KEY_U
> KEY_I
> KEY_O
> KEY_P
> KEY_ENTER
> KEY_A
> KEY_S
> KEY_D
> KEY_F
> KEY_G
> KEY_H
> KEY_J
> KEY_K
> KEY_L
> KEY_Z
> KEY_X
> KEY_C
> KEY_V
> KEY_B
> KEY_N
> KEY_M
> KEY_COMMA
> KEY_DOT
> KEY_SPACE

Arrow Keys

> KEY_UP
> KEY_DOWN
> KEY_LEFT
> KEY_RIGHT

## Part 5 - Editing Conversations

### 5.1 Overview

Conversations in IRE 0.05 and above are made using a simple language a bit like HTML.
A conversation can be started in one of two ways:

1. The player Talks to an object or a person
2. A VRM routine calls the function talk_to(name,start)

When a conversation takes place, the game will load in the file containing the conversation and process it interactively like a web browser.

Conversations are based on pages. At the top of the page is an image, normally a portrait of the person you're talking to.
Below this is the text of the conversation, and at the bottom are the choices you get of what to say.
Each choice is a link to another page, or a link to "exit" which ends the conversation.

Commands can also be embedded into the page, which can create objects, remove objects, change flags, and call VRM functions.
You can also use commands to make different things happen depending on whether a flag is true or false.

More commands will be added in the future as necessary.

### 5.2 Page structure and simple commands

Like HTML, pages are defined as text files with commands.
All commands are enclosed in [brackets] and they may affect all text until the end of the line.

Each page has it's own title. When the conversation starts it will look for the page called 'Start', although it may also look for other pages too in future.

The page starts with the command:
[page="start"]

..and continues until the command:
[endpage]

Everything between these two commands will be displayed on the screen, unless it is another command.

The commands you will need to know to make simple conversations are:

[nextpage=""]
[link=""]
[linkto=""]
[image=""]
[colour="#xxxxxx"]

Important tips!

- Anything outside the [page=""] line and the [endpage] line, is ignored. You can put comments there.
- There is no fixed limit to the size of the conversation file, as long as it will fit in memory.
- If you put the word $PLAYER anywhere in the text, it will be replaced by the player's individual name.
- Similarly $CHARNAME will be replaced by the individual name of the character you're talking to.

5.2.1 Simple page linking

There are two ways to link pages. [nextpage=""] is the most simple, so I'll explain it first.

Here's an example:

[page="start"]

This is the first page.
Press a key for the second page...
[nextpage="page2"]
[endpage]

[page="page2"]

This is the second page!
Press a key to finish.
[nextpage="exit"]
[endpage]

This will display two lines:

`This is the first page.`
`Press a key for the second page...`

When you press a key, the page will change and read two more lines:

`This is the second page!`
`Press a key to finish.`

..and when you press a key the conversation will end.

The command [nextpage="page2"] makes the program wait for a key to be pressed, and then it looks for a page titled 'page2' and displays that.

The command [nextpage="exit"] makes the conversation finish when a key is pressed.

5.2.2 Interactive page linking

Now let's look at [link=""] and [linkto=""]

These two commands are used together to provide the choices at the bottom of the page.
[link=""] displays the message at the bottom, and [linkto=""] is the page that the link will take you to.
LINK must come first, and LINKTO just afterwards, otherwise it may fail.

Here's an example:

[page="start"]
You see a shifty-looking man in a trenchcoat.

"Pssst! Wanna buy some stuff?"

[link="What 'stuff' have you got?"]
[linkto="whatstuff"]
[link="No! Get lost!"]
[linkto="getlost"]
[endpage]

[page="whatstuff"]
"The usual contrabands..Mars bars.. M&Ms... Terry's chocolate oranges.."

[link="Not today man, the feds are everywhere"]
[linkto="nottoday"]
[link="You're off your rocker!"]
[linkto="getlost"]
[endpage]

[page="getlost"]
"Suit yerself.."

He walks away in a huff.
[nextpage="exit"]
[endpage]

[page="nottoday"]
"Wo! Thanks for the tip, man."

He looks both ways and slips off into the night.
[nextpage="exit"]
[endpage]

You should be able to work out what that does. If not, put it into a file and try it out.

You can have a maximum of 10 links per page (this will take a lot of screen room!).

5.2.3 Images

The portrait at the top of the screen is set using the [image=""] command.
You must put this as the first command after the [page=""] line.
The word in quotes is the title of a Sprite found in the "Section: sprites" part of the scriptfile, main.txt.
See chapter 3.2.1 of this document.

Here's an example:

[page="start"]
[image="greengrocer"]

You see a small greengrocer.

"Good day sir, how can I help you?"

:
:
:

[endpage]

You must specify a portait for each page. This allows you to change the character's expression from page to page.

You can also specify a background image if you don't like the blackness.
This is done with the following command:

[backing="filename.pcx"]

The game will not look in the Scriptfile for this image, it will be loaded directly from disk.

This is actually what happens if you press F1 for help in The Flat. It loads a conversation called "help.txt" which is in the FLAT/ directory, and this is what it does:

[page="start"]
[backing="backings/help1.pcx"]
[nextpage="exit"]
[endpage]

This feature is considered experimental.

5.2.4 Setting the text colour

You may wish to change the colour of text in the body of the conversation.
This is done using the [colour=""] command. (You may also use [color=""] if you prefer)
It works in the same way as HTML, except that it only lasts for the rest of the line.

The colour is in quotes, and it is specified with a # followed by six hex values, just like HTML.
The first two set the amount of red in the colour (00-ff), the second two set the amount of green (00-ff) and the last two the amount of blue in the colour (00-ff).

You can get little java applets and things to work out the colours, just look for a good page about web design.
Here are some of the most commonly-used colours:

red: #ff0000
green: #00ff00
blue: #0000ff
pink: #ff00ff
yellow: #ffff00
cyan: #00ffff
orange: #ff8000
grey: #808080

Black would be #000000, but you can't change the background colour yet, so this would be invisible.
White is #ffffff, but this is the default anyway.

Generally I use medium grey [colour="#808080"] for narration, and leave the rest of the text white.

Returning to the sweet-pusher as an example:

[page="start"]
[colour="#808080"]You see a shifty-looking man in a trenchcoat.

"Pssst! Wanna buy some stuff?"

[link="What 'stuff' have you got?"]
[linkto="whatstuff"]
[link="No! Get lost!"]
[linkto="getlost"]
[endpage]

### 5.3 Advanced Conversations: conditional branching

Sometimes you want to have the same person behave differently when things happen in the game.
For example, you've just come across an important object in the game. You should now be able to ask people about it, by making new choices appear.

This is done with flags. A flag is a message that can either be true or false, depending on what has happened previously.

5.3.1 Checking for an object

The simplest case is 'Am I carrying such-and-such an object?' The result will either be true(yes) or false (no).

Here's an example. It's not really a conversation, but anyhow. If you're carrying 'The Death', it says so, otherwise it says you're not carrying it.

[page="start"]
System test: are you carrying that nasty weapon, THE DEATH?

[am_carrying the_death]
[if true]Yes, you are carrying it.
[if_not true]No, you are not carrying it.
[endpage]

Now, how does it work?

[am_carrying the_death]

This looks in the player's pocket for an object named 'the_death'.
If it is in your pocket, it will set the flag 'True' to be true.

The next part is clever.
[if true]Yes, you are carrying it.

[if true] Examines the flag called 'true', and then decides what to do. If 'true' is set true, it prints the text. Otherwise it does nothing at all.

[if_not true]No, you are not carrying it.

This again looks at the flag called 'true'. But it does the opposite thing! If 'true' is NOT true, it prints the text, else it does nothing.

Because both of these are looking for one of the two possible states, ONE of them will be displayed and the other won't.

You can also use [if false] instead of [if_not true].

(For the advanced reader: TRUE and FALSE are separate flags, but they are always set to be opposite.)

5.3.2 Important tips!

- You can check the same flag as many times as you like without it changing, so you can have multiple lines.

E.g.

[am_carrying mobile_phone]
[if true]"You have played this game for far too long, mortal!"
[if true]"It's time to go to bed..."

- What comes after the [if] command does not have to be text, it can be another command, too.

E.g.

[am_carrying large_stereo]
[if true]"This is a library, sir. I'm afraid I must ask you to leave."
[if true][nextpage="exit"]
[if false]"Welcome to the library. How can I help you?"
[if false][nextpage="howcanihelp"]

In this case, the librarian will ask you to leave and stop talking if you have the ghetto-blaster. If you don't, they will go onto a different page and continue the conversation.

If you want to do more complex actions conditionally, you can either use everal IF lines, or use the GOTO command to switch to another page. [goto=] is the same as [nextpage=], but it switches instantly, without waiting for a keypress.

Here's and example:

[page="something"]
[if murdered_king][goto="murderedking"]
[if murdered_queen][goto="murderedqueen"]

"Hello!"
:
:
:
[endpage]

[page="murderedking"]
"My God! You've murdered His Royal Highness! GUARDS!!!"

[nextpage="exit"]
[callvrm="callguards"]
[endpage]

[page="murderedqueen"]
"My God! You've murdered Her Majesty! GUARDS!!!"

[nextpage="exit"]
[callvrm="callguards"]
[endpage]

5.3.3 Checking for a party member

Similarly to looking for an object, you will also want to see if a particular person is in your party.

[is_in_party gordon_harris]
[if true]"Ah, any friend of Gordon's is a friend of mine."
[if true][nextpage="page2"]
[if false]"I don't know you, stranger!"
[if false][nextpage="exit"]

5.3.4 Using your own flags

You are not just lumbered with True and False, you can create any number of flags you like, up to 8192.

The commands you use to create flags are SET and CLEAR, which make the flag be true or false, depending on which one you used. (Set makes a flag true, clear makes it false).

The flags are automatically created as you try to use them. If you try to set or clear a flag which doesn't exist yet, it is created there and then. If you try to test a flag which doesn't exist , it is assumed to be false.

For example:

[if_not already_met]"Hello, I'm Gordon Harris."
"How can I help you?"
[set already_met]

The first time you have this conversation, he says "Hello, I'm Gordon Harris", because the flag already_met is false.
Then it prints "How can I help you?" which always appears.
Finally it sets the flag 'already_met' to be True, so the introduction will not be shown again, unless you do [clear already_met].

5.3.5 Personal Flags

The flags described above are fine for many circumstances, but they are 'global', that is, all the characters see the flag the same.
Clearly this is not good for the above example, since by meeting Gordon Harris, you would also have 'met' all the other characters in the game.

Once solution would be to have lots and lots of flags, for example 'met_gordon_harris' and 'met_kevin_parrot' etc, but this would be untidy.

Instead, there are 32 numbered flags, which are specific to the current person you're talking to.
These are called 'Personal Flags', or p-flags for short.

As I mentioned, the p-flags do not have names, they are numbered from 0 to 31.
If you need to keep track of each p-flag number, you can write a memo at the top of the file, before the first [page=""] line.

They have their own special [if] commands:

[if_pflag n] (or [if_personal_flag n])
[if_not_pflag n] (or [if_not_personal_flag n])

[set_pflag n] (or [set_personal_flag n])
[clear_pflag n] (or [clear_personal_flag n])

Here's an example:

[if_not_pflag 0]"Hello, I'm Gordon Harris."
"How can I help you?"
[set_pflag 0]

This time, it uses the personal flag specific to Gordon Harris. In fact, if you had more than one copy of Gordon Harris in the game, you would still be able to meet both of them individually.

### 5.4 Manipulating the game world

This is the most neat part of the conversation system.

By manipulating the environment , you will be able to do really neat stuff, like buying and selling, creating and destroying objects, and by calling a VRM function, absolutely anything else.

5.4.1 Calling VRM functions

There are now three ways to call VRM functions from a conversation.

1. [callvrm="function"]
2. [on_exit_callvrm="function"]
3. [set_behaviour="function"]

[callvrm=]

This calls the VRM function immediately. You should not call redraw() in the VRM function you are using, or the display will become corrupted.

VRM functions can interact with the conversation too, by setting flags (such as True and False) and p-flags.
This is a way to get information about the game state if there isn't a command to do that in the conversation.
You can also use it to move objects around, or open doors by talking to an intercom.

[on_exit_callvrm=]

This calls the VRM as soon as the conversation ends.
This should be used when the VRM will redraw the screen, or you are doing something drastic such as killing the player.

When the VRM is called, current_object will be set to the character you're talking to.

For example:

[page="start"]
"Hello."

[link="You're a b*st*rd!"]
[linkto="bstard"]
[endpage]

[page="bstard"]
[if_not_pflag 0]"Never say that to me again!"
[if_not_pflag 0][nextpage="exit"]
[if_pflag 0]"Now you die!"
[if_pflag 0][on_exit_callvrm="killplayer"]
[if_pflag 0][nextpage="exit"]
[set_pflag 0]
[endpage]

If you insult this guy twice, he kills you, by calling the VRM function 'killplayer'.

[set_behaviour=]

This changes the behaviour of the current object so that it calls this VRM every turn.

For example:

[set_behaviour="enemy_flee"]

or:

"In the beginning there was Darkness, and the Darkness was without form and void."
"And in addition to the Darkness there was also Me."
"And I moved upon the face of the Darkness and I saw that I was alone."

"Let there be light."
[set_behaviour="thermostellar_device_explode"]
[nextpage="exit"]

5.4.2 Creating and destroying objects

You can create objects directly in the player's pockets.
This has several uses, besides the obvious one in Ultima 6, where the King gives you a key when you talk to him.
It can also be used for trading, by creating the money in the player's backpack and destroying the object you sold, or vice-versa.

At present [create] does not check to see whether there is room in your backpack to carry the object.
However [destroy] (or [remove]) does check to see whether the object is in your backpack, so that the angry trader can poke you in the eye if you try to sell something you don't have.

This check is performed of course, by setting the global flags TRUE and FALSE to the appropriate value afterwards.

You also specify the amount of objects you want to create or destroy. In some cases this will be ignored, if the object is indivisible, but for other cases such as money, it will add or remove various quantities of that object from your backpack.

If you want to take away an amount of something, it will return FALSE if you don't have that much, to prevent you from being able to short-change the trader.

Here's an example, selling a TV set:

[destroy 1 tv]
[if false]"What are you trying to pull?"
[if true][create 1000 gold_coins]
[if true]"Done!"
[nextpage="start"]

Here's another, buying a TV set:

[destroy 2000 gold_coins]
[if false]"You can't afford it!"
[if true]"Thankyou, sir!"
[if true][create 1 tv]
[nextpage="start"]

5.4.3 The theory of the Conservation of Money

Now that example was very crude. The money was actually destroyed and the object was created on-demand.

This is what Ultima 6 and Ultima 7 do, but you might prefer it if the money and goods actually change hands.

This would mean that you could actually kill the trader after taking the money and get the TV back afterwards, but you would also have to make sure the trader is stuffed with cash, or he won't be able to afford the TV when you try to sell it!

If you prefer to work this way, instead of using CREATE and DESTROY, use GIVE and TAKE.
But don't blame me if the King gives the player the only copy of the key to the castle and the player loses it..

[take n objects]

This takes the specified object (or an amount of them)from the player's backpack and transfers it into the backpack of the character you're talking to. No loss!

Similarly,
[give n objects]
..will take the specified object(s) from the backpack of the character you're talking to, and transfer them to the player's backpack.

As an example, here's the buying and selling the TV again, but with the money and the TV being moved around instead of created and destroyed.

[take 1 tv]
[if false]"What are you trying to pull?"
[if true][give 1000 gold_coins]
[if true]"Done!"
[nextpage="start"]

Here's another, buying a TV set:

[take 2000 gold_coins]
[if false]"You can't afford it!"
[if true]"Thankyou, sir!"
[if true][give 1 tv]
[nextpage="start"]

Neither of these examples take into account whether the trader has the money or the TV.
This is more complex, since GIVE will change the state of TRUE and FALSE, so we'll need to use a temporary flag.

Here's the finished version..

[clear temp]
[take 1 tv]
[if false]"What are you trying to pull?"
[if false][nextpage="exit"]
[if true][set temp]
[if temp][give 1000 gold_coins]
[if temp][if true]"Done!"
[if temp][if false]"I'm sorry sir, I seem to have exceeded my budget for acquisitions."
[if temp][if false][give 1 tv]
[nextpage="start"]

[clear temp]
[take 2000 gold_coins]
[if false]"You can't afford it!"
[if true][set temp]
[if temp][give 1 tv]
[if temp][if true]"Thankyou, sir!"
[if temp][if false]"I'm sorry sir, we're out of stock."
[if temp][if false][give 2000 gold_coins]
[nextpage="start"]

## Part 6 - Game description files

A finished IRE game will consist of two files, something like:

MYGAME.RAR
MYGAME.GAM

The .RAR file will contain the resources, all the sound, graphics and level data.
The .GAM file is a text file containing the descriptions needed to make the .RAR file work.

Typically it will look like this:

`#`
`# Generic Description file`
`#`

`-file mygame.rar`
`-resdir mygame`
`-mapfile level1`

`-console_x 16`
`-console_y 320`
`-console_w 75`
`-console_h 17`

`-destroy_hp 150`

### 6.1 Crucial lines

The first three lines are most important.
These tell the IRE game runner where to load the data from, what directory it is kept in, and what the world file is.

'-file mygame.rar'
This is the name of the .RAR file where all the resources are kept.

'-resdir mygame'
This is the name of the directory inside the RAR file, where all the resources can be found.
I used RES for my general experiments, and FLAT for The Flat.

'-mapfile level1'
This is the world file which the game will try to load. It will look for level1.MAP, level1.MZ1 and level1.MZ2.

### 6.2 The text console

These lines control the position and size of the text console.

'-console_x' specifies the X position of the console.
'-console_y' specifies the Y position of the console.

'-console_w' specifies the width of the console in CHARACTERS. Not in pixels.
'-console_h' specifies the height of the console in LINES. Not in pixels.

### 6.3 Loading Screen

You can also have a loading screen for your game.
This is controlled by using the -LOG command.

There are three types of LOG:

'-log full'
This is the default. It runs in text mode, and displays full diagnostic information.

'-log partial PICTURE.PCX'
This will switch to graphics mode early on, and display the .PCX picture, with full diagnostic information superimposed.

'-log none PICTURE.PCX'
This will switch to graphics mode, and display the picture, but it will not show any diagnostic information as the game loads.

If you use '-log partial', you will want to specify where the information appears and how much there is.
This is done using '-logxy'

'-logxy Xposition Yposition Lines'
This consists of three numbers on the same line.
First, the X-coordinate where the text will appear.
Secondly, the Y coordinate where the text will appear.
Finally, the number of lines of text that will be displayed.
It is assumed that the width will always be around 60 columns.

For example:

-log partial mypic.pcx
-logxy 0 380 10

Will display the picture mypic.pcx, and display 10 lines of text starting at 0,380

### 6.4 Game parameters

'-destroy_hp'

This sets the health level which the object is destroyed at.
When any object's health is discovered to have fallen below this value, it will be obliterated.

The default is -150 health points.

## Part 7 - Conclusion

Thanks for reading this and showing your interest in IRE. If you like IRE, spread the word.
Have fun editing!.

Online References:

About IRE:

http://fly.to/ire

IT-HE Homepage:

http://members.tripod.com/~JPMorris

PICTVIEW, which can convert to and from .CEL files:

http://pascal.fjfi.cvut.cz/~patera

Contact Info:

If you have any questions at all about IRE or VRM programming, feel free to email me...

DOUG-15@bigfoot.com
b52g@usa.net

If you didn't get an answer for a few days, try this instead....

boff@globalnet.co.uk

End of Document