Specification Document

Version 2
28th November 2003
Matthew Wilson

Introduction

Transit Network will be a simulation/real-time strategy, muliplayer game based upon the simulation game Transport Tycoon, by Chris Sawyer (www.chrissawyer.com).
The game will be a 3D world with a 2D view (isometric - like Transport Tycoon, and a top-down view).
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Interface

The interface will consist of four main component groups:

• The view
• A toolbar
• A status bar
• Information windows

The view will be navigable using the mouse and cursor keys, and will display the 3D world using a 2D view (possible by virtue of parallel projection).

There will be a toolbar (and/or menu), containing all the functions available in the game. It will be displayed at the top of the screen.

There will also be a status bar at the bottom of the screen, showing general game information.

The other group of components is the information windows. These are floating windows which contain specific inforamtion about a part of the game. These can be moved around the screen and closed.
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Extensibility

The game will use configuration files (possibly in XML), and dynamic class loading to make it extensible. For example, if someone want's to add a new button to the toolbar, they would create a subclass of the relavent abstact class, then add an entry in the configuration file pointing to the class name and location. The program will then make an instance of the class from the information provided and add it to the tool bar.
Other things that could be done would be changing the functionality of elements of the game (eg the changing of views), or adding/changing objects in the 3D world, etc.
There may be a part of the game to add an object without having to go through the file editing, etc.
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Game Elements

-Map

The map will be square grid based with each square representing a land tile, with a similar land-manipulation system to RollerCoaster Tycoon. The land manipulation cost will be relatively high so that players are encouraged to be creative in track laying rather than just molding the land to their needs.
On the map will be towms and cities. These will be much larger and more detailed than towns in Transport Tycoon. The station size to town size ratio will be more like that in the real world. This also gives scope for subways/underground rail systems. Some maps could be covered entiely by a city and it's suburbs (like London or Tokyo).
The land will have 20 height levels (the lowest being 1 and ground level being 6). Each height level will be half the width/length of a land tile. There will be two possible slope angles for tiles: a height difference of 1 (trains and road vehicles can climb this), and a height difference of 2 (trains and road vehicles CAN'T climb this). This coupled with the high price of land manipulation should ensure interesting game play in track laying.

-Trains

The tracks will have 4 different directions (north-south, east-west, ne-sw, nw-se), and turns in the track will be curved like in real life (no 90 degree turns). The method for building the track will be to 'plan' the line and then confirm it. The land is then bought and track construction begins - this will take a certain amount of time. The user will be able to plan a line by the Transport Tycoon method (placing individual track pieces), or by a modified RollerCoaster Tycoon method (a dialogue box with possible tracks and directions to choose).

Stations will work on a first in first out (fifo) system. This means that if a train is loading a cargo at a station and another train with the capacity for the same cargo comes along, then it will not be filled until the first train leaves.

The orders a train will be able to have will be varied but simple. Destinations (stops) can be assigned one of the following:- stop (sell and load all possible passengers and cargo), load 25/50/75/100% (wait at station until a the train is x% full of one cargo), unload (drop all cargo even if station does not accept), non-stop (go straight through), and request stop (for passenger trains only). There may be another order - load-leave (train waits until full (25/50% etc) or when another train for the same cargo arrives).
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