2005 .plan - Liquid War 6
Description: Liquid War 6

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## Appendix A 2005 .plan

Here's my .plan file, which describes what I (Christian Mauduit) have planned for Liquid War 6. There's no garantee that what's written here is a precise description of the real future, however it should give a good idea of what I have in mind.

Note that the information here was written in summer 2005, it might or not be accurate now, as the main reason for plans to exist is that people never follow them. I'm no exception.

### A.1 Complete rewrite

Liquid War 6 will be an almost complete rewrite. I mean that common code between branches 5 and 6 might end up in representing 0% of the total code. I think this is a wise decision, for the current code is really hard to maintain, and would not survive any serious cleanup. LW5 was first written in 1998, for DOS, when I had much less experience in programming. In 7 years I - and other people as well - hacked major enhancements in it such as cross-platform support, network games, and if you compare release 5.0 with the latest 5.x.x release, you'll see that a bunch of things have changed. I had never expected I would patch and fix this game for so long, and it's no surprise that it's bloated today.

FYI, here's a list of what makes LW5 unsuitable for major improvements without a complete rewrite:

- global variable hell. Lots of things are stored in globals.
- hard-coded C GUI. Read src/level.c to get an idea of how horrible it is.
- hard-coded 256 colors paletted mode. A clever bet in 1998 (performance...). Not anymore.
- generally bloated code. Makes bug-finding very tricky.

### A.2 Technologies

Liquid War 6 will use a different technical framework than Liquid War 5.

#### A.2.1 Script + standard C + assembly

It happens that coding a large project in pure C is a waist of time, if possible at all.

If one applies the standard 80/20 rule to a computer game, one might state that 80% of the code eat up 20% of the CPU and the other 20% of the code eat up 80% of the CPU, the former being high-level glue code and the latter being low-level algorithmic code.

With Liquid War, one could speak of the 99/01 rule. I mean that 99% of the CPU time concerns only 1% of the code, and vice-versa. Basically, Liquid War has a very CPU-greedy core algorithm, still spends a fair amount of CPU displaying stuff (but this is delegated to the low-level game programming library) and the rest is totally unsignificant, in terms of CPU. Point is this "rest" represents the vast majority of the code, and also represents the very same buggy code I spend nights to patch on Liquid War 5. I'm talking about network code, GUI, and other high-level glue-code which are currently being written in C.

This idea is to write all this in a convenient scripting language. There won't be any impact on performances. I can't garantee Liquid War 6 will be blazingly fast, but for sure it won't be the scripting language fault. And of course if, as in Liquid War 3 and 5, I feel the need to implement some stuff in assembly for performances issues, I will do it.

We end up with a multi-language architecture: script + C + assembly.

My guess is that I'll use Scheme as an extension language. Python would be a good choice too. Let's say I'll give Scheme a chance, and if it's really not adapted, I'll switch back to Python. The point is that today I know Python and don't really know Scheme, but, well, it's always a pleasure for me to learn new things. It's fun.

So what is planned today is that Liquid War 6 will be a Scheme program, which will call callbacks functions written in C and/or assembly. These functions will do all the low-level time consuming algorithmic and graphical stuff. The rest of the code being entirely scripted.

#### A.2.2 OpenGL

Liquid War is not a 3D game, so why use OpenGL?

- it's a very convenient way to access video hardware acceleration with XFree86.
- low-end computers and/or computers without 3D acceleration can still run Liquid War 5.
- I'm interested in learning/using this API 8-)

This choice implies that I won't use Allegro anymore. Allegro stays a very convenient library and I would recommend it for it's excellent, easy to learn, powerfull, and stable. But for the needs of Liquid War 6 I'll use something else (because of OpenGL). I first thought of using GLUT but I might end up simply using SDL. The idea is just fo have an OpenGL wrapper which sets up OpenGL in a similar manner on all platforms, and handles basic things such as mouse or keyboard.

#### A.2.3 CSound

I've got two excellent books on Csound, and the will to learn how to use this tool.

I'll probably use Csound for a number of things, ranging from "bubbling sounds" to full blown music. Stay tuned 8-)

### A.3 Functionnalities

#### A.3.1 Visual enhancements

Of course Liquid War 6 will look nicer than Liquid War 5, blah blah blah. What do you think?

Maybe I'll try to use some OpenGL features to make it possible to play on a ball, on a Moebius ring, or other fancy things. I have zillion of ideas, future will decide which ones will be implemented first.

To make it clear, visual enhancements aren't my top-level priority. However I'll try and make room for these enhancements, and prepare the terrain correctly. So it's possible that the first releases of Liquid War 6 won't be that much better than Liquid War 5, but at least Liquid War 6 will have the possibility to evolve. Something Liquid War 5 doesn't have.

#### A.3.2 Rules enhancements

There are many things that could be done easily:

- several cursors for one team
- alliances between teams
- deep places on a map, where more liquid can reside
- circular maps which "connect" the left border to the right one
- ...

As for graphical improvements, this is not my top-level priority. Simply, I'll make the game ready-to-improve. Again, all these enhancements are very hard to code in Liquid War 5, else I would already have coded them. Network enhancements

That's my top-level prioriry.

Why is that? Well, think of Liquid War in terms of "what makes it a good game?" and "what makes it a poor game?".

It's a good game because:

- the idea is original
- the gameplay is addictive
- you can play on a LAN
- all the family can play
- it's cross-platform
- it's Free Software

It's a poor game because:

- it's somewhat ugly and has a retro "back in the eighties" look
- network games are slow on Internet
- there are not enough active Internet servers

For the ugliness, well, OpenGL and some artwork should make it. But for the network, what's the real problem?

The real problem is that in the current situation, the server needs to have all "keystrokes" before doing anything, and all players must be connected before a game starts. Here's what I plan to do to fix this:

- players will be able to connect on a game "on the fly". This is done by most online games, and it's IMHO a required features for a network mode to work on Internet (not speaking of local networks, but real wide online gaming). How this will fit with Liquid War's rules is not totally decided, but I already know of several way to achieve this.
- I'll implement an "anticipation" system "a la" U61. This means that no matter if a remote player has a poor network connection, things will behave as if everything was fine. Internally, the system keeps 2 images of the game. One which is "anticipated" and displayed to the player, and one which is validated but outdated, kept internally. It's a little hard to explain, consumes twice as much CPU and memory, but it works. It happens that today the lacking ressource for playing Liquid War online is more on the network side than on the local CPU and memory aspects.
- I'll take it to the next level and implement a "peer-to-peer-like" network model, in which any client can become a server. The idea behind is that if a server quits the game, then a client takes its role, letting the game continue for hours. This way one could virtually have a never ending Liquid War game which would last weeks. I believe this could be really cool. I also believe no proprietary game will ever implement that, for in this model there's no way to force people to access a centralized server, this server usually being the major key in the business model of a company which sells proprietary software.

This third point will be the real enhancement of Liquid War with version 6. It's one of the very points which drives me to rewrite it completely. First because it's impossible to implement it without some heavy work. Then because I find it very motivating.

#### A.3.3 Hey, you forgot my idea!!!

Many gamers submitted suggestions, either by mail or by posting messages on the mailing list.

Don't worry, I keep them. Not reading them here does not mean I won't implement them. It simply means I won't implement them first. I first need the game basically function before enhancing it with fancy stuff.

### A.4 Road map

As I stated on the mailing list, when thinking about Liquid War 6, think of years rather than months (unless I get fired, jobless, or spend several months in a hospital with a laptop).

Note that this road map takes it for granted that I'll be the lone coder on the project. It's unlikely that someone is going to help me for the first stages, until there's at least something real, something playable. Something that proves that the concept is valid. Besides, (real) team work implies a significant overhead, especially at project start. It's hard to figure out how to distribute tasks when the tasks themselves are not clearly identified. But for the rest (starting in 2007 or 2008), it's possible that external help might greatly... ...help!

- 2005 : Project framework should be done. This implies that the scripting engine is up and running, graphical mode works, config and data loading work, basic menus are available. Nothing playable.
- 2006 : Import the core algorithm from Liquid War 5, make the game playable in "demo mode" ("à la" Liquid War 2), implement the network "peer-to-peer-like" mode. At this stage, it will be possible to know wether Liquid War 6 is true vaporware or not.
- 2007 : glue all this together to make something usable by anyone, heavy work on the GUI, on the options, on error checking, many bug fixes. The goal is to have a game which is equivalent to Liquid War 5, with the network aspects pushed to the next level.
- 2008 : tadaaaaaaaaaaa! Release the game "publicly" - inform Freecode 8-) - and enhance it with all the feedback from gamers (bug reports and suggestions received since 1998). Work on artwork (both graphics and musics). Write documentation.
- 2009 : stabilize the game, patch it for all those things which had been forgotten back then in 2005, optimize for speed, bug-fix bug-fix bug-fix.
- 2010 : stop maintaining Liquid War 5, invite Liquid War fans and coders to a hudge party in my garden, sing all night, drink beers and wine, teach Liquid War strategies to my 5 and 6 year old daughters, remember the old times when Liquid War wasn't so cool 8-)