(Much of this text is stolen/edited from Chocolate Doom.)

1oom has been designed around a careful and deliberate philosophy that

attempts to recreate the original (“Vanilla”) DOS executables for

Master of Orion. This document describes some of that philosophy and

the reasoning behind it.

This document is descriptive, not proscriptive.

# Vanilla behavior

Ideally 1oom aims to recreate the behavior of the Vanilla binaries,

but different aspects of Vanilla behavior are held to varying degrees

of importance. It can be imagined as different “tiers”

of compatibility:

* The game and gameplay itself is of central importance. Here, the

Vanilla behavior ought to be maintained as accurately as possible.

This includes the look, feel and sound.

* The surrounding aspects of the game that aren’t part of the central

gameplay experience can be extended as long as there’s a good

reason and Vanilla behavior is respected.

“Vanilla” is defined as:

* Master of Orion v1.3.

Compatibility with older versions of the DOS binaries or newer hacked

binaries are out of scope.

# Compatibility

1oom aims to be compatible with Vanilla MOO1 in several different ways.

Examples are:

* Data file compatibility: the original data files (LBX) are used.

No additional data files are required or provided.

* Bug compatibility: the aim is to emulate compatibility of the

original game down to bugs that were present in the DOS

executables. Most bugs are fixed, but the AI behaviour is

maintained as closely as possible.

* Savegame file compatibility: 1oom provides a tool to convert savegames

to/from Vanilla format.

# Exceptions

1oom differs from Vanilla MOO1 in a number of ways. Here are some

examples of situations where changes are considered acceptable:

1. Vanilla behavior can be broken that is harmful, eg. can damage the

player’s computer, or is just outright misleading. For example:

- Vanilla has crashes that force the user to reboot the machine.

2. Supporting obsolete technology is not a goal: it’s considered

acceptable that 1oom does not support every type of hardware

from 1993. However, Chocolate Doom should aim to recreate

the functionality in a modern way. Examples of technologies that

aren’t supported are:

- No MS-DOS version.

A good litmus test of when it’s acceptable to break from Vanilla

behavior is to ask the question: “Although this is Vanilla behavior,

is there anyone who would want this?”

For example, emulating Vanilla bugs like the visplane overflow bug is

something that is useful for people making Vanilla format maps. On the

other hand, painstakingly emulating Vanilla Doom by starting with no

sound or music by default is not helpful to anyone.

# New features

While 1oom recreates the Vanilla behaviour, it also extends it:

* The "classic" UI (1oom_classic_*) will always remain reasonably close to

the one in the DOS binaries, but alternative UIs are within the scope.

* The "classic" AI will always remain reasonably close to the one in the

DOS binaries, but alternative AIs are within the scope.

* Doom-like file patching is supported via PBX files.

* Multiplayer! (not yet)

# Other philosophical aspects

1oom aims for maximal portability. That includes running on many

different CPUs, different operating systems and different devices

(ie. not just a desktop machine with a keyboard and mouse).

1oom does not need to be installed. The only required data files are the

LBX files from the original game. The other data files are the savegame

and configuration files.

1oom is and will always remain Free Software. It will never

include code that is not compatible with the GNU GPL.