ref: e38b186c31fae56b9e46f13e40ddecaae99228b0
parent: 50742cfc923a5be33398973072818f0c94950809
author: Simon Howard <fraggle@gmail.com>
date: Wed Apr 16 22:22:42 EDT 2014
Add first version of philosophy document.
--- a/Makefile.am
+++ b/Makefile.am
@@ -35,6 +35,7 @@
README \
README.Music \
NEWS \
+ PHILOSOPHY \
ChangeLog
EXTRA_DIST= \
--- /dev/null
+++ b/PHILOSOPHY
@@ -1,0 +1,157 @@
+
+Chocolate Doom has been designed around a careful and deliberate
+philosophy that attempts to recreate the original ("Vanilla") DOS+executables for Doom, Heretic, Hexen and Strife. This document
+describes some of that philosophy and the reasoning behind it.
+
+This document is descriptive, not proscriptive.
+
+== Vanilla behavior ==
+
+Ideally Chocolate Doom 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, and things like demo
+ compatibility.
+ * 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.
+ * The setup tool is not required to reproduce the behavior of the
+ Vanilla setup tool, even though it reproduces its look and feel.
+
+"Vanilla" is defined as:
+
+ * DOS Doom 1.9 (although there are actually multiple "1.9"s).
+ * DOS Heretic 1.3.
+ * DOS Hexen 1.1.
+ * DOS Strife 1.31.
+
+"Vanilla" does not include ports (either official or unofficial), such
+as console ports, Doom 95 or Doom 3: BFG Edition.
+
+== DOS tools ==
+
+Chocolate Doom includes some features that aren't part of Vanilla Doom
+but exist for compatibility with DOS tools that interact with it.
+These are considered part of the Vanilla experience and ought to be
+treated as such. Some examples are:
+
+ * The novert setting, which reproduces the functionality of
+ novert.exe.
+ * The -deh parameter, which loads Dehacked patches like dehacked.exe
+ does under DOS. Chocolate Doom imposes the same limitations that
+ Vanilla Dehacked does.
+
+== Exceptions ==
+
+Chocolate Doom differs from Vanilla Doom in a number of ways. In most
+cases these are subtle, minor differences. Nonetheless they deserve
+some explanation and justification. 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 uses unbounded sprintf and strcpy (security issue).
+ - Vanilla has crashes that force the user to reboot the machine.
+ - Vanilla has an out of memory message that recommends tweaking
+ CONFIG.SYS. As Chocolate Doom doesn't run under DOS, reproducing
+ this message would not be helpful.
+
+ 2. Subtly extending behavior is okay where it's not clear what the
+ Vanilla behavior is anyway. For example:
+
+ - Opening the menu releases mouse grab in Chocolate Doom.
+ - Chocolate Hexen's graphical startup screen runs in a window.
+
+ 3. Supporting obsolete technology is not a goal: it's considered
+ acceptable that Chocolate Doom does not support every type of
+ hardware from 1993. However, Chocolate Doom should aim to recreate
+ the functionality in a modern way. Examples of technology that
+ isn't supported are:
+
+ - No support for IPX networks, but TCP/IP is instead.
+ - No support for dial-up/serial connections; modern operating
+ systems have features that do that for you.
+ - No MS-DOS version.
+
+ 4. Changes are permitted that allow the player to be able play the
+ game. For example:
+
+ - There are new key bindings for actions that can't be rebound with
+ Vanilla Doom, because it's useful for portability to machines
+ that don't have a full keyboard.
+ - There are additional mouse or joystick key bindings that let you
+ perform actions with them that can only be done with the keyboard
+ in Vanilla Doom.
+ - Chocolate Doom includes some hacks to support the Doom 3: BFG
+ Edition IWAD files. The assumption is that being able to at least
+ play is better than nothing, even if it's not Vanilla behavior.
+
+ 5. Adding extra options to Vanilla functionality is permitted as long
+ as the defaults match Vanilla, it doesn't change gameplay and
+ there's a good reason for it. For example:
+
+ - PNG screenshots are supported because PCX is an obsolete format.
+ - Chocolate Doom has the vanilla_keyboard_mapping option that
+ allows the user to use the native keyboard mapping for their
+ computer, rather than always assuming a US layout.
+
+ 6. Changing configuration file defaults is permitted where there's a
+ very good reason. For example:
+
+ - Vanilla Doom defaults to no sound or music if a configuration
+ file is not found. Chocolate Doom defaults to having sound
+ effects and music turned on by default, because modern computers
+ support these; there's no need to configure hardware IRQ settings
+ to get sound working.
+
+ 7. Things can be changed if they're really just inconsequential. For
+ example:
+
+ - The startup messages in Chocolate Doom are not identical to
+ Vanilla Doom and are not necessarily in the same order.
+ - Vanilla Doom has command line options named -comdev, -shdev and
+ -regdev used by id internally for development; these have been
+ removed.
+
+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.
+
+== Other philosophical issues ==
+
+Chocolate Doom aims for maximal portability. That includes running on
+different CPUs, different operating systems and different devices (ie.
+not just a desktop machine with a keyboard and mouse).
+
+Chocolate Doom is and will always remain Free Software. It will never
+include code that is not compatible with the GNU GPL.
+
+Chocolate Doom aims to be minimalist and straightforward to configure;
+in particular, the setup tool should have a sane interface. Part of
+the inspiration for Chocolate Doom came from Boom's complicated maze
+of options menus (and a desire to avoid them). Too many preferences
+lead to a bad user interface; see Havoc Pennington's essay on Free
+Software UI:
+
+ http://ometer.com/free-software-ui.html
+
+Chocolate Doom has some options that are quite obscure and only really
+of interest to a small number of people. In these cases, the options
+are hidden away in configuration files and deliberately not exposed in
+the setup tool. The assumption is that if you care enough about those
+obscure features, editing a configuration file by hand should not be a
+huge problem for you.
+
+# vim: tw=70
+