2003-04-01 00:59:47 +00:00
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook V4.2//EN">
<!-- Conventions:
2 spaces per indent level
4 spaces from left edge for <screen> environment
2003-07-29 19:48:36 +00:00
5 newlines between level 1 sections.
3 newlines between level 2 sections.
128 characters per line
2003-04-01 00:59:47 +00:00
Problems:
“ and ” aren't yielding `` and ''.
-->
<!--
TODO:
=====
1. Panzer leader port: http://lgames.sourceforge.net/index.php
2. LBA port: http://www.yaz0r.net/
3. Add "blitting" and "blit" in video card terminology
4. Try to make it more clear that I want people to send info and interact with me.
5. Ultima: http://www.peroxide.dk/ultima/
6. Add X Strike Force to "XFree86 and You".
7. Write "Playing Games in X Without a Window Manager" in "Xfree86 and You".
8. Mention mobygames.com
-->
<article>
<articleinfo>
<title>The Linux Gamers' HOWTO</title>
<titleabbrev>LG-HOWTO</titleabbrev>
<author>
<personname>
<firstname>Peter</firstname>
<othername role="middle">Jay</othername>
<surname>Salzman</surname>
</personname>
<email>p@dirac.org</email>
</author>
<!-- year-month-day -->
2003-07-29 19:48:36 +00:00
<pubdate>v.0.9.34, 2003-07-29</pubdate>
2003-04-01 00:59:47 +00:00
<copyright>
<year>2001</year>
<holder>Peter Jay Salzman</holder>
</copyright>
<legalnotice>
<para>
<email>p@dirac.org</email> /
<ulink url="http://www.dirac.org/p"></ulink>.
</para>
<para>
Distributed subject to the Open Software License, ver 1.1
</para>
</legalnotice>
<abstract> <title>Abstract</title>
<para>The same questions get asked repeatedly on Linux related mailing lists and news groups. Many of them arise because
people don't know as much as they should about how things "work" on Linux, at least, as far as games go. Gaming can be a
tough pursuit; it requires knowledge from an incredibly vast range of topics from compilers to libraries to system
administration to networking to XFree86 administration ... you get the picture. Every aspect of your computer plays a role
in gaming. It's a demanding topic, but this fact is shadowed by the primary goal of gaming: to have fun and blow off some
steam.</para>
<para>This document is a stepping stone to get the most common problems resolved and to give people the knowledge to begin
thinking intelligently about what is going on with their games. Just as with anything else on Linux, you need to know a
little more about what's going on behind the scenes with your system to be able to keep your games healthy or to diagnose
and fix them when they're not.</para>
</abstract>
</articleinfo>
<sect1 id="administrata"><title>Administra</title>
<para>If you have ideas, corrections or questions relating to this HOWTO, please email me. By receiving feedback on this
howto (even if I don't have the time to answer), you make me feel like I'm doing something useful. In turn, it motivates me
to write more and add to this document. You can reach me at <email>p@dirac.org</email>. My web page is <ulink
url="http://www.dirac.org/p"></ulink> and my Linux pages are at <ulink url="http://www.dirac.org/linux"></ulink>. Please do
send comments and suggestions for this howto. Even if I don't take your suggestions, your input is graciously
received.</para>
<para>I assume a working knowledge of Linux, so I use some topics like runlevels and modules without defining them. If there
are enough questions (or even protests) I'll add more basic information to this document.</para>
<sect2 id="authorship"><title>Authorship and Copyright</title>
<para>This document is copyright (c) 2001 Peter Jay Salzman, <email>p@dirac.org</email>. Permission is granted to copy,
distribute and/or modify this document under the terms of the Open Software License, Version 1.1, except for the
provisions I list in the next paragraph. I hate HOWTO's that include the license; it's a tree killer. You can read the
OSL at <ulink url="http://opensource.org/licenses/osl-1.1.txt"></ulink>.</para>
2003-05-14 14:00:39 +00:00
<para>If you want to create a derivative work or publish this HOWTO for commercial purposes, I would appreciate it if you
contact me first. This will give me a chance to give you the most recent version. I'd also appreciate either a copy of
whatever it is you're doing or a spinach, garlic, mushroom, feta cheese and artichoke heart pizza.</para>
2003-04-01 00:59:47 +00:00
</sect2>
<sect2 id="acknowledgements"><title>Acknowledgements</title>
<para>Thanks to Mike Phillips who commented extensively on the howto. Thanks to Dmitry Samoyloff,
<email>dsamoyloff@yandex.ru</email>, for translating this document into Russian. It blew my mind when he told me that he
was translating my words to Russian. Further thanks goes to:</para>
<orderedlist>
<listitem><para>Moritz Muehlenhoff <email>jmm@Informatik.uni-bremen.de</email> for sending me updates (even if I'm
eternally behind on them...)</para></listitem>
2003-07-29 19:48:36 +00:00
<listitem><para>Fro?=do?=ric Delanoy for extensive diffs or correcting typos and docbook mistakes</para></listitem>
2003-04-01 00:59:47 +00:00
</orderedlist>
2003-07-29 19:48:36 +00:00
<para>I would also like to thank Michael Mc Donnell for sending in comments and corrections.</para>
2003-04-01 00:59:47 +00:00
</sect2>
<sect2 id="version"><title>Latest Versions and Translations</title>
<para>The latest version can be found at <ulink url="http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/lgh/LG-HOWTO"></ulink>
or <ulink url="http://www.dirac.org/linux/writing"></ulink>, but this is my own personal working copy. The version at my
personal web site might be broken if I'm working on the HOWTO. The version at sourceforge is bleeding edge but guaranteed
to be not broken, however it may have glitches, like unfinished paragraphs. :)</para>
<para>The most recent stable version can be found at <ulink url="http://www.tldp.org"></ulink>.</para>
<para>Dmitry Samoyloff <email>dsamoyloff@mail.ru</email> is the maintainer of the Russian translation. The most recent
version can be found at <ulink url="http://linuxgames.hut.ru/data/docs/HOWTO/LG-HOWTO-ru.html"></ulink>.</para>
</sect2>
</sect1>
<sect1 id="definitions"><title>Definitions: Types Of Games</title>
<para>Not everyone knows the different types of games that are out there, so in an effort to form a common language that we
can all use, I'll run through each game type and provide a very brief history.</para>
<sect2 id="arcade"><title>Arcade style</title>
<para>Although arcade games had their heydey in the 80's, they are nonetheless very popular. Nothing will ever replace
walking into a dark, crowded and noisy arcade gallery, popping a quarter into your favorite machine and playing an old
fashioned game of Space Invaders. Arcade style games attempt to simulate the arcade games themselves. There is such a
vast number of these things that it's nearly impossible to enumerate them all, but they include clones of Asteroids, Space
Invaders, Pac-Man, Missile Command and Galaxian.</para>
</sect2>
<sect2 id="cardboard"><title>Card, logic and board games</title>
<para>Computer based card games simulate a card game like poker or solitaire. The program can simulate
your opponent(s).</para>
<para>Logic games usually simulate some well known logic puzzle like Master Mind or the game where you
have put sliding numbered tiles in order inside a box.</para>
<para>Computer based board games simulate some kind of board game you'd play on a table top with
friends, like monopoly, Mille Bourne, chess or checkers. The program can simulate your opponent.</para>
</sect2>
<sect2 id="interactivefiction"><title>Text Adventure (aka Interactive Fiction)</title>
<para>Once upon a time, when Apple ][, Commodore, and Atari ruled the world, text adventures were the
game of choice of `intelligent folk'. You are given a scenario and can interact with the world you're
placed in:</para>
<screen>You are in a room. It is pitch dark and you're likely to be eaten by a grue.
> Light lantern with match.
You light the lantern. This room appears to be a kitchen. There's a table with a book in the center. You
also see an oven, refrigerator and a door leading east.
> Open the oven.
In the oven you see a brown paper bag.
> Take the bag. Open the bag. Close the oven.
Inside the bag is a clove of garlic and a cheese sandwich. The oven door is now closed.</screen>
<para>Back then, text adventures were self contained executables on a disk or casette. These days there's usually a data
file and an interpreter. The interpreter reads data files and provides the gaming interface. The data files are the
actual game itself, similar to the relationship between first person shooters (<xref linkend="fps">) and <filename
class="extension">wad</filename> files.</para>
<para>The first adventure game was Adventure (actually “ADVENT”, written on a PDP-1 in 1972). You can play
Adventure yourself (actually, a descendent); it comes with “bsd games” on most Linux distros. Text adventures
became popularized by Scott Adams (<xref linkend="scottadams">) and reached their height of popularity in the late 80's
with Infocom (<xref linkend="infocom">) which are also playable under Linux.</para>
<para>As computer graphics became easier and more powerful, text adventures gave rise to graphic adventures. The death of
interactive fiction more or less coincided with the bankruptcy of Infocom.</para>
</sect2>
<sect2 id="graphicaladventure"><title>Graphical Adventures</title>
<para>Graphical adventures are, at heart, text adventures on steroids. The degree to which they use graphics varies
widely. Back in the 80's, they were little more than text adventures which showed a screen of static graphics. When you
picked up an item, the background would be redrawn without the item appearing. The canonical example would be the
so-called `Hi-Res Adventures' like The Wizard And The Princess. Later on, the sophisticated graphical adventures had your
character roaming around the screen, and you could even use a mouse, but the interface remained purely text.</para>
<para>Next there are the `point and click adventures' which basically have no text interface at all, and often have
dynamic graphics, like a cat wandering around the room while you're deciding what to do next. In these games, you point
at an object (say, a book) and can choose from a pull-down list of functions. Kind of like object oriented adventuring.
:) There aren't many graphical adventures written natively for Linux. The only one I can think of is Hopkins FBI (which
happens to be my favorite game for Linux).</para>
</sect2>
<sect2><title>Simulation (aka Sims)</title>
<para>Simulations strive to immerse the player behind the controls of something they normally wouldn't have access to.
This could be something real like a fighter jet or something imaginary like a mechanized warrior combat unit. In either
case, sims strive for realism.</para>
<para>Some sims have little or no strategy. They simply put you in a cockpit to give you the thrill of piloting a plane.
Some are considerably complex, and there's often a fine line between sims and strats (<xref linkend="strategy">). A good
example would be Heavy Gear III or Flight Gear. These days sims and strats are nearly indistinguishable, but a long time
ago, sims were real time while strats were turn based. This is awkward for modern day use, since a game like Warcraft
which everyone knows as a strat, would be a sim by definition.</para>
</sect2>
<sect2 id="strategy"><title>Strategy (aka Strats)</title>
<para>Strategy games have their roots in old Avalon type board games like Panzer Leader and old war strategy games
published by SSI. Generally, they simulate some kind of scenario. The scenario can be peaceful, like running a
successful city (SimCity), illegal drug selling operation (DrugWars) or an all-out war strategy game like Myth II. The
types of games usually take a long time to complete and require a lot of brainpower.</para>
<para>Strats can be further divided into two classes: real time and turn based. Real time strats are based on the concept
of you-snooze-you-lose. For example, you're managing a city and a fire erupts somewhere. The more time it takes for you
mobilize the fire fighters, the more damage the fire does. Turn based strats are more like chess---the computer takes a
turn and then the player takes a turn.</para>
</sect2>
<sect2 id="fps"><title>First Person Shooter (aka FPS)</title>
<para>What light through yonder window breaks? It must be the flash of the double barreled shotgun! We have a long and
twisted history with FPS games which started when id Software open sourced code for Doom. The code base has forked and
merged numerous times. Other previously closed engines opened up, many engines are playable via emulators, many
commercial FPS games were released for Linux and there are quite a number of FPS engines which started life as open source
projects. Although you may not be able to play your <emphasis>favorite</emphasis> FPS under Linux (Half-Life plays great
under winex) Linux definitely has no deficiency here!</para>
<para>First person shooters are characterized by two things. First, you pretty much blow up everything you see. Second,
the action takes place in first person. That is, through the eyes of the character who's doing all the shooting. You
may even see your hands or weapon at the bottom of the screen. They can be set in fantasy (Hexen), science fiction (Quake
II), present day `real world' (Soldier Of Fortune) and many other settings.</para>
<para>Like text adventures, FPS fit the engine/datafile format. The engine refers to the actual game itself (Doom, Quake,
Heretic2) and plays out the maps and bad guys outlined by the datafile (<filename>doom2.wad</filename>,
<filename>pak0.pak</filename>, etc). Many FPS games allow people to write their own non-commercial datafile. There are
hundreds, even thousands of non-commercial Doom datafiles that you can download for free off the net. Often, companies
release their engines so the open source community so we can hack and improve them. However, the original data files are
kept proprietary. To this day, you still have to purchase <filename>doom.wad</filename>.</para>
</sect2>
<sect2><title>Side Scrollers</title>
<para>Side scrollers are similar to FPS but you view your character as a 2D figure who runs around various screens
shooting at things or performing tasks. Examples would be Abuse for Linux and the original Duke Nukem. They don't
necessarily have to be violent, like <application>xscavenger</application>, a clone of the old 8-bit game Lode
Runner.</para>
</sect2>
<sect2><title>Third Person Shooters</title>
<para>Similar to FPS, but you view your character in third person and in 3D. On modern third person shooters you can
usually do some really kick-butt maneuvers like Jackie Chan style back flips and side rolls. The canonical example would
be Tomb Raider. On the Linux platform, we have Heretic 2 and Heavy Metal FAKK2.</para>
</sect2>
<sect2 id="rpg"><title>Role Playing Game (aka RPG)</title>
<para>Anyone who has played games like Dungeons & Dragons or Call of Cthulhu knows exactly what an RPG is. You play a
character, sometimes more than one, characterized by traits (eg strength, dexterity), skills (eg explosives, basket
weaving, mechanics) and properties (levels, cash). As you play, the character becomes more powerful and the game adjusts
itself accordingly, so instead of fighting orcs, at high levels you start fighting black dragons. The rewards increase
correspondingly. At low levels you might get some gold pieces as a reward for winning a battle. At high levels, you
might get a magic sword or a kick-butt assault rifle.</para>
<para>RPG's generally have a quest with a well defined ending. In nethack you need to retrieve the amulet of Yendor for
your god. In Ultima II, you destroy the evil sorceress Minax. At some point, your character becomes powerful enough that
you can `go for it' and try to complete the quest.</para>
<para>While the insanely popular Ultima series, written by Richard Garriot (aka Lord British) for Origin, was not the
first RPG, it popularized and propelled the RPG genre into mainstream. Ultima I was released in 1987 and was the game
that launched 9 (depending on how you want to count them) very popular sequels, finishing with Ultima IX: Ascension. You
can play Ultima VII under Linux with Exult (<xref linkend="exult">).</para>
<para>The canonical RPG on Linux is Rogue (the ncurses library started life as a screen handling routine for Rogue!) and
it has infinite variants like Zangband and Nethack (which has many variants itself). Some RPG's are quite complicated and
great feats of programming. There seems to be a deficiency of commercial RPGs for Linux. Not counting the rogue
variants, there's also a deficiency of open source RPGs too.</para>
</sect2>
</sect1>
<sect1><title>Libraries</title>
<para>We'll run through the different gaming libraries you'll see under Linux.</para>
<sect2 id="glide2"><title>What is Glide2?</title>
2003-07-29 19:48:36 +00:00
<para>Glide2 is a low level graphics API and driver that accesses 3D hardware accelerated functions on 3dfx's Voodoo I, II
and III cards, under XFree86 3.x.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>A program can only use the special hardware accelerated features of these cards by using the Glide2 library in one
of two ways:</para>
2003-04-01 00:59:47 +00:00
<itemizedlist>
<listitem><para>directly written using Glide2 (Myth II, Descent III)</para></listitem>
<listitem><para>indirectly using Mesa built with a Glide2 backend to simulate OpenGL (Rune, Unreal
Tournament)</para></listitem>
</itemizedlist>
<para>3dfx opened up the specifications and source code to the open source community. This allowed Daryll Strauss to port
Glide2 to Linux which enabled XFree86 3.x users to use Voodoo I, II and III cards under Linux.</para>
<para>Since Glide2 accesses the video card directly, Glide2 applications will either need to be run by root or be setuid
root. A way around this was to create the kernel 3dfx module. This module (and its device file
<filename>/dev/3dfx</filename>) allows Glide2 graphical hardware acceleration for non-root users of non-setuid
applications.</para>
<para>Unfortunately, Glide2 is also a dead issue. It's only used for Voodoo I, II, III boards (which are becoming
outdated), under XFree86 3.x (most people use XFree86 4.x). And since 3dfx is now a defunct company, it's a sure bet that
no more work will be done on Glide2 and no more games will be written using Glide2.</para>
</sect2>
<sect2 id="glide3"><title>What is Glide3?</title>
<para>Unlike Glide2, Glide3 is not an API used for game programming. It exists only to support DRI on Voodoo III, IV and
V boards under XFree86 4.x. None of the games which use Glide2 will work with Glide3. This shouldn't be a surprise
since Glide2 and Glide3 support different video cards and different versions of XFree86. The only video card that can use
both Glide2 (under XFree86 3.x) and Glide3 (under XFree86 4.x) is the Voodoo III. It's reported that a Voodoo III using
Glide2 will outperform a Voodoo III using Glide3.</para>
<para>When you use a Voodoo III, IV or V under XFree86 4.x, you want to use a version of Mesa (see <xref linkend="mesa">)
which was compiled to use Glide3 as a backend to ensure hardware accelerated OpenGL on your system.</para>
</sect2>
<sect2 id="opengl"><title>What is OpenGL?</title>
<para>OpenGL is a high level graphics programming API originally developed by SGI, and it became an industry standard for
2D and 3D graphics programming. It's defined and maintained by the Architectural Revision Board (ARB), an organization
which include representatives from SGI, IBM, DEC, and Microsoft. OpenGL provides a powerful, complete and generic feature
set for 2D and 3D graphics operations.</para>
<para>There are 3 canonical parts to OpenGL:</para>
<itemizedlist>
<listitem><para>GL: The OpenGL core calls</para></listitem>
<listitem><para>GLU: The utility calls</para></listitem>
<listitem><para>GLUT: System independent window event handling (mouse events, keyboard events, etc.).</para></listitem>
</itemizedlist>
<para>OpenGL is not only an API, it's also an implementation, written by SGI. The implementation tries to use hardware
acceleration for various graphics operations whenever available, which depends on what videocard you have in you computer.
If hardware acceleration is not possible for a specific task, OpenGL falls back on software rendering. This means that
when you get OpenGL from SGI, if you want any kind of hardware acceleration at all, it must be OpenGL written and compiled
specifically for some graphics card. Otherwise, all you'll get is software rendering. The same thing is true for OpenGL
clones, like Mesa.</para>
<para>OpenGL is the open source equivalent to Direct3D, a component of DirectX (<xref linkend="directx">). The important
difference being that since OpenGL is open (and DirectX is closed), games written in OpenGL are much easier to port to and
co-develop on Linux than games written using DirectX.</para>
</sect2>
<sect2 id="mesa"><title>What is Mesa?</title>
<para>Mesa <<ulink url="http://www.mesa3d.org"></ulink>> is a free implementation of the OpenGL API, designed and
written by Brian Paul. While it's not officially certified (that would take more money than an open source project has),
it's an almost fully compliant OpenGL implementation conforming to the ARB specifications. It's reported that Mesa is
even faster than SGI's own OpenGL implementation.</para>
<para>Just like OpenGL, Mesa makes use of hardware acceleration whenever possible. When a particular graphics task isn't
able to be hardware accelerated by the video card, it's software rendered; the task is done by your computer's CPU
instead. This means that there are different builds of Mesa depending on what kind of video card you have. Each build
uses a different library as a backend renderer. For example, if you have a Voodoo I, II or III card under XFree86 3.x,
you'd use mesa+glide2 (written by David Bucciarelli) which is the Mesa implementation of OpenGL that uses Glide2 as a
backend to render for graphical operations.</para>
</sect2>
<sect2><title>What is DRI?</title>
<para>Graphics rendering has 3 players: the client application (like Quake 3), the X server and the hardware (the graphics
card). Previously, client applications were prohibited from writing directly to hardware, and there was a good reason for
this. A program that is allowed to directly write to hardware can crash the system in any number of ways. Rather than
trusting programmers to write totally bug free, cooperative programs that access hardware, Linux simply disallowed it.
However, that changed under X 4.x with DRI (Direct Rendering Infrastructure <<ulink
url="http://www.dri.sourceforge.net"></ulink>>. DRI allows X clients to write 3D rendering information directly to the
video card in a safe and cooperative manner.</para>
<para>DRI gets the X server out of the way so the 3D driver (Mesa or OpenGL) can talk directly to the
hardware. This speeds things up. The 3D rendering information doesn't even have to be hardware
accelerated. On a technical note, this has a number of virtues.</para>
<itemizedlist>
<listitem><para>Vertex data doesn't have to be encoded/decoded via GLX.</para></listitem>
<listitem><para>Graphics data isn't sent over a socket to the X server.</para></listitem>
<listitem><para>On uni-processor machines the CPU doesn't have to change context between XFree86 and its client to render
the graphics.</para></listitem>
</itemizedlist>
</sect2>
<sect2><title>What is GLX?</title>
<para>GLX is the X extension used by OpenGL programs, it is the glue between the platform independent OpenGL and platform
dependent X.</para>
</sect2>
<sect2><title>What is Utah GLX?</title>
<para>Utah-GLX is the precursor to DRI. It makes some different design decisions regarding separation of data and methods
of accessing the video card like relying on root access rather than creating the kernel infrastructure for secure access.
It provides support for a few cards which are not well supported by DRI like the ATI Rage Pro family, S3 Virge (although
anyone using this for gaming is, well, nuts), and an open source TNT/TNT2 driver (which is very incomplete). The TNT/TNT2
driver is based on reverse-engineering of the obfuscated source code release of the X 3.3 drivers by nVidia. However,
they're really incomplete, and effectively, unusable.</para>
</sect2>
<sect2 id="xlib"><title>What is xlib?</title>
<para>Every once in awhile you'll see some sicko (said with respect) write a game in xlib. It is a set of C libraries
which comprise the lowest level programming interface for XFree86. Any graphics programming in X ultimately makes use of
the xlib library.</para>
<para>It's not an understatement to say that xlib is long winded, arcane and complicated. Because of this, there are lots
of libraries like SDL (<xref linkend="sdl">) for 2D graphics, OpenGL (<xref linkend="opengl">) for 3D graphics and widget
sets (<xref linkend="widgetset">) for widgets within windows which hide the details of different aspects of xlib
programming.</para>
<para>While some games are written in xlib, like the Doom Editor Yadex, xlib itself is not a serious game writing library.
Most games don't need the low-level interface that xlib provides. In addition, by using the higher level libraries, a
game writer can develop his game on multiple platforms, even ones that don't use XFree86.</para>
</sect2>
<sect2 id="widgetset"><title>What is a widget set?</title>
<para>Widgets are objects that make up a GUI application's interface. They include things like text entry boxes, pulldown
menus, slider bars, radio buttons and much more. A widget set is a collection of related widgets that are designed to
have a common interface and a consistant "feel". Gtk is the canonical widget set on Linux, but there are many others like
fltk (a small C++ widget set), Xaw, Qt (the widget set of KDE), and Motif (the widget set used by Netscape). Motif used
to be the king of widget sets in the Unix world, but it was very expensive to license. The Open Group finally opened up
Motif's license for open source operating systems, but it was too little too late. There are many completely open source
widget sets which are more complete and much nicer looking than Motif, including Lesstif, a totally free Motif
clone.</para>
</sect2>
<sect2 id="sdl"><title>What is SDL (Simple DirectMedia Layer)?</title>
<para>SDL <<ulink url="http://www.libsdl.org"></ulink>> is a library by Sam Lantiga (graduate of UCD, yeah!). It's
actually a meta-library, meaning that not only is it a graphics library which hides the details of xlib programming, it
provides an easy interface for sound, music and event handling. It's LGPL'd and provides joystick and OpenGL support as
well. Unlike xlib (<xref linkend="xlib">), SDL is very suited for game programming.</para>
<para>The most striking part of SDL is that it's a cross platform library. Except for a few details, a program written in
SDL will compile under Linux, MS Windows, BeOS, MacOS, MacOS X, Solaris, IRIX, FreeBSD, QNX and OSF. There are SDL
2003-07-29 19:48:36 +00:00
extensions written by various people to do things like handle any graphics format you care to mention, play mpegs, display
2003-04-01 00:59:47 +00:00
truetype fonts, sprite handling and just about everything under the sun. SDL is an example of what all graphics libraries
should strive for.</para>
<para>Sam had an ulterior motive for writing such a cool library. He was the lead programmer for Loki Software (he now
codes for Blizzard Software), which used SDL in all of its games except for Quake3.</para>
</sect2>
<!-- sent an email 12 june 2002 about comments/suggestions. No reply so far. -->
<sect2 id="ggi"><title>What is GGI?</title>
<para>GGI <<ulink url="http://www.ggi-project.org"></ulink>> is a project which aims to implement a graphics
abstraction layer in lower level code, put graphics hardware support into a common codebase, and bring higher stability
and portability to graphics applications. LibGGI applications run on SVGAlib, fb, and X servers among others. Judging
from their screenshots, this is quite a powerful library.</para>
<para>Applications that use LibGGI directly include Heroes, Ultrapoint, Quake, and Berlin. Most applications that use
SVGALib can be run on X or any other LibGGI backend by using a wrapper library which re-implements SVGALib (<xref
linkend="svgalib">) using LibGGI. SDL (<xref linkend="sdl">) and clanlib (<xref linkend="clanlib">) applications can
display on LibGGI but often the native drivers for these libraries are faster, however it's a good way to get SDL,
clanlib, and SVGALib applications to run where they would not before.</para>
<para>GGI has a sister project, KGI, which is developing a kernel-level alternative to systems like the linux framebuffer
and the DRI. This project is much less far along than LibGGI itself, but promises to combine DRI-level speeds and the
stability and security UNIX users expect.</para>
</sect2>
<!-- sent an email 12 june 2002 about comments/suggestions -->
<sect2 id="svgalib"><title>What is SVGAlib? Frame buffer? Console?</title>
<para>The console is the dark non-graphical screen you look at when your computer first boots up (and you don't have
<application>xdm</application> or <application>gdm</application> running). This is opposed to the X environment which has
all sorts of GUI things like xterms. It's a common misconception that X means graphics and console means no graphics.
There are certainly graphics on the console—we will discuss the two most common ways to achieve this.</para>
<para>SVGAlib is a graphics library that lets you draw graphics on the console. There are many graphical applications and
games that use SVGAlib like <application>zgv</application> (a console graphical image viewer),
<application>prboom</application> and <application>hhexen</application>. I happen to be a fan of this library and of
graphical console games in general; they are extremely fast, fullscreen and compelling. There are three downsides to
SVGAlib. First, SVGAlib executables need to be run by root or be setuid root, however, the library releases root status
immediately after the executable begins to run. Secondly, SVGAlib is video card dependent–if your video card isn't
supported by SVGAlib, you're out of luck. Third, SVGAlib is Linux only. Games written in SVGAlib will only work on
Linux.</para>
<para>Frame buffers are consoles implemented by a graphics mode rather than a BIOS text mode. Why simulate text mode in a
graphical environment? This allows us to run graphical things in console, like allowing us to choose any font we want the
console to display (which is normally set by BIOS). There's a good Frame Buffer HOWTO available from LDP. Graphical
console games written using the frame buffer suffer from the same deficiencies of the SVGA library: not all hardware is
supported and the code will only run on Linux.</para>
</sect2>
<sect2 id="openal"><title>What is OpenAL?</title>
<para>OpenAL <<ulink url="http://www.openal.org"></ulink>> aims to be for sound what OpenGL is for graphics.
Jointly developed by Loki Software and Creative Labs, it sets out to be a vendor neutral and cross platform API for audio.
It is licensed LGPL and the specs can be had for free from the OpenAL website. OpenAL is fully functional, but now that
Loki Software is no more its future development is questionable.</para>
</sect2>
<sect2 id="directx"><title>What is DirectX?</title>
<para>DirectX is a collection of proprietary multimedia API's, first developed by Microsoft in 1995, for its various
Windows OS's. It's a mistake to say something like "DirectX is like OpenGL" or "DirectX is like SDL", as is commonly
said in DirectX tutorials. Multimedia API's are more centralized on Windows than they are on Linux. A more accurate
2003-07-29 19:48:36 +00:00
statement would be something like "DirectX is like DRI, OpenGL and SDL combined". As of June 2003, the most recent version
of DirectX is 9.0. The components of DirectX are:</para>
2003-04-01 00:59:47 +00:00
<variablelist>
<varlistentry><term>DirectDraw</term>
<listitem><para>DirectDraw gives direct access to video memory, like DRI, so 2D graphics can be blitted directly to the
video card. DirectDraw is like the graphical component of SDL, but the direct video card access is done by DRI rather
than SDL. This is why a game can easily take out a Windows system but should not take down a Linux
system.</para></listitem></varlistentry>
<varlistentry><term>Direct3D (D3D)</term>
<listitem><para>Direct3D, like OpenGL, provides a 3D graphics API. Whereas OpenGL is open source, lower level and
compiles under a multitude of operating systems, D3D is proprietary, higher level and only compiles on Windows. D3D
first appeared in DirectX 2, released in 1996.</para></listitem></varlistentry>
<varlistentry><term>DirectXAudio</term>
<listitem><para>Direct Audio is a combination of 2 audio API's, DirectSound and DirectMusic, which allows direct access
to the sound card for sound and music playback.</para></listitem></varlistentry>
<varlistentry><term>DirectInput</term>
<listitem><para>DirectInput gives support for gaming input devices such as joysticks.</para></listitem></varlistentry>
<varlistentry><term>DirectPlay</term>
<listitem><para>DirectPlay gives support for simplified networking for multiplayer gaming.</para>
</listitem></varlistentry>
<varlistentry><term>DirectShow</term>
<listitem><para>DirectShow provides support for movie files like AVI and MPG. It was a separate API from DirectX, but
was integrated with DirectX 8.</para></listitem></varlistentry>
<varlistentry><term>DirectSetup</term>
<listitem><para>This API provides a way to install DirectX from within an application to simplify game
installation.</para></listitem></varlistentry>
</variablelist>
<para>DirectX is "kind of" supported by winex (<xref linkend="winex">), poorly supported by wine (<xref
linkend="wine">), barely supported by vmware (<xref linkend="vmware">) and unsupported by Win4Lin (<xref
linkend="win4lin">).</para>
<para>One comment about portability. Each component of DirectX has multiple corresponding library on
Linux. Moreover, a game writer who uses libraries like OpenGL, GGI or SDL will write a game which will
trivially compile on Windows, Linux and a multitude of other OS's. Yet game companies persist using
DirectX and therefore limit their audience to Windows users only. If you're a game writer, please
consider using cross platform libraries and stay away from DirectX.</para>
2003-07-29 19:48:36 +00:00
<para>A company named realtechVR started an open source project, DirectX Port, <<ulink
url="http://www.v3x.net/directx"></ulink>> which, like wine, provides a Direct3D emulation layer that implements
Direct3D calls. The project was focused on the BeOS platform, but is now focused on MacOS and Linux. You can get the
latest cvs from their sourceforge page at <<ulink url="http://sourceforge.net/projects/dxglwrap"></ulink>>.</para>
2003-04-01 00:59:47 +00:00
</sect2>
<sect2 id="clanlib"><title>Clanlib</title>
<para>ClanLib is a medium level development kit. At its lowest level, it provides a platform
independent (as much as that is possible in C++) way of dealing with display, sound, input, networking,
files, threading and such. ClanLib builds a generic game development framework, giving you easy
handling of resources, network object replication, graphical user interfaces (GUI) with theme support,
game scripting and more.</para>
</sect2>
</sect1>
<sect1><title>XFree86 and You</title>
2003-07-29 19:48:36 +00:00
<para>If you're going to game under X, it's crucial that you know a bit about X. The "X Window User HOWTO", and especially
"man XF86Config" are <emphasis>required</emphasis> reading. Don't short change yourself; read them. They have an extremely
high "information to space" ratio. Many problems can be fixed easily if you know your way around
<filename>XF86Config</filename> (or <filename>XF86Config-4</filename>).</para>
2003-04-01 00:59:47 +00:00
<sect2><title>Getting information about your X system</title>
<para>Whether you're trying to diagnose an X problem or requesting help from a mailing list or Usenet newsgroup, you'll
want to have as much information available as possible. These are a set of tools you can use to obtain that
information.</para>
<sect3><title>Probeonly</title>
<para>One of the best diagnostic tools and sources of information about your X system is <command>probeonly</command>
output. To use it, kill X if it's already running and from a console, type:</para>
<screen>
X -probeonly 2> X.out
</screen>
<para>Yes, that's a single dash; so much for standards. The output of X goes to stderr, so we have to redirect
stderr with "2>" to a file named <filename>X.out</filename>. This file will have almost everything there is to know about your X system.
It's crucial that you know the difference between the various markers you'll see in probeonly output:</para>
<screen>
(--) probed (**) from config file (==) default setting
(++) from command line (!!) notice (II) informational
(WW) warning (EE) error (??) unknown.
</screen>
<para>Here's an example of some information I gleaned from my output:</para>
<para>I'm running at 16 bpp color:</para>
<screen>
(**) TDFX(0): Depth 16, (--) framebuffer bpp 16
</screen>
<para>X has detected what my videocard chipset and videoram are:</para>
<screen>
(--) Chipset 3dfx Voodoo5 found
(--) TDFX(0): VideoRAM: 32768 kByte Mapping 65536 kByte
</screen>
</sect3>
<!-- here -->
<sect3><title>Getting info about your setup: xvidtune</title>
<para><application>xvidtune</application> is your friend when your X screen is shifted a little bit too far to the
right, or if the vertical length is too small to fit on your monitor. However, it's a great diagnostic tool also.
It'll give you:</para>
<itemizedlist>
<listitem><para>the hsync/vsync range specified in your XF86Config file</para></listitem>
<listitem><para>the 4 horizontal and 4 vertical numbers which defines your videomode (the 1st horizontal/vertical
numbers gives the screen resolution). These 8 numbers will tell you which modeline your X uses. See the XFree86 Video
2003-07-29 19:48:36 +00:00
Timings Howto for more information. Note that explicit modelines are no longer necessary, since XFree 4.0.1 and up
computes modetimings automatically based on your monitor's and video card's capabilities. However, there may be times
when you'll want to play around with mode timings, like for weird hardware or if want to tweak your
display.</para></listitem>
2003-04-01 00:59:47 +00:00
<listitem><para>the "dot clock" your videocard is running at.</para></listitem>
</itemizedlist>
</sect3>
<sect3><title>Getting info about your setup: xwininfo</title>
<para><command>xwininfo</command> tells you all sorts of information about X windows. And actually, your "background"
or "root" window is considered a window too. So when xwininfo asks you to click on the window you want the information
on, click on your background. It'll tell you things like screen and window resolution, color depth, window gravity
state (which gives a hint to the window manager about where to place new windows), backing store usage and more.</para>
</sect3>
<sect3><title>Other sources of information</title>
<para><command>xdpyinfo</command> gives cool stuff, like X version and loaded extensions (invaluable when trying to see
what's missing, like GLX, DRI, XFree86-VidMode, etc.).</para>
</sect3>
<sect3><title>Getting information about your 3D system</title>
2003-07-29 19:48:36 +00:00
<para><command>glxinfo</command> gives lots of useful information about OpenGL like whether direct rendering enabled,
the currently installed versions of glx and mesa, vendor/renderer strings, the GL library files being used and
2003-04-01 00:59:47 +00:00
more.</para>
</sect3>
</sect2>
2003-07-29 19:48:36 +00:00
<sect2 id="nowm"><title>Playing Games In X Without a Window Manager</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>When playing a game under X, you should consider starting X without a window manager (wm). Heavy weight wm's, like
Enlightenment, may produce a noticeable slow down. Even light weight wm's, like twm, rob your CPU of clock cycles (and in
twm's case, even full screen games will have a frame around the window). To run a game without a wm, modify
<filename>.xinitrc</filename>, which tells X what to run upon starting, in your home directory. Here is what my .xinitrc
looks like:</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<screen>
#quake3 +set r_gldriver libGR.so.1
#exec ut
#lsdldoom -server 2
#exec tribes2
exec /usr/bin/enlightenment
</screen>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>You'll usually see a window or desktop manager being executed from this file (GNOME or KDE). Comment out the lines
containing the wm or desktop manager with a pound sign (#) and place your game on a new line with any command line
arguments you want to pass. If the game is not located in your $PATH, give its full path name. Note that this is for
people who use `startx' to start X.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>I never use things like gdm or run-level 5 (so I'm not positive here), but I suspect that if you do, you'll need to
do things a bit differently. My best guess is to go to single user mode (run-level 1) by:</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<screen>
# telinit 1
</screen>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>then edit .xinitrc, then go back to run-level 5 by</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<screen>
# telinit 5
</screen>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Then when you stop playing, go to run-level 1, modify .xinitrc then go back to run-level 5. I don't use this stuff,
so I'm not sure, but you may need to kill gdm. I'd appreciate some feedback on this.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect2>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect1>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect1><title>Various Topics</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect2 id="mtrr"><title>Memory Type Range Registers</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Starting with Pentium class processors and including Athlon, K6-2 and other CPUs, there are Memory Type Range
Registers (MTRR) which control how the processor accesses ranges of memory locations. Basically, it turns many smaller
separate writes to the video card into a single write (a burst). This increases efficiency in writing to the video card and
can speed up your graphics by 250% or more.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>See <filename>/usr/src/linux/Documentation/mtrr.txt</filename> for details. Note that since this file was written,
XFree86 has been patched to automatically detect your video RAM base address and size and set up the MTRRs.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect2>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect2 id="milkingperformance"><title>Milking performance from your system for all it's worth</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<itemizedlist>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<listitem><para>If for some reason you're using X 3.3, follow the instructions given by <filename>mtrr.txt</filename> (see
section <xref linkend="mtrr"> to set up your MTRRs. X 4.0 does this automatically for you.</para></listitem>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<listitem><para>If you're playing a game under X, don't run a window manager, and <emphasis>certainly</emphasis> don't run a
desktop manager like GNOME or KDE. See section <xref linkend="nowm"> for details.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Kill all non-essential processes (you'll have to do this as root) by using the startup scripts on your system. On
Debian, the startup scripts for run-level 2 are located in /etc/rc2.d/. You can kill a service in an orderly manner by
sending its startup script the `stop' command:</para>
2003-04-01 00:59:47 +00:00
<screen>
# cd /etc/rc2.d
# ./ntpd stop
</screen>
<para>Another (radical) option is to simply put yourself in single-user mode with</para>
<screen>
# telinit 1
</screen>
2003-07-29 19:48:36 +00:00
<para>This will even get rid of getty; your system will only be running whatever is absolutely crucial to its operation.
You'll have something like 10 processes running. The downside is that you'll have to play the game as root. But your
process table will be a ghost town, and all that extra CPU will go straight to your game.</para></listitem>
2003-04-01 00:59:47 +00:00
</itemizedlist>
</sect2>
<sect2><title>About libraries on Linux</title>
<para>A common problem you'll see in gaming is a library file not being found. They're kind of mysterious
and have funny names, so we'll go over libraries on Linux for a bit. There are two types of libraries,
static and dynamic. When you compile a program, by default, <command>gcc</command> uses dynamic
libraries, but you can make <command>gcc</command> use static libraries instead by using the
<option>-static</option> switch. Unless you plan on compiling your games from source code, you'll
mainly be interested in dynamic libraries.</para>
<sect3><title>Dynamic libraries</title>
<para>Dynamic libraries, also called a “shared library”, provide object code for an
application while it's running. That is, code gets linked into the executable at run time, as opposed
to compile time. They're analagous to the <literal>.dll</literal>'s used by Windows. The program
responsible for linking code “on the fly” is called <command>/etc/ld.so</command>, and the
dynamic libraries themselves usually end with <literal>.so</literal> with a version number, like:</para>
<screen>
/usr/lib/libSDL.so
/lib/libm.so.3
</screen>
<para>When using <command>gcc</command>, you refer to these libraries by shaving off the strings
<literal>lib</literal>, <literal>.so</literal> and all version numbers. So to use these two libraries,
you would pass <command>gcc</command> the <literal>-lSDL -lm</literal> options. <command>gcc</command>
will then `place a memo inside the executable' that says to look at the files <filename>
/usr/lib/libSDL.so</filename> and <filename>/lib/libm.so.3</filename> whenever an SDL or math function
is used.</para>
</sect3>
<sect3><title>Static libraries</title>
<para>In contrast to dynamic libraries which provide code while the application runs, static libraries
contain code which gets linked (inserted) into the program while it's being compiled. No code gets
inserted at run time; the code is completely self-contained. Static libraries usually end with
<literal>.a</literal> followed by a version number, like:</para>
<screen>
/usr/lib/libSDL.a
/usr/lib/libm.a
</screen>
<para>The <literal>.a</literal> files are really an archive of a bunch of <literal>.o</literal> (object)
files archived together, similar to a tar file. You can use the <command>nm</command> to see what
functions a static library contains:</para>
<screen>
% nm /usr/lib/libm.a
...
e_atan2.o:
00000000 T __ieee754_atan2
e_atanh.o:
00000000 T __ieee754_atanh
00000000 r half
00000010 r limit
00000018 r ln2_2
...
</screen>
<para>When using <command>gcc</command>, you refer to these libraries by shaving off the strings
“lib”, “.a” and all version numbers. So to use these two libraries, you would
pass <command>gcc</command> the <literal>-lSDL -lm</literal> options. <command>gcc</command> will then
`bolt on' code from <filename class="libraryfile">/usr/lib/SDL.a</filename>> and <filename class="libraryfile">/usr/lib/libm.a</filename>
whenever it sees a math function during the compilation process.</para>
</sect3>
<sect3><title>How are library files found</title>
<para>If you compile your own games, your biggest problem with libraries will either be that
<command>gcc</command> can't find a static library or perhaps the library doesn't exist on your system.
When playing games from binary, your library woes will be either be that <command>ld.so</command> can't
find the library or the library doesn't exist on your system. So it makes some sense to talk about how
<command>gcc</command> and <command>ld.so</command> go about finding libraries in the first
place.</para>
<para><command>gcc</command> looks for libraries in the ``standard system directories'' plus any
directories you specify with the <option>-L</option> option. You can find what these standard system
directories are with <command>gcc -print-search-dirs</command></para>
<para><command>ld.so</command> looks to a binary hash contained in a file named
<filename>/etc/ld.so.cache</filename> for a list of directories that contain available dynamic
libraries. Since it contains binary data, you cannot modify this file directly. However, the file is
generated from a text file <filename>/etc/ld.so.conf</filename> which you can edit. This file contains
a list of directories that you want <command>ld.so</command> to search for dynamic libraries. If you
want to start putting dynamic libraries in <filename>/home/joecool/privatelibs</filename>, you'd add
this directory to <filename>/etc/ld.so.conf</filename>. Your change doesn't actually make it into
<filename>/etc/ld.so.cache</filename> until you run <command>ldconfig</command>; once it's run,
<command>ld.so</command> will begin to look for libraries in your private directory.</para>
<para>Also, even if you just add extra libraries to your system, you must update
<filename>ld.so.cache</filename> to reflect the presense of the new libraries.</para>
</sect3>
</sect2>
</sect1>
<sect1><title>When Bad Things Happen To Good People</title>
<para>Of course we can't cover every Bad Thing that happens, but I'll outline some items of common
sense.</para>
<para>There are two types of bad things: random and repeatable. It's very difficult to diagnose or fix
random problems that you don't have any control over when they happen or not. However, if the problem is
repeatable "it happens when I press the left arrow key twice", then you're in business.</para>
<sect2><title>RTFM!</title>
<para>Read the friendly manual. The `manual' can take on a few forms. For open source games there's
the readme files that come with the game. Commercial games will have a printed manual and maybe some
readme files on the CD the game came on. Don't forget to browse the CD your game came on for helpful
tips and advice.</para>
<para>Don't forget the game's website. The game's author has probably seen people with your exact same
problem many times over and might put information specific to that game on the website. A prime example
of this is Loki Software's online FAQs located at
<ulink url="http://faqs.lokigames.com"></ulink>.</para>
</sect2>
<sect2><title>Look For Updates and Patches</title>
<para>If you're playing an open source game that you compiled, make sure you have the newest version by
checking the game's website. If your game came from a distro make sure there's not an update rpm/deb
for the game.</para>
<para>Commercial game companies like Loki release patches for their games. Often a game will have MANY
patches (Myth2) and some games are unplayable without them (Heretic2). Check the game's website for
patches whether you have a problem running the game or not; there may be an update for a security
problem that you may not even be aware of.</para>
<para>By the way, Loki now has a utility that searches for Loki Software on your hard drive and
automatically updates them. Check out <ulink url="http://updates.lokigames.com"></ulink>.</para>
</sect2>
<sect2><title>Newsgroups</title>
<para>If you don't know what netnews (Usenet) is, then this is definitely worth 30 minutes of your time
to learn about. Install a newsreader. I prefer console tools more, so I use tin, but slrn is also
popular. Netscape has a nice graphical "point and click" newsreader too.</para>
<para>For instance, I can browse Loki Software's news server with <command>tin -g
news.lokigames.com</command>. You can also specify which news server to use using the
<varname>$NNTP</varname> environment variable or with the file
<filename>/etc/nntpserver</filename>.</para>
</sect2>
<sect2><title>Google Group Search</title>
<para>Every post made to Usenet gets archived at
Google's database at <ulink url="http://groups.google.com"></ulink>. This
archive used to be at <ulink url="http://www.deja.com"></ulink>, but was bought by Google. Many people still know the archive as
"deja".</para>
<para>It's almost certain that whatever problem you have with Linux, gaming related or not, has already
been asked about and answered on Usenet. Not once, not twice, but many times over. If you don't
understand the first response you see (or if it doesn't work), then try one of the other many replies.
If the page is not in a language you can understand, there are many translation sites which will convert
the text into whatever language you like, including
<ulink url="http://www.freetranslation.com"></ulink> and
<ulink url="http://translation.lycos.com"></ulink>. My web browser of choice, Opera (available at
<ulink url="http://www.opera.com "></ulink> allows you to use the right mouse button to select a
portion of text and left click the selection to translate it into another language. Very useful when a
Google group search yields a page in German which looks useful and my girlfriend (who reads German well)
isn't around.</para>
<para>The Google group search has a basic and advanced search page. Don't bother with the simple
search. The advanced search is at <ulink url="http://groups.google.com/advanced_group_search"></ulink></para>
<para>It's easy to use. For example, if my problem was that Quake III crashed everytime Lucy jumps, I
would enter "linux quake3 crash lucy jumps" in the "Find messages with all of the words" textbox.</para>
<para>There are fields for which newsgroup you want to narrow your search to. Take the time to read and
understand what each field means. I promise you. You won't be disappointed with this service. Use it,
and you'll be a much happier person. Do note that they don't archive private newsgroups, like Loki
Software's news server. However, so many people use Usenet, it almost doesn't matter.</para>
</sect2>
<sect2><title>Debugging: call traces and core files</title>
<para>This is generally not something you'll do for commercial games. For open source games, you can
help the author by giving a corefile or stack trace. Very quickly, a core file (aka core dump) is a
file that holds the "state" of the program at the moment it crashes. It holds valuable clues for the
programmer to the nature of the crash -- what caused it and what the program was doing when it happened.
If you want to learn more about core files, I have
a great gdb tutorial at <ulink url="http://www.dirac.org/linux"></ulink>.</para>
<para>At the *very* least, the author will be interested in the call stack when the game crashed. Here
is how you can get the call stack at barf-time:</para>
<para>Sometimes distros set up their OS so that core files (which are mainly useful to programmers)
aren't generated. The first step is to make your system allow unlimited coresizes:</para>
<screen>
ulimit -c unlimited
</screen>
<para>You will now have to recompile the program and pass the -g option to gcc (explaining this is
beyond the scope of this document). Now, run the game and do whatever you did to crash the program and
dump a core again. Run the debugger with the core file as the 2nd argument:</para>
<screen>
$ gdb CoolGameExecutable core
</screen>
<para>And at the (gdb) prompt, type "backtrace". You'll see something like:</para>
<screen>
#0 printf (format=0x80484a4 "z is %d.\n") at printf.c:30
#1 0x8048431 in display (z=5) at try1.c:11
#2 0x8048406 in main () at try1.c:6
</screen>
<para>It may be quite long, but use your mouse to cut and paste this information into a file. Email the
author and tell him:</para>
<orderedlist numeration="arabic">
<listitem><para>The game's name</para></listitem>
<listitem><para>Any error message that appears on the screen when the game crashes.</para></listitem>
<listitem><para>What causes the crash and whether it's a repeatable crash or not.</para></listitem>
<listitem><para>The call stack</para></listitem>
</orderedlist>
<para>If you have good bandwidth, ask the author if he would like the core file that his program dumped.
If he says yes, then send it. Remember to ask first, because core files can get very, very big.</para>
</sect2>
<sect2 id="savedgames"><title>Saved Games</title>
2003-07-29 19:48:36 +00:00
<para>If your game allows for saved games, then sending the author a copy of the saved game is useful because it helps the
tech reproduce whatever is going wrong. For commercial games, this option is more fruitful than sending a core file or
call stack since commercial games can't be recompiled to include debugging information. You should definitely ask before
sending a save game file because they tend to be long, but gaming companies usually have lots of bandwidth. Mike Phillips
(formerly of Loki Software) mentioned that sending in saved games to Loki is definitely a good thing.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Needless to say, this only applies if your game crashes reproducably at a certain point. If the game segfaults
every time you run it, or is incredibly slow, a saved game file won't be of much help.</para>
2003-04-01 00:59:47 +00:00
</sect2>
<sect2><title>What to do when a file or library isn't being found (better living through strace)</title>
<para>Sometimes you'll see error messages that indicate a file wasn't found. The file could be a
library:</para>
<screen>
% ./exult
./exult: error while loading shared libraries: libSDL-1.2.so.0: cannot load shared object
file: No such file or directory
</screen>
<para>or it could be some kind of data file, like a <filename class="extension">wad</filename> or <filename class="extension">map</filename> file:</para>
<screen>
% qf-client-sdl
IP address 192.168.0.2:27001 UDP Initialized Error: W_LoadWadFile: couldn't load gfx.wad
</screen>
<para>Suppose <filename>gfx.wad</filename> is already on my system, but couldn't be found because it isn't in the right
2003-07-29 19:48:36 +00:00
directory. Then where IS the right directory? Wouldn't it be helpful to know where these programs looked for the missing
files?</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>This is where strace shines. strace tells you what system calls are being made, with what arguments, and what their
return values are. In my `Kernel Module Programming Guide' (due to be released to LDP soon), I outline everything you may
want to know about strace. But here's a brief outline using the canonical example of what strace looks like. Give the
command:</para>
2003-04-01 00:59:47 +00:00
<screen>
strace -o ./LS_LOG /bin/ls
</screen>
2003-07-29 19:48:36 +00:00
<para>The -o option sends strace's output to a file; here, LS_LOG. The last argument to strace is the program we're
inspecting, here, "ls". Look at the contents of LS_LOG. Pretty impressive, eh? Here is a typical line:</para>
2003-04-01 00:59:47 +00:00
<screen>
open(".", O_RDONLY|O_NONBLOCK|0x18000) = 4
</screen>
2003-07-29 19:48:36 +00:00
<para>We used the <function>open()</function> system call to open "." with various arguments, and "4" is the return value
of the call. What does this have to do with files not being found?</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Suppose I want to watch the StateOfMind demo because I can't ever seem to get enough of it. One day I try to run it
and something bad happens:</para>
2003-04-01 00:59:47 +00:00
<screen>
% ./mind.i86_linux.glibc2.1
Loading & massaging...
Error:Can't open data file 'mind.dat'.
</screen>
<para>Let's use strace to find out where the program was looking for the data file.</para>
<screen>
strace ./mind.i86_linux.glibc2.1 2> ./StateOfMind_LOG
</screen>
<para>Pulling out vim and searching for all occurrences of <filename>mind.dat</filename>, I find the following lines:</para>
<screen>
open("/usr/share/mind.dat",O_RDONLY) = -1 ENOENT (No such file)
write(2, "Error:", 6Error:) = 6
write(2, "Can\'t open data file \'mind.dat\'."..., ) = 33
</screen>
2003-07-29 19:48:36 +00:00
<para>It was looking for <filename>mind.dat</filename> in only one directory. Clearly, <filename>mind.dat</filename>
isn't in <filename class="directory">/usr/share</filename>. Now we can try to locate <filename>mind.dat</filename> and
move it into <filename>/usr/share</filename>, or better, create a symbolic link.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>This method works for libraries too. Suppose the library <filename class="libraryfile">libmp3.so.2</filename> is in
<filename class="directory">/usr/local/include</filename> but your new game "Kill-Metallica" can't find it. You can use
strace to determine where Kill-Metallica was looking for the library and make a symlink from <filename
class="symlink">/usr/local/include/libmp3.so.2</filename> to wherever Kill-Metallica was looking for the library
file.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>strace is a very powerful utility. When diagnosing why things aren't being found, it's your best ally, and is even
faster than looking at source code. As a last note, you can't look up information in source code of commercial games from
Lokisoft or Tribsoft. But you can still use strace with them!</para>
2003-04-01 00:59:47 +00:00
</sect2>
<sect2 id="hosedconsoles"><title>Hosed consoles</title>
<para>Sometimes a game will exit abnormally and your console will get `hosed'. There are a few definitions of a hosed
console. The text characters could look like gibberish. Your normally nice black screen could look like a quasi-graphics
screen. When you press <keycap>ENTER</keycap>, a newline doesn't get echo'ed to the screen. Sometimes, certain keys of
the keyboard won't respond. Logging out and back in won't work, but there are a few things that might:</para>
<itemizedlist>
<listitem><para>At the prompt, type "reset". This should clear up many problems, including consoles hosed by an SVGAlib
or ncurses based game.</para></listitem>
2003-07-29 19:48:36 +00:00
<listitem><para>Try running the game again and normally. Once I had to kill Quake III in a hurry, so I performed a
<keysym>Ctl-Alt-Backspace</keysym>. The console was hosed with a quasi-graphics screen. Running Quake III and quitting
normally fixed the problem.</para></listitem>
2003-04-01 00:59:47 +00:00
<listitem><para>The commands deallocvt and openvt will work for most of the other problems you'll have.
<command>deallocvt N</command> kills terminal <literal>N</literal> entirely, so that <literal>Alt-FN</literal> doesn't
even work anymore. <command>openvt -c N</command> starts it back up.</para></listitem>
<listitem><para>If certain keys on your keyboard don't work, be creative. If you want to reboot but the `o' key doesn't
work, try using halt. One method I've come up with is typing a command at the prompt and using characters on the screen
with mouse cut/paste. For example, you can type "ps ax", and you're sure to have an `h', `a', `l' and a `t' somewhere
on the screen. You can use the mouse to cut and paste the word "halt".</para></listitem>
<listitem><para>The most regrettable option is a reboot. If you can, an orderly shutdown is preferable; use "halt" or
"shutdown". If you can't, ssh in from a another machine. That sometimes works when your console is very badly hosed.
In the worst case scenario, hit the reset or power switch.</para></listitem>
</itemizedlist>
<para>Note that if you use a journalling filesystem like ext3, reiserfs or xfs, hitting the power switch isn't all that
bad. You're still supposed to shutdown in an orderly manner, but the filesystem integrity will be maintained. You won't
see an fsck for the partitions that use the journalling filesystem.</para>
</sect2>
<sect2><title>Locked System</title>
<para>When a computer "locks", also called "hung", the keyboard and mouse become completely unresponsive. This is a
direct consequence of a bug in the Linux kernel. While Linux is known for stability, these things do happen, especiallly
for gaming which entails highly synchronized hardware events which occur very fast, even to a computer. When a computer
locks, it can be a "hard lock", meaning the kernel has completely stopped functioning. This often indicates misbehaving
or faulty hardware. There's no recovery from this kind of lock other than pressing the reset or power button. The lock
can also be a "soft lock", meaning that the kernel is still functioning in some capacity. It's possible to recover from
this gracefully.</para>
<itemizedlist>
<listitem><para>The first thing you should try is to hit <literal>control-alt-backspace</literal> which kills X. If you
gain control of your system, the kernel wasn't really locked in the first place. If this didn't work after a few
seconds, you'll definitely want to reboot the system using the following instructions.</para></listitem>
<listitem><para>Use <literal>control-alt-delete</literal> to reboot the system. You'll know this worked if you hear the
computer beep after a few seconds (this is BIOS saying "I'm OK" during a power on cycle).</para></listitem>
<listitem><para>Log into another system and ssh into the hung system. If you can ssh in, reboot or halt the
system.</para></listitem>
<listitem><para>If you can't ssh into the system, you'll need to use the "magic SysRq key" which is documented in
<filename>/usr/src/linux/Documentation/sysrq.txt</filename>. Here's a summary for the x86 architecture (see the
documentation for other architectures). Note if your keyboard doesn't have a <keycap>SysRq</keycap> key, use the
<keycap>PrintScreen</keycap> key:
<orderedlist>
<listitem><para>Hit <literal>alt-SysRq-s</literal>. This will attempt to sync your mounted filesystems so that
changes to files get flushed to disk. You may hear disk activity. If you're looking at a console, the system should
print the devices which were flushed.</para></listitem>
<listitem><para>A few seconds later, hit <literal>alt-SysRq-u</literal>. This will attempt to remount all your
mounted filesystems as read-only). You should hear disk activity. If you're looking at a console, the system will
print the devices which were remounted.</para></listitem>
<listitem><para>A few seconds later, use <literal>alt-SysRq-b</literal> to reboot the system.</para></listitem>
<listitem><para>You can hit <literal>alt-SysRq-h</literal> for a very terse help screen.</para></listitem>
</orderedlist></para></listitem>
</itemizedlist>
<para>To use the magic SysRq key, your kernel needs to have been compiled with magic SysRq support. You'll find this
option under "<literal>Kernel Hacking | Kernel Debugging | Magic SysRq key</literal>" in whatever kernel config menu you
like to use. If the magic SysRq key sequence doesn't shut your system down gracefully, your kernel has crashed hard and
you'll need to use the reset or power button to recover.</para>
</sect2>
</sect1>
2003-07-29 19:48:36 +00:00
<sect1><title>Video Cards</title>
<sect2><title>History</title>
<para>Once upon a time, a company in San Jose, California named 3dfx Interactive was king of the gaming video card market.
In October 1996 they released the Voodoo I, which was a phenomenal success. It was the first hardware accelerated card,
but only rendered 3D; it had to be piggybacked with a 2D video card. The idea was that 2D rendering was handled by a high
quality 2D video card (Matrox was immensely popular at the time) but 3D information (see Glide2, section <xref
linkend="glide2">) would be passed to the Voodoo I and rendered, using the Voodoo's fast hardware to perform the necessary
graphics calculations. They released the Voodoo Rush in April 1996. It should've been a more powerful card, with a 50MHz
GPU and 8MB of RAM. Even better, it was their first combined 2D/3D card, meaning that it freed up a valuable PCI slot
(most PC's only had a couple of PCI slots back then) but the Rush wasn't as popular. 3dfx removed the multi-texturing
unit from the Rush, and it was outperformed by the Voodoo I. At the time, ATI had their Rage series and Nvidia had their
Riva 128, but the Voodoo I blew them all away.</para>
<para>This was a good time for Linux. id Software's open sourced the Doom codebase and ported Quake I to Linux (December
1996). We were getting our first tastes of real commercial gaming. Life was simple: you purchased a Voodoo. And it felt
good, because 3dfx open sourced their drivers. The king of video cards worked with Linux developers. Not only did we
have the best video cards, but the drivers were all open source.</para>
<para>In March 1998, 3dfx released their Voodoo II, with its 3.6GB/sec memory bandwith, 12MB of video memory and 90MHz
core. It supported resolutions up to 1024x768. This was 3dfx in its heyday. Like the Voodoo I, the Voodoo II was a 3D
only card, and piggy backed with a 2D video card. The Voodoo Banshee was released in September 1998 as a combined 2D/3D
card, like the Rush. Despite the faster 100MHz core, the Banshee was outperformed by the Voodoo II because its
multi-texturing unit was removed, like with the Rush. And again like the Rush, it wasn't popular. But 3dfx reigned
supreme, and nobody could touch them.</para>
<para>In April 1999, the Voodoo III was released. There were a number of Voodoo III's, ranging from a 143MHz core speed
to 183MHz. There were TV-out versions. There were PCI and AGP versions (it was the first AGP video card). It was
another success, but 3dfx began to lose ground to Nvidia, which released their TNT 2. The TNT 2 outperformed the Voodoo
II, and accelerated 3D graphics at full 32 bit color, while the Voodoo's were stuck at 16 bit color. But life was still
good for Linux. We had a card that was almost neck-to-neck with Nvidia, our drivers were open source, and in December
1999, id Software gave us a huge gift: they open sourced the Quake I codebase.</para>
<para>Then Nvidia released the GeForce 256 in October 1999. 3dfx's Voodoo IV, its direct competitor, was about a year
late which is very bad when you're competing for a bleeding edge market. While Nvidia was putting real R&D into their
cards, 3dfx was simply adding more and faster RAM. The Voodoo IV and V rendered in full 32bpp color, had great AA support
(section <xref linkend="aa">), featured a 2nd GPU, more memory, and was arguably the king of of video cards. However,
3dfx's late release of the Voodoo IV and V coupled with the fact that the GeForce could be had for half the price meant
that 3dfx was sinking fast. For Linux, the newest Voodoo's could only accelerate at 16 and 24 bit color. Worse still,
the Voodoo V's 2nd GPU was unused by the Linux driver (and to this day, the Voodoo V is functionally equivalent to the
single GPU Voodoo IV on Linux). Most Windows users were switching to Nvidia, and despite the fact that the Nvidia drivers
were proprietary, even Linux users began to jump onto the Nvidia bandwagon. VA Linux, the largest Linux server vendor,
put Nvidia into their machines.</para>
<para>Then in April 2000, 3dfx was attacked on a different front: ATI started releasing their first generation Radeons.
Until this point, ATI had always been an innovative (they developed their own 3D acceleration chips in 1996, about the
same time as 3dfx), but sleepy graphics chipset manufacturer. The Radeons were their first 3D accelerated card that
gamers took any real serious interest in. Their Radeons trounced both Nvidia and 3dfx. They worked with Linux
developers, open sourced all their drivers and were hailed as the great hope for Linux gaming. Nvidia came back with
fists swinging, but this was all too much for 3dfx. Between losing the benchmark wars to the GeForce and Radeon, their
lateness with new cards and high prices, 3dfx lost its market share and didn't have the funds to stay into business. On
April 18 2001, they sold most of their assets and technology to Nvidia, and in October 2002, they finally declared
bankruptcy.</para>
<para>The demise of 3dfx was quite sudden and a slap in the face to the open source community. I still remember my friend
Gabe Rosa emailing me with just "<literal>Look at /.</literal>" and seeing the news. It was the 2nd worst day for Linux
gaming (the 1st being the demise of Loki). And it was also a shame. 3dfx was getting ready to release a new Voodoo V
featuring 4 GPU's which would've trounced the ATI and Nvidia offerings, as well as a new card code named "Rampage" which
reportedly would've put them firmly back as the king of the hill. There are reports that the Rampage's technology (which
was sold to Nvidia) went into the GeForce 5900. Not too shabby for 3 year old technology!</para>
<para>At first, things were still simple. Linux gamers would either keep their open source Voodoos, get an open source
Radeon or a closed source GeForce. However, with bigger and better games on the horizon, it was only a matter of time
before the Voodoos would no longer be a viable graphics card for modern gaming. People were still using Voodoo's, but
they were essentially out of the game at this point.</para>
<para>ATI started to release a tremendous number of versions of each video card, and keeping up with them and their
terminology started to become very difficult. ATI, together with NVidia, played king of hill. Their products have been
neck to neck ever since, with GeForce taking the lead a bit more times than the Radeon. But the Radeon's drivers were
open source, so many Linux users stuck by them. Then things got even more complicated.</para>
<para>ATI started becoming more and more reluctant to open source drivers for their new releases, and suddenly, it wasn't
clear who the "good guy" was anymore. Nvidia's party line was they license some of their GL code from another company,
and is thus non-releasable. Presumably, ATI doesn't want to release drivers to keep their trade secrets, well, a secret.
And it gets worse. The ATI Linux drivers have been plagued by extremely poor performance. Even when an ATI offering is
better than the current GeForce offering for Windows, the card is always trounced by GeForce on Linux. Because of the ATI
Linux driver woes, Linux users cannot use MS Windows based benchmarks or card stats. They simply don't apply to us. And
that's pretty much where we are right now.</para>
<para>As a last note, the only systematic Linux video card benchmarking effort I'm aware of was done, unfortunately, in
March 2001, between a Radeon 32 DDR and a GeForce 2. You can read it for yourself at <ulink
url="http://www.linuxhardware.org/features/01/03/19/0357219.shtml"></ulink>, but conclusion is that the GeForce 2 firmly
and soundly trounced the Radeon 32 DDR.</para>
</sect2>
<sect2><title>Current Status (13 July 2003)</title>
<para>Nvidia's latest offering is the GeForce 5900, based on the NV35 chipset. It's well supported by Linux with high
quality but proprietary drivers. They do not release information to Linux developers, and so you need to use their binary
only drivers; they are not part of XFree86. Nvidia uses a convenient combined driver architecture; their driver will
support the TNT 2 all the way up to the GeForce 5900.</para>
<para>ATI's has worked with Linux developers for all their Radeons up to and including the Radeon 9200. These cards have
2D and 3D support in XFree86. I'm not entirely sure of the quality of these open source drivers, however, Soldier of
Fortune I and Heavy Metal still have opaque texture problems under first generation Radeons. Beyond the 9200, you need to
use ATI's binary only proprietary drivers, available in rpm format from ATI's website. These drivers are piss poor; a
friend of mine claims his GeForce 4400 outperforms his Radeon 9700 pro. That's shameful.</para>
<para>On paper, and in the Windows benchmarks, the Radeon 9800 trounces the ill-conceived GeForce 5800 and slightly edges
out the GeForce 5900 according to the latest benchmarks. On paper, it's simply the more impressive card. But again, the
driver issue makes this information unusable for us. If you have your heart set to buy the best card for Linux, you'll
want to go with the GeForce 9800. Just prepare to be eating Ramen noodles for a few months; both cards are hellaciously
expensive.</para>
<sect3><title>SVGAlib Support</title>
<para>As of June 2002, SVGAlib support Radeon cards is shaky. Developers have reported that SVGAlib works on the
Radeon 7500, Radeon QD (64MB DDR model) but has problems on the Radeon VE.</para>
<para>I have no information about SVGAlib and the GeForce cards.</para>
</sect3>
</sect2>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect2><title>Which Video Card Should I Buy? (13 July 2003)</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>The answer was very difficult last year, but here's my take on it these days:</para>
2003-04-01 00:59:47 +00:00
<orderedlist numeration="arabic">
2003-07-29 19:48:36 +00:00
<listitem><para>All GeForce cards require a proprietary driver which will "taint" your kernel. However, all ATI cards
beyond the Radeon 9200 also require a proprietary driver that will "taint" your kernel as well.</para></listitem>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<listitem><para>Nvidia has proven that they care enough about Linux to write and maintain current and very high quality
drivers for Linux. Even when ATI open sourced its video card driver, they played the "we'll make Linux developers write
our drivers for us" game. Their current proprietary drivers are lousy.</para></listitem>
<listitem><para>The current Radeon 9800 barely beats out the GeForce 5900 in benchmarks and card specs, but Linux users
won't benefit from this because of the 9800's poor drivers.</para></listitem>
<listitem><para>ATI has a very long history of dropping support for hardware as fast as they can get away with
it.</para></listitem>
<listitem><para>On MS Windows, when the GeForce beat out its main competing Radeon, the review claimed that the Radeon
generally had better visuals. I have no idea how this translates to Linux.</para></listitem>
</orderedlist>
<para>Given all this, most people will want to by a GeForce at this point in time.</para>
2003-04-01 00:59:47 +00:00
</sect2>
2003-07-29 19:48:36 +00:00
<sect2><title>Definitions: Video Card and 3D Terminology</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>We'll cover video card and 3D graphics terminology. This material isn't crucial to actually getting a game working,
but may help in deciding what hardware and software options are best for you.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect3 id="textures"><title>Textures</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>A rendered scene is basically made up of polygons and lines. A texture is a 2D image (usually a bitmap) covering
the polygons of a 3D world. Think of it as a coat of paint for the polygons.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect3>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect3 id="tl"><title>T&L: Transform and Lighting</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>The T&L is the process of translating all the 3D world information (position, distance, and light sources)
into the 2D image that is actually displayed on screen.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect3>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect3 id="aa"><title>AA: Anti Aliasing</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Anti aliasing is the smoothing of jagged edges along a rendered curve or polygon. Pixels are rectangular objects,
so drawing an angled line or curve with them results in a 'stair step' effect, also called the 'jaggies'. This is when
pixels make, what should be a smooth curve or line, jagged. AA uses CPU intensive filtering to smooth out these jagged
edges. This improves a game's visuals, but can also dramatically degrade performance.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>AA is used in a number of situations. For instance, when you magnify a picture, you'll notice lines that were
once smooth become jagged (try it with The Gimp). Font rendering is another big application for AA.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>AA can be done either by the application itself (as with The Gimp or the XFree86 font system) or by hardware, if
your video card supports it. Since AA is CPU intensive, it's more desirable to perform it in hardware, but if we're
talking about semi-static applications, like The Gimp, this really isn't an issue. For dynamic situations, like games,
doing AA in hardware can be crucial.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect3>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect3 id="fsaa"><title>FSAA: Full Screen Anti-Aliasing</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>FSAA usually involves drawing a magnified version of the entire screen in a separate framebuffer, performing AA on
the entire image and rescaling it back to the normal resolution. As you can imagine, this is extremely CPU intensive.
You will never see non hardware accelerated FSAA.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect3>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect3 id="mipmapping"><title>Mip Mapping</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Mip mapping is a technique where several scaled copies of the same texture are stored in the video card memory to
represent the texture at different distances. When the texture is far away a smaller version of the texture (mip map)
is used. When the texture is near, a bigger one is used. Mip mapping can be used regardless of filtering method (<xref
linkend="texturefiltering">). Mip mapping reduces memory bandwidth requirements since the images are in hardware, but
it also offers better quality in the rendered image.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect3>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect3 id="texturefiltering"><title>Texture Filtering</title>
<para>Texture filtering is the fundamental feature required to present sweet 3D graphics. It's used for a number of
purposes, like making adjacent textures blend smoothly and making textures viewed from an angle (think of looking at a
billboard from an extreme angle) look realistic. There are several common texture filtering techniques including
point-sampling, bilinear, trilinear and anisotropic filtering.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>When I talk about 'performance hits', keep in mind that the performance hit depends on what resolution you're
running at. For instance, at a low resolution you may get only a very slight hit by using trilinear filtering instead
of bilinear filtering. But at high resolutions, the performance hit may be enormous. Also, I'm not aware of any card
that uses anisotropic texture filtering. TNT drivers claim they do, but I've read that these drivers still use
trilinear filtering when actually rendering an image to the screen.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect4><title>Point Sampling Texture Filtering</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Point sampling is rare these days, but if you run a game with 'software rendering' (which you'd need to do if
you run a 3D accelerated game without a 3D accelerated board) you're likely to see it used.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect4>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect4><title>Bilinear Texture Filtering</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Bilinear filtering is a computationally cheap but low quality texture filtering. It approximates the gaps
between textures by sampling the color of the four closest (above, below, left and right) texels. All modern 3D
accelerated video cards can do bilinear filtering in hardware with no performance hit.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect4>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect4><title>Trilinear Texture Filtering</title>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<para>Trilinear filtering is a high quality bilinear filter which uses the four closest pixels in the second most
suitable mip map to produce smoother transitions between mip map levels. Trilinear filtering samples eight pixels
and interpolates them before rendering. Trilinear filtering always uses mip mapping. Trilinear filtering
eliminates the banding effect that appears between adjacent mip map levels. Most modern 3D accelerated video cards
can do trilinear filtering in hardware with no performance hit.</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
</sect4>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect4><title>Anisotropic Texture Filtering</title>
<para>Anisotropic filtering is the best but most CPU intensive of the three common texture filtering methods.
Trilinear filtering is capable of producing fine visuals, but it only samples from a square area which in some cases
is not the ideal method. Anisotropic (meaning 'from any direction') samples from more than 8 pixels. The number of
sampled pixels and which sampled pixels it uses depends on the viewing angle of the surface relative to your screen.
It shines when viewing alphanumeric characters at an angle.</para>
</sect4>
</sect3>
<sect3><title>Z Buffering</title>
<para>A Z buffer is a portion of RAM which represents the distance between the viewer (you) and each pixel of an object.
Many modern 3D accelerated cards have a Z buffer in their video RAM, which speeds things up considerably, but Z
buffering can also be done by the application's rendering engine. However, this sort of thing clearly should be done in
hardware wherever possible.</para>
<para>Every object has a stacking order, like a deck of cards. When objects are rendered into a 2D frame buffer, the
rendering engine removes hidden surfaces by using the Z buffer. There are two approaches to this. Dumb engines draw
far objects first and close objects last, obscuring objects below them in the Z buffer. Smart engines calculate what
portions of objects will be obscured by objects above them and simply not render the portions that you won't see anyhow.
For complicated textures this is a huge savings in processor work.</para>
</sect3>
</sect2>
</sect1>
<sect1><title>Sound</title>
<sect2><title>Which sound card is best?</title>
<para>By the word "best" I mean best for gaming. Gamers want high quality sound for our games with the least amount of
tinkering. On the other hand, a musician would have a very different concept of what "best sound card" would mean.
If you're a musician, you might want to check out the <ulink url="http://www.linuxdj.com/audio/quality/">Linux Audio
Quality HOWTO</ulink>.</para>
<para>Now that Linux is beginning to mature, this question isn't as important as it used to be. Once upon a time,
soundcards without onboard MIDI chips (most PCI sound cards) didn't do MIDI. This was mostly a problem for things like
xdoom or lxdoom using musserv. These days we have MIDI emulators like Timidity and libraries like SDL which don't require
hardware MIDI support. Frankly, I've had many cards and I can't tell the difference between any of them for gaming. If
you want to do things like convert a record LP to digital format, then your choice of a soundcard with a professional
grade A/D converter is absolutely crucial. For this HOWTO, we'll assume that you're more of a gamer than a studio
recording engineer.</para>
<para>Your decision should be based on what will be the easiest to configure. If you already have a card and it works
well, that's good enough. If you're in the market to buy a sound card, get something that will take you a second to
configure. PCI cards are much easier to deal with than ISA since you don't need to tell their drivers about which system
resources (IRQ, DMA, I/O addresses) to use. Some ISA cards ARE plug-n-play, like the Creative AWE-64, and the Linux
kernel has come a long way in auto configuring them.</para>
<para>My personal recommendation is any card which has the es1370 or es1371 chip, which uses the es1370 and es1371 sound
drivers on Linux. These cards include the older Ensoniq es1370 and newer Creative PCI-128. These cards are extremely
cheap and trivial to get working under Linux.</para>
<para>I used to be a fan of the Creative Soundblaster AWE 32, AWE 64 and AWE 64 gold soundcards. These ISA PnP cards are
well supported by both OSS and Alsa. They all use the same E-mu 8000 synthesis chip which enables them to play 32 voices
simultaneously (they have 32 "channels"). A few notes: First, the Soundblaster AWE HOWTO is very out of date. Second, the
AWE 64 and AWE 64 gold can play 64 voices simultaneously, but this is done in software. Creative never released a Linux
driver for these cards (and they never released programming information to Linux developers), so Linux users cannot use
the extra 32 channels on the AWE 64 and AWE 64 gold. As far Linux users are concerned, all three cards are completely
identical (although the AWE 64 gold has gold plated connectors, which are better for sound quality than the more common
steel connectors).</para>
<para>The Creative Soundblaster Live! is an extremely popular PCI sound card these days. I've never owned one, so I
cannot comment here. However, there have been numerous reports about serious problems with the Live! and AMD motherboards
that use the 686b southbridge. A google search should turn up alot of information on this problem.</para>
<para>A more relevent issue is speakers, but even here the difference isn't huge. I've had expensive Altec Lansing
speakers perform only slightly better than el-cheapo speakers. You get what you pay for with speakers, but don't expect a
huge difference. You'll want to get something with a separate sub-woofer; this does make a difference at a cost of extra
power and connector wires.</para>
2003-04-01 00:59:47 +00:00
</sect2>
<sect2><title>Why isn't my sound working?</title>
<para>First of all, it's probably not the game, it's probably your setup. AFAIK, there are 3 options to getting a sound
card configured under Linux: the free OSS sound drivers that come with the Linux kernel, the Alsa drivers and the
commercial OSS sound drivers. Personally, I prefer the free OSS drivers, but many people swear by Alsa. The commercial
OSS drivers are good when you're having trouble getting your sound card to work by free methods. Don't discount them;
they're very cheap (like 10 or 20 bucks), support bleeding edge sound cards and take a lot of guesswork out of the
configuring process.</para>
<para>There are 5 things that can go wrong with your sound system:</para>
<orderedlist numeration="arabic">
<listitem><para>Shared interrupt</para></listitem>
<listitem><para>Misconfigured driver</para></listitem>
<listitem><para>Something's already accessing the sound card</para></listitem>
<listitem><para>You're using the wrong driver</para></listitem>
<listitem><para>A permissions problem</para></listitem>
</orderedlist>
<sect3><title>Shared interrupt</title>
<para>The first thing to do is to figure out if you have an IRQ conflict. ISA cards can't share interrupts. PCI
cards can share interrupts, but certain types of high bandwidth cards simply don't like to share, including network
and sound cards. To find out whether you have a conflict, do a "cat /proc/interrupts". Output on my system
is:</para>
<screen>
$ cat /proc/interrupts
CPU0 CPU1
0: 24185341 0 XT-PIC timer
1: 224714 0 XT-PIC keyboard
2: 0 0 XT-PIC cascade
5: 2478476 0 XT-PIC soundblaster
5: 325924 0 XT-PIC eth0
11: 131326 0 XT-PIC aic7xxx
12: 2457456 0 XT-PIC PS/2 Mouse
14: 556955 0 XT-PIC ide0
NMI: 0 0
LOC: 24186046 24186026
ERR: 1353
</screen>
<para>The second column is there because I have 2 CPU's in this machine; if you have one CPU (called UP, or
uniprocessor), you'll have only 1 CPU column. The numbers on the left are the assigned IRQ's and the strings to the
right indicate what device was assigned that IRQ. You can see I have an IRQ conflict between the soundcard
(soundblaster) and the network card (eth0). They both share IRQ 5. Actually, I cooked this example up because I
wanted to show you what an IRQ conflict looks like. But if I did have this conflict, neither my network nor my sound
would work well (or at all!).</para>
<para>If my sound card is PCI, the preferred way of fixing this would be to simply move one of the cards to a
different slot and hope the BIOS sorts things out. A more advanced way of fixing this would be to go into BIOS and
assign IRQ's to specific slots. Modern BIOS'es can do this.</para>
</sect3>
<sect3><title>Misconfigured driver</title>
<para>Sometimes, a card is hardwired to use a certain IRQ. You'll see this on ISA cards only. Alternatively, some
ISA cards can be set to use a specific IRQ using jumpers on the card itself. With these types of cards, you need to
pass the correct IRQ and memory access, "I/O port", to the driver.</para>
2003-07-29 19:48:36 +00:00
<para>This is a sound card specific issue, and beyond the scope of this HOWTO.</para>
<!-- FIXME: I should write about how to pass info to the driver. -->
2003-04-01 00:59:47 +00:00
</sect3>
<sect3><title>Something is already accessing your sound card</title>
<para>Perhaps an application is already accessing your soundcard. For example, maybe you have an MP3 player that's
paused? If something is already accessing your card, other applications won't be able to. Even though it was written
to share the card between applications, I've found that esd (the enlightenment sound daemon) sometimes doesn't work
correctly. The best tool to use here is lsof, which shows which processes are accessing a file. Your sound card is
represented by <filename class="devicefile">/dev/dsp</filename>. Right now, I'm listening to an MP3 (not a Metallica
MP3, of course...) with mp3blaster.</para>
<screen>
# lsof /dev/dsp
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
mp3blaste 1108 p 6w CHR 14,3 662302 /dev/dsp
</screen>
<para><command>fuser</command> is similar; but it lets you send a signal to any process accessing the device
file.</para>
<screen>
# fuser -vk /dev/dsp
USER PID ACCESS COMMAND
/dev/dsp root 1225 f.... mp3blaster
root 1282 f.... mp3blaster
</screen>
<para>After issuing this command, mp3blaster was killed with SIGKILL. See the man pages for lsof and fuser; they're
very useful. Oh, you'll want to run them as root since you'll be asking for information from processes that may be
owned by root.</para>
</sect3>
<sect3><title>You're using the wrong driver (or no driver)</title>
<para>There are only two ways to configure your card:</para>
<orderedlist numeration="arabic">
<listitem><para>Support must be compiled directly into the kernel</para></listitem>
<listitem><para>You must have the correct driver loaded into memory</para></listitem>
</orderedlist>
<para>You can find out which driver your sound card is using by doing "lsmod" or looking at the output of "dmesg".
Since sound is crucial for me, I always compile sound into my kernels. If you don't have a driver loaded, you need to
figure out what's been compiled into your kernel. That's not so straight forward. Your best bet is to compile your
kernel. BTW, let me say that compiling your own kernel is the first step towards proficiency with Linux. It's
painful the first time you do it, but once you do it correctly, it becomes very easy down the right, especially if you
keep all your old .config files and make use of things like "make oldconfig". See the Kernel HOWTO for details.</para>
<para>If you haven't compiled the kernel yourself, there is an overwhelmingly good chance that your system is set up
to load sound drivers as modules. That's the way distros do things. Have everything under the sun compiled as a
module and try to load them all. So if you don't see your sound card's driver with lsmod, your card probably isn't
configured yet.</para>
</sect3>
<sect3><title>Permissions Problem</title>
<para>If the sound card works when you're root but not any other user, you probably have a permissions problem. If
this is the case, as root, look at the group owner of the sound card using <literal>ls -l /dev/dsp</literal>; it'll
probably be <literal>audio</literal>. Then, as root, add your non-root user to the audio group in
<filename>/etc/group</filename>. For example, I added the users p and wellspring to group audio on my system:</para>
<screen>
audio:x:29:p,wellspring
</screen>
<para>Then log out and log back in as the non-root user. Your sound card should work. Thanks to James Barton for
reminding me to add this to the howto.</para>
</sect3>
</sect2>
</sect1>
2003-07-29 19:48:36 +00:00
<sect1><title>Miscellaneous Problems</title>
<sect2><title>Hardware Acceleration Problems</title>
<para>XFree86 4.x provides a more centralized and self-contained approach to video. Much of the funkyness like kernel
modules for non-root access of video boards is, thankfully, gone.</para>
<sect3><title>Hardware acceleration isn't working at all</title>
<para>If you're getting like 1 fps, then your system isn't using hardware 3D acceleration. There's one of two things
that can be going on.</para>
<orderedlist numeration="arabic">
<listitem><para>Your 3D system is misconfigured (more likely)</para></listitem>
<listitem><para>Game X is misconfigured (less likely)</para></listitem>
</orderedlist>
<para>The first step is to figure out which one is happening.</para>
<orderedlist numeration="arabic">
<listitem><para>If you have X 4.0 (X 3.* users procede to step 2), look at the output of <command>X
-probeonly</command>. You'll see:</para>
<screen>(II) XXXXXX: direct rendering enabled</screen>
<para>or</para>
<screen>(II) XXXXXX: direct rendering disabled</screen>
<para>where XXXXXXX depends on which video card you have. If direct rendering is disabled, then your X
configuration is definitely faulty. Your game is not at fault. You need to figure out why DRI is disabled. The
most important tool for you to use at this point is the `DRI Users Guide'. It is an excellently written document
that gives you step by step information on how to get DRI set up correctly on your machine. A copy is kept at
<ulink url="http://www.xfree86.org/4.0/DRI.html"></ulink>.</para>
<para>Note that if you pass this test, your system is CAPABLE of direct rendering. Your libraries can still be
wrong. So procede to step 2.</para></listitem>
<listitem><para>There is a program called glxgears which comes with the "mesademos" package. You can get mesademos
with Debian (<command> apt-get install mesademos</command>) or you can hunt for the rpm on <ulink
url="http://www.rpmfind.net"></ulink>. You can also download and compile the source yourself from the mesa
homepage.</para>
<para>Running glxgears will show some gears turning. The xterm from which you run glxgears will read "X
frames in Y seconds = X/Y FPS". You can compare your system to the list of benchmarks below.</para>
<screen>
CPU TYPE VIDEO CARD X VERSION AVERAGE FPS
</screen>
<para>Compiling Mesa and DRI modules yourself can increase your FPS by 15 FPS; quite a performance boost! So if
your number is, say, about 20 FPS slower than a comparable machine, chances are that glxgears is falling back on
software rendering. In other words, your graphics card isn't 3D accelerating graphics.</para>
<para>More important than FPS is having a constant FPS for small and large windows. If hardware acceleration is
working, the FPS for glxgears should be nearly independent of window size. If it's not, then you're not getting
hardware acceleration.</para></listitem>
</orderedlist>
</sect3>
</sect2>
<sect2><title>Hardware acceleration works only for the root user</title>
<sect3><title>XFree86 4.x</title>
<para>If the following lines aren't present in your XF86Config file, put them in:</para>
<screen>
Section "DRI"
Mode 0666
EndSection
</screen>
<para>This allows all non-root users to use DRI. For the paranoid, it's possible to restrict DRI to only a few
non-root users. See the DRI User Guide.</para>
</sect3>
<sect3><title>XFree86 3.x</title>
<sect4><title>Voodoo cards</title>
<para>Voodoo card hardware acceleration only takes place ONLY at 16bpp color and fails silently when starting X
in another color depth.</para>
<para>Also, Voodoo cards need the <filename>3dfx.o</filename> kernel module and a <filename
class="devicefile">/dev/3dfx</filename> device file (major 107, minor 0) for non-root hardware acceleration.
Neither the module nor the device file are used under XFree86 4.x.</para>
</sect4>
</sect3>
</sect2>
</sect1>
2003-04-01 00:59:47 +00:00
<sect1><title>Emulation and Virtual Machines</title>
<para>Linux gets ragged on a lot because we don't have the wealth of games that other platforms have. Frankly, there's enough
games for me, although it would be really nice to have some of the bleeding edge games and classics like Half-life and
2003-07-29 19:48:36 +00:00
Carmageddon. Fortunately, we have more emulators than you can shake a stick at. Although playing an emulated game is
sometimes not quite as fun as playing it on the native machine, and getting some of the emulators to work well can be a
difficult task, they're here, and there's alot of them!</para>
2003-04-01 00:59:47 +00:00
2003-07-29 19:48:36 +00:00
<sect2><title>What is a virtual machine?</title>
2003-04-01 00:59:47 +00:00
<para>A "real computer" provides an operating system many things, including a CPU, I/O channels, memory, a BIOS to provide
low level access to motherboard and I/O resources, etc. When an operating system wants to write to a hard drive, it
communicates through a device driver that interfaces directly with the hardware device memory.</para>
<para>However, it's possible to give a program all the hardware resources it needs. When it wants to access a hard drive,
give it some memory to write to. When it wants to set an IRQ, give it some bogus instructions that lets it think it set
an IRQ. If you do this correctly, then in principle, there's no way for the poor application to know whether it's really
accessing hardware or tricked by being given resources which simulate hardware. A virtual machine is the environment
which tricks applications into believing they're running on a real computer. It provides all the services that a real
computer would provide.</para>
<para>VM's were used initially in the 1960's to emulate time shared operating systems, but these days we use them to run
software which was written for foreign operating systems, or more commonly, an entire operating system. Because of the
nature of the VM, the foreign OS can't tell the difference between operating in a VM or in a "real" machine.</para>
</sect2>
2003-07-29 19:48:36 +00:00
2003-04-01 00:59:47 +00:00
<sect2><title>Apple 8-bit</title>
<para>All the 8-bit Apple ][ emulators require a copy of the original ROM, for whichever system you want to emulate, in a
file. If you search hard enough, you can find file copies of the ROMs for the Apple ][, ][+, ][e, ][c and //gs. They
are still copyrighted by Apple, and you can only use them legally if you actually own one of these computers.</para>
<sect3><title>KEGS</title>
<para>KEGS is an Apple II emulator written by Kent Dickey
<email>kentd@cup.hp.com</email> which was originally written for HP-UX, but improved
and customized for Linux. It runs under X at any color depth, and supports changeable
memory sizes, joysticks, and sound. KEGS boots all Apple II variants, and supports
all of the Apple ]['s graphics modes. I can't find a working homepage for this
application.</para>
</sect3>
<sect3><title>apple2 and xapple2</title>
<para>The SVGAlib based <filename>apple2</filename> and X based <filename>xapple2</filename> can emulate any Apple ][
variant except for the //gs. The interface is a bit funky, but usable. Configuration is also a bit funky; this
emulator would benefit from an SVGA or X based configuration tool. It supports the undocumented portion of the 6502
instruction set which some games rely on. <filename>apple2</filename> is currently being maintained by Michael
Deutschmann <email>michael@talamasca.ocis.net</email> and seems to be developed at a slow but constant pace. I don't
think this application has a homepage.</para>
</sect3>
</sect2>
<sect2><title>DOS</title>
<sect3 id="dosemu"><title><application>dosemu</application></title>
<para>dosemu <<ulink url="http://www.dosemu.org"></ulink>> is the canonical
DOS emulator on Linux. When you think of DOS, don't think of things like PROCOM PLUS OR
OTHER PROGRA~1 WHICH HAVE SHORT NAMES AND ARE IN ALL CAPS. There are some real classics
that were written for DOS like Carmageddon, Redneck Rampage and Tomb Raider. dosemu can
run these. Unfortunately, it can take alot of effort to get dosemu to work, and of Jan
2002, the sound code is somewhat broken. Not a big deal when you're trying to run
Wordperfect or an old database application. It's an absolute show stopper for gaming.
Getting dosemu to work well is not easy, but unfortunately, for DOS games it's the best
avenue. Good luck. If you have success using dosemu, I would like to hear from you.
</para>
</sect3>
</sect2>
<sect2><title>Win16</title>
<sect3><title>Wabi</title>
<para><application>Wabi</application> is a commercial Win16 emulator. That is, it'll
run Windows 16-bit applications from a Windows 3.1, Windows 3.11 or Windows for
Workgroups 3.11 environment. <application>Wabi</application> was originally created
by SCO Unix a long time ago and then was purchased by Caldera sometime in mid year
2001.</para>
<para>Wabi is fast and does a good job for what it does, although I've heard it said that
wabi for Solaris is more stable than Linux. It might be useful for playing older Win16
games, but there are three problems:</para>
<itemizedlist>
<listitem><para> You must have a licensed copy of Windows 3.1/3.11 or WfW 3.11.</para></listitem>
<listitem><para> Wabi is awfully expensive for what it does.</para></listitem>
<listitem><para> Wabi doesn't work under 32bpp or 24bpp color.</para></listitem>
</itemizedlist>
<para>Wabi does NOT do DOS itself, but it looks like it can use a DOS emulator as a
backend for running DOS programs. There was talk about Wabi 3.0 which would've done
Win32 emulation, but AFAIK, this project was shelved indefinitely. I think Wabi
will run under Linux on all architectures (can someone verify this?)</para>
</sect3>
</sect2>
<sect2 id="win32"><title>Win32</title>
<sect3 id="wine"><title><application>wine</application></title>
<para>Wine <<ulink url="http://www.winehq.com"></ulink>>, which bears the GNUish acronym "Wine Is Not An
Emulator" is a non-commercial implementation of the Win32 API. The reason why it's not an emulator is subtle and not
of much interest to most non computer scientists, so we'll call it an emulator here (it really does run-time
translation of calls to the Win32 API to POSIX/X11 calls). Wine has come a long way, and is capable of emulating many
important programs, which is great news for Linux users who want this sort of stuff.</para>
<para>Wine does <literal remap="bf">not</literal> provide the DOS API, so you can't use it to run DOS applications.
For that, you should look at dosemu (<xref linkend="dosemu">). Wine has never been too good at implementing DirectX,
although a number of games are known to work under wine. For gaming you might want to look at winex (<xref
linkend="winex">).</para>
<para>In addition to run-time translation of the Win32 API to POSIX/X11 (it runs Windows applications on Linux), wine
also does compile-time tranlation of the Win32 API to POSIX/X11 (it compiles Windows application source code on
Linux). In this sense, wine is a Windows-to-Linux porting utility. The x86 architecture isn't required, but is
recommended since it allows actual x86 binary execution as well as direct DLL usage).</para>
<para>You can use wine `with Windows', which means that wine uses libraries that actually come with Microsoft Windows
itself. This is legal only if you own a copy of Windows which isn't currently being used on a computer. It's said
that wine has the best success when run with Windows. You can also run wine without Windows. The people at <ulink
url="http://www.winehq.com">winehq</ulink> are writing their own set of libraries called <literal>libwine</literal>
which implements the Win32 API with no Microsoft code at all.</para>
<para>Wine was originally licenced under the MIT/X11 license, so it could be used for both commercial and
non-commercial purposes. In mid 2002, parts of wine were re-licensed under the LGPL so that it could only be used for
non-commercial puposes. This presents a problem for companies like Transgaming (<xref linkend="winex">) and prompted
a fork of wine called ReWind (<xref linkend="rewind">).</para>
</sect3>
<sect3 id="rewind"><title><application>rewind</application></title>
<para>Rewind <<ulink url="http://rewind.sourceforge.net/"></ulink>> was started by Eric Pouech (a wine
2003-07-29 19:48:36 +00:00
developer) and Ove Ko?=ven (a winex developer) in response to wine's license change (<xref linkend="wine">). It started
2003-04-01 00:59:47 +00:00
out life as a snapshot of the last version of wine which was completely licensed under the MIT/X11 license. The aim
is to keep rewind MIT/X11 based so that companies like Transgaming can offer wine based products.</para>
</sect3>
<sect3 id="winex"><title><application>winex</application></title>
<para>Winex is released by a company called Transgaming <<ulink url="http://www.transgaming.com"></ulink>>. The
developers take wine (see <xref linkend="wine">) and add DirectX / DirectDraw support. Although winex is commercial,
they have an interesting business model.</para>
<para>The end user (you) can download the source code for free. However, for 5 US dollars per month, you can become
a subscriber of Transgaming. Being a subscriber of Transgaming gives three major benefits:</para>
<itemizedlist>
<listitem><para> Subscribers can download convenient packaged versions of winex in deb, rpm or tar.gz format whenever
they want, including updates.</para></listitem>
<listitem><para> There are monthly polls where subscribed users can take votes on what they want winex developers to
work on. For instance, they can vote for things like "Improve support for copy protected programs", "Better
Installshield support" or "Improve DirectX 8.0 support". As far as I can see, the developers really do listen to the
subscriber polls.</para></listitem>
<listitem><para>The Transgaming website has a few user support forums. On one hand, they use the most godawful,
horrible, confusing, wasteful, moronic format I've ever seen and I hope to god I never see a forum with a format as
bad as Transgaming's. On the other hand, you can ask for help and the developers are VERY good about getting around
to your answer; their vigilance is quite impressive. Non-subscribers can browse the forums, but only subscribers can
post (and therefore, ask for support).</para></listitem>
</itemizedlist>
<para>The developers of winex were going to release their Installshield, DirectX and DirectDraw enhancements to wine
"every so often". In return, as wine maturation improved, the winex developers were going to take the new versions of
wine and use them for winex. However, since the birth of Transgaming, parts of wine have been re-licensed under the
more restrictive GNU LGPL license (<xref linkend="wine">). This basically means that versions of wine that are
released past the date of the re-licensing can no longer be used by winex. Therefore, winex will now be based on
rewind (<xref linkend="rewind">).</para>
</sect3>
<sect3 id="win4lin"><title>Win4Lin</title>
2003-07-29 19:48:36 +00:00
<para>Win4Lin <<ulink url="http://www.netraverse.com"></ulink>> is a commercial product by Netraverse. Like
vmware (<xref linkend="vmware">) it uses the virtual machine approach to running Windows applications, so you'll get a
big window from which you can boot Windows and run all kinds of Windows applications. Unlike vmware, win4lin only
does Windows 95/98/ME, but this turns out to be better for gamers. Because win4lin concentrates on these operating
systems, reports say that it's faster and does a better job at running games under these operating system than vmware.
It's also much cheaper than vmware. The most recent version of Win4Lin as of June 2003 is 5.0.</para>
2003-04-01 00:59:47 +00:00
<itemizedlist>
<listitem><para>It does not support DirectX or DirectDraw, while vmware has "limited" support for
DirectX.</para></listitem>
<listitem><para>It only supports serial and parallel devices. This is important for people who use USB joysticks.
Note that vmware supports up to 2 USB devices.</para> </listitem>
2003-07-29 19:48:36 +00:00
<listitem><para>As of June 2003, expect to pay $89.99 without printed docs and $99.99 with printed docs. In addition,
there isn't an evaluation copy available, although you get a 30 day money back guarantee. However, since it's
commercial you do get tech support. vmware is considerably more expensive.</para></listitem>
2003-04-01 00:59:47 +00:00
<listitem><para>Like vmware, you're required to have a licensed copy of Win95 or Win98. Win4Lin cannot use an
existing Windows installation the way wine can.</para></listitem>
<listitem><para>It only runs on x86 architectures.</para></listitem>
</itemizedlist>
<para>If your goal is to run Win95/98/ME applications on Linux, without USB and on the x86 architecture, Win4Lin's
cost and focus on Win95 type OS's make it a better choice than vmware. However, if you must have USB support or run
Linux on a platform other than x86, vmware is your only option.</para>
<para>Now if you're goal is to run Win95 type OS games under Linux, Win4Lin almost seems better than vmware. The
show-stopper is the fact that vmware has limited DirectX support while Win4Lin has none. This fact alone makes both
Win4Lin and vmware unsuitable for most hardcore gaming purposes. But if you're going to give it a try, you're more
likely to have success with vmware.</para>
</sect3>
<sect3 id="vmware"><title>VMWare</title>
<para></para>
</sect3>
</sect2>
</sect1>
<sect1 id="interpreters"><title>Interpreters</title>
<sect2><title>SCUMM Engine (LucasArts)</title>
<para>Lucasarts wrote an engine for point and click adventures named SCUMM (Script Creation Utility for Maniac Mansion).
They wrote many graphical adventures using SCUMM, like their famous Monkey Island series (all three). Ludvig Strigeus
<email>strigeus@users.sourceforge.net</email> was able to reverse engineer the SCUMM format and write an interpreter for
SCUMM based games that compiles under Linux and Win32 named scummvm <<ulink
url="http://scummvm.sourceforge.net/"></ulink>>. Their website is very good, and chock full of any kind of information
about SCUMM and playing these games under scummvm.</para>
<para>A compatibility page is maintained at the scummvm website. FWIW, I've been able to finish many of the games that
are listed as 90% done with no problems. scummvm is rock solid, and allows you to purchase SCUMM based Lucas Arts games,
copy the data files to your hard drive and play them under Linux. As of February 2002, I've been following their cvs,
and this project is undergoing constant development. Kudos to the scummvm team.</para>
</sect2>
<sect2><title>AGI: Adventure Gaming Interface (Sierra)</title>
<para>The older Sierra DOS graphical adventure games used a scripting language named AGI (Adventure Gaming Interface).
Some examples of games written in AGI would be Leisure Suit Larry I (EGA), Space Quest I and II, King's Quest II, Mixed-Up
Mother Goose and others. These games can be played using <application>sarien</application>on> <<ulink
url="http://sarien.sourceforge.net"></ulink>>, an open source interpreter for AGI games.</para>
<para>Sarien was written in SDL, so it should run on any platform that can compile SDL programs. In addition, there are
versions for DOS, Strong-Arm based pda's, QNS (holy cow! embedded gaming!), MIPS based systems and SH3/4 based Pocket
PC's. The developers are clearly out of their minds (in a good way!). Sarien also has numerous enhancements not found
in the original games, like a Quake style pull-down console, picture and dictionary viewer, enhanced sound and support for
AGDS, a Russian AGI clone. Sarien is under development and the developers have been very good about documenting the
Sarien internals if anyone wants to get involved in hacking it.</para>
</sect2>
<sect2><title>SCI: SCript Interpreter or Sierra Creative Interpreter (Sierra)</title>
<para>The newer Sierra graphical adventure games (we're talking about the late 80's here) used an interpreter named SCI.
There were many versions of SCI since Sierra was constantly improving its engine. The original SCI games were DOS based,
but Sierra eventually started releasing Win32 SCI based games. Some examples of games written with SCI are Leisure Suit
Larry 1 (VGA), Leisure Suit Larry 2-7, Space Quest 3-6, King's Quest 4-6, Quest For Glory 1-4 and many others. Compared
with AGI games, SCI adventures have better music support, a more complex engine and loads of bells and whistles.</para>
<para>Many SCI based games (games written in SCI0) can be played using <application>freesci</application>, available at
<ulink url="http://freesci.linuxgames.com"></ulink>. Like Sarien, FreeSCI has many graphics targets including SDL, xlib
and GGI, so this game can compile and run under an incredible number of platforms. The developers have done a fantastic
job of documenting and FAQing their application.</para>
</sect2>
<sect2 id="infocom"><title>Infocom Adventures (Infocom, Activision)</title>
<para>The Z-machine is a well documented <<ulink url="http://www.gnelson.demon.co.uk/zspec/index.html"></ulink>>
virtual machine designed by Infocom to run their interactive fiction games. This allowed them to write game data files in
a cross platform manner, since only the engine itself, the Z-machine, would be platform dependent. Z-machine went through
a number of revisions during the lifetime of Infocom, and two further revisions (V7 and V8 created by Graham Nelson) after
the Infocom's demise. The later versions even supported limited sound and graphics!</para>
<para>One of the most popular Z-machine interpreters is Frotz <<ulink
url="http://www.cs.csubak.edu/~dgriffi/proj/frotz/"></ulink>>. This excellently done page has many nice links for
interactive fiction fans. Frotz is GPL, runs all versions of Z-machine and will compile on most versions of Unix. Frotz
has spawned many forks, like a version for PalmOS and Linux based PDA's.</para>
<para>jzip <<ulink url="http://jzip.sourceforge.net/"></ulink>> is another very popular Z-machine interpreter that
will run V1-V5 and V8 Z-machine data files. jzip is very portable; it compiles on all Unices, OS/2, Atari ST and
DOS.</para>
<para>There are actually many other Z-machine interpreters like nitfol and rezrov (written in Perl!). Each interpreter
has its own set of strengths, and you can find links to them on the home pages for Frotz and jzip.</para>
</sect2>
<sect2 id="scottadams"><title>Scott Adams Adventures (Adventure International)</title>
<para>Scott Adams is, arguably, the father of interactive fiction. Although he himself was inspired by the first piece of
interactive fiction, Adventure, Scott brought adventuring to the masses. His games were available for Atari, Apple 2,
Commodore, Sorcerer, TI, and CPM. His company, Adventure International, released a number of much loved games between
1978 and 1984 before folding. He recently released a new game (a Linux version is not available) but since the decline
of adventuring, he has pretty much kept out of the gaming industry.</para>
<para>Alan Cox wrote scottfree, a Scott Adams adventure game file interpreter for Unix. Using scottfree and any of the
Scott Adams data files which can be downloaded from Scott's website <<ulink url="http://www.msadams.com/"></ulink>>
you can enjoy these classics.</para>
</sect2>
<sect2><title>Ultima Underworld: The Stygian Abyss (Origin, Blue Sky Productions)</title>
<para>The Underworld Adventures project <<ulink url="http://uwadv.sourceforge.net/"></ulink>> is an effort to port
the 1992 classic, Ultima Underworld: The Stygian Abyss, to modern operating systems like Linux, MacOS X, and Windows. It
uses OpenGL for 3D graphics, SDL for platform specific tasks and is released under the GNU GPL. Underworld Adventures
provides an impressive graphics system which uses the original game files, so you'll need the original game disk to
play.</para>
<para>Underworld Adventures also provides a bunch of tools for you to display the level maps, tools for examining uw1
conversation scripts and more.</para>
</sect2>
<sect2 id="exult"><title>Ultima 7 (Origin, Electronic Arts)</title>
<para>Ultima 7 is actually 2 games: part I (The Black Gate) and part II (Serpent Island) which uses a slightly enhanced
version of The Black Gate's engine. In addition, an addon disk was released to both part I (The Forge Of Virtue) and part
II (The Silver Seed).</para>
<para>A team of people developed <application>Exult</application>on> <<ulink
url="http://exult.sourceforge.net/"></ulink>> which is an open source interpreter that will run both parts of Ultima 7
and their addon disks. Exult is written in C++ using SDL, so it will compile on any platform that can compile SDL
programs. It also features some enhancements over the original versions of the Ultima VII engine. You'll need to
purchase a copy of Ultima 7 to play. The developers have no plans on extending Exult to interpret the other Ultimas since
the engines changed so radically between releases.</para>
<para>The Exult team has also been hard at work creating a map editor, Exult Studio, and a script compiler that will let
users create their own RPG in the Ultima style.</para>
</sect2>
<sect2><title>System Shock (Electronic Arts, Origin)</title>
<para>System Shock is a classic first person shooter/adventure from 1994, which puts it as a contemporary of Doom.
However, its engine is much more feature rich than the original Doom: for example, System Shock had 3D sprites, free look
and a facility to have objects on top of each other, giving the illusion of a full 3D map, like Quake. Game reviewers
agree that this game has the features of Quake with a story-line more compelling than Half-life. The System Shock engine
was optimized for sophistication, while Doom's engine was optimized for throwing lots of monsters at you; a completely
different appoach. Quite impressive for such an old game!</para>
<para>The System Shock Hack Project <<ulink url="http://madeira.physiol.ucl.ac.uk/tsshp/sshock.html"></ulink>> is an
attempt to update the game for modern operating systems. The project uses SDL and is released under the modified BSD
license. While you need the original game files to play SSHP, it should work with the System Shock demo, which is freely
available.</para>
</sect2>
</sect1>
<sect1><title>Websites And Resources</title>
<sect2><title>Meta gaming websites</title>
<para>These are some resources for Linux gamers no matter what kind of game you enjoy to play.</para>
<variablelist>
<varlistentry><term>The Linux Game Tome: <ulink url="http://www.happypenguin.org"></ulink></term>
<listitem><para> About the games themselves.</para></listitem></varlistentry>
<varlistentry><term>linuxgames: <ulink url="http://www.linuxgames.com"></ulink></term>
<listitem><para> Linux gaming news</para></listitem></varlistentry>
<varlistentry><term><ulink url="http://www.holarse.net"></ulink></term>
<listitem><para>Linux meta gaming site for German speaking folk.</para></listitem></varlistentry>
<varlistentry><term>Mobygames: <ulink url="http://www.mobygames.com"></ulink></term>
<listitem><para>A database of all known computer games. It's very complete and is one of my favorite
sites.</para></listitem></varlistentry>
</variablelist>
</sect2>
<sect2><title>Commercial Linux Game Resources</title>
<sect3><title>Where to buy commercial games</title>
<para>ebgames <<ulink url="http://www.tuxgames.com"></ulink>> no longer officially sells Linux software. They
stopped selling Linux games and distributions at around the same time Loki Software declared bankruptcy, which is a
2003-07-29 19:48:36 +00:00
shame because they had the lowest prices on Linux games I've ever seen. However, occasionally, they'll have things
2003-04-01 00:59:47 +00:00
like Code Warrior or Redhat Linux on sale.</para>
<variablelist>
<varlistentry><term>Tux Games: <ulink url="http://www.tuxgames.com"></ulink></term><listitem><para>
Your one stop shop for buying any commercial Linux game (software vendors like Tribsoft and Loki have online shops
at their websites too).</para></listitem></varlistentry>
</variablelist>
</sect3>
<sect3><title>Who Used To Release Games For Linux</title>
<para>These are companies that used to release games for Linux but for whatever reasons aren't actively involved in
Linux games anymore.</para>
<variablelist>
<varlistentry><term>Loki Software: <ulink url="www.lokigames.com"></ulink></term>
<listitem><para>As the company that brought CTP and Quake3 to Linux, Loki was the father of Linux gaming. They
were one of the first and had, by far, the most titles (I own ALL of them). Loki ported games to Linux, mostly
using the SDL library. Loki's death in January 2002 was the biggest setback Linux has ever had in its attempt to
capture the general desktop market. Linuxgames.com has a nice Loki timeline at <ulink
url="url">http://www.linuxgames.com/articles/lokitimeline</ulink></para></listitem></varlistentry>
<varlistentry><term>Tribsoft: <ulink url="url">www.tribsoft.com</ulink></term>
<listitem><para>Tribsoft released Jagged Alliance 2, an excellent rpg/strat which claimed 2+ weeks of my life.
There were slated to release Europai Universalis, Majesty and Unfinished Business. However, as of 3Jan01, Mathieu
Pinard of Tribsoft said that he was taking a break and Tribsoft would no longer release games for awhile. He'll
still support JA2 but don't expect patches or updates.</para></listitem></varlistentry>
<varlistentry><term>MP Entertainment: <ulink url="http://www.hopkinsfbi.com"></ulink></term>
<listitem><para>MP Entertainment released Hopkins FBI, my favorite game ever released for Linux. More violent than
Quake. More nudity than Hustler. More camp than <ulink
url="http://www.flatwaremedia.com/liberace/gallery.cfm">Liberace</ulink>. It's a comic book on your monitor. They
were slated to release Hopkins FBI II and a few other titles, but it's been a few years since the announcements with
no sign that the games are coming. They've ignored all my attempts at finding out more information, so I have to
conclude that MP Entertainment is in the same status as Tribsoft. You can still purchase or download a demo of
Hopkins FBI from their website. If anyone has more information on this company or the author of Hopkins, please
contact me.</para></listitem></varlistentry>
<varlistentry><term>Phantom EFX: <ulink url="http://www.phantomefx.com"></ulink></term>
<listitem><para>They offer Reel Deal Slots, which is very nicely done! I'm not much for card/gambling games, but
this game is impressive! Because their Linux guy quit the company, Reel Deal Slots is their first, and so far, last
release for Linux.</para></listitem></varlistentry>
</variablelist>
</sect3>
</sect2>
<sect2><title>Other Resources</title>
<para>This section has URL's that should be mentioned but didn't have a separate section within the howto, so I list them
here as a kind of appendix.</para>
<variablelist>
<varlistentry><term>Linux Game Publishing: <ulink url="http://www.linuxgamepublishing.com"></ulink></term>
<listitem><para>Linux Publishing doesn't sell directly to the public, but provides professional game publishing to
authors of publishing. I think this means disk copying, packaging and selling to
retailers.</para></listitem></varlistentry>
<varlistentry><term>XFree86 Homesite: <ulink url="http://www.xfree86.org"></ulink></term>
<listitem><para>XFree86 home page</para></listitem></varlistentry>
<varlistentry><term>Linux Game Development Center: <ulink url="http://lgdc.sunsite.dk/index.html"></ulink></term>
<listitem><para>This is the canonical website for people who want to program games under Linux. It's a clearing house
of information that contains well written articles on all aspects of game programming (not necessarily Linux
specific), links to important game programming resources, interviews, reviews, polls and lots of other stuff. It's
hard to imagine a better website on the subject.</para></listitem></varlistentry>
<varlistentry><term>Linux Gamers' FAQ <ulink url="http://www.icculus.org/lgfaq/"></ulink></term>
<listitem><para>Despite the astounding fact that the Linux Gamers' FAQ doesn't mention the Linux Gamers' HOWTO as a
resource anywhere in their text, I regard the FAQ as a good companion to this HOWTO. I've tried to keep game specific
information in this HOWTO at a minimum. The FAQ takes the opposite approach; they mainly focus on the games
themselves, including game specific problems and where to get Linux games in the first place. The FAQ and HOWTO are
complementary in this regard, and I've tried to not reproduce their content. Despite the authors being a bit surly,
their effort with the FAQ is very good. If you want a general source of information on game specific questions, the
FAQ is a fantastic place to start with. In addition, the FAQ keeps a fairly large database of Linux
Games.</para></listitem></varlistentry>
2003-07-29 19:48:36 +00:00
<varlistentry><term>Linux Audio Quality HOWTO <ulink url="http://www.linuxdj.com/audio/quality/"></ulink></term>
<listitem><para>This HOWTO is mainly of interest to musicians who want professional or semi professional sound cards
for the recording and making of music on a computer. The information is very detailed, and perhaps overkill for
gamers.</para></listitem></varlistentry>
2003-04-01 00:59:47 +00:00
</variablelist>
</sect2>
</sect1>
</article>
<!--
vim:textwidth=128:
-->
2003-04-01 22:49:24 +00:00
