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The Linux Gamers' HOWTO
Peter Jay Salzman
Frédéric Delanoy
Copyright © 2001, 2002 Peter Jay Salzman
Copyright © 2003, 2004 Peter Jay Salzman, Frédéric Delanoy
2004-11-13 v.1.0.6
Abstract
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.
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.
<p(at)dirac(dot)org> / [http://www.dirac.org/p] http://www.dirac.org/p.
Distributed subject to the Open Software License, ver 1.1
-----------------------------------------------------------------------------
Table of Contents
1. Administra
1.1. Authorship and Copyright
1.2. Acknowledgements
1.3. Latest Versions and Translations
2. Definitions: Types Of Games
2.1. Arcade style
2.2. Card, logic and board games
2.3. Text Adventure (aka Interactive Fiction)
2.4. Graphical Adventures
2.5. Simulation (aka Sims)
2.6. Strategy (aka Strats)
2.7. First Person Shooter (aka FPS)
2.8. Side Scrollers
2.9. Third Person Shooters
2.10. Role Playing Game (aka RPG)
3. Libraries
3.1. What is Glide2?
3.2. What is Glide3?
3.3. What is OpenGL?
3.4. What is Mesa?
3.5. What is DRI?
3.6. What is GLX?
3.7. What is Utah GLX?
3.8. What is xlib?
3.9. What is a widget set?
3.10. What is SDL (Simple DirectMedia Layer)?
3.11. What is GGI?
3.12. What is SVGAlib? Frame buffer? Console?
3.13. What is OpenAL?
3.14. What is DirectX?
3.15. Clanlib
4. XFree86 and You
4.1. Getting information about your X system
4.2. Playing Games In X Without a Window Manager
5. Various Topics
5.1. Memory Type Range Registers
5.2. Milking performance from your system for all it's worth
5.3. About libraries on Linux
6. When Bad Things Happen To Good People
6.1. RTFM!
6.2. Look For Updates and Patches
6.3. Newsgroups
6.4. Google Group Search
6.5. Debugging: call traces and core files
6.6. Saved Games
6.7. What to do when a file or library isn't being found (better living
through strace)
6.8. Hosed consoles
6.9. Locked System
7. Video Cards
7.1. History
7.2. Current Status (1 March 2004)
7.3. Which Video Card Should I Buy? (1 March 2004)
7.4. Definitions: Video Card and 3D Terminology
8. Sound
8.1. Which sound card is best?
8.2. Why isn't my sound working?
9. Miscellaneous Problems
9.1. Hardware Acceleration Problems
9.2. Hardware acceleration works only for the root user
10. Emulation and Virtual Machines
10.1. What is a virtual machine?
10.2. Apple 8-bit
10.3. DOS
10.4. Win16
10.5. Win32
11. Interpreters
11.1. SCUMM Engine (LucasArts)
11.2. AGI: Adventure Gaming Interface (Sierra)
11.3. SCI: SCript Interpreter or Sierra Creative Interpreter (Sierra)
11.4. Infocom Adventures (Infocom, Activision)
11.5. Scott Adams Adventures (Adventure International)
11.6. Ultima Underworld: The Stygian Abyss (Origin, Blue Sky Productions)
11.7. Ultima 7 (Origin, Electronic Arts)
11.8. System Shock (Electronic Arts, Origin)
12. Websites And Resources
12.1. Meta gaming websites
12.2. Commercial Linux Game Resources
12.3. Other Resources
1. Administra
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 <p
(at)dirac(dot)org>. My web page is [http://www.dirac.org/p] http://
www.dirac.org/p and my Linux pages are at [http://www.dirac.org/linux] http:/
/www.dirac.org/linux. Please do send comments and suggestions for this howto.
Even if I don't take your suggestions, your input is graciously received.
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.
-----------------------------------------------------------------------------
1.1. Authorship and Copyright
This document is copyright (c) 2001-2002 Peter Jay Salzman, <p(at)dirac(dot)
org>; 2003-2004 Peter Jay Salzman and Frédéric Delanoy. 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 [http://opensource.org/licenses/osl-1.1.txt] http://
opensource.org/licenses/osl-1.1.txt.
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.
-----------------------------------------------------------------------------
1.2. Acknowledgements
Thanks goes out to these people for extensive comments, corrections, and
diffs. Their effort is above and beyond the call of duty:
Frédéric Delanoy, Moritz Muehlenhoff <jmm(at)Informatik(dot)uni-bremen(dot)de
>, Mike Phillips, Ioan Rogers <buck(at)aiur(dot)co(dot)uk>
I would also like to thank the following people for sending in comments and
corrections. Without their help, there would be more typos and mistakes than
you could shake a stick at:
Michael McDonnell
-----------------------------------------------------------------------------
1.3. Latest Versions and Translations
The latest version can be found at [http://cvs.sourceforge.net/cgi-bin/
viewcvs.cgi/lgh/LG-HOWTO] http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/lgh/
LG-HOWTO or [http://www.dirac.org/linux/writing] http://www.dirac.org/linux/
writing, 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. :)
The most recent stable version can be found at [http://www.tldp.org] http://
www.tldp.org.
-----------------------------------------------------------------------------
1.3.1. Russian
Dmitry Samoyloff <dsamoyloff(at)yandex(dot)ru> is the maintainer of the
Russian translation. The most recent version can be found at [http://
www.dirac.org/linux/writing] http://www.dirac.org/linux/writing.
-----------------------------------------------------------------------------
1.3.2. Hungarian
László Daczi <dacas(at)korhaz(dot)rethy(dot)hu>, the Hungarian LDP
coordinator, announced that a Hungarian translation was produced by Szilard
Ivan, and is available at [http://tldp.fsf.hu/HOWTO/Linux-Gamers-HOWTO-hu]
http://tldp.fsf.hu/HOWTO/Linux-Gamers-HOWTO-hu.
-----------------------------------------------------------------------------
2. Definitions: Types Of Games
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.
-----------------------------------------------------------------------------
2.1. Arcade style
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.
-----------------------------------------------------------------------------
2.2. Card, logic and board games
Computer based card games simulate a card game like poker or solitaire. The
program can simulate your opponent(s).
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.
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.
-----------------------------------------------------------------------------
2.3. Text Adventure (aka Interactive Fiction)
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:
+-----------------------------------------------------------------------------------------+
| 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 some garlic and a cheese sandwich. The oven door is now closed. |
| |
+-----------------------------------------------------------------------------------------+
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 (Section 2.7) and wad files.
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 (Section 11.5) and reached their height of
popularity in the late 80's with Infocom (Section 11.4) which are also
playable under Linux.
As computer graphics became easier and more powerful, text adventures gave
rise to graphic adventures. The death of commercial interactive fiction more
or less coincided with the bankruptcy of Infocom.
-----------------------------------------------------------------------------
2.4. Graphical Adventures
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.
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).
-----------------------------------------------------------------------------
2.5. Simulation (aka Sims)
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.
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 (Section 2.6). 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.
-----------------------------------------------------------------------------
2.6. Strategy (aka Strats)
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), or not, like 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.
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.
-----------------------------------------------------------------------------
2.7. First Person Shooter (aka FPS)
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 favorite FPS
under Linux (Half-Life plays great under winex) Linux definitely has no
deficiency here!
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.
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 (doom2.wad, pak0.pak, 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 to 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 doom.wad.
-----------------------------------------------------------------------------
2.8. Side Scrollers
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 xscavenger, a clone of the old 8-bit
game Lode Runner.
-----------------------------------------------------------------------------
2.9. Third Person Shooters
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.
-----------------------------------------------------------------------------
2.10. Role Playing Game (aka RPG)
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.
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.
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 (Section 11.7).
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.
-----------------------------------------------------------------------------
3. Libraries
We'll run through the different gaming libraries you'll see under Linux.
-----------------------------------------------------------------------------
3.1. What is Glide2?
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.
A program can only use the special hardware accelerated features of these
cards by using the Glide2 library in one of two ways:
  * directly written using Glide2 (Myth II, Descent III)
  * indirectly using Mesa built with a Glide2 backend to simulate OpenGL
(Rune, Unreal Tournament)
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.
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 /dev/3dfx)
allows Glide2 graphical hardware acceleration for non-root users of
non-setuid applications.
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.
-----------------------------------------------------------------------------
3.2. What is Glide3?
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.
When you use a Voodoo III, IV or V under XFree86 4.x, you want to use a
version of Mesa (see Section 3.4) which was compiled to use Glide3 as a
backend to ensure hardware accelerated OpenGL on your system.
-----------------------------------------------------------------------------
3.3. What is OpenGL?
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.
There are 3 canonical parts to OpenGL:
  * GL: The OpenGL core calls
  * GLU: The utility calls
  * GLUT: OS independent window event (mouse, keyboard, etc.) handler.
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.
OpenGL is the open source equivalent to Direct3D, a component of DirectX (
Section 3.14). 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.
-----------------------------------------------------------------------------
3.4. What is Mesa?
Mesa <[http://www.mesa3d.org] http://www.mesa3d.org> 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.
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.
-----------------------------------------------------------------------------
3.5. What is DRI?
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 <[http://www.dri.sourceforge.net] http:/
/www.dri.sourceforge.net>. DRI allows X clients to write 3D rendering
information directly to the video card in a safe and cooperative manner.
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.
  * Vertex data doesn't have to be encoded/decoded via GLX.
  * Graphics data isn't sent over a socket to the X server.
  * On uni-processor machines the CPU doesn't have to change context between
XFree86 and its client to render the graphics.
-----------------------------------------------------------------------------
3.6. What is GLX?
GLX is the X extension used by OpenGL programs, it is the glue between the
platform independent OpenGL and platform dependent X.
-----------------------------------------------------------------------------
3.7. What is Utah GLX?
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.
-----------------------------------------------------------------------------
3.8. What is xlib?
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.
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 (Section
3.10) for 2D graphics, OpenGL (Section 3.3) for 3D graphics and widget sets (
Section 3.9) for widgets within windows which hide the details of different
aspects of xlib programming.
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.
-----------------------------------------------------------------------------
3.9. What is a widget set?
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.
-----------------------------------------------------------------------------
3.10. What is SDL (Simple DirectMedia Layer)?
SDL <[http://www.libsdl.org] http://www.libsdl.org> 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 (Section 3.8), SDL is very suited for game programming.
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 extensions written by various people to do things like handle any
graphics format you care to mention, play mpegs, display truetype fonts,
sprite handling and just about everything under the sun. SDL is an example of
what all graphics libraries should strive for.
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.
-----------------------------------------------------------------------------
3.11. What is GGI?
GGI <[http://www.ggi-project.org] http://www.ggi-project.org> 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.
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 (
Section 3.12) using LibGGI. SDL (Section 3.10) and clanlib (Section 3.15)
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.
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.
-----------------------------------------------------------------------------
3.12. What is SVGAlib? Frame buffer? Console?
The console is the dark non-graphical screen you look at when your computer
first boots up (and you don't have xdm or gdm 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.
SVGAlib is a graphics library that lets you draw graphics on the console.
There are many graphical applications and games that use SVGAlib like zgv (a
console graphical image viewer), prboom and hhexen. 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.
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
Framebuffer 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.
-----------------------------------------------------------------------------
3.13. What is OpenAL?
OpenAL <[http://www.openal.org] http://www.openal.org> aims to be for sound
what OpenGL is for graphics. It started as a joint project between Loki
Software and Creative Labs, setting out to be a vendor neutral and cross
platform API for audio - the audio equivalent of OpenGL (Section 3.3). Loki
is no longer in business, but Creative and the Open Source community have
kept the project alive. It is licensed LGPL and the specs can be obtained for
free from the OpenAL website. It has support from nVidia (nForce2/3 based
motherboards come with OpenAL MS Windows libraries for the on-board audio),
Apple has added OpenAL to their audio framework for OSX and it can also be
found powering the Epic Games Unreal Engine
Currently, it's not all cross-platform goodness. There is almost no support
for enhancements like EAX or any hardware acceleration on Linux, though it
does it exist in the Windows implementation. However, if you have a Creative
SoundBlaster or Audigy sound card (with an emu10x chip), and you use ALSA
sound drivers, you can get OpenAL libraries from [http://www.lost.org.uk]
http://www.lost.org.uk that provide hardware acceleration and decent surround
support.
-----------------------------------------------------------------------------
3.14. What is DirectX?
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 statement would be something
like "DirectX is like DRI, OpenGL and SDL combined". As of October 2004, the
most recent version of DirectX is 9c. The components of DirectX are:
DirectDraw
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.
Direct3D (D3D)
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.
DirectAudio
DirectAudio is a combination of 2 audio API's, DirectSound and
DirectMusic, which allows direct access to the sound card for sound and
music playback.
DirectInput
DirectInput gives support for gaming input devices such as joysticks.
DirectPlay
DirectPlay gives support for simplified networking for multiplayer
gaming.
DirectShow
DirectShow provides support for movie files like AVI and MPG. It was a
separate API from DirectX, but was integrated with DirectX 8.
DirectSetup
This API provides a way to install DirectX from within an application to
simplify game installation.
Depending on the version of DirectX you're talking about, DirectX support in
winex (Section 10.5.3) ranges from well supported to "kind of" supported.
It's poorly supported by wine (Section 10.5.1), barely supported by vmware (
Section 10.5.5) and unsupported by Win4Lin (Section 10.5.4).
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.
A company named realtechVR started an open source project, DirectX Port, <
[http://www.v3x.net/directx] http://www.v3x.net/directx> 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 <[http://
sourceforge.net/projects/dxglwrap] http://sourceforge.net/projects/dxglwrap>.
-----------------------------------------------------------------------------
3.15. Clanlib
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.
-----------------------------------------------------------------------------
4. XFree86 and You
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 required
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 XF86Config (or XF86Config-4).
-----------------------------------------------------------------------------
4.1. Getting information about your X system
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.
-----------------------------------------------------------------------------
4.1.1. Probeonly
One of the best diagnostic tools and sources of information about your X
system is probeonly output. To use it, kill X if it's already running and
from a console, type:
+---------------------------------------------------------------------------+
| X -probeonly 2> X.out |
| |
+---------------------------------------------------------------------------+
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 X.out. 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:
+---------------------------------------------------------------------------+
| (--) probed (**) from config file (==) default setting |
| (++) from command line (!!) notice (II) informational |
| (WW) warning (EE) error (??) unknown. |
| |
+---------------------------------------------------------------------------+
Here's an example of some information I gleaned from my output:
I'm running at 16 bpp color:
+---------------------------------------------------------------------------+
| (**) TDFX(0): Depth 16, (--) framebuffer bpp 16 |
| |
+---------------------------------------------------------------------------+
X has detected what my videocard chipset and videoram are:
+---------------------------------------------------------------------------+
| (--) Chipset 3dfx Voodoo5 found |
| (--) TDFX(0): VideoRAM: 32768 kByte Mapping 65536 kByte |
| |
+---------------------------------------------------------------------------+
-----------------------------------------------------------------------------
4.1.2. Getting info about your setup: xvidtune
xvidtune 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:
  * the hsync/vsync range specified in your XF86Config file
  * 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
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.
  * the "dot clock" your videocard is running at.
-----------------------------------------------------------------------------
4.1.3. Getting info about your setup: xwininfo
xwininfo 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.
-----------------------------------------------------------------------------
4.1.4. Other sources of information
xdpyinfo gives cool stuff, like X version and loaded extensions (invaluable
when trying to see what's missing, like GLX, DRI, XFree86-VidMode, etc.).
-----------------------------------------------------------------------------
4.1.5. Getting information about your 3D system
glxinfo 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 more.
-----------------------------------------------------------------------------
4.2. Playing Games In X Without a Window Manager
When playing a game under X, you should consider starting X without a window
manager (WM). Heavyweight WMs, like Enlightenment, or full-blown desktop
environments like GNOME or KDE, may produce a noticeable slow down. Even
lightweight WMs, like twm, rob your CPU of clock cycles (and in twm's case,
even full screen games will have a frame around the window). Running a game
without a WM or DE depends on how you access X. If you usually log in to a
Virtual Console and start X with "startx" try the following:
Modify ~/.xinitrc, which tells X what to run upon starting. Here is what my
.xinitrc looks like:
+---------------------------------------------------------------------------+
| #quake3 +set r_gldriver libGR.so.1 |
| #exec ut |
| #lsdldoom -server 2 |
| #exec tribes2 |
| exec /usr/bin/enlightenment |
| |
+---------------------------------------------------------------------------+
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.
If you log directly into X using gdm, then things are a little different.
These instructions are for gdm 2.4 or greater. They *may* work with kde, but
I cannot say for certain.
First, check your gdm.conf (usually in /etc/X11/gdm or /etc/gdm) file for a
line that says begins "SessionDesktopDir=blah". One of the directories listed
as options should be "/usr/share/xsessions", and is the directory which will
be used in this example. As root, change to the "/usr/share/xsessions"
directory and take a look at its contents. It should contain some .desktop
files, each corresponding to an entry you'll see in gdm's Session menu, e.g
gnome.desktop, enlightenment.destop. This example will show you how to log in
to Doom3. Copy any of the desktop files to "doom3.desktop" and open the new
file in your favourite text editor. The file will be full of alternative
languages, so cut out everything you don't want and make the file look like
this:
+---------------------------------------------------------------------------+
| [Desktop Entry] |
| Encoding=UTF-8 |
| Name=DOOM III |
| Comment=iD's Doom III |
| #if game is not in path, remember to put the full path here |
| Exec=/usr/games/doom3/doom3 |
| # no icon yet, only the top three are currently used |
| Icon= |
| Type=Application |
| |
+---------------------------------------------------------------------------+
Save the file and log out of your window manager. At the gdm login screen,
you should now see "DOOM III" as an option in "Sessions". Naturally you can
add a .desktop file for each game you have installed
-----------------------------------------------------------------------------
5. Various Topics
5.1. Memory Type Range Registers
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.
See /usr/src/linux/Documentation/mtrr.txt 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.
-----------------------------------------------------------------------------
5.2. Milking performance from your system for all it's worth
  * If for some reason you're using X 3.3, follow the instructions given by
mtrr.txt (see Section 5.1) to set up your MTRRs. X 4.0 does this
automatically for you.
  * If you're playing a game under X, don't run a window manager, and
certainly don't run a desktop manager like GNOME or KDE. See Section 4.2
for details.
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:
+---------------------------------------------------------------+
| # cd /etc/rc2.d |
| # ./ntpd stop |
| |
+---------------------------------------------------------------+
Another (radical) option is to simply put yourself in single-user mode
with
+---------------------------------------------------------------+
| # telinit 1 |
| |
+---------------------------------------------------------------+
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.
-----------------------------------------------------------------------------
5.3. About libraries on Linux
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, gcc uses dynamic libraries, but you
can make gcc use static libraries instead by using the -static switch. Unless
you plan on compiling your games from source code, you'll mainly be
interested in dynamic libraries.
-----------------------------------------------------------------------------
5.3.1. Dynamic libraries
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
.dll's used by Windows. The program responsible for linking code ??on the fly
?? is called /etc/ld.so, and the dynamic libraries themselves usually end
with .so with a version number, like:
+---------------------------------------------------------------------------+
| /usr/lib/libSDL.so |
| /lib/libm.so.3 |
| |
+---------------------------------------------------------------------------+
When using gcc, you refer to these libraries by shaving off the strings lib,
.so and all version numbers. So to use these two libraries, you would pass
gcc the -lSDL -lm options. gcc will then `place a memo inside the executable'
that says to look at the files /usr/lib/libSDL.so and /lib/libm.so.3 whenever
an SDL or math function is used.
-----------------------------------------------------------------------------
5.3.2. Static libraries
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 .a
followed by a version number, like:
+---------------------------------------------------------------------------+
| /usr/lib/libSDL.a |
| /usr/lib/libm.a |
| |
+---------------------------------------------------------------------------+
The .a files are really an archive of a bunch of .o (object) files archived
together, similar to a tar file. You can use the nm to see what functions a
static library contains:
+---------------------------------------------------------------------------+
| % 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 |
| ... |
| |
+---------------------------------------------------------------------------+
When using gcc, 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 gcc the -lSDL -lm options. gcc will then `bolt on' code from /usr/lib/
SDL.a and /usr/lib/libm.a whenever it sees a math function during the
compilation process.
-----------------------------------------------------------------------------
5.3.3. How are library files found
If you compile your own games, your biggest problem with libraries will
either be that gcc 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 ld.so can't find the library or the library doesn't exist
on your system. So it makes some sense to talk about how gcc and ld.so go
about finding libraries in the first place.
gcc looks for libraries in the ``standard system directories'' plus any
directories you specify with the -L option. You can find what these standard
system directories are with gcc -print-search-dirs
ld.so looks to a binary hash contained in a file named /etc/ld.so.cache 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 /etc/ld.so.conf which you can edit. This file
contains a list of directories that you want ld.so to search for dynamic
libraries. If you want to start putting dynamic libraries in /home/joecool/
privatelibs, you'd add this directory to /etc/ld.so.conf. Your change doesn't
actually make it into /etc/ld.so.cache until you run ldconfig; once it's run,
ld.so will begin to look for libraries in your private directory.
Also, even if you just add extra libraries to your system, you must update
ld.so.cache to reflect the presence of the new libraries.
-----------------------------------------------------------------------------
5.3.4. Finding Out What Libraries a Game Depends On
Most commercial Linux games will be dynamically linked against various LGPL
libraries, such as OpenAL or SDL. For these examples, Bioware's NeverWinter
Nights <[http://nwn.bioware.com] http://nwn.bioware.com> will be used.
To find out what libraries a game uses, we can use the "ldd" command. Cd to /
usr/games/nwn, or wherever you installed it and take a look at the files. You
should see a file called nwmain; this is the actual game binary. Type "ldd
nwmain" and you'll see:
+---------------------------------------------------------------------------+
| $ ldd nwmain |
| linux-gate.so.1 => (0xffffe000) |
| libm.so.6 => /lib/libm.so.6 (0x40027000) |
| libpthread.so.0 => /lib/libpthread.so.0 (0x40049000) |
| libGL.so.1 => /usr/lib/libGL.so.1 (0x4009b000) |
| libGLU.so.1 => /usr/X11R6/lib/libGLU.so.1 (0x40103000) |
| libmss.so.6 => not found |
| libSDL-1.2.so.0 => /usr/lib/libSDL-1.2.so.0 (0x40178000) |
| libc.so.6 => /lib/libc.so.6 (0x401ff000) |
| /lib/ld-linux.so.2 (0x40000000) |
| libGLcore.so.1 => /usr/lib/libGLcore.so.1 (0x40319000) |
| libnvidia-tls.so.1 => /usr/lib/libnvidia-tls.so.1 (0x409f1000) |
| libXext.so.6 => /usr/X11R6/lib/libXext.so.6 (0x409f3000) |
| libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x40a01000) |
| libdl.so.2 => /lib/libdl.so.2 (0x40acd000) |
| libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x40ad1000) |
| libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x40b88000) |
| libasound.so.2 => /usr/lib/./libasound.so.2 (0x40b90000) |
| |
+---------------------------------------------------------------------------+
ldd shows all the libraries a dynamic executable relies on, and shows you
where they are. It also "pulls in" the dependencies of the dependencies. For
instance, while NWN does not itself depend on libnvidia-tls.so, the Nvidia
supplied libGL on my system does.
Missing libraries?
In the example above, we can see that nwmain wants libmss.so.6, and the
linker cannot find it. Usually, a missing library is a crash waiting to
happen. There is one other thing to consider though: The majority of games
are actually launched by a "wrapper", a shell script that performs some magic
prior to launching the game. In the case of NWN, the wrapper is called nwn.
Let's take a look at that now:
+-------------------------------------------------------------------------------+
| $ less nwn |
| #!/bin/sh |
| |
| # This script runs Neverwinter Nights from the current directory |
| |
| export SDL_MOUSE_RELATIVE=0 |
| export SDL_VIDEO_X11_DGAMOUSE=0 |
| |
| # If you do not wish to use the SDL library included in the package, remove |
| # ./lib from LD_LIBRARY_PATH |
| export LD_LIBRARY_PATH=./lib:./miles:$LD_LIBRARY_PATH |
| |
| ./nwmain $@ |
| |
+-------------------------------------------------------------------------------+
This script sets up some environment variables, then launches the game binary
with whatever command line options we added. The relevant part here is the
environment variable called "LD_LIBRARY_PATH". This is a way of adding to the
linkers search path. Try copying the line to your shell and seeing what
happens when you re-run ldd.
+---------------------------------------------------------------------------+
| $ export LD_LIBRARY_PATH=./lib:./miles:$LD_LIBRARY_PATH |
| $ ldd nwmain |
| linux-gate.so.1 => (0xffffe000) |
| libm.so.6 => /lib/libm.so.6 (0x40027000) |
| libpthread.so.0 => /lib/libpthread.so.0 (0x40049000) |
| libGL.so.1 => /usr/lib/libGL.so.1 (0x4009b000) |
| libGLU.so.1 => /usr/X11R6/lib/libGLU.so.1 (0x40103000) |
| libmss.so.6 => ./miles/libmss.so.6 (0x40178000) |
| libSDL-1.2.so.0 => ./lib/libSDL-1.2.so.0 (0x401ec000) |
| libc.so.6 => /lib/libc.so.6 (0x4025e000) |
| /lib/ld-linux.so.2 (0x40000000) |
| libGLcore.so.1 => /usr/lib/libGLcore.so.1 (0x40378000) |
| libnvidia-tls.so.1 => /usr/lib/libnvidia-tls.so.1 (0x40a50000) |
| libXext.so.6 => /usr/X11R6/lib/libXext.so.6 (0x40a52000) |
| libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x40a60000) |
| libdl.so.2 => /lib/libdl.so.2 (0x40b2c000) |
| libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x40b30000) |
| libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0x40be7000) |
| |
+---------------------------------------------------------------------------+
As you can see, this gives us slighly different results. The NWN library
directories have been prepended to the search path, so now the linker can
find libmss.so.6 in the "./miles" directory, and also finds the local copy of
libSDL first, no longer using the system copy.
There's another benefit of these scripts: they are easily edited to allow you
to provide your own copy of a library. Any game-supplied copy of a library
such as OpenAL or SDL is likely to be compiled for the lowest common
denominator, probably i486 or i686. If you have a Pentium4 or an AthlonXP,
you could compile you own version specifically for your processor. The
compiler will try to optimise the resulting binary, giving some increase in
performance. See the homepage for GCC for more information this at the GCC
site.
Making NWN use your system copy is easy. It says so in the wrapper script!
Remove "./lib:" from the LD_LIBRARY_PATH line, and you're good to go.
Another nice little trick is for games that use OpenAL for their sound output
(e.g. Unreal based games: UT, Postal, Rune, etc.). Since the Open Sound
System's (OSS) deprecation in favour of ALSA, all Linux distributions I've
seen now ship with ALSA support as default, with OSS support actually being
supplied via ALSA's compatability modules. The copies of openal.so
distributed with games often do NOT support ALSA, so making the game use a
copy compiled yourself will allow you to use ALSA natively.
-----------------------------------------------------------------------------
6. When Bad Things Happen To Good People
Of course we can't cover every Bad Thing that happens, but I'll outline some
items of common sense.
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.
-----------------------------------------------------------------------------
6.1. RTFM!
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.
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 [http://faqs.lokigames.com] http://
faqs.lokigames.com.
-----------------------------------------------------------------------------
6.2. Look For Updates and Patches
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.
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.
By the way, Loki now has a utility that searches for Loki Software on your
hard drive and automatically updates them. Check out [http://
updates.lokigames.com] http://updates.lokigames.com.
-----------------------------------------------------------------------------
6.3. Newsgroups
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.
For instance, I can browse Loki Software's news server with tin -g
news.lokigames.com. You can also specify which news server to use using the
$NNTP environment variable or with the file /etc/nntpserver.
-----------------------------------------------------------------------------
6.4. Google Group Search
Every post made to Usenet gets archived at Google's database at [http://
groups.google.com] http://groups.google.com. This archive used to be at
[http://www.deja.com] http://www.deja.com, but was bought by Google. Many
people still know the archive as "deja".
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
[http://www.freetranslation.com] http://www.freetranslation.com and [http://
translation.lycos.com] http://translation.lycos.com. My web browser of
choice, Opera (available at [http://www.opera.com] http://www.opera.com)
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 wife
(who reads German well) isn't around.
The Google group search has a basic and advanced search page. Don't bother
with the simple search. The advanced search is at [http://groups.google.com/
advanced_group_search] http://groups.google.com/advanced_group_search.
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.
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.
-----------------------------------------------------------------------------
6.5. Debugging: call traces and core files
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 [http://www.dirac.org/linux] http://
www.dirac.org/linux.
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:
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:
+---------------------------------------------------------------------------+
| ulimit -c unlimited |
| |
+---------------------------------------------------------------------------+
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:
+---------------------------------------------------------------------------+
| $ gdb CoolGameExecutable core |
| |
+---------------------------------------------------------------------------+
And at the (gdb) prompt, type "backtrace". You'll see something like:
+---------------------------------------------------------------------------+
| #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 |
| |
+---------------------------------------------------------------------------+
It may be quite long, but use your mouse to cut and paste this information
into a file. Email the author and tell him:
1. The game's name
2. Any error message that appears on the screen when the game crashes.
3. What causes the crash and whether it's a repeatable crash or not.
4. The call stack
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.
-----------------------------------------------------------------------------
6.6. Saved Games
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.
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.
-----------------------------------------------------------------------------
6.7. What to do when a file or library isn't being found (better living
through strace)
Sometimes you'll see error messages that indicate a file wasn't found. The
file could be a library:
+-----------------------------------------------------------------------------------------+
| % ./exult |
| ./exult: error while loading shared library: libSDL-1.2.so.0: cannot load shared object |
| file: No such file or directory |
| |
+-----------------------------------------------------------------------------------------+
or it could be some kind of data file, like a wad or map file:
+-----------------------------------------------------------------------------------------+
| % qf-client-sdl |
| IP address 192.168.0.2:27001 UDP Initialize Error: W_LoadWadFile: couldn't load gfx.wad |
| |
+-----------------------------------------------------------------------------------------+
Suppose gfx.wad is already on my system, but couldn't be found because it
isn't in the right directory. Then where IS the right directory? Wouldn't it
be helpful to know where these programs looked for the missing files?
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:
+---------------------------------------------------------------------------+
| strace -o ./LS_LOG /bin/ls |
| |
+---------------------------------------------------------------------------+
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:
+---------------------------------------------------------------------------+
| open(".", O_RDONLY|O_NONBLOCK|0x18000) = 4 |
| |
+---------------------------------------------------------------------------+
We used the open() system call to open "." with various arguments, and the
return value of the call is 4. What does this have to do with files not being
found?
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:
+---------------------------------------------------------------------------+
| % ./mind.i86_linux.glibc2.1 |
| Loading & massaging... |
| Error:Can't open data file 'mind.dat'. |
| |
+---------------------------------------------------------------------------+
Let's use strace to find out where the program was looking for the data file.
+---------------------------------------------------------------------------+
| strace ./mind.i86_linux.glibc2.1 2> ./StateOfMind_LOG |
| |
+---------------------------------------------------------------------------+
Pulling out vim and searching for all occurrences of mind.dat, I find the
following lines:
+---------------------------------------------------------------------------+
| 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 |
| |
+---------------------------------------------------------------------------+
It was looking for mind.dat in only one directory. Clearly, mind.dat isn't in
/usr/share. Now we can try to locate mind.dat and move it into /usr/share, or
better, create a symbolic link.
This method works for libraries too. Suppose the library libmp3.so.2 is in /
usr/local/include 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 /usr/local/include/libmp3.so.2 to wherever Kill-Metallica
was looking for the library file.
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!
-----------------------------------------------------------------------------
6.8. Hosed consoles
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 ENTER, a newline doesn't get echo'ed to
the screen. Sometimes, certain keys of the keyboard won't respond. Logging
out and back in don't always work, but there are a few things that might:
  * If you don't see any character on the screen as you type in, your
terminal settings may be wrong. Try "stty echo". This should let input
characters echo again.
  * At the prompt, type "reset". This should clear up many problems,
including consoles hosed by an SVGAlib or ncurses based game.
  * Try running the game again and normally. Once I had to kill Quake III in
a hurry, so I performed a Ctl-Alt-Backspace. The console was hosed with a
quasi-graphics screen. Running Quake III and quitting normally fixed the
problem.
  * The commands deallocvt and openvt will work for most of the other
problems you'll have. deallocvt N kills terminal N entirely, so that
Alt-FN doesn't even work anymore. openvt -c N starts it back up.
  * 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".
  * 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.
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 normally see an fsck for the partitions that use the
journalling filesystem.
-----------------------------------------------------------------------------
6.9. Locked System
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.
  * The first thing you should try is to hit control-alt-backspace 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.
  * Use control-alt-delete 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).
  * Log into another system and ssh into the hung system. If you can ssh in,
reboot or halt the system.
  * If you can't ssh into the system, you'll need to use the "magic SysRq
key" which is documented in /usr/src/linux/Documentation/sysrq.txt.
Here's a summary for the x86 architecture (see the documentation for
other architectures). Note if your keyboard doesn't have a SysRq key, use
the PrintScreen key:
1. Hit alt-SysRq-s. 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.
2. A few seconds later, hit alt-SysRq-u. 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.
3. A few seconds later, use alt-SysRq-b to reboot the system.
4. You can hit alt-SysRq-h for a very terse help screen.
To use the magic SysRq key, your kernel needs to have been compiled with
magic SysRq support. You'll find this option under "Kernel Hacking | Kernel
Debugging | Magic SysRq key" 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.
-----------------------------------------------------------------------------
7. Video Cards
7.1. History
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 3.1) 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.
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.
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.
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.
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 7.4.3), 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.
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, and 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.
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 "Look
at /." 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!
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.
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.
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.
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 [http://www.linuxhardware.org/
features/01/03/19/0357219.shtml] http://www.linuxhardware.org/features/01/03/
19/0357219.shtml, but conclusion is that the GeForce 2 firmly and soundly
trounced the Radeon 32 DDR.
-----------------------------------------------------------------------------
7.2. Current Status (1 March 2004)
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. nVidia
uses a convenient combined driver architecture; their driver will support the
TNT 2 all the way up to the GeForce 5900. Although their drivers are closed
source, as a company, nVidia has been supportive and good to Linux users.
ATI's has worked with Linux developers for their Radeons up to and including
the Radeon 9200, which 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. It's claimed that these
drivers are piss poor; a friend of mine claims his GeForce 4400 outperforms
his Radeon 9700 pro. That's shameful.
On paper, and in the Windows benchmarks, the Radeon 9800 trounces the
ill-conceived GeForce 5800 and slightly edges out the GeForce 5900. 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 5900.
-----------------------------------------------------------------------------
7.2.1. SVGAlib Support
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.
I have no information about SVGAlib and the GeForce cards.
-----------------------------------------------------------------------------
7.3. Which Video Card Should I Buy? (1 March 2004)
The answer was very difficult last year, but here's my take on it these days:
1. 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.
2. 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 below par.
3. 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 driver
issues..
4. ATI has a very long history of dropping support for hardware as fast as
they can get away with it.
5. 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.
Don't get the GeForce 5800. Card reviews claim that it has some serious
[http://www.hardocp.com/article.html?art=NDIx] heat, noise, and dust issues.
It's informally called the "dust buster" because of noise its fan makes.
If you absolutely only want open source drivers on your system, the Radeon
9200 is the best card you can buy.
If you have a Linux/Windows dual boot, consider either the Radeon 9800 or the
GeForce 5900. The Radeon will be slightly stronger on Windows. The GeForce
will be stronger on Linux.
If you have a Linux only system, the GeForce 5900 is your best bet. As of
today, the 256MB version comes in at a whopping $350, however, the 128MB
version is more reasonable.
-----------------------------------------------------------------------------
7.4. Definitions: Video Card and 3D Terminology
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.
-----------------------------------------------------------------------------
7.4.1. Textures
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.
-----------------------------------------------------------------------------
7.4.2. T&L: Transform and Lighting
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.
-----------------------------------------------------------------------------
7.4.3. AA: Anti Aliasing
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.
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.
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.
-----------------------------------------------------------------------------
7.4.4. FSAA: Full Screen Anti-Aliasing
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.
-----------------------------------------------------------------------------
7.4.5. Mip Mapping
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 (Section 7.4.6). Mip mapping reduces
memory bandwidth requirements since the images are in hardware, but it also
offers better quality in the rendered image.
-----------------------------------------------------------------------------
7.4.6. Texture Filtering
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.
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.
-----------------------------------------------------------------------------
7.4.6.1. Point Sampling Texture Filtering
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.
-----------------------------------------------------------------------------
7.4.6.2. Bilinear Texture Filtering
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.
-----------------------------------------------------------------------------
7.4.6.3. Trilinear Texture Filtering
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.
-----------------------------------------------------------------------------
7.4.6.4. Anisotropic Texture Filtering
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.
-----------------------------------------------------------------------------
7.4.7. Z Buffering
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.
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.
-----------------------------------------------------------------------------
8. Sound
8.1. Which sound card is best?
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 Linux Audio Quality HOWTO.
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.
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.
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.
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).
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.
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.
-----------------------------------------------------------------------------
8.2. Why isn't my sound working?
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.
There are 5 things that can go wrong with your sound system:
1. Shared interrupt
2. Misconfigured driver
3. Something's already accessing the sound card
4. You're using the wrong driver
5. A permissions problem
-----------------------------------------------------------------------------
8.2.1. Shared interrupt
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:
+---------------------------------------------------------------------------+
| $ 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 |
| |
+---------------------------------------------------------------------------+
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!).
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.
-----------------------------------------------------------------------------
8.2.2. Misconfigured driver
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.
This is a sound card specific issue, and beyond the scope of this HOWTO.
-----------------------------------------------------------------------------
8.2.3. Something is already accessing your sound card
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 /dev/dsp. Right now, I'm listening to an MP3 (not a Metallica
MP3, of course...) with mp3blaster.
+---------------------------------------------------------------------------+
| # lsof /dev/dsp |
| COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME |
| mp3blaste 1108 p 6w CHR 14,3 662302 /dev/dsp |
| |
+---------------------------------------------------------------------------+
fuser is similar; but it lets you send a signal to any process accessing the
device file.
+---------------------------------------------------------------------------+
| # fuser -vk /dev/dsp |
| |
| USER PID ACCESS COMMAND |
| /dev/dsp root 1225 f.... mp3blaster |
| root 1282 f.... mp3blaster |
| |
+---------------------------------------------------------------------------+
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.
-----------------------------------------------------------------------------
8.2.4. You're using the wrong driver (or no driver)
There are only two ways to configure your card:
1. Support must be compiled directly into the kernel
2. You must have the correct driver loaded into memory
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.
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.
-----------------------------------------------------------------------------
8.2.5. Permissions Problem
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 ls -l /dev/dsp; it'll probably be audio. Then,
as root, add your non-root user to the audio group in /etc/group. For
example, I added the users p and wellspring to group audio on my system:
+---------------------------------------------------------------------------+
| audio:x:29:p,wellspring |
| |
+---------------------------------------------------------------------------+
Don't forget to use grpconv if you use shadow passwords (which should be the
case on most recent distributions) in order to maintain a consistent group
configuration. 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.
-----------------------------------------------------------------------------
9. Miscellaneous Problems
9.1. Hardware Acceleration Problems
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.
-----------------------------------------------------------------------------
9.1.1. Hardware acceleration isn't working at all
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.
1. Your 3D system is misconfigured (more likely)
2. Game X is misconfigured (less likely)
The first step is to figure out which one is happening.
1. If you have X 4.0 (X 3.* users procede to step 2), look at the output of
X -probeonly. You'll see:
+---------------------------------------------------------------+
|(II) XXXXXX: direct rendering enabled |
+---------------------------------------------------------------+
or
+---------------------------------------------------------------+
|(II) XXXXXX: direct rendering disabled |
+---------------------------------------------------------------+
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 [http://www.xfree86.org/4.0/DRI.html] http://www.xfree86.org/4.0/
DRI.html.
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.
2. There is a program called glxgears which comes with the "mesademos"
package. You can get mesademos with Debian ( apt-get install mesademos)
or you can hunt for the rpm on [http://www.rpmfind.net] http://
www.rpmfind.net. You can also download and compile the source yourself
from the mesa homepage.
Running glxgears will show some gears turning. The xterm from which you
run glxgears will display "X frames in Y seconds = X/Y FPS". You can
compare your system to the list of benchmarks below.
+---------------------------------------------------------------+
| CPU TYPE VIDEO CARD X VERSION AVERAGE FPS |
| |
+---------------------------------------------------------------+
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.
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.
-----------------------------------------------------------------------------
9.2. Hardware acceleration works only for the root user
9.2.1. XFree86 4.x
If the following lines aren't present in your XF86Config-4 file, put them in:
+---------------------------------------------------------------------------+
| Section "DRI" |
| Mode 0666 |
| EndSection |
| |
+---------------------------------------------------------------------------+
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.
-----------------------------------------------------------------------------
9.2.2. XFree86 3.x
9.2.2.1. Voodoo cards
Voodoo card hardware acceleration only takes place ONLY at 16bpp color and
fails silently when starting X in another color depth.
Also, Voodoo cards need the 3dfx.o kernel module and a /dev/3dfx device file
(major 107, minor 0) for non-root hardware acceleration. Neither the module
nor the device file are used under XFree86 4.x.
-----------------------------------------------------------------------------
10. Emulation and Virtual Machines
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 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!
-----------------------------------------------------------------------------
10.1. What is a virtual machine?
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.
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.
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.
-----------------------------------------------------------------------------
10.2. Apple 8-bit
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.
-----------------------------------------------------------------------------
10.2.1. KEGS
KEGS is an Apple II emulator written by Kent Dickey <kentd(at)cup(dot)hp(dot)
com> 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.
-----------------------------------------------------------------------------
10.2.2. apple2 and xapple2
The SVGAlib based apple2 and X based xapple2 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. apple2 is currently being
maintained by Michael Deutschmann <michael(at)talamasca(dot)ocis(dot)net> and
seems to be developed at a slow but constant pace. I don't think this
application has a homepage.
-----------------------------------------------------------------------------
10.3. DOS
10.3.1. dosemu
dosemu <[http://www.dosemu.org] http://www.dosemu.org> 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.
-----------------------------------------------------------------------------
10.4. Win16
10.4.1. Wabi
Wabi 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. Wabi was originally created by SCO Unix a long time ago and then
was purchased by Caldera sometime in mid year 2001.
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:
  * You must have a licensed copy of Windows 3.1/3.11 or WfW 3.11.
  * Wabi is awfully expensive for what it does.
  * Wabi doesn't work under 32bpp or 24bpp color.
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?)
-----------------------------------------------------------------------------
10.5. Win32
10.5.1. wine
Wine <[http://www.winehq.com] http://www.winehq.com>, 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.
Wine does not provide the DOS API, so you can't use it to run DOS
applications. For that, you should look at dosemu (Section 10.3.1). 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 (Section
10.5.3).
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).
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 [http://www.winehq.com] winehq are writing
their own set of libraries called libwine which implements the Win32 API with
no Microsoft code at all.
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 (Section 10.5.3) and prompted a fork of wine called ReWind (
Section 10.5.2).
-----------------------------------------------------------------------------
10.5.2. rewind
Rewind <[http://rewind.sourceforge.net/] http://rewind.sourceforge.net/> was
started by Eric Pouech (a wine developer) and Ove Kåven (a winex developer)
in response to wine's license change). It started 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.
-----------------------------------------------------------------------------
10.5.3. winex
Winex is released by a company called Transgaming <[http://
www.transgaming.com] http://www.transgaming.com>. The developers take wine
(see Section 10.5.1) and add DirectX / DirectDraw support. Although winex is
commercial, they have an interesting business model.
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:
  * Subscribers can download convenient packaged versions of winex in deb,
rpm or tar.gz format whenever they want, including updates. They have
also more functionality than the publicly available tarball: the latter
is an older version which lacks some of the newest features, like support
for copy protected programs.
  * 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.
  * 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).
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 (Section 10.5.1). 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 (Section 10.5.2).
-----------------------------------------------------------------------------
10.5.4. Win4Lin
Win4Lin <[http://www.netraverse.com] http://www.netraverse.com> is a
commercial product by Netraverse. Like vmware (Section 10.5.5) 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. It suffers nevertheless from some limitations:
  * It does not support DirectX or DirectDraw, while vmware has "limited"
support for DirectX.
  * 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.
  * As of June 2003, expect to pay $89.99 without printed docs and $99.99
with printed docs. In addition, there isn't an evaluation copy available,
although you get a 30 day money back guarantee. However, since it's
commercial you do get tech support. vmware is considerably more
expensive.
  * Like vmware, you're required to have a licensed copy of Win95 or Win98.
Win4Lin cannot use an existing Windows installation the way wine can.
  * It only runs on x86 architectures.
-----------------------------------------------------------------------------
10.5.5. VMWare
VMWare is a virtual machine that runs multiple operating systems
simultaneously on a standard PC: supported OSes include Microsoft ones,
Linux, Novell Netware and FreeBSD. You can among others use it to run a MS
Windows OS and launch your favourite game there. You can even run another
Linux under Linux; useful is you want to test another distro for instance.
Amazing! Now for the bad sides. You should definitely have a good
configuration in order to run it; they claim the minimum is a 500MHz x86 CPU
with 128MB RAM, but a faster processor and at least 256MB RAM seem to be the
bare minimum if you want reasonable performance. Not all Linux distributions
are supported: newest RedHat's, Mandrake's and Suse's are, but you're out of
luck if you have an other version and/or distribution (like Debian).
Moreover, vmware has only limited support for DirectX, and you might not be
able to play recent games.
See [http://www.vmware.com] http://www.vmware.com for more information. It's
not very cheap (about 300$ for the Workstation version), but you can get a 30
day evaluation copy.
-----------------------------------------------------------------------------
10.5.6. What should I choose?
First of all, you should try an emulator. Although some games may work with
wine, you'll probably get the most success with winex: its DirectX support is
constantly improving. As of version 3.1, the DirectX 8 support is nearly
complete, but this may not be the case with older DirectX versions (are
consequently older games).
You might also try a virtual machine like Win4Lin or VMWare instead of an
emulator. 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.
Now if your 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.
-----------------------------------------------------------------------------
11. Interpreters
11.1. SCUMM Engine (LucasArts)
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 <strigeus(at)users(dot)sourceforge(dot)net> was able to reverse
engineer the SCUMM format and write an interpreter for SCUMM based games that
compiles under Linux and Win32 named scummvm <[http://scummvm.sourceforge.net
/] http://scummvm.sourceforge.net/>. Their website is very good, and chock
full of any kind of information about SCUMM and playing these games under
scummvm.
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.
-----------------------------------------------------------------------------
11.2. AGI: Adventure Gaming Interface (Sierra)
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 sarienon> <
[http://sarien.sourceforge.net] http://sarien.sourceforge.net>, an open
source interpreter for AGI games.
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.
-----------------------------------------------------------------------------
11.3. SCI: SCript Interpreter or Sierra Creative Interpreter (Sierra)
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.
Many SCI based games (games written in SCI0) can be played using freesci,
available at [http://freesci.linuxgames.com] http://freesci.linuxgames.com.
Like Sarien, FreeSCI has many graphics targets including SDL, xlib and GGI,
so this program can compile and run under an incredible number of platforms.
The developers have done a fantastic job of documenting and FAQing their
application.
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11.4. Infocom Adventures (Infocom, Activision)
The Z-machine is a well documented <[http://www.gnelson.demon.co.uk/zspec/
index.html] http://www.gnelson.demon.co.uk/zspec/index.html> 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!
One of the most popular Z-machine interpreters is Frotz <[http://
www.cs.csubak.edu/~dgriffi/proj/frotz/] http://www.cs.csubak.edu/~dgriffi/
proj/frotz/>. 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.
jzip <[http://jzip.sourceforge.net/] http://jzip.sourceforge.net/> 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.
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.
-----------------------------------------------------------------------------
11.5. Scott Adams Adventures (Adventure International)
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.
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 <[http://www.msadams.com/] http://
www.msadams.com/> you can enjoy these classics.
-----------------------------------------------------------------------------
11.6. Ultima Underworld: The Stygian Abyss (Origin, Blue Sky Productions)
The Underworld Adventures project <[http://uwadv.sourceforge.net/] http://
uwadv.sourceforge.net/> 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.
Underworld Adventures also provides a bunch of tools for you to display the
level maps, tools for examining uw1 conversation scripts and more.
-----------------------------------------------------------------------------
11.7. Ultima 7 (Origin, Electronic Arts)
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).
A team of people developed Exult <[http://exult.sourceforge.net/] http://
exult.sourceforge.net/> 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.
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.
-----------------------------------------------------------------------------
11.8. System Shock (Electronic Arts, Origin)
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!
The System Shock Hack Project <[http://madeira.physiol.ucl.ac.uk/tsshp/
sshock.html] http://madeira.physiol.ucl.ac.uk/tsshp/sshock.html> 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.
-----------------------------------------------------------------------------
12. Websites And Resources
12.1. Meta gaming websites
These are some resources for Linux gamers no matter what kind of game you
enjoy to play.
The Linux Game Tome: [http://www.happypenguin.org] http://
www.happypenguin.org
About the games themselves.
[http://www.linuxgames.com] Linuxgames
Linux gaming news
[http://www.holarse.net] http://www.holarse.net
Linux meta gaming site for German speaking folk.
[http://www.mobygames.com] Mobygames
A database of all known computer games. It's very complete and is one of
my favorite sites.
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12.2. Commercial Linux Game Resources
12.2.1. Where to buy commercial games
ebgames <[http://www.ebgames.com] http://www.ebgames.com> 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 shame because they had the lowest prices on Linux games I've ever
seen. However, occasionally, they'll have things like Code Warrior or Redhat
Linux on sale.
Tux Games: [http://www.tuxgames.com] http://www.tuxgames.com
Your one stop shop for buying any commercial Linux game (software vendors
like Tribsoft and Loki have online shops at their websites too).
-----------------------------------------------------------------------------
12.2.2. Who Used To Release Games For Linux
These are companies that used to release games for Linux but for whatever
reasons aren't actively involved in Linux games anymore.
Loki Software: [http://www.lokigames.com] http://www.lokigames.com
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 [http://www.linuxgames.com/
articles/lokitimeline] http://www.linuxgames.com/articles/lokitimeline
Tribsoft: [http://www.tribsoft.com] http://www.tribsoft.com
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.
MP Entertainment: [http://www.hopkinsfbi.com] http://www.hopkinsfbi.com
MP Entertainment released Hopkins FBI, my favorite game ever released for
Linux. More violent than Quake. More nudity than Hustler. More camp than
[http://www.flatwaremedia.com/liberace/gallery.cfm] Liberace. 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 FBI, please contact
me.
Phantom EFX: [http://www.phantomefx.com] http://www.phantomefx.com
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.
-----------------------------------------------------------------------------
12.3. Other Resources
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.
Linux Game Publishing: [http://www.linuxgamepublishing.com] http://
www.linuxgamepublishing.com
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.
XFree86 Homesite: [http://www.xfree86.org] http://www.xfree86.org
XFree86 home page
Linux Game Development Center: [http://lgdc.sunsite.dk/index.html] http://
lgdc.sunsite.dk/index.html
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.
Linux Gamers' FAQ: [http://www.icculus.org/lgfaq/] http://www.icculus.org/
lgfaq/
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.
Linux Audio Quality HOWTO: [http://www.linuxdj.com/audio/quality/] http://
www.linuxdj.com/audio/quality/
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.
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