Multiplatform Gaming
Like many others out there I have slowly been moving away from
traditional Windows based PC software, and have been moving towards
applications made for Mac and Linux. Thanks to Section 508, which was
passed in the United States in 2001, accessibility has drastically
improved for the Mac and Linux operating systems. Both operating
systems
ship with built in screen reading, magnification, and Braille reading
software that normally costs the average Windows PC user hundreds of
dollars to own and upgrade. If a blind computer user owns a Mac or
Linux
system the screen reader and magnification software is free.
The free screen reader and magnification software isn’t the only
bonuses
to using an operating system such as Ubuntu Linux 8.04. A Linux user
can
download and use several free high quality applications such as Open
Office 2.4, Mozilla firefox 3.0, Pigeon Instant messenger, Evolution
Email/calendar client, and more. Many of these applications are now
accessible out of the box, and work very well with the built in Orca
screen reader/magnifier software that ships with Linux. As a result of
all these accessibility improvements Windows is no longer the only
option for a blind computer user. We have a choice between using a Mac
with Mac OS Leopard, a PC running Ubuntu Linux 8.04, or a Pc running
Windows Vista.
However, like a lot of our sighted counterparts, many blind computer
users do like to play games in our free time. Unfortunately the
majority
of accessible games have been specifically designed for Microsoft
Windows only. Like many mainstream game developers most blind game
programmers don’t want to learn new programming languages, find new
development tools, and learn new software development kits in order to
write games for Mac and Linux. Fortunately, USA games has just
finished
some research that may make this much easier for the average blind
game
developer to make games that will run smoothly on Mac OS, windows, and
Linux without a lot of changes in the game’s source code.
Very recently I have downloaded the SDK for SDL.net that is
specifically
designed for Visual Basic 2005 and C-sharp 2005 developers. SDL is a
cross platform game development API similar to Microsoft’s DirectX
API.
SDL is a core API for Mac OS Leopard and Ubuntu Linux 8.04, and
there is
an easy install for Microsoft Windows 2000, XP, and vista. With
SDL.net
and the open source .Net framework, mono, games can easily be
written in
Visual basic or C-Sharp, and then run on systems running Mac OS,
Linux,
windows, and any other operating system with mono and SDL installed.
During our testing of SDL.net we found the API should be pretty decent
for the game developer wishing to create side-scrollers, arcade games,
board games, etc. the sDL Mixer features are good enough for most
practical uses, but does seam to lack full 3D audio which is really
the
only drawback I have found to using SDL instead of DirectX. In
addition,
SDL.net does support joysticks, mice, and keyboards so there is a
universal way to handle all of these devices on every operating system
out there without too much hassle for the game developer. Finally,
since
I have written the majority of my games in Visual C# 2005 I won’t
have
to rewrite all of my games from scratch in order to make them
multiplatform compatible. I merely have to rewrite the sections of
code
that currently use DirectX and replace it with SDL. That is
thankfully a
process that may take weeks instead of months to accomplish.
In order to insure full cross platform accessibility we have decided
to
officially drop Sapi 5.x support in all of our new titles. Instead we
will use prerecorded wav files to speak game messages like Draconis
Entertainment, GMA Games, PCS Games, etc are already doing in their
game
products. This really is the only practical way for doing speech on
several different platforms without having to write a new text to
speech
interface to support Sapi, Gnome-Speech, and Apple speech drivers
all at
once. Each operating system has its own way for handling text to
speech
output, and often it is like comparing apples to oranges. So we feel
creating our own sudo speech system is the best way to do this
effectively.
In our research we did a bench mark test between the built in Java
Javax.Sampled.Sound API and the SDL Mixer API and SDL with C# was much
more processor efficient in loading and unloading sampled wav file
data.
What this means is something that would be much more processor
intensive
like using prerecorded speech was much smoother using C# with SDL than
using Java with its own built in sound mixer API. So this too is a
good
reason to go the SDL route.
In the end we added up all the reasons to drop DirectX and Sapi and
have
discovered it is worth the effort to go to SDL for all of our new game
titles. Yes, there will be some drawbacks to switching to the new
technology such as we won’t be able to use force feedback controllers,
but those are problematic anyway with Microsoft’s DirectInput and .Net
Framework languages. SDL doesn’t have native 3d audio support, but it
can be added by writing a custom 3D processor that adjusts the SDL
volume and panning controls. This might require some additional
research
and experimentation, but it looks like it should be easy enough to do.
