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A JavaScript Gameboy Emulator, Detailed In 8 Parts
Two9A writes "JavaScript has shed its image of being a limited language, tied to DOM manipulation in a browser; in recent years, new engines and frameworks have given JS a reputation as a language capable of bigger things. Mix this in with the new elements of HTML5, and you have the capacity to emulate a game console or other system, with full graphical output. This series of articles looks in detail at how an emulator is written in JavaScript, using the example of the Gameboy handheld: starting at the CPU, and (as of part 8) running a copy of Tetris."
...but whenever I use one, I can't help but think "I sure wish this was written in Javascript, so there wouldn't be any way to save my game. Saved games are for pussies. And sure, it wouldn't support sound, but who needs that when you've got the beautiful noise of your computer fans running on full blast, thanks to its excessive CPU usage!"
Both sound and client-side data storage are features of HTML5.
Real men write their GB emulators in Minecraft.
I'm curious how he plans on handling dynamically generated sound from the GB ROM. Doing CPU and Graphics are usually the easy parts of emulating, but getting smooth dynamic sound without much latency is the challenge I've had to deal with when doing web-based emulators. Most web-based systems are designed to load a static set of sounds from a server, not dynamically generate them in the code.
Flash 10 provides some dynamic sound capability, but it has a rather large latency (~250ms). I blogged about this while writing my NES emulator in flash.
I read through these articles hoping for some insight on dynamically generated sound, but it doesn't look like he's gotten that far.
Things you think are in the Constitution, but are not.
I've said it before, and I'll say it again:
You can write damn near anything in JavaScript if you really want to, but the better question is if you should.
And yes, that includes half (but only half!) of the stuff you'll find done in JavaScript in web apps.
Both sound and client-side data storage are features of HTML5.
I've heard of the HTML5 <audio> element. But as I understand it, it's designed for playing pre-recorded audio, not audio synthesized in real time as would be necessary for an emulator. The only reference that the page linked from "sound" makes to synthesis is in the context of text-to-speech for a textual description track. Even if you generate .wav into a data: URI, I know of no way within this spec to link multiple data: URIs to play gaplessly.
You can write damn near anything in JavaScript if you really want to, but the better question is if you should.
If your users have access to a web browser but lack the privileges to install a native client on machines that they use, then you have no choice but to write your application in a language that runs inside the web browser. This is often the case in break rooms, public libraries, and university computer labs, where the user isn't the owner, or with locked-down appliances, where even the owner of the device isn't an administrator.
JavaScript is truly a horrifyingly discussing,
intrinsically retched,
soul darkening, succubus from the abysmal depths of conceivable depravity.
To know its stench
is to know the crippling limitations of our future.
To recognize its sloven decadence
and remain indifferent
is to burn the righteous.
No faith,
however moving and spectacular,
could light a path of its continuation.
No argument,
however complex and equivocated,
could elevate such a encumbering and wearisome burden.
There is no failure so inadequate,
or stagnation so bereft of utility
as that of JavaScript.
Thankyou.
And here's a Vic20 emulator in Javascript HTML5
http://www.mdawson.net/vic20beta/vic20.php
Saying that you shouldn't write this in JavaScript because of the limitations of JavaScript in web browsers is like saying people shouldn't write Apps in Java because Applets are limited. It's not JavaScript that is the problem per se, but the limitations of the Interpreter. If you want to write something like this in JavaScript, you should consider compiling the JavaScript instead.
Using the Unity Framework ( http://unity3d.com ), you could write the emulator in JavaScript, compile it, and have a cross platform emulator that would work on Mac, PC, Wii, Iphone, Android, and PS3 with hardware accelerated 3d, support for sound, etc. Something like 20-25 of the top 100 Iphone Apps were made using Unity, and it is a pretty good platform for making 3d games.
I kind of like Javascript, I have written and maintained HUGE applications in many languages. To be honest, the worst was Java, not Javascript. Javascript is light, easy to understand, highly extensible (see JQuery or mootools) and once something is written to the standards it usually runs EVERYWHERE there is a reasonably modern web browser. Something which is not true of Flash or Java. Just look at how many people use it and write in it! Talk about a successful language! I'm fluent in Ruby, Python, Perl, Java and UNIX/Linux standard C. I've used C++, C#, AS3 and even Scheme on various professional jobs before. And I think I like Ruby best, but not by much. Javascript has a certain simple elegance that even Ruby doesn't have. It's what Java could have been. If Gosling hadn't been so strict type happy.
I have a theory that the truth is never told during the nine-to-five hours. - Hunter S. Thompson
That actually is the case. If you look in to it, you find that fully functional Gameboy emulators, with sound and everything, ran well on 486-Pentium class computers. They were written in C/C++ of course, often with some assembly thrown in. The Gameboy is not challenging to emulate since it is low resolution, gray scale (with very few steps), has a small memory, slow simple CPU, and so on.
All this really demonstrates is that even if your language sucks and runs on a slow platform (webbrowser's interpreters don't count as fast) that eventually there's enough CPU power to throw at it. It isn't really a testament to Javascript, it is a testament to modern CPUs.