Friday, March 12, 2010
Politically Motivated Games
Yesterday, at GDC's award ceremonies, a recorded message from a White House spokesperson was played, outlining a plan for game developers to compete for prize money by making games about nutrition and fitness education, to fight obesity.
Correct me if I'm wrong, but as far as I know, video games have previously been used by the U.S. government in the context of specific simulations for internal training/education needs; they have not been used as part of a national propoganda effort before. As innocuous as this particular competition may seem, it points towards a future where game designers are employing their talents to massively sway public opinion. It's not just Jesse Schell's future of universial points systems, but something perhaps more insidious and worrisome - a form of mass-media manipulation that distorts factual behavior in favor of gameplay biased towards the administration's viewpoints. Imagine the government forcing developers to avoid "anti-American" gameplay.
I do not have a strong opinion one way or the other about whether this is a future we want; I think that the medium can be employed equally well in both rebellious and nationalistic contexts. I am compelled by self-interest, however, to enjoy the limelight, as it is one further indication of the rising stock of game makers these days. I might even participate in this competition, if I can think of a good sixteen-week game to make for it. I do support the goal of healthy lifestyle habits, after all.
Monday, March 08, 2010
Liberation - haXe/Flash asset framework
I'll expand on this later, but for now, here's a link to the project:
http://bitbucket.org/triplefox/liberation/
The wiki page has some documentation. I want to do a video tutorial later.
Posted by James Hofmann at 10:26 AM Comments
Edited on: Friday, March 12, 2010 10:24 PM
Categories: Projects
Edited on: Friday, March 12, 2010 10:24 PM
Categories: Projects
Thursday, February 04, 2010
Flash 10 versus JS/HTML5: The Tour Guide
I have seen an enormous amount of uninformed speculation regarding what the Flash and JS/HTML5 platforms are each capable of as of right now(February 2010). This post is an attempt to comprehensively round up the differences by going through the Flash API and filtering through it to create a "FAQ" of features worthy of direct comparison, with the focus being "what does Flash offer that is not covered in existing or proposed spec?" I used a variety of sources to research this info and linked to them as appropriate; I offer this with the disclaimer that my expertise mostly lies on the Flash side of things, and even there, I have probably made mistakes and omissions in attempting this ambitious piece of documentation. Please help me improve this overview by telling me what's wrong, what's inaccurate, or if there's a side of the story I'm missing.
Features
| Name of Flash API class, namespace or feature | Notes | Can JS/HTML5 Do It? |
| Accessibility, AccessibilityProperties | Display objects on the Flash stage can provide descriptions, keyboard shortcuts, and different behavior for screen readers. | This is a wide-ranging issue and deserves to be addressed with its own post. HTML5 introduces several new accessability concerns, most notably Canvas and its ability to replace traditional layout entirely. Not all issues are resolved. The best answer I've found on the subject is in this Stack Overflow thread. |
| BitmapData | An API for low-level manipulation of bitmaps. | Yes, Canvas contains similar bitmap-manipulation methods, albeit performance may differ. |
| Graphics | A set of methods you can use to create a vector shape. | Yes, with SVG or Canvas. |
| Loader | A class used to load SWF and image files. | Yes, with URI resources and DOM manipulation. |
| flash.filters | A set of classes for bitmap filter effects(glow, blur, convolution, etc.) | Emulatable, possibly with lower performance. SVG contains a filter effects spec which could potentially be applied to all document elements. WebGL also allows programmable shaders. |
| Camera, Microphone | Captures video/audio from a local webcam or microphone. | Proposed post-HTML5: device tag |
| Sound | Loads and plays back MP3 and WAV audio from files or streams. Besides built-in pan and volume controls, real-time inspection and manipulation via Actionscript are allowed. | audio tag plays back sound and streams; however, as currently specified it is a black box and does not allow inspection/maniplation. An extension to <audio> in Firefox for these features has been prototyped. |
| Video | Displays live or recorded video via embedding, streaming, or progressive download. Sorenson Spark, ON2 VP6, H.264 codecs are supported for video, and ADPCM, HE-AAC, and MP3 are supported for audio. Source |
video tag
plays back video, and allows for a scriptable user interface using
HTML/JS equivalent to any Flash interface. However, codec support
differs across existing implementations due to patent
considerations; however, interest in an open video standard is
extremely high now, so I expect this problem to resolve itself
soon.
Continuous streaming(as opposed to progressive download of a file)
is not discussed in detail in the current spec.
|
|
|
The FileReference class provides a means to upload and download files between a user's computer and a server. An operating-system dialog box prompts the user to select a file to upload or a location for download. FileReference may also be used to read and write local files. | the "file" input type supports custom upload behavior, and the DOM now supports drag and drop elements. File download triggers from JS already exist. |
| The SWF format, LocalConnection, Security, ApplicationDomain | SWF files are independent namespaces that can run simultaneously, sandboxed from each other, and may optionally open themselves up to intercommunicate. Each SWF's namespace may contain fields representing various resources. SWF interconnectivity is primarily used in applications to provide a lightweight front-end or preloader for other content. |
While the overall nature of the SWF format is a foreign concept,
iframes have a similar namespace access ability.
|
| DisplayObject and Stage | Flash builds its runtime display around the "Stage," which is a tree-structure of DisplayObjects and DisplayObjectContainers; all the kinds of things Flash can display(vectors, bitmaps, video...) are inherited from DisplayObject. Elements on the Stage can attach input event listeners and use the visual display to inform functionality(e.g. overlayed elements will take a mouse click topmost-first). DisplayObjects are able to access all of the available effects and filters, making it easy to apply effects to both single elements and deeply nested groups. | The DOM bears broad similarity to the Stage, both being tree structures and using event listeners attached to nodes, but being focused on a document rather than a display makes the actual implementation far different. Nothing prevents the overall functionality from being emulated, however. |
| Socket, XMLSocket |
The Socket class enables code to make socket connections and to
read and write raw binary data. Socket is a "raw" TCP/IP
connection with user-definable endianness. XMLSocket is the
precursor to the general Socket and allows ASCII data to be sent,
delimited by \00 markers.
Since Flash 7, server-side
policy files have been used to control cross-domain
interactions; one policy file is used for loading data, and a
second is used for sockets. The overall system is called the meta-policy
system.
|
WebSocket is
most similar to XMLSocket in nature; i.e. it is text-oriented, not
a low level TCP socket.
Cross-domain access control is being added to HTTP.
|
| PrintJob | The PrintJob class lets you create content and print it to one or more pages. | Browsers have "print page" built in; Canvas elements can save to an image with toDataUrl(). Similar functionality to the Flash API should be possible with window.print(). |
| Shader, ShaderFilter, ShaderJob | A Shader instance represents a Pixel Bender shader kernel in ActionScript. Pixel Bender implements image processing algorithms(filters or effects) in a hardware-independent manner. Pixel Bender uses a parallelized, XML-based graph language. Documentation | Filters and shaders can be emulated in JS; SVG contains filtering options. WebGL allows programmable shaders. WebWorkers provide a more general-purpose paralleization method. |
| setClipboard | Copies string data to the operation system clipboard. "getClipboard" is not allowed for security reasons. | Firefox and WebKit presently provide internal APIs for clipboard use. The draggable attribute includes some language dealing with drag+drop events and the clipboard. Access to the clipboard is a tricky problem because of security risks surrounding its contents and the potential of data theft from an unaware user. HTML5 also has a proposed Undo API. |
| TextField and Text Layout Framework |
TextField provides an API to print and input text with options for
formatting, selection, and HTML text.
Text Layout Framework is a "next-gen" text implementation in
Flash, containing new features for layout, UI controls, and
internationalization.
|
Two issues here: Input and output. Output will come first.
In the past web developers have resorted to using Flash's embedded
font support to achieve a unique typeface. Going forwards, CSS
@font-face will allow embedded fonts, covering this deficiency.
Common layouts are doable within existing CSS; Canvas and SVG are
available as last-resort options if your text needs demand
elaborate transformations or filters.
TextField's input support is known to be buggy, especially for
non-English input; browser forms are more reliable input editors,
but less visually flexible. A "fancy-text" input is probably
emulatable from within SVG or Canvas.
The new features of Text Layout Framework are impressive. It
should fix some of the existing issues with TextField, and the
implementation is open-source, which bodes well for future
inclusion in a standard.
|
| RTMP, RTMFP, and Protected Streaming |
The Real Time Messaging Protocol is a proprietary protocol for
streaming audio, video and data. It has three variations: plain
TCP using port 1935, RTMPT, which encapsulates itself in an HTTP
request to traverse restrictive firewalls, and RTMPS, which uses
HTTPS. RTMP allows streaming of multiple data channels, and
includes remote procedure call methods. Adobe has multiple server
implementations available for the RTMP series, the latest of which
is Stratus.
The Real Time Messaging Flow Protocol is a UDP-based version of
RTMP with additional peer-to-peer functionality, allowing users to
connect directly with microphone and webcam streaming.
Protected Streaming is Adobe's term for the DRM solution provided
by the RTMP series; Flash Media Server is able to encrypt media
on-the-fly to prevent a variety of data theft attacks.
|
There is no exact equivalent to any of this. Some of it can be
emulated in some fashion, but not necessarily with the same
performance characteristics owing to differences in protocol
capabilities between a low-level TCP/UDP implementation and what
can be done with HTTP and Web Sockets. The main power of RTMP is
that it is designed specifically for the Flash platform and works
directly on its API(see NetStream).
The peer-to-peer features of RTMFP are wholly unique.
HTML5/JS is unlikely to ever gain a spec for DRM, both because of
the political implications of the technology, and because past DRM
solutions, including Adobe's, have a track record of being quickly
broken. The "analog loophole" will remain a viable option for the
foreseeable future, if nothing else.
|
Implementation Strength
There's a second set of considerations to address beyond the API, of
course, and that's in the overall performance/reliability/security
considerations that color the implementations of each platform. I'll
admit to some guesswork, some bias, and handwavy estimation going on
here, especially where I try to extrapolate.
- Flash has taken the initative to speed itself up, starting with Flash 9 and the move to Actionscript 3. This language upgrade involved a new VM that could optimize against static type annotations and manipulate ByteArrays(raw byte data). Flash 10 has added Vector(typed arrays) and a "fast ByteArray", used by the Alchemy C->AVM2 compiler and haXe's Memory API. These speedups have enabled some dramatic new uses of Flash for the coders sophisticated enough to make use of them. Flash can also parallelize through Pixel Bender and the Shader class. This approach does have some demonstrated utility for general computation.
JS/HTML5 equivalents: JS is not as fast....yet. Web Workers look
like an elegant near-term parallelization solution. JS5 has no real
equivalent to AS3's annotated types or ByteArray, but the "ECMAScript
Harmony" project aims to continue pursuing those language features and
others that were left over from the ECMA4 process. Google's Native
Client effort should also deserve a mention, since it also attacks
low-level performance, but in a far more comprehensive way than just
memory manipulation. And, of course, general-case JS performance
continues to improve dramatically.
- Flash also has a reasonably fast software renderer....at least, if you are running on Windows. (It is abysmal to useless everywhere else, in my experience.) The 3D support introduced in Flash 10 is not a real solution for 3D acceleration, but the 2D, at least, seems to be more mature than the existing implementations of Canvas, and it is much more comprehensive for immediate use-cases, especially in terms of effects and filters.
JS/HTML5 equivalents: Canvas has been proof-of-concepted multiple
times over as an acceptable 2D graphics solution for typical existing
browser apps, including games. (The JS emulations of the Game
Boy and NES are
proof of soft real-time bitmap manipulation ability, Another
World JS shows off flat-poly rendering, and this
particle demo makes hefty use of alpha-blended gradients.) Now that
efforts are starting to consolidate on WebGL,
which is a very promising standard, it is possible that JS will leapfrog
past Flash for high-performance browser graphics. Adobe probably faces a
major engineering challenge in reconciling 3D against their existing
graphics use-cases, as this has been an oft-requested feature for years
running. Regardless, the strong set of built-in graphics features,
optimized filters and effects, and tool support remain compelling
reasons to use Flash.
- Flash being Windows-centric with respect to graphics brings up another point, which is that Flash has historically overpromised on what it can do across platforms; major differences in both performance and behavior across platforms have brought a lot of ire down upon the plugin over the years, and it is not especially known for spec-correctness or stability either(although, again, on Windows, at least, it is stable most of the time and backwards compatible with most content). The Flash security model is also rather byzantine, between the multiple-SWF-namespaces, the meta-policy system, and some odd restrictions on how different media types may be loaded or streamed(for example: Video can be loaded remotely, or embedded in the SWF, but cannot be loaded from bytes, while Sound can be loaded from all sources.), and several major exploits have been found in the plugin regardless.
JS/HTML5 equivalents: Browsers, as a group, have had a better
track record of correct behavior, backwards compatibility, security, and
stability. The addition of cross-domain access-control headers to HTTP
through this draft spec
should provide similar functionality to the Flash cross-domain security
model, but with a less "hackish" approach to implementation.
Conclusion
Because Flash has been able to quickly implement some "low-hanging
fruit" performance features, it will stay ahead of the game for the
moment. But the indications are that Flash's codebase has grown quite
creaky and inflexible, and unless Adobe can summon the resources to
overhaul the code, support all the platforms properly, and continue
pushing out new features, the browsers are likely to resolve their
current issues and pull ahead for most use-cases in just another year or
two; games and other media-intensive apps will lag behind, out of sheer
ecosystem inertia, but the provisions to support them are mostly visible
on the horizon. And it is worth remembering that there's a fundamental
conceptual difference between the browser "document/resource"
orientation and the Flash "display/SWF namespace" orientation; the Flash
model simplifies distribution of "apps as content" like games because it
can bundle the content into one file, and I don't see a spec out there
that provides that equivalent ability to the browser. This isn't a
deal-breaker, but it makes it harder to support a portal-style business
model with interchangable programmatic content.
Personally, I am hedging my bet by using haXe.
I am happily using Flash for current projects, but the bulk of my code
will remain portable. As well, haXe is an excellent "language upgrade"
to both JS and Actionscript.
Posted by James Hofmann at 12:55 PM Comments
Edited on: Tuesday, February 09, 2010 10:42 AM
Categories: Articles
Edited on: Tuesday, February 09, 2010 10:42 AM
Categories: Articles
Saturday, January 16, 2010
Suggest Nothing
Firefox's "Awesome Bar" is touted as a major feature. Besides entering URLs, it lets you browse to recent sites and enter incomplete data to reach often-used sites without explicitly adding bookmarks.
I decided to turn it off, and I think it was a good decision.
My reasoning: When I had it on, I would simply rely on the top five or six sites I had listed for "something to do" any time I was at the computer, bored, and didn't know what to do. But, of course, the Internet is not five or six sites. It's millions.
I bookmark things that are useful to my immediate work. "Fun sites" I have to remember the URL and manually enter now, or laboriously browse through my history to find. It encourages both restraint and curiosity, because it changes the results of effort: instead of typing in the same old URL, I could try punching something new into Google and see what comes up. And more often than not, that's a more productive and valuable option than the various online echo chambers that I would naturally gravitate to.
Thursday, January 07, 2010
Wednesday, January 06, 2010
Resourceful Game Development
I use the term "resourceful" to indicate my perpetual discontent with the status quo of how games are made. I'm always looking for ways to put them together more quickly, more reliably, and with better results.
I also have a tendency to get into the nitty-gritty details and internalize every aspect of the game-making process by doing it - hence, "resourceful" also describes my use of a broad array of skills, my unwillingness to be typecast within one field alone.
Posted by James Hofmann at 1:48 AM Comments
Edited on: Wednesday, January 06, 2010 1:49 AM
Categories: Articles
Edited on: Wednesday, January 06, 2010 1:49 AM
Categories: Articles