Labyrinth Game in the browser

By dougt | Published: December 21, 2009

A few months ago, I mentioned the game Labyrinth and how I wanted this to work in the browser. Syd Lawrence took up the cause and put together a cool implementation.

Play it here. You must be running Firefox 3.6 RC or better.

This uses the new orientation events added to Firefox 3.6.

Syd also put together a demo of what orientation looks like for those that do not have Firefox 3.6:

This web feature is going to be standardized in the W3C in one of two working groups.  The general idea is to separate out acceleration (values in g) and orientation (values in degrees for azimuth, roll, pitch).  More on that next year when we figure out where the work will be done!

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ncat ascii art

By dougt | Published: December 21, 2009
config.status: creating config.h
(  )   /\   _                 (
\ |  (  \ ( \.(               )                      _____
\  \ \  `  `   ) \             (  ___                 / _   \
(_`    \+   . x  ( .\            \/   \____-----------/ (o)   \_
- .-               \+  ;          (  O                           \____
)        \_____________  `              \  /
(__                +- .( -'.- <. - _  VVVVVVV VV V\                \/
(_____            ._._: <_ - <- _  (--_AAAAAAA__A_/                |
.    /./.+-  . .- /  +--  - .     \______________//_              \_______
(__ ' /x  / x _/ (                                  \___'          \     /
, x / ( '  . / .  /                                      |           \   /
/  /  _/ /    +                                      /              \/
'  (__/                                             /                  \
NMAP IS A POWERFUL TOOL -- USE CAREFULLY AND RESPONSIBLY
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Fast Flash in Fennec

By dougt | Published: November 29, 2009

For the last few days, we have been making Flash fast in Fennec.

Our situation in Fennec is that we have a hidden browser element that contains the flash object/embed element. When a paint needs to happen, we draw whatever the plugin wants to draw into a canvas or sent of canvas elements. These canvas elements are what the user sees on the screen — they are part of Fennec’s tile manager. Now these draws to the tile manager consistent of a 16bpp to 24bpp conversion (I am told that the flash is optimized for 16bpp), then a copy to a gfxXLibSurface, then a final blit to the screen. This final bit also contains a 24bpp->16bpp conversion because the screen is 16bpp. To make matters much worse, many plugins intersect multiple canvases in the tile manager which causes this drawing path to happen multiple times per video frame. The end result is that we were getting no more than 4-5 fps.

We took some incremental steps to improvement performance, but we were no where close to double digit fps.

At this point, we decided to just draw directly to the screen avoiding the tile manager completely. This allowed us to render without any conversions and only one copy — the plugin could write directly to X11 shared memory.

In making this decision, we would lose a bunch of information that Gecko provides such as where the plugin should be position relative to other elements, and how it should be clipped.  The solution we came up with was to let Fennec tell each of the object and embed elements where they should be drawn.  The frame painting code would honor the position and clip that the front end set.  In this way, we could have plugins do the right thing during pans and when content is below the Fennec sidebars/urlbar.

You can check out how Fennec positions elements here:

http://mxr.mozilla.org/mobile-browser/source/chrome/content/browser.js#2937

The end result in this work is that we get over 25fps when Sorenson encoded videos.  Over the next weeks and months, I hope to see more video content honoring Fennec’s user agent and provide optimized content.  (YouTube and other sites do not recognized Fennec’s UA, yet).

This fast path is only implemented on Maemo, but it can be implemented on any platform assuming the plugin has support to draw directly into a memory buffer.

You also can check out the details in bug 528551.

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Geolocation support in add-ons

By dougt | Published: November 12, 2009

Today, I checked-in a set of changes that will allow mozilla addons the ability to acquire the location information. It is pretty simple to do:

geolocation = Cc["@mozilla.org/geolocation;1"]
.getService(Ci.nsIDOMGeoGeolocation);
geolocation.watchPosition(successCallback);

In this trivial example, the object |geolocation| is fully compatible with the W3C’s geolocation object that exists under the navigator object in web content. |successCallback| will be called when Firefox acquires your position.

The prompting of the user is left up to your application. All addons hosted on addons.mozilla.org must follow the guidelines and prompt the user.

If you have questions about what is permissible, please contact me.

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