Re: [Gnash] plugin update

[Nicolas Cannasse]

Rob Savoye wrote:
> I've made a few more changes to the plugin, although they're only of use 
> to other developers. I implemented processing the arguments passed in 
> when the new data stream is created by Firefox, and add a special one. 
> If you pass "debug=waitforgdb", firefox will print out the PID of the 
> thread, and block waiting for you to attach GDB. This is the easiest way 
> I've found to debug the plugin itself, because by this time the plugin 
> is loaded, and all issues with shared libraries go away. I was getting 
> tired of having to just printf things...
>
> Anyway, this one still draws the boring OpenGL triangle and square by 
> default. For the brave at heart, you can go to plugin.cpp:561 and flip 
> the #ifdef to watch the plugin launch, and then play the movie. (sort 
> of...) At this time I'm still getting weird issues with OpenGL and 
> threading, but that's the next focus of debugging...
>
> With the plugin set to download all the flash movies to /tmp that it 
> comes across, I think mortgage company ads have the highest amount, 
> followed by realtors.
>
>     - rob -

The problem with OpenGL is that it doesn't support multithreading. You 
need then to use some kind of system-wide lock when doing OGL 
operations. You can have several independant OGL context (at least on 
Windows by using wglMakeCurrent) but only one selected at a time.

When writing a Firefox plugin I got some problems with
OpenGL as well, while everything was working nicely with DirectX. Two 
things in particular :
- initializing an OpenGL context in the the same thread that Firefox was 
making everything hangs. I needed then to have a separate thread and 
communicate through messages
- changing the PixelFormat for OpenGL (using SetPixelFormat, on Windows) 
was making a small but perceptive lag that was degrading user experience.

Back then, it was a crossplatform 3D engine that was able to display 
animated SWF on textures, but the plugins for Firefox and IE were only 
developed for Windows.

I haven't look at the Gnash graphics renderer yet, but if it's not the 
case, you should consider rendering the whole SWF scene into a memory 
pointer and only at presentation time display the buffer using either 
OGL, DirectX or whatever the plugin is providing. The "plugin" should 
also be able to give the renderer a pointer to render to (with width, 
height and stride informations) for small devices.

Nicolas