[Public WebGL] using the same context with multiple canvases

Ian Hickson [email protected]
Wed Dec 12 19:33:51 PST 2012

On Thu, 13 Dec 2012, Gregg Tavares (社ç~T¨) wrote:
> On Thu, Dec 13, 2012 at 1:13 AM, Tony Parisi <[email protected]> wrote:
> >
> > I just wanted to throw my opinion in to mirror Ian's, that if we go 
> > down this path, it should work for 2d canvas drawing contexts as well. 
> > a) seems just as useful for 2D drawing and b) I would think that 
> > consistency with the other canvas context behavior would be highly 
> > desirable.
> I agree it would be highly desirable to have consistency. But if you go 
> back in the thread it seems that Ian is not noticing that:
> (a) In WebGL we need "creation attributes"
> (b) The creation attributes need to be different for each "canvas" (either
> on each cavnas or on some other object that can be associated with a
> canvas). In other words i need to be able to create:
>    a canvas that is only RGB vs RGBA (for GL compatibility and speed)
>    a canvas that is anti-aliased vs not
>    a canvas that is double buffered vs single buffered (for speed)
>    a canvas that is composited assuming un-premultipled alpha vs
> premultipled alpha (for GL compatibility)
>    ...
> (c) we need to be able to use 1 context that can work across all of 
> those types of canvases therefore those options can not be part of the 
> context but must be part of some other object (canvas or drawingbuffer)
> The solution Ian has suggested so far does not cover those cases AFAICT.

Is this something that would make sense as arguments to setContext()?

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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