Re: minutes, 3 November 2011 FX Taskforce F2F meeting at TPAC 2011

On 11/3/11 9:50 PM, Alex Danilo wrote:
> Hi All,
>
> 	Small comment relating to the compositing blend mode
> discussion below:
>
> --Original Message--:
>> <snip/>
>>     CC: I think we need to first make sure this is implementable, even
>>     on gpus and on mobile with reasonable performance
>>
>>     VH: I would say the implementability is not a question, because we
>>     know filters are implemented
>>     ... and largely compositing is a shorthand for filters
>>     ... it might not be optimal and efficient though
>>
>>     CC: we might need to make changes to the spec to allow efficient
>>     implementations
>>
>>     <cabanier>  correct. and we know compositing is working well on
>>     mobile devices since Flash is alreayd using it
>> <snip/>
> 	I do think the actual blend operators will map well onto
> GPU or S/W renderers, but P-D is another matter altogether. So as
> was suggested before maybe we need to pull out the P-D
> operators into a separate property. That would also allow
> you to do something like an 'in' combined with 'color-burn' for
> much better render control - and the P-D stuff really is orthogonal
> to the blend functions anyway.
>

We came to a similar conclusion when working on a Canvas based web 
application, with "in" and "arbitrary pixel shader" being quite handy 
for drawing effects.

Also, when working with filters, there are a lot of computers out there 
with relatively basic gpus; you can't expect the gpus of those machines 
to do much more than basic composite operations. Those machines will 
also have relatively slow cpus.

-Charles