Re: [Paracomp-spec] RFC : Extension EXT_datatype_float - floating point datatypes for compositing

[Balázs T. <tb...@gm...>]

On Fri, May 30, 2008 at 11:53:03AM +0530, Shree Kumar wrote:
> Hi Randy,
>
> Randall Frank wrote:
> > Hello,
> >    I have to ask why not 16bit ints, perhaps in W space?
>
> That's a good idea too. 16 bit unsigned ints would be good
> enough for alpha blending. Using 16 bits for just the W component
> seems like an improvement over using 16 bits for all components
> - but I'm not sure how this will affect the readback speed
> from the GPU.
>
> I'm keen to hear what folks from TU Budapest think about this.

We think, that we'll have trouble with the readback, as there is no
pixel format like A16R8G8G8 or similar. So we have to read back the
RGB and the A channels separately and combine them together somehow.

> 16 bit int/unsigned int could be a separate extension too.

The R16 int/uint format looks to be a good idea, as well as the R16F.

Balazs