Re: [Gnu3dkit-discuss] GL slang draft

[Brent Gulanowski]

On Thursday, February 27, 2003, at 12:39  PM, Philippe C.D. Robert 
wrote:

> Hi,
>
> FYI the GL slang draft has been posted


This is disappointing:

> Related OpenGL state is also automatically tracked if used by the 
> shader. A fragment shader cannot
> change a fragment's x/y position. To support parallelism at the 
> fragment processing level, fragment
> shaders are written in a way that expresses the computation required 
> for a single fragment, and access to
> neighboring fragments is not allowed. A fragment shader is free to 
> read multiple values from a single
> texture, or multiple values from multiple textures. The values 
> computed by the fragment shader are
> ultimately used to update frame-buffer memory or texture memory, 
> depending on the current OpenGL
> state and the OpenGL command that caused the fragments to be generated.

If I understand that correctly, it means that you cannot simulate 
things like aberrations in a lens or depth of field using the fragment 
shader. (The latter I see in the OGL PG is to be done with the 
accumulation buffer.) Or does it mean that you have to do some kind of 
two-stage process?

It seems to mean that the kinds of filters associated with photoshop, 
like blurs, swirls, bleeds, and other such things are still not ready 
for hardware acceleration. I was hoping that visualizers like for 
iTunes and WinAmp would be able to move their work to the card, but it 
seems unlikely.

--
Brent Gulanowski                                address@hidden

http://inkubator.idevgames.com/
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