On Montag 08 Mai 2006 18:54, Ville Syrjälä wrote:
> On Sun, May 07, 2006 at 10:52:54PM +0200, Stefan Lucke wrote:
> > 
> > Ok, here is the latest one (done against DirectFB cvs from 2006-04-14).
> > But I'd like to have a comment from Ville, as I count him as _the_
> > reference of matrox programming.
> 
> :)
> 
> I actually experimented with something similar some time ago but I 
> didn't get the patch into a good enough shape so it was left gathering 
> dust on my HD. My approach was done without a new blitting flag. My idea 
> was that a blit should handle the fields properly without any flags. 
> I've attached the patch. I just excavated it from my source tree which 
> was a real mess so it might not even compile.
> 
> The code is also a little strange as it tries to avoid writing to TEXORG 
> because that will flush the texture cache. 

What is the disadvantage of flushing texture cache ?

> It also allows one to swap  
> the fields by specifying differently aligned y-coordinates to source and 
> destination. 

Good idea: DSBLIT_SWAPFIELDS ?

> Unfortunately these two features also made the code do  
> wrong things. Currently it leaves *ORG registers pointing to field 0 but 
> it can start blitting from using field 1 coordinates. Now that I think 
> about it it might be best to solve the problem by not switching *ORG for 
> different fields but instead just modify the blit coordinates.

Do you suggest just changing those values, set in matroxDoBlitTMU() ?
Doesn't that reduce max texture width (from 2048 to 1024) for 
interleaved interlaced?

> 
> Maybe the whole idea of flagless field blit is too much :) 

My opinion is, when introducing new features, give them a new name.
That leaves the decision of using them to app developer and does
not change behavoiur of existing programs.

> There are  
> certainly some unresolved issues like what to do with separated -> 
> progressive stretch blit. Also the code is getting more and more complex 
> due to all these fields and planes.

With my patch there are still some TODOs:
 - handle separate fields
 - what should be done when operation is upscaling

But for now it is only used for TV-out in softdevice.

-- 
Stefan Lucke

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