Chat Transcript: ATI's texture filtering algorithms

What's your point? Do not NVIDIA and ATI expose linear mip filtering? Do I have to spell out everything for you?

-FUDie

 

Dave,

Have you actually checked the quality on ATI cards set all the way to performance? If so, I take it that you are implying that Nvidia's default is better than ATI's performance setting?

 

u simply misrepresented the complaint...
people didnt complain ATI for coming up with a solution for something that adapts to the situation, they complain they wasnt informed of such "adaptive" solution and so unknowingly still assuming they are having full trilinear filtering when it is not...

btw. such "optimization" is fine if they make a note of it beforehand...

i hope u are upset not because it is ati ...

himomo!

 

thats the same way why brilinear is a cheat for nvidia... Are nvidia suppose to file a report with us every time they develop a new technology?

not necessary, they can simply be done by adding a new option saying "adaptive trilinear", dont masquerade as legacy full trilinear filtering when it is not..
they gonna let nvidia know anyway if they patent it... so thats not a reason or excuse...

is the adaptive trilinear equal or better than the leagacy full trilinear filtering (as told by the ATI engineer)???
time will tell...!!!

himomo!

 

nvidia probably forget to inform us, u know we should not expect them to inform us of every technogology change.... and they should have probably announced they are patenting it when get caught...

 

it is nothing more than a show, regurgitate the prepared PR... dodging questions conveniently.... tho i appreciate ati's effort for trying to stage the show...

so the point is we have to prove whether this adaptive filtering equals or better than the original one.... and this is one yet to be proved...

himomo!

 

as is now we cant disable "adaptive" trilinear filtering either and we didnt told of this feature before... the fact ati "rectify" it later once got caught doesnt mean he wasnt cheating.... ati is still cheating unless its quality equal or better than the original...


remember:
ATI has consistently encouraged use of tools for IQ analysis that don't show the effects of ATI's adaptive method.
why the need to do that if the benefit/quality is maintained in all cases??? isnt it a good hint of cheating...?

himomo!

 

oh my, this shows you dont understand what is going on here at all!

The very fact that color mip maps DO display with full trilinear speaks very GOOD things about the adaptive nature of the algorithm.
you seem to think this is like brilinear - ie, a constant reduction in quality.
IT IS NOT. It is adaptive, and will adjust itself when nessesary - like a case where each mip map level is totally different from the one before...

 

If it were a PR show, they would have sent PR folk to answer, not engineers.

 

Re: whql test

could you please give me quote or test number from the specs? maybe i missed something, i couldnt find the word trilinear a single time in them.....so if this tests exist, they dont seem to be documented in the specs for me.

 

some people are just braindump..

 

I have to say I found the chat to be informative and full of reasonable answers to even flame-loaded questions at a few points. I admit I'm not very fond of the idea of companies changing filtering methods in hardware generations without announcing the change first, the answers and the evidence available on the net so far have persuaded me that their adaptive filtering algorithm does not sacrifice from IQ while it increases performance. I just hope they announce such changes prior to implementation next time to eliminate such silly fuss.

Yalaz Ozkanli

 

Re: whql test

Did you search on "Trilinear" or "Linear"?

 

They used to. They used to do such nice things like announce new technologies, expose methods for using it in API and document the behaviour. This once common practice brought us SGIS_texture_filter4, EXT_texture_compression_s3tc, 3DFX_texture_compression_FXT1
etc etc.
Wonder why they did that .. why wouldnt the respective IHVs simply silently compressed the textures in their drivers ( maybe even analysing the textures for suitability ) and simply provided their new wonderful technologies for end users ...

 

The issue bothers mainly gfxcard-happy geeks...
Wha'ts the best PR move when you have such a audience ? sent the PR folks to answer the questions or send a couple of top-engineers who design the stuff the geeks have wet dreams about ?

nuff said

 

because texture compression in a GOOD way takes long, and thus, texture uploading would get very slow, wich would NOT be liked by anyone. the other solution would be to compress in a bad way (not analizing the image good, quantize without taking the whole data-set into account, etc), wich would result in very bad image quality.

if it could be done without hurting at all, it would've been done.

 

What is piecewise linear about "If X < Threshold return A" ?

As you may know, constant functions (though representable by a "line") are not considered linear.

So a piecewise fuction of constant and linear functions, is *not* piecewise linear in any means of the word.

/nitpicking mode off

regards, alex

 

If you think that there are no PR people with good hardware knowledge, you are mistaken.

 

Ahh... mathematics Allow me to play too. Linear functions have the form of:

f(x) = a*x + b

and we call them linear because a) they are a straight line b) the 'x' is in the power of 1.

So, as you can see, if you have a=0 and b=A, you have the function:

f(x) = A

That function is a subcase of the linear functions. So it is STILL a linear function

edit: Here's one of the links that google got me, I am sure you can find a lot more : http://people.hofstra.edu/faculty/Stefan_Waner/RealWorld/tutorialsf0/frames1_3.html

 

Yeah f(x)=b is a linear fonction.