Jump to content
  • Advertisement
Sign in to follow this  

ATI's new R520 hardware - no SM3 vertex texturing..

This topic is 4605 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

There's a more general thread on the ATI Radeon X1x00 series here... but I was just reading the coverage over at Beyond3D and I spotted this little fragment:
Quote:
From this page: However, one element of Vertex Shader 3.0 compliance is the capability for vertex texturing, yet there appears to be an absence of any texture lookup capabilities from ATI's diagrams
I'm gonna go double check my docs, but from that article it indicates that vertex texturing via D3D9 only works with a set of texture formats as exposed by the driver. The ATI hardware exposes no texture formats as compatible. It seems that there is a loophole in the SM3 specification that allows the hardware to be "SM3 compliant" yet effectively disable vertex texturing. Clever loophole I suppose.
Quote:
as somewhat of an alternative to Vertex Texturing ATI will be promoting the use of a new extension to DirectX know as Render to Vertex Buffer... --- Snip --- ...rather than rendering to a displayable surface or texture the results are rendered to a buffer in memory that can be directly read as an input to the vertex shader. The upshot of this process is that an application can have access to the capabilities of the Pixel Shader which can then be fed back into the geometry processing pipeline, which should result in a superset of capabilities of vertex texturing and should actually perform better than current vertex texturing schemes because the pixel pipelines are inherently built to better cope with the latencies of texturing.
Sounds clever from a hardware point of view, but a little clunky from a graphics engine / software development point of view. Anyone here played with vertex texturing on the GeForce 6x00/7x00? Do they have the same limitation? Can they do this "R2VB" stuff that's mentioned by ATI? A little tech demo I was thinking about would require vertex texturing support [headshake]... Cheers, Jack

Share this post


Link to post
Share on other sites
Advertisement
I thought that their stalling of the PC graphics tech front for a year+ was bad enough, but yet it continues on. It's obvious that ATI only cares about money, and not the advancement of one of the most beneficial aspects of computing.

Meanwhile, everyone with a 6000 series nVidia card is sitting here waiting for their GPU to become useful to its full extent.

Share this post


Link to post
Share on other sites
Rather an old particle: http://www.theregister.co.uk/2004/05/04/ati_confirms_no_shader_3/


Quote:
Obviously the pixel-shader processors have been upgraded to provide full support for SM 3.0.

http://www.hardwareanalysis.com/content/article/1817

Share this post


Link to post
Share on other sites
Dang, that's annoying. I was kinda pumped for this new line of cards to come out, too. The stream output stuff is interesting and useful, but it will be really annoying to implement code that uses it just for ATI cards. In essence, not only will you have different code paths for each D3D version, but also for the IHV's (within DX9 anyways).

Share this post


Link to post
Share on other sites
Quote:
Original post by Sneftel
That's a little strange. Didn't the x800 support vertex texturing?

I'm not aware of any previous ATI hardware supporting (properly or otherwise) vertex texturing. The previous parts did "hack" a form of "hardware instancing" through SM2 that is normally (iirc) reserved for SM3 hardware...

Quote:
It's obvious that ATI only cares about money, and not the advancement of one of the most beneficial aspects of computing.

Sad truth is that pretty much any/every company on this planet is only concerned about money. If innovation and advancement of a "benefitial aspect" is likely to generate them more $$$ then they'll probably go for it [rolleyes]

Jack

Share this post


Link to post
Share on other sites
Damn. I was looking forward to ATI's new cards as well. Was hoping that if ATI finally came out with some cards in the same league as Nvidia's flagship models, we'd finally see some price competition again so prices would come down to reasonable levels. To me, SM3.0 is all about vertex texturing. Alas, I guess we'll have to wait.

My guess is that one reason ATI's been so late on providing SM3.0 hardware is that they've been busy working on chips for the Revolution and Xbox 360. Those are two totally different chips and the teams can't even talk to eachother because of agreements with Nintendo and Microsoft. So its basically double the work. I'm sure they've got people working on the PC cards but they've probably taken a backseat to the development of the console chips right now.

neneboricua

Share this post


Link to post
Share on other sites
Quote:
Original post by neneboricua19
To me, SM3.0 is all about vertex texturing. Alas, I guess we'll have to wait.

Yup, but given that a lot of the high-end/commercial engines tend to have seperate codepaths for NV/ATI (even if just for performance) I'd imagine we'll still see vertex texturing effects on the Radeon X1x00 cards.

Fundamentally it also seems that it makes vertex texturing a 2-pass approach, which is a fundamental difference (as I read it) from the standards implementation. Thus any code will probably be very different [headshake]

Quote:
Original post by neneboricua19
My guess is that one reason ATI's been so late on providing SM3.0 hardware is that they've been busy working on chips for the Revolution and Xbox 360.

That's probably a substantial factor, but in that article I linked in my original post it seemed like they also had some unfortunate (and badly timed) engineering problems to contend with.

Hopefully they'll take this as a small stumble and do whatever they can to make sure they don't carry it over into whatever they come up with next [grin]

Jack

Share this post


Link to post
Share on other sites
Quote:
Original post by jollyjeffers
Hopefully they'll take this as a small stumble and do whatever they can to make sure they don't carry it over into whatever they come up with next [grin]

Considering the D3D10 caps are all-or-nothing, they are gonna be pretty much forced to implement the full shader specs. Performance is certainly another issue, though...

You have got to love their spec sheets - "Shader Model 3.0 done right" [lol] What a crock of $*#(@

Share this post


Link to post
Share on other sites
Quote:
Original post by circlesoft
You have got to love their spec sheets - "Shader Model 3.0 done right" [lol] What a crock of $*#(@

[lol] I like it ...

Although, as mentioned above, it seems they found a perfectly valid loophole in the specs that Microsoft were "okay with", thus it is technically implemented correctly. Just in a somewhat retarded way from a software engineering perspective.

Jack

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

Participate in the game development conversation and more when you create an account on GameDev.net!

Sign me up!