ATI vertex texture fetch in HLSL
Author
Hello,
I was just wondering, has there been any change in the current ATI SM3 hardware assortment, in the sense that it now does allow for (efficient) vertex texture fetches HLSL? The original topic (including my "piece of bullshit" comparisson) on this was also posted in this forum, so I thought I'd ask around here again [smile]
I've *finally* decided to get myself a GeForce 7800 to try to implement GPU GeoClipmaps using these vertex textures as described in the GPU Gems 2 book, but without proper support on ATI hardware I can't very well use it in anything but a tech demo. Well, not without a backup codepath anyway. Would anyone happen to have some (firsthand) experience to offer about using vertex textures in HLSL, preferrably on cards from both vendors?
Thanks in advance!
I'm not aware of anything having changed since the thread you mentioned. ATI don't support proper vertex texturing via the API - you have to use R2VB instead. Basically means you've gotta implement two paths, one for Gf6/Gf7 and another for X1k's.
Jack
Jack
Author
*sigh* Thanks Jack
Ah well, I was already thinking about implementing the GeoClipmaps on the CPU as well for compatibility with SM2 hardware, so I guess that'll have to do for ATI 'SM3' hardware too. I haven't got a clue how to use R2VB in Managed DirectX and I'm not inclined to waste my time on finding out how or even if it's implemented [headshake]
I'm wasting enough time as is :p
I don't know if there's any public info on SM4 specs available yet, but will NVidia's 'proper' way of doing vertex textures become the minimum for SM4 hardware? Even an educated guess would be very welcome, if available.
Ah well, I was already thinking about implementing the GeoClipmaps on the CPU as well for compatibility with SM2 hardware, so I guess that'll have to do for ATI 'SM3' hardware too. I haven't got a clue how to use R2VB in Managed DirectX and I'm not inclined to waste my time on finding out how or even if it's implemented [headshake]
I'm wasting enough time as is :p
I don't know if there's any public info on SM4 specs available yet, but will NVidia's 'proper' way of doing vertex textures become the minimum for SM4 hardware? Even an educated guess would be very welcome, if available.
See this post about managed R2VB.
R2VB is available on all SM2 ATI cards and up, so if SM2 cards are the lowest you're supporting, it's worth trying an R2VB path.
As for SM4 docs, the D3D10 docs are in the last 3 SDKs, and fully describe what D3D10 hardware will support.
R2VB is available on all SM2 ATI cards and up, so if SM2 cards are the lowest you're supporting, it's worth trying an R2VB path.
As for SM4 docs, the D3D10 docs are in the last 3 SDKs, and fully describe what D3D10 hardware will support.
Quote:Original post by remigiusAs Eyal said, the D3D10 documentation should give you a pretty good idea.
I don't know if there's any public info on SM4 specs available yet, but will NVidia's 'proper' way of doing vertex textures become the minimum for SM4 hardware? Even an educated guess would be very welcome, if available.
Resources are substantially more flexible in how and where they can be used in the D3D10 pipeline. I'm not aware of a specific "vertex texturing" or "render to vertex buffer" feature - more that they would be specific uses of a more generalised technology.
hth
Jack
Author
Quote:See this post about managed R2VB.
Hmm, I feel quite stupid about missing that one, thanks for pointing it out.
I just checked out the source and it looks pretty neat, but on my X850 I got a few artifacts with polygons seemingly not getting rendered at times. Guess I'll have to take that up with Acid2 [wink]
Quote:As for SM4 docs, the D3D10 docs are in the last 3 SDKs, and fully describe what D3D10 hardware will support.
Edited: Ok, never mind, I really should head off to bed... With all the stream rerouting on SM4 hardware, vertex texturing obviously seems to be just a specific application of this general concept (and perhaps even redundant?).
In any case, thanks and good night :)
Quote:Original post by jollyjeffers
I'm not aware of anything having changed since the thread you mentioned. ATI don't support proper vertex texturing via the API - you have to use R2VB instead. Basically means you've gotta implement two paths, one for Gf6/Gf7 and another for X1k's.
Jack
Popular myth about R2VB: It's only for X1k cards.
Reality: It is for all cards since the Radeon 9500.
Just thought I'd lend my two cents.
Quote:Original post by Cypher19
Popular myth about R2VB: It's only for X1k cards.
Reality: It is for all cards since the Radeon 9500.
Just thought I'd lend my two cents.
Why didn't ATI release their nifty extension way back then? If they had actually grown a little support, maybe it would have become really widespread (even becoming standardized into D3D and on other manufacturer's hardware).
Quote:Original post by remigius
Edited: Ok, never mind, I really should head off to bed... With all the stream rerouting on SM4 hardware, vertex texturing obviously seems to be just a specific application of this general concept (and perhaps even redundant?).
Vertex texturing might still be used. After all, especially on cards that use the same pipelines for vertex and pixel shaders (like ATI's is supposed to be), you should be able to get fast texture access in vertex shaders.
Still, I supposed that a lot of algorithms will use streams and stream output instead, or direct buffer accesses (even constant buffer accesses, since constant buffers in D3D10 support 4096 constants, enough for example for the 64x64 values used by the geo clipmaps algorithm).
Quote:Why didn't ATI release their nifty extension way back then? If they had actually grown a little support, maybe it would have become really widespread (even becoming standardized into D3D and on other manufacturer's hardware).
Maybe they found it was possible as they were conducting research on D3D10 features (and realized that the requirements needed on the hardware were met on their older chips?), or as a part of the planned Uberbuffer support for OGL? Alternatively, why did it take so long for ATi to bring on adaptive AA when the X1k released, temporal AA when the Xx00 series was launched, even though both of those work on the Radeon 9x00 cores?
This topic is closed to new replies.
Advertisement
Popular Topics
Advertisement
