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Is ultrashadow on nv35 an API that has to be programmed for or is it just tweaked hardware that automatically speeds up shadows? Will it benefit Halflife 2 or does Valve use an incompatible shadow drawing technique?
It has to be programmed for. It requires the game developer to add support for it.
Doesn't Eliteforce 2 support it?
The term itself is a PR/marketing ploy. It just means the card has hardware support targeted at accelerating stencil buffers.
It is not a new technology, but is pretty expensive, in terms of frame rate, so they have only been used in limited fashion. Newer cards are getting fast enough to make them useful.
The same code that powers this feature would work on any other video card that supported stencil buffers. The application has to be written to use these buffers, regardless of what the hardware can do.
Originally posted by Skuzzy
The term itself is a PR/marketing ploy. It just means the card has hardware support targeted at accelerating stencil buffers.
It is not a new technology, but is pretty expensive, in terms of frame rate, so they have only been used in limited fashion. Newer cards are getting fast enough to make them useful.
The same code that powers this feature would work on any other video card that supported stencil buffers. The application has to be written to use these buffers, regardless of what the hardware can do.
???
AFAIK, UltraShadow is a nVidia proprietary technology which currently ONLY works on the NV35 ( not any other NV3x, but probably will also work on the NV36 )
The system is a developer-activated ( requires support and programming by the developer ) optimization for shadow volumes. Shadow volumes exist in GPUs for a number of generations now, but this technology's goal is to make it go faster, nothing else.
Uttar
DivotMaker
06-19-03, 04:02 PM
Originally posted by Uttar
???
AFAIK, UltraShadow is a nVidia proprietary technology which currently ONLY works on the NV35 ( not any other NV3x, but probably will also work on the NV36 )
The system is a developer-activated ( requires support and programming by the developer ) optimization for shadow volumes. Shadow volumes exist in GPUs for a number of generations now, but this technology's goal is to make it go faster, nothing else.
Uttar
It also is currently functional only in OpenGL, not Direct 3D, but nVidia is working to rectify this...
Originally posted by Uttar
???
AFAIK, UltraShadow is a nVidia proprietary technology which currently ONLY works on the NV35 ( not any other NV3x, but probably will also work on the NV36 )
The system is a developer-activated ( requires support and programming by the developer ) optimization for shadow volumes. Shadow volumes exist in GPUs for a number of generations now, but this technology's goal is to make it go faster, nothing else.
Uttar
Poorly stated on my part Uttar. I know it is an NV35 feature. Also know it is used for speeding up the 'shadow' process. Shadow volumes use stencil buffers, as part of the deal. Uhmmm...are you sure it is proprietary? If so,..then I stand corrected and apologize for the error.
extreme_dB
06-19-03, 04:30 PM
UltraShadow is "proprietary" insofar as Nvidia is using their own technique to accelerate shadow volumes, but every company has their own technique for accelerating features!
It's just marketing speak, like "Truform" (for N-patches).
That is what I thought as well extreme_db. So you program it just like regular shadow volumns then? I should think that would be the case, but I have not used it yet.
I will try to get one of the guys to run a test on it.
It is an optimization to save fillrate with stencil shadow volumes by limiting the drawing to those parts of the scene that can be in shadow. It does in the z direction what before you could only do in x and y.
NVIDIA's presentation explains it quite well, look at the PDF on this page (http://www.nvidia.com/view.asp?IO=feature_ultrashadow). The x/y technique (which works on all boards) is explained here (http://developer.nvidia.com/view.asp?IO=shadow_volume_intersection).
Thank you Bert. Good info! (hehe,..like a kid at Christmas when I get to read stuff like this) :D
GlowStick
06-19-03, 05:15 PM
Originally posted by Dazz
Doesn't Eliteforce 2 support it?
That would be neat, Elite force 2 did have ALOT of stencile shadow stuff put into it, they may have added UltraShadow ot it.
The demo looks GREAT!
So, anyone know if Halflife 2's shadow rendering method is compatible with ultrashadow?
1stly, the support is not automatic. Its not just PR for meaning accelerated stencil shadow volumes.
It has to be explicitly added by the developer. And if ATI want to use similar technology, they will have to license it from NV, as I believe NV has a patent on it.
Half-life 2 only use shadow buffer shadows for the characters, not stencil buffer shadows, so it wont get any benefit from this. All doom3 engine games will get benefit.
Nvidia really needs to get the NV36 out with Ultrashadow supported in it. No good to have a feature of the rest of your chips doesn't support the feature....... :o
gstanford
06-20-03, 08:54 AM
Ultrashadow is proprietary to nVidia and patented to boot.
The interesting thing is that John Carmack had a say in the development of Ultrashadow and Doom 3 will benefit from it.
JC could probably have helped ATi out also if he had been so inclined, however, it is interesting to recall that after the Doom 3 alpha leak JC stated that the company responsible would not be seeing any further or special optimisations for their architecture as far as Doom 3 was concerned... :D
Hanners
06-20-03, 09:15 AM
Originally posted by gstanford
...it is interesting to recall that after the Doom 3 alpha leak JC stated that the company responsible would not be seeing any further or special optimisations for their architecture as far as Doom 3 was concerned... :D
Did he say that? Links?
From what i can tell Ultra Shadow is AA Shadows so i assume OpenGL games can take advantage of it.
What do you mean by "AA Shadows" ?
Well i remember from a review of a FX5900 that Ultra Shadow is a form of antialiasing for shadows, then showed a picture from Elite Force 2 of it in action.
UltraShadow has nothing to do with anti-aliased shadows. It is simply a way and means of telling the hardware which parts of the scene it should ignore when dealing with stencil shadow volumes. Its basically just a stencil shadow occlusion system, to help improve performance.
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