Lets face it, Its been a hell of a rough month for Crytek, not only was their much vaunted 1.2 patch severely delayed, they finally released the patch only to withdraw it today. We had planned a look at this patch on ATI hardware with new beta drivers but unfortunately it seems rather pointless presenting an indepth article detailing frames per second differences at various resolutions when the patch has been removed from public consumption. Nonetheless we have seen this is a hot topic of conversation on our forums, so Stuart and myself feel we should post something detailing a little of the apparent mysteries involved with this patch and forthcoming ATI drivers.
This is the official statement today on the withdrawal of Patch 1.2,
"Far Cry patch 1.2 has shown unexpected behaviour on specific hardware configurations. These matters are mainly due to incompatibilities with several optimisations brought lately to the code, with the intent to please a large number of users.
We're currently asking CRYTEK to work on delivering a new patch as soon as possible. Until then we have decided to remove the patch 1.2 from the official UbiSoft websites."
We will be very interested to see what will have changed when it reappears, remember the benchmark disappearing from Tomb Raider: Angel of Darkness?
A few weeks ago we received an advance copy of FarCry 1.2 from Nvidia. This build of 1.2 was sent out as it added Shader Model 3.0 support to enhance performance (but not image quality at this time) on the 6800 series graphics cards and we detailed the performance impact of the changes in a previous article.
Lets have a look at the patch that "never quite was". To get the full benefits of the patch you would have required an X800 class graphics card, DirectX9.0b, FarCry 1.2 and Catalyst build 8.041 or above. If you have these you’ll get the full feature set:
SM 2.0b and
Geometry Instancing
The 2nd option is to have a R3xx or above graphics card (9500,9600,9700,9800, X600 or X300 ) DirectX 9.0b, FarCry 1.2 and Catalyst 8.041. With this setup Geometry Instancing support is possible.
Thats right people, the NV40/SM3.0 isnt the only card/Shader Model that can provide instancing, any of ATI’s DX9 hardware supports this feature, in the words of some ATI employees (off the record) "even using DirectX9.0b"
So what does this mean?
Instancing:
Lets look at the feature common to all ATI cards first. Geometry Instancing (/Vertex Instancing) allows for more detailed graphics. A specific example in Farcry is that distant vegetation is no longer rendered as sprites, the render changes to a more detailed animated vegetation. (Effectively the objects like grass or tree’s in the distance can now be animated like the vegetation near your character rather than be static 2d sprites). Overall performance will be lower by removing the usage of 2D sprites and increasing the geometry level. Geometry Instancing will make this higher detail option a better option for RADEON X800 users.
To see the real benefits of instancing, you can manipulate the amount of geometry on the screen with Far Cry’s e_vegetation_sprites_distance_ratio parameter. This engine setting controls the point at which truly rendered (using geometry) vegetation is replaced by 2D sprites (billboards). The default value is “1”. Substituting a higher value pushes the threshold at which this substitution occurs to a distance further from the viewpoint.
Type the following in the command console: \e_vegetation_sprites_distance_ratio 100
This will eliminate the usage of 2D sprites as vegetation, and draw full animated vegetation throughout the scene
<img src="http://www.driverheaven.net/zardon/farcryandati/farcryimages.jpg" width="706" height="330">
Shader Model 2.0b path:
The main benefit of the Shader Model 2.0b path in FarCry is that you have much improved one pass lighting support. As this improves the performance of indoor areas (due to heavy use of lighting) the SM 2.0b path gives benefit in many levels within FarCry. Additionally the 2.0b path gives added support for other complex shaders throughout the game, again boosting performance.
It should also be noted that the support for the above features is not unique to FarCry, any game developer using DX9 will be able to use the above features on the ATI Radeon.
We have been playing with these new features today and its relatively simple to enable the above features.
Firstly open the Farcry Console using the ` key.
For SM2.0b path type (without quotes) “\r_sm2bpath 1” and hit return.
For Instancing support type (again without quotes) “\r_GeomInstancing 1”
Of course if your enabling Instancing you’re going to want to bump up the vegetation detail, to do this you need to change your Farcry settings from (e_vegetation_sprites_distance_ratio,1.000000) to (e_vegetation_sprites_distance_ratio,100.0000). This change removes spite vegetation and replaces it with animated vegetation throughout the scene.
So to recap:
The major performance increase is due to improvements in the lighting shader. The new patch enables the effect of three lights to be calculated in one pass (previously, each light required its own pass). It is possible, with a bit of extra work, for four lights to be calculated in a single pass on ATI hardware, but Crytek has not made the changes that would enable this. This is the major performance increase on both ATI and Nvidia hardware.
The second performance increase is through the use of instancing. Instancing is a technique by which large numbers of identical objects can be grouped together and processed as a batch, greatly reducing the load on the CPU. Uses in FarCry include trees and grass. In the original version of the game, only trees and clumps of grass close to the player were rendered as geometry (that is, as a collection of triangles with textures painted across them). Further from the viewer they were replaced by "billboards" - a flat image of a tree that always faces the viewer. This increases frame rates, but at some cost to realism. Instancing allows the distance at which geometry must be replaced by billboards to be increased significantly (to the extent that essentially nothing the viewer sees is a billboard) with only a very small hit to performance.
SM3.0 includes instancing, a feature nvidia have promoted heavily, saying that it proves the superiority of their hardware - while this is certainly a major talking and selling point, all X800 cards (and even 9500,9600,9700,9800) are capable of instancing. We have a beta driver in our possession which reflects this and associated performance gains, and it will be in the publicly posted CATALYST 4.8. We dont feel until a final patch is available from Crytek we should post our detailed findings as there is every possibility between now and the next release this could change.
We can give you rough indications of percentage increases - on the research map with Far Cry v1.2 \r_sm2bpath 1 and HLSL compiler profile 2.0b we saw increases of 13% at 1024x768, 21% at 1280x1024 and 25% at 1600x1200. Nothing to be sniffed at.
So what about the juicy gossip? Well to say today has been a dramatic day is an understatement, during our testing period for the last 12 hours or so we have spent alot of time on the phone and in email to many people in the industry, one such person in the industry even stated this:
"Nvidia encouraged Crytek to use partial precision in the shaders wherever possible. This means that many of the shaders will run in 16-bit precision, not the 32-bit precision (a requirement of SM3.0) that they are touting to the press. Ironically, while promoting the 32-bit precision of SM3.0 as a "must have", Nvidia is asking developers to use less precision than was available in SM1.0 - that is, all the way back in DirectX8! Even more ironically, ATI hardware will run most of the FarCry shaders more accurately (ATI hardware runs all shaders in 24-bit precision). Microsoft, the owner of DirectX, defines 24-bit and greater as "full precision" and 16-bit as "partial precision", Nvidia has claimed that ATI paid Crytek to delay the patch and include ATI features (the figure mentioned was $500k!)."
So there you have it, some of the facts, and some rumours.... nonetheless Crytek has committed to delivering 3Dc support in patch v1.3, which will provide higher detail images, or free up memory with better compression than traditional normal map compression options. FarCry is a great example of a next generation title that uses normal maps extensively. When the "final" patch arrives, we will be giving it a good going over and posting indepth results.
I guess its in the hands of Crytek, lets hope we still arent waiting two months from now, and with Doom3 just around the corner, more importantly will anyone care?
Allan "Zardon" Campbell
Stuart "Veridian3" Davidson
