Ubisoft has revealed that Far Cry 2 uses DirectX 10.1 to improve AA by reading the multisampled depth buffer. What's interesting is that this is also enabled on all Nvidia DirectX 10 GPUs.
A few days ago, we learned that Ubisoft's hugely anticipated free-roaming shooter Far Cry 2
would support DirectX 10.1 extensions for cards that support the latest-available version of Microsoft's API.
Today, we have gathered some more information from Ubisoft on the implementation and it's quite an interesting one because the capabilities are also enabled on all Nvidia GeForce 8, 9 and GTX 200 GPUs, even though they don't comply with DX10.1's requirements.
"The Ubisoft team wanted to enhance the anti-aliasing through the reading of the multisampled depth Z-buffers,
explained Vincent Greco, Worldwide Production Technical Coordinator at Ubisoft. "This feature was enabled by either using DX10.1 or using a DX10.0 extension supported by Nvidia DirectX 10 GPUs.
All of Nvidia's DirectX 10 GPUs support a superset of DX10, but don't fully support all of DirectX 10.1's requirements so Nvidia cannot claim compliance with DX10.1.
When we asked what DirectX 10.1 features Nvidia supported back in May, the company was very cagey, with Tony Tamasi claiming that
"the red team will go out and try to get every ISV to implement things that aren't supported [by our GPUs] for competitive reasons. That really isn't good for game developers, Microsoft and also for us too. So I'd rather not say what [DX10.1] features we don't support.
"I can tell you that one thing we support for sure is reading from the multisample depth buffer [with deferred rendering], which right now seems to be the thing that people are finding interesting in 10.1. And so for the ISVs that are doing that, we're supporting them directly [and exposing the feature to them],
" explained Tamasi.
So how does this affect performance? "In the case of Far Cry 2, either option will work with similar performance,
" said Greco.
Stay tuned for our Far Cry 2
review tomorrow - there's also plenty more exciting Far Cry 2
coverage to follow after that as well. In the meantime, feel free to discuss these developments in the forums