Bullet Interview and Questions about SDK's

Erwin,
Hello,
My name is Paul Marini and I am the owner of www.hitechlegion.com.
I was wondering if I may have the opportunity to speak to you
personally, and possibly for an Interview.
I would like to talk about Bullet, ATI and NVIDIA.
I have questions that you may be to answer regarding some misconceptions.
I think possibly a phone conversation to break the ice and familiarize
ourselves with each other would be great first.
Then possibly a live radio interview, which after air will be posted on
the Hi Tech Legion website.
Hopefully we could arrange something soon.
Thank you,
Paul
contact info in sig below.

--
Paul E. Marini Jr.
Administrator
Hi Tech Legion
www.hitechlegion.com

Erwins first answer:

Hi Paul,

Thanks for your interest in Bullet physics library. Unfortunately I'm at work, and my employer doesn't want me to do phone or radio interviews.

But if it doesn't take too much time, I can answer some questions over email.

Thanks,
Erwin

So I responded:

Erwin,
Thanks for the quick reply.
1. I would like to know a little more about Bullet.
2. What is your true partnership with ATI are they doing the R&D with you or are they funding Bullet for the project.
3. Is it true that at this time you use NVIDIA Geforce for development?
4. If 3 is yes why?
5. Since ATI doesn't have a Graphics Card that supports Open CL how can you develop an open physics API with ATI.
6. I know DX 11 is on the way but who is developing for it right now.
7. Will this API be reverse compatible with dx 9 and 10 video cards.

I have more but I don't want to take up too much of your time.
Thanks in advance,
Paul

This is Erwins second Reply:

Hi Paul,

I'm under some NDA's so I can't disclose too much, but here is the gist:

1) Bullet Physics Library is an open source physics library, used by professional game developers and Hollywood movie studios.
Games using Bullet fully or partially include GTA IV, Free Realms, Trials HD on XBox 360 and High Velocity Bowling on PlayStation 3.
Movies using Bullet Physics for special effects include Disney Bolt, Hancock, and the upcoming 2012 movie.
The library is available for all platforms including PC, Mac OS X, iPhone, Nintendo Wii, XBox 360 and it has PlayStation 3 SPU optimizations.
We have been working for a while on GPU physics acceleration, and showed the first results at the GDC in March 2009 in San Francisco:
http://www.bulletphysics.com/wordpress/?p=64

2) Bullet is non-proprietary and we collaborate with several hardware vendors including Intel, NVidia, Apple and AMD
to make sure the OpenCL version runs on all platforms. AMD supports Bullet OpenCL development and we do R&D with their engineers.

3) We develop on NVidia Geforce, but we also work and test OpenCL on AMD GPU and CPU and other hardware,
to make sure Bullet OpenCL version runs fine on all platforms.

4) We develop on NVidia GPU, because our Macbook PRO is equipped with the 9400/9600M. Also the NVidia SDK example code has been very useful.

5) Actually both NVidia and AMD/ATI support OpenCL GPU acceleration on Apple Snow Leopard right now.
We can't discuss details of our work with AMD GPU hardware on PC, but we expect public availability of their GPU drivers for PC later this year.

6) We found that OpenCL, CUDA and DX11 Computer Shaders are all very similar, and conversions of data-parallel kernels between them is often trivial.

7) OpenCL works fine on NVidia 8800 and better. Our NDA with AMD doesn't allow to disclose details on AMD GPU OpenCL just yet.
Developers can sign up to get early access with both NVidia and AMD OpenCL programs for more details.

Thanks,
Erwin

I also found a previous quote from Erwin while surfing the Web.

“Bullet’s GPU acceleration via OpenCL will work with any compliant drivers, we use NVIDIA GeForce cards for our development and even use code from their OpenCL SDK, they are a great technology partner.”

This made me question some things ATI has said about NVIDIA being “proprietary”, if there is an NVIDIA SDK for OpenCL, then they are developing it. Due to NDA, Erwin was unable to comment if an SDK for OpenCL for ATI (GPU). So is there an SDK that ATI has developed? These were my next line of questions for Dave Hoff of ATI.

When I asked about an SDK and work on OpenCL, he went right back to marketing how great the future potential is going to be because it’s open source. No direct answer, yes or no, just we showcased it at GDC. I wasn’t there so, when I asked what, he responded that it was showcased at GDC.

I decided to do a little more research and found that Havok and ATI had teamed up at GDC to show Havok cloth for physics (OpenCL). Great! But wait again! Didn’t ATI just announce that they were going to partner with Bullet? What happened to Havok? Now I also remembered reading an article that NVIDIA was also considering porting PhysX to OpenCL. Guess what, they already have a structured physics engine, and when I read Dave the quote from question number six above he agreed with the comment: “Trivial” to convert the kernel. So how open is this new physics going to be? Why do we need three different (NVIDIA, ATI, Havok) Open CL SDK’s for physics? Isn’t the beauty of OpenCL that everything will work and it’s not proprietary? Are we still looking at a programming code that, even though Open Source, will make it proprietary depending on the SDK the developer chooses to use, thus giving one video card an edge over the other?

We can all see the benefits of open source but my next question is, will developers use three SDK’s (of course, this is speculation) or will we still see them choosing one or the other depending on agreements made between them and the primary SDK providers? In the end, it seems open source may become a choice for use without having to pay for licensing fees.

“A software engineer typically receives the SDK from the target system developer. Often the SDK can be downloaded directly via the Internet. Many SDKs are provided for free to encourage developers to use the system or language. Sometimes this is used as a marketing tool.”

Since my question was not answered by ATI about a viable SDK for OpenCL, I checked on the Khronos groups’ website. ATI does have an SDK in development and it had been submitted to the Khronos group for certification. Their Beta 3 release was certified conformant on 9-3-2009. So why, may I ask, didn’t Dave Hoff divulge this information? My questions were simple and to the point. Why wasn’t the question answered? The submission and conformance is for CPU not GPU. GPU has been submitted but not certified. The buzz is by the end of the year we should see something.

So, technically, there is nothing now. What we have is a great video card that has future potential. Not the here and now.

When I questioned Dave about the quote from above number three and four he told me that Erwin would not know because he is irrelevant and ATI has their own team from Bullet working with them.

Honestly I was perplexed; Erwin to the best of my knowledge is the main developer for Bullet. So I had to send Erwin an email asking about Dave’s comment.

Erwin’s direct answer:

“I'm the main author of the Bullet physics library, and lead a small team developing it within Sony Computer Entertainment US R&D. Does that sound irrelevant?”

So I would think it safe to say that NVIDIA has the only certified OpenCL GPU SDK at this time.

Wednesday part 4 – Is Stream dead as we know it?

Part 1

Part 2