One Last Thing and Closing Thoughts
The final bit of DX11 we'll touch on is the update to HLSL (MS's High Level Shader Language) in version 5.0 which brings some very developer friendly adjustments. While HLSL has always been similar in syntax to C, 5.0 adds support for classes and interfaces. We still don't get to use pointers though.
These changes are being made because of the sheer size of shader code. Programmers and artists need to build or generate either a single massive shader or tons of smaller shader programs for any given game. These code resources are huge and can be hard to manage without OOP (Object Oriented Programming) constructs. But there are some differences to how things work in other OOP languages. For instance, there is no need for memory management (because there are no pointers) or constructors / destructors in HLSL. Tasks like initialization are handled through updates to constant buffers, which generally reflect member data.
Aside from the programmability aspect, classes and interfaces were added to support dynamic shader linkage to combat the intricacy of developing with huge numbers of resources and effects. Dynamic linking allows the application to decide at runtime what shaders to compile and link and enables interfaces to be left ambiguous until runtime. At runtime, shaders are dynamically linked and based on what is linked all possible function bodies are then compiled and optimized. Compiled hardware-native code isn't inlined until the appropriate SetShader function is called.
The flexibility this provides will enable development of much more complex and dynamic shader code, as it won't all need to be in one giant block with lots of "ifs", nor will there need to be thousands of smaller shaders cluttering up the developers mind. Performance of the shaders will still limit what can be done, but with this step DirectX helps reduce code complexity as a limiting factor in development.
With all of this - the ability to perform unordered memory accesses, multi-threading, tessellation, and the Compute Shader - DX11 is pretty aggressive. The complexity of the upgrade, however, is mitigated by the fact that this is nothing like the wholesale changes made in the move from DX9 to DX10: DX11 is really just a superset of DX10 in terms of features. This enables the ability for DX11 to run on down-level hardware (where DX11 specific features are not used), which when combined with the enhancements to HLSL with OOP and dynamic shader linking mean that developers should really have fewer qualms about moving from DX10 to DX11 than we saw with the transition from DX9. (Of course, that's nothing new: the first DX8 games shipped when DX9 was out, and it wasn't until DX10 that we saw a reasonable number of DX9 titles.)
To be fair, the OS upgrade requirement also threw a wrench in the gears. That won't be a problem this time, as Vista still sucks but will be getting DX11 support and Windows 7 looks like a better upgrade option for XP users than Vista. Developers who haven't already moved from DX9 may well skip DX10 altogether in favor of DX11 depending on the predicted ship dates of their titles; all signs point to DX11 as setting the time frame when we start to see the revolution promised with the move to DX10 take place. Developers have had time to familiarize themselves with the extended advantages of programmability offered by DX10, coding for DX11 will be much easier though OOP constructs and multi-threaded support, and if the features don't entice them, the ability to run on down-level hardware with a better coding environment might just seal the deal.
I'm still an OpenGL developer at this point, and I've dabbled a bit with DirectX at times. But DirectX 11 (and my disappointment with OpenGL 3.0) mark the first time I think I might actually make the switch. The first preview of DX11 is already available in the latest DX SDK. When I've got time I'll have to download it and get started. Hopefully the implementation is as attractive as the pitch. Wish me luck.
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DerekWilson - Saturday, January 31, 2009 - link
These figures include "shipped" versions of Vista that people chose to downgrade to XP. It includes systems that came preinstalled, even the "vista capable" systems that people might have chosen to replace with another OS out of the box or after it didn't deliver what they expected.No Vista isn't as bad now as it was at first, but that first impression really does matter and significantly affected DirectX10 adoption, development efforts, perception, and all sorts of things that have a lasting impact on the entire industry.
Also, MS designed DX10 to be tied to the WDDM when they didn't need to in order to expose functionality for developers to use the new features of hardware. They didn't need to do this at all, and we could have had DX10 and DX11 on XP if MS hadn't wanted to push sales of Vista through needless requirements that tied future versions of DirectX to it.
michal1980 - Friday, January 30, 2009 - link
Vista bigger problem was Image. It started a bit rocky, and by the time it was 'fixed' people allready wrote it off. M$ was/is smart enough to know a damaged brand, and instead of releasing Vista Sp2, they slapped a new name on it.I do have a bit of a chip on my should about win7, from what I read, i'd love to upgrade.
But good lord, I own 2 ultimate, and 3 home preimum licenses. I hope M$ has some nice deals for vista users, because i'm going to feel a bit ripped of having an OS with a 2 year life span.
frozentundra123456 - Sunday, February 1, 2009 - link
I agree that it is a ripoff to have an OS with such a short life span. Is the "planned obsolescence" in the worst form??LeStuka - Saturday, January 31, 2009 - link
I read somewhere that Vista Ultimate owners will get a free/reduced price upgrade.. Not sure how reputable that is (my memory is a bit hazy on it) but is defiantely worth some research.marsbound2024 - Friday, January 30, 2009 - link
Let me start off by saying I was enthralled by this article. Very well detailed and well explained. There were a few occasions, however, where I wished for more explanation (or maybe my eyes skipped over an explanation you might have provided earlier in the article). I will admit, I am not as highly inclined on software as many people might be here. I am a great deal more interested in hardware usually, but when it comes to APIs such as DirectX and operating systems and their features such as Windows 7, then I am usually engrossed in those. What exactly are LODs and what is OOP constructs and what is HLSL? Now admittedly I can use Google to find all of this out, but it would be nice to have this consolidated into your article (if it was, but my eyes skimmed over that part, then I apologize; though I read your article pretty much word for word).There are a few grammatical errors such as instead of "that" you put "than" or maybe it was "then" and you said "a architectures" or something to that effect. This doesn't really matter but I thought I'd throw that out there.
I'd really like to know if the upcoming generation GPUs in June/July will make use of DirectX11? I suppose this depends on how quickly Microsoft can a good, full-featured SDK out there, perhaps. Also, albeit a bit off-topic, but any thoughts on when Windows 7 might be released to consumers? Are we still thinking later this year in time for the holiday season or the old Microsoft "by the first quarter of 2010" or whatever it was (i.e.: January possibly)?
DerekWilson - Saturday, January 31, 2009 - link
Sorry about leaving out some definitions there ... I went back and added in some explanation of what HLSL and OOP stand for and what LOD is.We suspect that the first round of hardware that comes out after Windows 7 is available will support DX11 ... We haven't had confirmation on that from either vendor yet, but that's our strong feeling at this point.
michal1980 - Friday, January 30, 2009 - link
Author just seems to have a huge chip on his shoulder.good article, that quite frankly left a bad taste in my mouth because of the unexplained, and un-needed vista bashing
tommy2q - Saturday, January 31, 2009 - link
vista 64 bit has been great for me. it's faster than xp pro on my computer and more stable.DerekWilson - Friday, January 30, 2009 - link
I don't have a problem explaining myself, I just thought it was unnecessary -- I apologize.It's not that I have a chip on my shoulder, it is simply a fact that Vista had and has problems that caused issues with the uptake of DX10. It's not a personal problem, it's just information.
First, obviously an OS upgrade was required to get DX10. People were turned off to this idea because of initial problems that were resolved after a period of time. But much damage was done.
For the first year of it's life, many drivers and applications were unstable and buggy, especially sound and graphics and especially under 64-bit Vista. MultiGPU support had its own problems, but that's a whole other barrel of monkeys. When SP1 hit most of our problems were resolved.
Performance for many tasks are decreased under Vista, though, again, much of this has been fixed. But the problem is that uptake of Vista was damaged because of this, especially among hardcore gamers and especially because there weren't any DX10 only titles or Vista only titles that were compelling (and no, Lost Planet was not compelling). Also, in cases like Crysis, DX10 incurs a huge performance hit and many gamers prefer to run DX9 anyway for the higher performance.
OS X also made huge strides and is a terrific OS. For usability, people have started to realize they had a choice in large part because Vista failed at the beginning to deliver what it promised. And choice is good.
MS recognized that they had a problem and implemented and extended again and again downgrade options to Windows XP for customers who were unsatisfied with Vista. They have significantly invested in and sped up development on Windows 7 in order to deliver an option that will regain customer interest. They've also dumped tons of money into ad campaigns like mojave and seinfeld.
Vista is not a failure in terms of total sales or market penetration as compared to other pieces of software, but it absolutely is compared to other major milestone MS OS releases. They needed to deliver a WinXP and they delivered a WinME ...
The degree to which people hung on to XP and the problems with Vista have certainly caused a delay in a full transition to DX10 programming by game developers.
Vista failed to be truly viable vehicle for pushing forward graphics technology on the whole not because it totally sucks, is lame, or any one person doesn't like it. It failed on its merits because it didn't come out of the gate as strong as it needed to be.
Certainly many developers have done some cool things with DX10. Which is great. But building a platform where people like the Beta more than their current stable OS is a good start to getting people interested in dropping Vista for Windows 7 and inspiring hold outs to finally move from Windows XP to Windows 7.
I wasn't trying to "bash" vista. I feel like I was just calling it like it is.
archer75 - Saturday, January 31, 2009 - link
All of the "problems" with Vista you mentioned actually aren't even Microsoft's or Vista's fault. Drivers are applications are the responsibilities of 3rd parties. It is they who dropped the ball. Most companies grew up with XP and that is what people learned to write drivers and apps for. With the necessary change to the driver model in Vista these people had to learn a new way of writing drivers. A necessary change but it took time.Also everything that SP1 fixed, was fixed long before SP1. All of those updates were available on the knowledge base. All SP1 did was put them in one neat little package. People like myself had those updates long before SP1.
I also run x64 and have since beta. My system has had quality drivers on day 1 and I never had any stability issues either.
Obviously an OS upgrade was required for DX10. And why wouldn't it be? Do you give away all of your new features in your old products? What company does that? You put new features in new products. Apple does this. Hell, ilife 09 is leopard only. They force you to upgrade regularly.