   What is DirectX 10?
  Pausing the game also pauses the particles was a big thing in DirectX games. In the old times, particles were continuing and dropping to the ground when you pause the game.DirectX 9 bring many interesting things to games. It was a huge difference after old DirectXs. Especially high quality reflections.F.E.A.R. game, Half-life 2 source engine games, Unreal Engine 3 games are very good examples for capability of DX9.Then the DX10 came out. They said it will be done scratch over, it will have lots of new features that we can't even imagine. They showed some pictures to show us DirectX9 can't even close to do them. They also said DX10 will need Vista only because it is really hi-tech and can only work in new constructed Vista.There is even some videos that overlyhype DX10 and show it like a miracle:Ok, but I can't really see any difference between them, yet a huge difference?I once tried the DX9-DX10 option in Hellgate London with my Vista laptop. No change in graphics. There was not even a speed change.I played Crysis with ultra high graphics that they said only Vista can work, in my XP desktop. It was really good quality, but it was working in DirectX 9?Crysis game was locking "ultra high" options and you need to tweak the game config a little bit to use that graphics. But with that option unlocked, graphics in DX9/XP and DX10/Vista PCs was absolutely the same.Was this just a show off?Was this option locked just to show people "DX9 only have this features" -> High quality, "DX10 have this features" -> Ultra high quality.If DX10 is not different from DX9, What is DirectX 10?Is it just a Vista version for DX9? That's all?Now they are developing DX11 and they will probably release it for Windows 7.Is DX11 will be a DX9 version for Windows 7 also?   
  Most D3D10 games I've seen have been naïve ports of D3D9 ones - that is, they don't actually take advantage of 10's new features.Most features introduced in D3D10 are oriented towards performance improvements - take, for example, geometry shaders and instancing improvements. However, if the engine does not take advantage of these, the results may well look like D3D9.D3D9 will continue to work just fine on Windows 7. In addition, D3D11 (available for Vista too) allows you to code against D3D9 and D3D10 hardware, albeit with reduced feature sets.With D3D11, tessellation (fine geometric details), compute shaders (ultra-high performance calculation), multi-threaded rendering core (allowing full utilization of multiple CPU cores) and other new features have the potential to improve performance and quality dramatically.If you want detailed documentations of these APIs, download the DirectX SDK from MSDN. It contains D3D9, D3D10 and D3D11 (preliminary) documentation. With the launch of 7, D3D11 steps out of beta/rc status.   ;Quote:Original post by BonecrusherPausing the game also pauses the particles was a big thing in DirectX games. In the old times, particles were continuing and dropping to the ground when you pause the game.DirectX 9 bring many interesting things to games. It was a huge difference after old DirectXs. Especially high quality reflections.F.E.A.R. game, Half-life 2 source engine games, Unreal Engine 3 games are very good examples for capability of DX9.Then the DX10 came out. They said it will be done scratch over, it will have lots of new features that we can't even imagine. They showed some pictures to show us DirectX9 can't even close to do them. They also said DX10 will need Vista only because it is really hi-tech and can only work in new constructed Vista.There is even some videos that overlyhype DX10 and show it like a miracle:Ok, but I can't really see any difference between them, yet a huge difference?I once tried the DX9-DX10 option in Hellgate London with my Vista laptop. No change in graphics. There was not even a speed change.I played Crysis with ultra high graphics that they said only Vista can work, in my XP desktop. It was really good quality, but it was working in DirectX 9?Crysis game was locking "ultra high" options and you need to tweak the game config a little bit to use that graphics. But with that option unlocked, graphics in DX9/XP and DX10/Vista PCs was absolutely the same.Was this just a show off?Was this option locked just to show people "DX9 only have this features" -> High quality, "DX10 have this features" -> Ultra high quality.If DX10 is not different from DX9, What is DirectX 10?Is it just a Vista version for DX9? That's all?Now they are developing DX11 and they will probably release it for Windows 7.Is DX11 will be a DX9 version for Windows 7 also?DirectX10 was a fundamental rewrite/redesign of DX9 and previous. There were a lot of major changes, but the average user probably wouldn't notice them too much for a variety of reasons, nor would they likely even understand how/why it was important. For example, most of the state change and drawing functions were moved back into user mode over kernel mode, resulting in fewer context switches and a slight increase in performance. Thing is, most DX10-class renderers are still naive ports of DX9-class ones, and already avoid calling these functions like the plague. Thus, by the principle of (unintentional) useless micro-optimization, any performance benefits would be/are marginal. That is not to say that DX10 is not faster in this regard, merely that this becomes insignificant due to how it was used.The Vista-only kicker has to do with the driver model and the so-called 'lost device' states that occur whenever a user alt-tabs or switches focus. Remember that little hang that you experience when switching back to your app? This is because your game/whatever has to recreate a good chunk of the resources it used, such as handles to miscellaneous textures, effect variables and the like. The Vista model avoids this entirely; you can never lose the device due to how and where the management takes place. Since this is such a fundamental aspect of the API, you would need to port the ENTIRE Vista driver model back to XP, which would (surprise, surprise) entail modifying a substantial portion of the OS, to the point where you're pretty much making it Vista anyway. Otherwise you're left with breaking all DX10 applications on XP-- you lose devices, but nobody's going to be checking (remember, it isn't even feasible right now!) so you're screwed.Constant buffers, which are designed to massively speed up shader constant management, also appear to be entirely unused in every DX10-class renderer I've been able to examine. Zero mention of them anywhere in the shader source, and they would be there if used. Another example of a useful feature that just wasn't taken advantage of.On the flip side, geometry shaders were somewhat underwhelming. The idea of being able to generate triangles on-the-fly has some extremely far-reaching implications, but unfortunately performance wasn't even close to the level it needed to be in order to make them a silver bullet. It is also my understanding that the situation has improved somewhat in this aspect, as more modern silicon can run them much faster, but I can't speak with 100% authority on this one. I'm hoping that the hull/domain shaders don't turn out this way for DX11.There also happens to be a number of little changes, such as a far more robust system for handling multisampling/antialiasing, API-level support for depth readback, and interesting little novelties like texture arrays, but I fear I've already gotten a little too technical. Long story short-- it's different, it's better, and it's very poorly understood.   ;  good answer, thanks   